15274f052SJens Axboe /* 25274f052SJens Axboe * "splice": joining two ropes together by interweaving their strands. 35274f052SJens Axboe * 45274f052SJens Axboe * This is the "extended pipe" functionality, where a pipe is used as 55274f052SJens Axboe * an arbitrary in-memory buffer. Think of a pipe as a small kernel 65274f052SJens Axboe * buffer that you can use to transfer data from one end to the other. 75274f052SJens Axboe * 85274f052SJens Axboe * The traditional unix read/write is extended with a "splice()" operation 95274f052SJens Axboe * that transfers data buffers to or from a pipe buffer. 105274f052SJens Axboe * 115274f052SJens Axboe * Named by Larry McVoy, original implementation from Linus, extended by 12c2058e06SJens Axboe * Jens to support splicing to files, network, direct splicing, etc and 13c2058e06SJens Axboe * fixing lots of bugs. 145274f052SJens Axboe * 150fe23479SJens Axboe * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> 16c2058e06SJens Axboe * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> 17c2058e06SJens Axboe * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> 185274f052SJens Axboe * 195274f052SJens Axboe */ 205274f052SJens Axboe #include <linux/fs.h> 215274f052SJens Axboe #include <linux/file.h> 225274f052SJens Axboe #include <linux/pagemap.h> 23d6b29d7cSJens Axboe #include <linux/splice.h> 2408e552c6SKAMEZAWA Hiroyuki #include <linux/memcontrol.h> 255274f052SJens Axboe #include <linux/mm_inline.h> 265abc97aaSJens Axboe #include <linux/swap.h> 274f6f0bd2SJens Axboe #include <linux/writeback.h> 28630d9c47SPaul Gortmaker #include <linux/export.h> 294f6f0bd2SJens Axboe #include <linux/syscalls.h> 30912d35f8SJens Axboe #include <linux/uio.h> 3129ce2058SJames Morris #include <linux/security.h> 325a0e3ad6STejun Heo #include <linux/gfp.h> 3335f9c09fSEric Dumazet #include <linux/socket.h> 345274f052SJens Axboe 3583f9135bSJens Axboe /* 3683f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 3783f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 3883f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 3983f9135bSJens Axboe * attempt to reuse this page for another destination. 4083f9135bSJens Axboe */ 4176ad4d11SJens Axboe static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, 425abc97aaSJens Axboe struct pipe_buffer *buf) 435abc97aaSJens Axboe { 445abc97aaSJens Axboe struct page *page = buf->page; 459e94cd4fSJens Axboe struct address_space *mapping; 465abc97aaSJens Axboe 479e0267c2SJens Axboe lock_page(page); 489e0267c2SJens Axboe 499e94cd4fSJens Axboe mapping = page_mapping(page); 509e94cd4fSJens Axboe if (mapping) { 515abc97aaSJens Axboe WARN_ON(!PageUptodate(page)); 525abc97aaSJens Axboe 53ad8d6f0aSJens Axboe /* 549e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 559e94cd4fSJens Axboe * writeback completing on this page, since we'll remove it 569e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 579e94cd4fSJens Axboe * page, allowing the disk blocks to be reused by someone else 589e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 599e94cd4fSJens Axboe * ensues. 60ad8d6f0aSJens Axboe */ 61ad8d6f0aSJens Axboe wait_on_page_writeback(page); 62ad8d6f0aSJens Axboe 63266cf658SDavid Howells if (page_has_private(page) && 64266cf658SDavid Howells !try_to_release_page(page, GFP_KERNEL)) 65ca39d651SJens Axboe goto out_unlock; 664f6f0bd2SJens Axboe 679e94cd4fSJens Axboe /* 689e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 699e94cd4fSJens Axboe * and return good. 709e94cd4fSJens Axboe */ 719e94cd4fSJens Axboe if (remove_mapping(mapping, page)) { 721432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 735abc97aaSJens Axboe return 0; 745abc97aaSJens Axboe } 759e94cd4fSJens Axboe } 769e94cd4fSJens Axboe 779e94cd4fSJens Axboe /* 789e94cd4fSJens Axboe * Raced with truncate or failed to remove page from current 799e94cd4fSJens Axboe * address space, unlock and return failure. 809e94cd4fSJens Axboe */ 81ca39d651SJens Axboe out_unlock: 829e94cd4fSJens Axboe unlock_page(page); 839e94cd4fSJens Axboe return 1; 849e94cd4fSJens Axboe } 855abc97aaSJens Axboe 8676ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 875274f052SJens Axboe struct pipe_buffer *buf) 885274f052SJens Axboe { 895274f052SJens Axboe page_cache_release(buf->page); 901432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 915274f052SJens Axboe } 925274f052SJens Axboe 930845718dSJens Axboe /* 940845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 950845718dSJens Axboe * is a page cache page, IO may be in flight. 960845718dSJens Axboe */ 97cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 985274f052SJens Axboe struct pipe_buffer *buf) 995274f052SJens Axboe { 1005274f052SJens Axboe struct page *page = buf->page; 10149d0b21bSJens Axboe int err; 1025274f052SJens Axboe 1035274f052SJens Axboe if (!PageUptodate(page)) { 10449d0b21bSJens Axboe lock_page(page); 1055274f052SJens Axboe 10649d0b21bSJens Axboe /* 10749d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 10873d62d83SIngo Molnar * splice, if this is the first page. 10949d0b21bSJens Axboe */ 1105274f052SJens Axboe if (!page->mapping) { 11149d0b21bSJens Axboe err = -ENODATA; 11249d0b21bSJens Axboe goto error; 1135274f052SJens Axboe } 1145274f052SJens Axboe 11549d0b21bSJens Axboe /* 11673d62d83SIngo Molnar * Uh oh, read-error from disk. 11749d0b21bSJens Axboe */ 11849d0b21bSJens Axboe if (!PageUptodate(page)) { 11949d0b21bSJens Axboe err = -EIO; 12049d0b21bSJens Axboe goto error; 12149d0b21bSJens Axboe } 12249d0b21bSJens Axboe 12349d0b21bSJens Axboe /* 124f84d7519SJens Axboe * Page is ok afterall, we are done. 12549d0b21bSJens Axboe */ 12649d0b21bSJens Axboe unlock_page(page); 12749d0b21bSJens Axboe } 12849d0b21bSJens Axboe 129f84d7519SJens Axboe return 0; 13049d0b21bSJens Axboe error: 13149d0b21bSJens Axboe unlock_page(page); 132f84d7519SJens Axboe return err; 13370524490SJens Axboe } 13470524490SJens Axboe 135708e3508SHugh Dickins const struct pipe_buf_operations page_cache_pipe_buf_ops = { 1365274f052SJens Axboe .can_merge = 0, 137f84d7519SJens Axboe .map = generic_pipe_buf_map, 138f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 139cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1405274f052SJens Axboe .release = page_cache_pipe_buf_release, 1415abc97aaSJens Axboe .steal = page_cache_pipe_buf_steal, 142f84d7519SJens Axboe .get = generic_pipe_buf_get, 1435274f052SJens Axboe }; 1445274f052SJens Axboe 145912d35f8SJens Axboe static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, 146912d35f8SJens Axboe struct pipe_buffer *buf) 147912d35f8SJens Axboe { 1487afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 149912d35f8SJens Axboe return 1; 1507afa6fd0SJens Axboe 1511432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 152330ab716SJens Axboe return generic_pipe_buf_steal(pipe, buf); 153912d35f8SJens Axboe } 154912d35f8SJens Axboe 155d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 156912d35f8SJens Axboe .can_merge = 0, 157f84d7519SJens Axboe .map = generic_pipe_buf_map, 158f84d7519SJens Axboe .unmap = generic_pipe_buf_unmap, 159cac36bb0SJens Axboe .confirm = generic_pipe_buf_confirm, 160912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 161912d35f8SJens Axboe .steal = user_page_pipe_buf_steal, 162f84d7519SJens Axboe .get = generic_pipe_buf_get, 163912d35f8SJens Axboe }; 164912d35f8SJens Axboe 165825cdcb1SNamhyung Kim static void wakeup_pipe_readers(struct pipe_inode_info *pipe) 166825cdcb1SNamhyung Kim { 167825cdcb1SNamhyung Kim smp_mb(); 168825cdcb1SNamhyung Kim if (waitqueue_active(&pipe->wait)) 169825cdcb1SNamhyung Kim wake_up_interruptible(&pipe->wait); 170825cdcb1SNamhyung Kim kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 171825cdcb1SNamhyung Kim } 172825cdcb1SNamhyung Kim 173932cc6d4SJens Axboe /** 174932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 175932cc6d4SJens Axboe * @pipe: pipe to fill 176932cc6d4SJens Axboe * @spd: data to fill 177932cc6d4SJens Axboe * 178932cc6d4SJens Axboe * Description: 17979685b8dSRandy Dunlap * @spd contains a map of pages and len/offset tuples, along with 180932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 181932cc6d4SJens Axboe * function will link that data to the pipe. 182932cc6d4SJens Axboe * 18383f9135bSJens Axboe */ 184d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 185912d35f8SJens Axboe struct splice_pipe_desc *spd) 1865274f052SJens Axboe { 18700de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 188912d35f8SJens Axboe int ret, do_wakeup, page_nr; 1895274f052SJens Axboe 1905274f052SJens Axboe ret = 0; 1915274f052SJens Axboe do_wakeup = 0; 192912d35f8SJens Axboe page_nr = 0; 1935274f052SJens Axboe 19461e0d47cSMiklos Szeredi pipe_lock(pipe); 1955274f052SJens Axboe 1965274f052SJens Axboe for (;;) { 1973a326a2cSIngo Molnar if (!pipe->readers) { 1985274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1995274f052SJens Axboe if (!ret) 2005274f052SJens Axboe ret = -EPIPE; 2015274f052SJens Axboe break; 2025274f052SJens Axboe } 2035274f052SJens Axboe 20435f3d14dSJens Axboe if (pipe->nrbufs < pipe->buffers) { 20535f3d14dSJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); 2063a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 2075274f052SJens Axboe 208912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 209912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 210912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 211497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 212912d35f8SJens Axboe buf->ops = spd->ops; 2137afa6fd0SJens Axboe if (spd->flags & SPLICE_F_GIFT) 2147afa6fd0SJens Axboe buf->flags |= PIPE_BUF_FLAG_GIFT; 2157afa6fd0SJens Axboe 2166f767b04SJens Axboe pipe->nrbufs++; 217912d35f8SJens Axboe page_nr++; 218912d35f8SJens Axboe ret += buf->len; 219912d35f8SJens Axboe 2206f767b04SJens Axboe if (pipe->inode) 2215274f052SJens Axboe do_wakeup = 1; 2225274f052SJens Axboe 223912d35f8SJens Axboe if (!--spd->nr_pages) 2245274f052SJens Axboe break; 22535f3d14dSJens Axboe if (pipe->nrbufs < pipe->buffers) 2265274f052SJens Axboe continue; 2275274f052SJens Axboe 2285274f052SJens Axboe break; 2295274f052SJens Axboe } 2305274f052SJens Axboe 231912d35f8SJens Axboe if (spd->flags & SPLICE_F_NONBLOCK) { 23229e35094SLinus Torvalds if (!ret) 23329e35094SLinus Torvalds ret = -EAGAIN; 23429e35094SLinus Torvalds break; 23529e35094SLinus Torvalds } 23629e35094SLinus Torvalds 2375274f052SJens Axboe if (signal_pending(current)) { 2385274f052SJens Axboe if (!ret) 2395274f052SJens Axboe ret = -ERESTARTSYS; 2405274f052SJens Axboe break; 2415274f052SJens Axboe } 2425274f052SJens Axboe 2435274f052SJens Axboe if (do_wakeup) { 244c0bd1f65SJens Axboe smp_mb(); 2453a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2463a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 2473a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2485274f052SJens Axboe do_wakeup = 0; 2495274f052SJens Axboe } 2505274f052SJens Axboe 2513a326a2cSIngo Molnar pipe->waiting_writers++; 2523a326a2cSIngo Molnar pipe_wait(pipe); 2533a326a2cSIngo Molnar pipe->waiting_writers--; 2545274f052SJens Axboe } 2555274f052SJens Axboe 25661e0d47cSMiklos Szeredi pipe_unlock(pipe); 2575274f052SJens Axboe 258825cdcb1SNamhyung Kim if (do_wakeup) 259825cdcb1SNamhyung Kim wakeup_pipe_readers(pipe); 2605274f052SJens Axboe 26100de00bdSJens Axboe while (page_nr < spd_pages) 262bbdfc2f7SJens Axboe spd->spd_release(spd, page_nr++); 2635274f052SJens Axboe 2645274f052SJens Axboe return ret; 2655274f052SJens Axboe } 2665274f052SJens Axboe 267708e3508SHugh Dickins void spd_release_page(struct splice_pipe_desc *spd, unsigned int i) 268bbdfc2f7SJens Axboe { 269bbdfc2f7SJens Axboe page_cache_release(spd->pages[i]); 270bbdfc2f7SJens Axboe } 271bbdfc2f7SJens Axboe 27235f3d14dSJens Axboe /* 27335f3d14dSJens Axboe * Check if we need to grow the arrays holding pages and partial page 27435f3d14dSJens Axboe * descriptions. 27535f3d14dSJens Axboe */ 276047fe360SEric Dumazet int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) 27735f3d14dSJens Axboe { 278047fe360SEric Dumazet unsigned int buffers = ACCESS_ONCE(pipe->buffers); 279047fe360SEric Dumazet 280047fe360SEric Dumazet spd->nr_pages_max = buffers; 281047fe360SEric Dumazet if (buffers <= PIPE_DEF_BUFFERS) 28235f3d14dSJens Axboe return 0; 28335f3d14dSJens Axboe 284047fe360SEric Dumazet spd->pages = kmalloc(buffers * sizeof(struct page *), GFP_KERNEL); 285047fe360SEric Dumazet spd->partial = kmalloc(buffers * sizeof(struct partial_page), GFP_KERNEL); 28635f3d14dSJens Axboe 28735f3d14dSJens Axboe if (spd->pages && spd->partial) 28835f3d14dSJens Axboe return 0; 28935f3d14dSJens Axboe 29035f3d14dSJens Axboe kfree(spd->pages); 29135f3d14dSJens Axboe kfree(spd->partial); 29235f3d14dSJens Axboe return -ENOMEM; 29335f3d14dSJens Axboe } 29435f3d14dSJens Axboe 295047fe360SEric Dumazet void splice_shrink_spd(struct splice_pipe_desc *spd) 29635f3d14dSJens Axboe { 297047fe360SEric Dumazet if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) 29835f3d14dSJens Axboe return; 29935f3d14dSJens Axboe 30035f3d14dSJens Axboe kfree(spd->pages); 30135f3d14dSJens Axboe kfree(spd->partial); 30235f3d14dSJens Axboe } 30335f3d14dSJens Axboe 3043a326a2cSIngo Molnar static int 305cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 306cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 307cbb7e577SJens Axboe unsigned int flags) 3085274f052SJens Axboe { 3095274f052SJens Axboe struct address_space *mapping = in->f_mapping; 310d8983910SFengguang Wu unsigned int loff, nr_pages, req_pages; 31135f3d14dSJens Axboe struct page *pages[PIPE_DEF_BUFFERS]; 31235f3d14dSJens Axboe struct partial_page partial[PIPE_DEF_BUFFERS]; 3135274f052SJens Axboe struct page *page; 31491ad66efSJens Axboe pgoff_t index, end_index; 31591ad66efSJens Axboe loff_t isize; 316eb20796bSJens Axboe int error, page_nr; 317912d35f8SJens Axboe struct splice_pipe_desc spd = { 318912d35f8SJens Axboe .pages = pages, 319912d35f8SJens Axboe .partial = partial, 320047fe360SEric Dumazet .nr_pages_max = PIPE_DEF_BUFFERS, 321912d35f8SJens Axboe .flags = flags, 322912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 323bbdfc2f7SJens Axboe .spd_release = spd_release_page, 324912d35f8SJens Axboe }; 3255274f052SJens Axboe 32635f3d14dSJens Axboe if (splice_grow_spd(pipe, &spd)) 32735f3d14dSJens Axboe return -ENOMEM; 32835f3d14dSJens Axboe 329cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 330912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 331d8983910SFengguang Wu req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 332047fe360SEric Dumazet nr_pages = min(req_pages, spd.nr_pages_max); 3335274f052SJens Axboe 3345274f052SJens Axboe /* 335eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 33682aa5d61SJens Axboe */ 33735f3d14dSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, spd.pages); 338431a4820SFengguang Wu index += spd.nr_pages; 339eb20796bSJens Axboe 3405274f052SJens Axboe /* 341eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 342431a4820SFengguang Wu * readahead/allocate the rest and fill in the holes. 343eb20796bSJens Axboe */ 344431a4820SFengguang Wu if (spd.nr_pages < nr_pages) 345cf914a7dSRusty Russell page_cache_sync_readahead(mapping, &in->f_ra, in, 346cf914a7dSRusty Russell index, req_pages - spd.nr_pages); 347431a4820SFengguang Wu 348932cc6d4SJens Axboe error = 0; 349eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 350eb20796bSJens Axboe /* 351eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 352eb20796bSJens Axboe * the first hole. 3535274f052SJens Axboe */ 3547480a904SJens Axboe page = find_get_page(mapping, index); 3557480a904SJens Axboe if (!page) { 356e27dedd8SJens Axboe /* 357eb20796bSJens Axboe * page didn't exist, allocate one. 3587480a904SJens Axboe */ 3597480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3605274f052SJens Axboe if (!page) 3615274f052SJens Axboe break; 3625274f052SJens Axboe 3637480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3640ae0b5d0SNick Piggin GFP_KERNEL); 3655274f052SJens Axboe if (unlikely(error)) { 3665274f052SJens Axboe page_cache_release(page); 367a0548871SJens Axboe if (error == -EEXIST) 368a0548871SJens Axboe continue; 3695274f052SJens Axboe break; 3705274f052SJens Axboe } 371eb20796bSJens Axboe /* 372eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 373eb20796bSJens Axboe * to avoid convoluting the logic below even more. 374eb20796bSJens Axboe */ 375eb20796bSJens Axboe unlock_page(page); 3765274f052SJens Axboe } 3777480a904SJens Axboe 37835f3d14dSJens Axboe spd.pages[spd.nr_pages++] = page; 379eb20796bSJens Axboe index++; 380eb20796bSJens Axboe } 381eb20796bSJens Axboe 382eb20796bSJens Axboe /* 383eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 384eb20796bSJens Axboe * pages, fill in the partial map, etc. 385eb20796bSJens Axboe */ 386eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 387eb20796bSJens Axboe nr_pages = spd.nr_pages; 388eb20796bSJens Axboe spd.nr_pages = 0; 389eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 390eb20796bSJens Axboe unsigned int this_len; 391eb20796bSJens Axboe 392eb20796bSJens Axboe if (!len) 393eb20796bSJens Axboe break; 394eb20796bSJens Axboe 395eb20796bSJens Axboe /* 396eb20796bSJens Axboe * this_len is the max we'll use from this page 397eb20796bSJens Axboe */ 398eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 39935f3d14dSJens Axboe page = spd.pages[page_nr]; 400eb20796bSJens Axboe 401a08a166fSFengguang Wu if (PageReadahead(page)) 402cf914a7dSRusty Russell page_cache_async_readahead(mapping, &in->f_ra, in, 403d8983910SFengguang Wu page, index, req_pages - page_nr); 404a08a166fSFengguang Wu 4057480a904SJens Axboe /* 4067480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 4077480a904SJens Axboe */ 4087480a904SJens Axboe if (!PageUptodate(page)) { 4097480a904SJens Axboe lock_page(page); 4107480a904SJens Axboe 4117480a904SJens Axboe /* 41232502b84SMiklos Szeredi * Page was truncated, or invalidated by the 41332502b84SMiklos Szeredi * filesystem. Redo the find/create, but this time the 41432502b84SMiklos Szeredi * page is kept locked, so there's no chance of another 41532502b84SMiklos Szeredi * race with truncate/invalidate. 4167480a904SJens Axboe */ 4177480a904SJens Axboe if (!page->mapping) { 4187480a904SJens Axboe unlock_page(page); 41932502b84SMiklos Szeredi page = find_or_create_page(mapping, index, 42032502b84SMiklos Szeredi mapping_gfp_mask(mapping)); 42132502b84SMiklos Szeredi 42232502b84SMiklos Szeredi if (!page) { 42332502b84SMiklos Szeredi error = -ENOMEM; 4247480a904SJens Axboe break; 4257480a904SJens Axboe } 42635f3d14dSJens Axboe page_cache_release(spd.pages[page_nr]); 42735f3d14dSJens Axboe spd.pages[page_nr] = page; 42832502b84SMiklos Szeredi } 4297480a904SJens Axboe /* 4307480a904SJens Axboe * page was already under io and is now done, great 4317480a904SJens Axboe */ 4327480a904SJens Axboe if (PageUptodate(page)) { 4337480a904SJens Axboe unlock_page(page); 4347480a904SJens Axboe goto fill_it; 4357480a904SJens Axboe } 4367480a904SJens Axboe 4377480a904SJens Axboe /* 4387480a904SJens Axboe * need to read in the page 4397480a904SJens Axboe */ 4407480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 4417480a904SJens Axboe if (unlikely(error)) { 442eb20796bSJens Axboe /* 443eb20796bSJens Axboe * We really should re-lookup the page here, 444eb20796bSJens Axboe * but it complicates things a lot. Instead 445eb20796bSJens Axboe * lets just do what we already stored, and 446eb20796bSJens Axboe * we'll get it the next time we are called. 447eb20796bSJens Axboe */ 4487480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 449eb20796bSJens Axboe error = 0; 450eb20796bSJens Axboe 4517480a904SJens Axboe break; 4527480a904SJens Axboe } 453620a324bSJens Axboe } 454620a324bSJens Axboe fill_it: 45591ad66efSJens Axboe /* 456620a324bSJens Axboe * i_size must be checked after PageUptodate. 45791ad66efSJens Axboe */ 45891ad66efSJens Axboe isize = i_size_read(mapping->host); 45991ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 460eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 46191ad66efSJens Axboe break; 46291ad66efSJens Axboe 46391ad66efSJens Axboe /* 46491ad66efSJens Axboe * if this is the last page, see if we need to shrink 46591ad66efSJens Axboe * the length and stop 46691ad66efSJens Axboe */ 46791ad66efSJens Axboe if (end_index == index) { 468475ecadeSHugh Dickins unsigned int plen; 469475ecadeSHugh Dickins 470475ecadeSHugh Dickins /* 471475ecadeSHugh Dickins * max good bytes in this page 472475ecadeSHugh Dickins */ 473475ecadeSHugh Dickins plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; 474475ecadeSHugh Dickins if (plen <= loff) 47591ad66efSJens Axboe break; 476475ecadeSHugh Dickins 47791ad66efSJens Axboe /* 47891ad66efSJens Axboe * force quit after adding this page 47991ad66efSJens Axboe */ 480475ecadeSHugh Dickins this_len = min(this_len, plen - loff); 481eb20796bSJens Axboe len = this_len; 48291ad66efSJens Axboe } 483620a324bSJens Axboe 48435f3d14dSJens Axboe spd.partial[page_nr].offset = loff; 48535f3d14dSJens Axboe spd.partial[page_nr].len = this_len; 48682aa5d61SJens Axboe len -= this_len; 48791ad66efSJens Axboe loff = 0; 488eb20796bSJens Axboe spd.nr_pages++; 489eb20796bSJens Axboe index++; 4905274f052SJens Axboe } 4915274f052SJens Axboe 492eb20796bSJens Axboe /* 493475ecadeSHugh Dickins * Release any pages at the end, if we quit early. 'page_nr' is how far 494eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 495eb20796bSJens Axboe */ 496eb20796bSJens Axboe while (page_nr < nr_pages) 49735f3d14dSJens Axboe page_cache_release(spd.pages[page_nr++]); 498f4e6b498SFengguang Wu in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; 499eb20796bSJens Axboe 500912d35f8SJens Axboe if (spd.nr_pages) 50135f3d14dSJens Axboe error = splice_to_pipe(pipe, &spd); 50216c523ddSJens Axboe 503047fe360SEric Dumazet splice_shrink_spd(&spd); 5047480a904SJens Axboe return error; 5055274f052SJens Axboe } 5065274f052SJens Axboe 50783f9135bSJens Axboe /** 50883f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 50983f9135bSJens Axboe * @in: file to splice from 510932cc6d4SJens Axboe * @ppos: position in @in 51183f9135bSJens Axboe * @pipe: pipe to splice to 51283f9135bSJens Axboe * @len: number of bytes to splice 51383f9135bSJens Axboe * @flags: splice modifier flags 51483f9135bSJens Axboe * 515932cc6d4SJens Axboe * Description: 516932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 517932cc6d4SJens Axboe * used as long as the address_space operations for the source implements 518932cc6d4SJens Axboe * a readpage() hook. 519932cc6d4SJens Axboe * 52083f9135bSJens Axboe */ 521cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 522cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 523cbb7e577SJens Axboe unsigned int flags) 5245274f052SJens Axboe { 525d366d398SJens Axboe loff_t isize, left; 5268191ecd1SJens Axboe int ret; 527d366d398SJens Axboe 528d366d398SJens Axboe isize = i_size_read(in->f_mapping->host); 529d366d398SJens Axboe if (unlikely(*ppos >= isize)) 530d366d398SJens Axboe return 0; 531d366d398SJens Axboe 532d366d398SJens Axboe left = isize - *ppos; 533d366d398SJens Axboe if (unlikely(left < len)) 534d366d398SJens Axboe len = left; 5355274f052SJens Axboe 536cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 537723590edSMiklos Szeredi if (ret > 0) { 538cbb7e577SJens Axboe *ppos += ret; 539723590edSMiklos Szeredi file_accessed(in); 540723590edSMiklos Szeredi } 5415274f052SJens Axboe 5425274f052SJens Axboe return ret; 5435274f052SJens Axboe } 544059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 545059a8f37SJens Axboe 5466818173bSMiklos Szeredi static const struct pipe_buf_operations default_pipe_buf_ops = { 5476818173bSMiklos Szeredi .can_merge = 0, 5486818173bSMiklos Szeredi .map = generic_pipe_buf_map, 5496818173bSMiklos Szeredi .unmap = generic_pipe_buf_unmap, 5506818173bSMiklos Szeredi .confirm = generic_pipe_buf_confirm, 5516818173bSMiklos Szeredi .release = generic_pipe_buf_release, 5526818173bSMiklos Szeredi .steal = generic_pipe_buf_steal, 5536818173bSMiklos Szeredi .get = generic_pipe_buf_get, 5546818173bSMiklos Szeredi }; 5556818173bSMiklos Szeredi 5566818173bSMiklos Szeredi static ssize_t kernel_readv(struct file *file, const struct iovec *vec, 5576818173bSMiklos Szeredi unsigned long vlen, loff_t offset) 5586818173bSMiklos Szeredi { 5596818173bSMiklos Szeredi mm_segment_t old_fs; 5606818173bSMiklos Szeredi loff_t pos = offset; 5616818173bSMiklos Szeredi ssize_t res; 5626818173bSMiklos Szeredi 5636818173bSMiklos Szeredi old_fs = get_fs(); 5646818173bSMiklos Szeredi set_fs(get_ds()); 5656818173bSMiklos Szeredi /* The cast to a user pointer is valid due to the set_fs() */ 5666818173bSMiklos Szeredi res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos); 5676818173bSMiklos Szeredi set_fs(old_fs); 5686818173bSMiklos Szeredi 5696818173bSMiklos Szeredi return res; 5706818173bSMiklos Szeredi } 5716818173bSMiklos Szeredi 572b2858d7dSMiklos Szeredi static ssize_t kernel_write(struct file *file, const char *buf, size_t count, 573b2858d7dSMiklos Szeredi loff_t pos) 5740b0a47f5SMiklos Szeredi { 5750b0a47f5SMiklos Szeredi mm_segment_t old_fs; 5760b0a47f5SMiklos Szeredi ssize_t res; 5770b0a47f5SMiklos Szeredi 5780b0a47f5SMiklos Szeredi old_fs = get_fs(); 5790b0a47f5SMiklos Szeredi set_fs(get_ds()); 5800b0a47f5SMiklos Szeredi /* The cast to a user pointer is valid due to the set_fs() */ 581b2858d7dSMiklos Szeredi res = vfs_write(file, (const char __user *)buf, count, &pos); 5820b0a47f5SMiklos Szeredi set_fs(old_fs); 5830b0a47f5SMiklos Szeredi 5840b0a47f5SMiklos Szeredi return res; 5850b0a47f5SMiklos Szeredi } 5860b0a47f5SMiklos Szeredi 5876818173bSMiklos Szeredi ssize_t default_file_splice_read(struct file *in, loff_t *ppos, 5886818173bSMiklos Szeredi struct pipe_inode_info *pipe, size_t len, 5896818173bSMiklos Szeredi unsigned int flags) 5906818173bSMiklos Szeredi { 5916818173bSMiklos Szeredi unsigned int nr_pages; 5926818173bSMiklos Szeredi unsigned int nr_freed; 5936818173bSMiklos Szeredi size_t offset; 59435f3d14dSJens Axboe struct page *pages[PIPE_DEF_BUFFERS]; 59535f3d14dSJens Axboe struct partial_page partial[PIPE_DEF_BUFFERS]; 59635f3d14dSJens Axboe struct iovec *vec, __vec[PIPE_DEF_BUFFERS]; 5976818173bSMiklos Szeredi ssize_t res; 5986818173bSMiklos Szeredi size_t this_len; 5996818173bSMiklos Szeredi int error; 6006818173bSMiklos Szeredi int i; 6016818173bSMiklos Szeredi struct splice_pipe_desc spd = { 6026818173bSMiklos Szeredi .pages = pages, 6036818173bSMiklos Szeredi .partial = partial, 604047fe360SEric Dumazet .nr_pages_max = PIPE_DEF_BUFFERS, 6056818173bSMiklos Szeredi .flags = flags, 6066818173bSMiklos Szeredi .ops = &default_pipe_buf_ops, 6076818173bSMiklos Szeredi .spd_release = spd_release_page, 6086818173bSMiklos Szeredi }; 6096818173bSMiklos Szeredi 61035f3d14dSJens Axboe if (splice_grow_spd(pipe, &spd)) 61135f3d14dSJens Axboe return -ENOMEM; 61235f3d14dSJens Axboe 61335f3d14dSJens Axboe res = -ENOMEM; 61435f3d14dSJens Axboe vec = __vec; 615047fe360SEric Dumazet if (spd.nr_pages_max > PIPE_DEF_BUFFERS) { 616047fe360SEric Dumazet vec = kmalloc(spd.nr_pages_max * sizeof(struct iovec), GFP_KERNEL); 61735f3d14dSJens Axboe if (!vec) 61835f3d14dSJens Axboe goto shrink_ret; 61935f3d14dSJens Axboe } 62035f3d14dSJens Axboe 6216818173bSMiklos Szeredi offset = *ppos & ~PAGE_CACHE_MASK; 6226818173bSMiklos Szeredi nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 6236818173bSMiklos Szeredi 624047fe360SEric Dumazet for (i = 0; i < nr_pages && i < spd.nr_pages_max && len; i++) { 6256818173bSMiklos Szeredi struct page *page; 6266818173bSMiklos Szeredi 6274f231228SJens Axboe page = alloc_page(GFP_USER); 6286818173bSMiklos Szeredi error = -ENOMEM; 6296818173bSMiklos Szeredi if (!page) 6306818173bSMiklos Szeredi goto err; 6316818173bSMiklos Szeredi 6326818173bSMiklos Szeredi this_len = min_t(size_t, len, PAGE_CACHE_SIZE - offset); 6334f231228SJens Axboe vec[i].iov_base = (void __user *) page_address(page); 6346818173bSMiklos Szeredi vec[i].iov_len = this_len; 63535f3d14dSJens Axboe spd.pages[i] = page; 6366818173bSMiklos Szeredi spd.nr_pages++; 6376818173bSMiklos Szeredi len -= this_len; 6386818173bSMiklos Szeredi offset = 0; 6396818173bSMiklos Szeredi } 6406818173bSMiklos Szeredi 6416818173bSMiklos Szeredi res = kernel_readv(in, vec, spd.nr_pages, *ppos); 64277f6bf57SAndrew Morton if (res < 0) { 64377f6bf57SAndrew Morton error = res; 6446818173bSMiklos Szeredi goto err; 64577f6bf57SAndrew Morton } 6466818173bSMiklos Szeredi 6476818173bSMiklos Szeredi error = 0; 6486818173bSMiklos Szeredi if (!res) 6496818173bSMiklos Szeredi goto err; 6506818173bSMiklos Szeredi 6516818173bSMiklos Szeredi nr_freed = 0; 6526818173bSMiklos Szeredi for (i = 0; i < spd.nr_pages; i++) { 6536818173bSMiklos Szeredi this_len = min_t(size_t, vec[i].iov_len, res); 65435f3d14dSJens Axboe spd.partial[i].offset = 0; 65535f3d14dSJens Axboe spd.partial[i].len = this_len; 6566818173bSMiklos Szeredi if (!this_len) { 65735f3d14dSJens Axboe __free_page(spd.pages[i]); 65835f3d14dSJens Axboe spd.pages[i] = NULL; 6596818173bSMiklos Szeredi nr_freed++; 6606818173bSMiklos Szeredi } 6616818173bSMiklos Szeredi res -= this_len; 6626818173bSMiklos Szeredi } 6636818173bSMiklos Szeredi spd.nr_pages -= nr_freed; 6646818173bSMiklos Szeredi 6656818173bSMiklos Szeredi res = splice_to_pipe(pipe, &spd); 6666818173bSMiklos Szeredi if (res > 0) 6676818173bSMiklos Szeredi *ppos += res; 6686818173bSMiklos Szeredi 66935f3d14dSJens Axboe shrink_ret: 67035f3d14dSJens Axboe if (vec != __vec) 67135f3d14dSJens Axboe kfree(vec); 672047fe360SEric Dumazet splice_shrink_spd(&spd); 6736818173bSMiklos Szeredi return res; 6746818173bSMiklos Szeredi 6756818173bSMiklos Szeredi err: 6764f231228SJens Axboe for (i = 0; i < spd.nr_pages; i++) 67735f3d14dSJens Axboe __free_page(spd.pages[i]); 6784f231228SJens Axboe 67935f3d14dSJens Axboe res = error; 68035f3d14dSJens Axboe goto shrink_ret; 6816818173bSMiklos Szeredi } 6826818173bSMiklos Szeredi EXPORT_SYMBOL(default_file_splice_read); 6836818173bSMiklos Szeredi 6845274f052SJens Axboe /* 6854f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 686016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 6875274f052SJens Axboe */ 68876ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 6895274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 6905274f052SJens Axboe { 6916a14b90bSJens Axboe struct file *file = sd->u.file; 6925274f052SJens Axboe loff_t pos = sd->pos; 693a8adbe37SMichał Mirosław int more; 6945274f052SJens Axboe 695a8adbe37SMichał Mirosław if (!likely(file->f_op && file->f_op->sendpage)) 696a8adbe37SMichał Mirosław return -EINVAL; 697a8adbe37SMichał Mirosław 69835f9c09fSEric Dumazet more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; 69935f9c09fSEric Dumazet if (sd->len < sd->total_len) 70035f9c09fSEric Dumazet more |= MSG_SENDPAGE_NOTLAST; 701a8adbe37SMichał Mirosław return file->f_op->sendpage(file, buf->page, buf->offset, 702f84d7519SJens Axboe sd->len, &pos, more); 7035274f052SJens Axboe } 7045274f052SJens Axboe 7055274f052SJens Axboe /* 7065274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 7075274f052SJens Axboe * basically three cases: 7085274f052SJens Axboe * 7095274f052SJens Axboe * - Destination page already exists in the address space and there 7105274f052SJens Axboe * are users of it. For that case we have no other option that 7115274f052SJens Axboe * copying the data. Tough luck. 7125274f052SJens Axboe * - Destination page already exists in the address space, but there 7135274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 7145274f052SJens Axboe * through to last case. 7155274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 7165274f052SJens Axboe * the page cache and avoid the copy. 7175274f052SJens Axboe * 71883f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 71983f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 72083f9135bSJens Axboe * file address space page cache. This is possible if no one else has 72183f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 72283f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 72383f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 7245274f052SJens Axboe */ 725328eaabaSMiklos Szeredi int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 7265274f052SJens Axboe struct splice_desc *sd) 7275274f052SJens Axboe { 7286a14b90bSJens Axboe struct file *file = sd->u.file; 7295274f052SJens Axboe struct address_space *mapping = file->f_mapping; 730016b661eSJens Axboe unsigned int offset, this_len; 7315274f052SJens Axboe struct page *page; 732afddba49SNick Piggin void *fsdata; 7333e7ee3e7SJens Axboe int ret; 7345274f052SJens Axboe 7355274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 7365274f052SJens Axboe 737016b661eSJens Axboe this_len = sd->len; 738016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 739016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 740016b661eSJens Axboe 741afddba49SNick Piggin ret = pagecache_write_begin(file, mapping, sd->pos, this_len, 742afddba49SNick Piggin AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); 7439e0267c2SJens Axboe if (unlikely(ret)) 744afddba49SNick Piggin goto out; 7455274f052SJens Axboe 7460568b409SJens Axboe if (buf->page != page) { 74776ad4d11SJens Axboe char *src = buf->ops->map(pipe, buf, 1); 748e8e3c3d6SCong Wang char *dst = kmap_atomic(page); 7495abc97aaSJens Axboe 750016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 7515274f052SJens Axboe flush_dcache_page(page); 752e8e3c3d6SCong Wang kunmap_atomic(dst); 75376ad4d11SJens Axboe buf->ops->unmap(pipe, buf, src); 7545abc97aaSJens Axboe } 755afddba49SNick Piggin ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, 756afddba49SNick Piggin page, fsdata); 7570568b409SJens Axboe out: 7585274f052SJens Axboe return ret; 7595274f052SJens Axboe } 760328eaabaSMiklos Szeredi EXPORT_SYMBOL(pipe_to_file); 7615274f052SJens Axboe 762b3c2d2ddSMiklos Szeredi static void wakeup_pipe_writers(struct pipe_inode_info *pipe) 763b3c2d2ddSMiklos Szeredi { 764b3c2d2ddSMiklos Szeredi smp_mb(); 765b3c2d2ddSMiklos Szeredi if (waitqueue_active(&pipe->wait)) 766b3c2d2ddSMiklos Szeredi wake_up_interruptible(&pipe->wait); 767b3c2d2ddSMiklos Szeredi kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 768b3c2d2ddSMiklos Szeredi } 769b3c2d2ddSMiklos Szeredi 770b3c2d2ddSMiklos Szeredi /** 771b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed - feed available data from a pipe to a file 772b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 773b3c2d2ddSMiklos Szeredi * @sd: information to @actor 774b3c2d2ddSMiklos Szeredi * @actor: handler that splices the data 775b3c2d2ddSMiklos Szeredi * 776b3c2d2ddSMiklos Szeredi * Description: 777b3c2d2ddSMiklos Szeredi * This function loops over the pipe and calls @actor to do the 778b3c2d2ddSMiklos Szeredi * actual moving of a single struct pipe_buffer to the desired 779b3c2d2ddSMiklos Szeredi * destination. It returns when there's no more buffers left in 780b3c2d2ddSMiklos Szeredi * the pipe or if the requested number of bytes (@sd->total_len) 781b3c2d2ddSMiklos Szeredi * have been copied. It returns a positive number (one) if the 782b3c2d2ddSMiklos Szeredi * pipe needs to be filled with more data, zero if the required 783b3c2d2ddSMiklos Szeredi * number of bytes have been copied and -errno on error. 784b3c2d2ddSMiklos Szeredi * 785b3c2d2ddSMiklos Szeredi * This, together with splice_from_pipe_{begin,end,next}, may be 786b3c2d2ddSMiklos Szeredi * used to implement the functionality of __splice_from_pipe() when 787b3c2d2ddSMiklos Szeredi * locking is required around copying the pipe buffers to the 788b3c2d2ddSMiklos Szeredi * destination. 789b3c2d2ddSMiklos Szeredi */ 790b3c2d2ddSMiklos Szeredi int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, 791b3c2d2ddSMiklos Szeredi splice_actor *actor) 792b3c2d2ddSMiklos Szeredi { 793b3c2d2ddSMiklos Szeredi int ret; 794b3c2d2ddSMiklos Szeredi 795b3c2d2ddSMiklos Szeredi while (pipe->nrbufs) { 796b3c2d2ddSMiklos Szeredi struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 797b3c2d2ddSMiklos Szeredi const struct pipe_buf_operations *ops = buf->ops; 798b3c2d2ddSMiklos Szeredi 799b3c2d2ddSMiklos Szeredi sd->len = buf->len; 800b3c2d2ddSMiklos Szeredi if (sd->len > sd->total_len) 801b3c2d2ddSMiklos Szeredi sd->len = sd->total_len; 802b3c2d2ddSMiklos Szeredi 803a8adbe37SMichał Mirosław ret = buf->ops->confirm(pipe, buf); 804a8adbe37SMichał Mirosław if (unlikely(ret)) { 805b3c2d2ddSMiklos Szeredi if (ret == -ENODATA) 806b3c2d2ddSMiklos Szeredi ret = 0; 807b3c2d2ddSMiklos Szeredi return ret; 808b3c2d2ddSMiklos Szeredi } 809a8adbe37SMichał Mirosław 810a8adbe37SMichał Mirosław ret = actor(pipe, buf, sd); 811a8adbe37SMichał Mirosław if (ret <= 0) 812a8adbe37SMichał Mirosław return ret; 813a8adbe37SMichał Mirosław 814b3c2d2ddSMiklos Szeredi buf->offset += ret; 815b3c2d2ddSMiklos Szeredi buf->len -= ret; 816b3c2d2ddSMiklos Szeredi 817b3c2d2ddSMiklos Szeredi sd->num_spliced += ret; 818b3c2d2ddSMiklos Szeredi sd->len -= ret; 819b3c2d2ddSMiklos Szeredi sd->pos += ret; 820b3c2d2ddSMiklos Szeredi sd->total_len -= ret; 821b3c2d2ddSMiklos Szeredi 822b3c2d2ddSMiklos Szeredi if (!buf->len) { 823b3c2d2ddSMiklos Szeredi buf->ops = NULL; 824b3c2d2ddSMiklos Szeredi ops->release(pipe, buf); 82535f3d14dSJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); 826b3c2d2ddSMiklos Szeredi pipe->nrbufs--; 827b3c2d2ddSMiklos Szeredi if (pipe->inode) 828b3c2d2ddSMiklos Szeredi sd->need_wakeup = true; 829b3c2d2ddSMiklos Szeredi } 830b3c2d2ddSMiklos Szeredi 831b3c2d2ddSMiklos Szeredi if (!sd->total_len) 832b3c2d2ddSMiklos Szeredi return 0; 833b3c2d2ddSMiklos Szeredi } 834b3c2d2ddSMiklos Szeredi 835b3c2d2ddSMiklos Szeredi return 1; 836b3c2d2ddSMiklos Szeredi } 837b3c2d2ddSMiklos Szeredi EXPORT_SYMBOL(splice_from_pipe_feed); 838b3c2d2ddSMiklos Szeredi 839b3c2d2ddSMiklos Szeredi /** 840b3c2d2ddSMiklos Szeredi * splice_from_pipe_next - wait for some data to splice from 841b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 842b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 843b3c2d2ddSMiklos Szeredi * 844b3c2d2ddSMiklos Szeredi * Description: 845b3c2d2ddSMiklos Szeredi * This function will wait for some data and return a positive 846b3c2d2ddSMiklos Szeredi * value (one) if pipe buffers are available. It will return zero 847b3c2d2ddSMiklos Szeredi * or -errno if no more data needs to be spliced. 848b3c2d2ddSMiklos Szeredi */ 849b3c2d2ddSMiklos Szeredi int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) 850b3c2d2ddSMiklos Szeredi { 851b3c2d2ddSMiklos Szeredi while (!pipe->nrbufs) { 852b3c2d2ddSMiklos Szeredi if (!pipe->writers) 853b3c2d2ddSMiklos Szeredi return 0; 854b3c2d2ddSMiklos Szeredi 855b3c2d2ddSMiklos Szeredi if (!pipe->waiting_writers && sd->num_spliced) 856b3c2d2ddSMiklos Szeredi return 0; 857b3c2d2ddSMiklos Szeredi 858b3c2d2ddSMiklos Szeredi if (sd->flags & SPLICE_F_NONBLOCK) 859b3c2d2ddSMiklos Szeredi return -EAGAIN; 860b3c2d2ddSMiklos Szeredi 861b3c2d2ddSMiklos Szeredi if (signal_pending(current)) 862b3c2d2ddSMiklos Szeredi return -ERESTARTSYS; 863b3c2d2ddSMiklos Szeredi 864b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) { 865b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 866b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 867b3c2d2ddSMiklos Szeredi } 868b3c2d2ddSMiklos Szeredi 869b3c2d2ddSMiklos Szeredi pipe_wait(pipe); 870b3c2d2ddSMiklos Szeredi } 871b3c2d2ddSMiklos Szeredi 872b3c2d2ddSMiklos Szeredi return 1; 873b3c2d2ddSMiklos Szeredi } 874b3c2d2ddSMiklos Szeredi EXPORT_SYMBOL(splice_from_pipe_next); 875b3c2d2ddSMiklos Szeredi 876b3c2d2ddSMiklos Szeredi /** 877b3c2d2ddSMiklos Szeredi * splice_from_pipe_begin - start splicing from pipe 878b80901bbSRandy Dunlap * @sd: information about the splice operation 879b3c2d2ddSMiklos Szeredi * 880b3c2d2ddSMiklos Szeredi * Description: 881b3c2d2ddSMiklos Szeredi * This function should be called before a loop containing 882b3c2d2ddSMiklos Szeredi * splice_from_pipe_next() and splice_from_pipe_feed() to 883b3c2d2ddSMiklos Szeredi * initialize the necessary fields of @sd. 884b3c2d2ddSMiklos Szeredi */ 885b3c2d2ddSMiklos Szeredi void splice_from_pipe_begin(struct splice_desc *sd) 886b3c2d2ddSMiklos Szeredi { 887b3c2d2ddSMiklos Szeredi sd->num_spliced = 0; 888b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 889b3c2d2ddSMiklos Szeredi } 890b3c2d2ddSMiklos Szeredi EXPORT_SYMBOL(splice_from_pipe_begin); 891b3c2d2ddSMiklos Szeredi 892b3c2d2ddSMiklos Szeredi /** 893b3c2d2ddSMiklos Szeredi * splice_from_pipe_end - finish splicing from pipe 894b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 895b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 896b3c2d2ddSMiklos Szeredi * 897b3c2d2ddSMiklos Szeredi * Description: 898b3c2d2ddSMiklos Szeredi * This function will wake up pipe writers if necessary. It should 899b3c2d2ddSMiklos Szeredi * be called after a loop containing splice_from_pipe_next() and 900b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed(). 901b3c2d2ddSMiklos Szeredi */ 902b3c2d2ddSMiklos Szeredi void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) 903b3c2d2ddSMiklos Szeredi { 904b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) 905b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 906b3c2d2ddSMiklos Szeredi } 907b3c2d2ddSMiklos Szeredi EXPORT_SYMBOL(splice_from_pipe_end); 908b3c2d2ddSMiklos Szeredi 909932cc6d4SJens Axboe /** 910932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 911932cc6d4SJens Axboe * @pipe: pipe to splice from 912932cc6d4SJens Axboe * @sd: information to @actor 913932cc6d4SJens Axboe * @actor: handler that splices the data 914932cc6d4SJens Axboe * 915932cc6d4SJens Axboe * Description: 916932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 917932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 918932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 919932cc6d4SJens Axboe * pipe_to_user. 920932cc6d4SJens Axboe * 92183f9135bSJens Axboe */ 922c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 923c66ab6faSJens Axboe splice_actor *actor) 9245274f052SJens Axboe { 925b3c2d2ddSMiklos Szeredi int ret; 9265274f052SJens Axboe 927b3c2d2ddSMiklos Szeredi splice_from_pipe_begin(sd); 928b3c2d2ddSMiklos Szeredi do { 929b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_next(pipe, sd); 930b3c2d2ddSMiklos Szeredi if (ret > 0) 931b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_feed(pipe, sd, actor); 932b3c2d2ddSMiklos Szeredi } while (ret > 0); 933b3c2d2ddSMiklos Szeredi splice_from_pipe_end(pipe, sd); 9345274f052SJens Axboe 935b3c2d2ddSMiklos Szeredi return sd->num_spliced ? sd->num_spliced : ret; 9365274f052SJens Axboe } 93740bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 9385274f052SJens Axboe 939932cc6d4SJens Axboe /** 940932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 941932cc6d4SJens Axboe * @pipe: pipe to splice from 942932cc6d4SJens Axboe * @out: file to splice to 943932cc6d4SJens Axboe * @ppos: position in @out 944932cc6d4SJens Axboe * @len: how many bytes to splice 945932cc6d4SJens Axboe * @flags: splice modifier flags 946932cc6d4SJens Axboe * @actor: handler that splices the data 947932cc6d4SJens Axboe * 948932cc6d4SJens Axboe * Description: 9492933970bSMiklos Szeredi * See __splice_from_pipe. This function locks the pipe inode, 950932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 951932cc6d4SJens Axboe * 952932cc6d4SJens Axboe */ 9536da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 9546da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 9556da61809SMark Fasheh splice_actor *actor) 9566da61809SMark Fasheh { 9576da61809SMark Fasheh ssize_t ret; 958c66ab6faSJens Axboe struct splice_desc sd = { 959c66ab6faSJens Axboe .total_len = len, 960c66ab6faSJens Axboe .flags = flags, 961c66ab6faSJens Axboe .pos = *ppos, 9626a14b90bSJens Axboe .u.file = out, 963c66ab6faSJens Axboe }; 9646da61809SMark Fasheh 96561e0d47cSMiklos Szeredi pipe_lock(pipe); 966c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 96761e0d47cSMiklos Szeredi pipe_unlock(pipe); 9686da61809SMark Fasheh 9696da61809SMark Fasheh return ret; 9706da61809SMark Fasheh } 9716da61809SMark Fasheh 9726da61809SMark Fasheh /** 97383f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 9743a326a2cSIngo Molnar * @pipe: pipe info 97583f9135bSJens Axboe * @out: file to write to 976932cc6d4SJens Axboe * @ppos: position in @out 97783f9135bSJens Axboe * @len: number of bytes to splice 97883f9135bSJens Axboe * @flags: splice modifier flags 97983f9135bSJens Axboe * 980932cc6d4SJens Axboe * Description: 98183f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 98283f9135bSJens Axboe * the given pipe inode to the given file. 98383f9135bSJens Axboe * 98483f9135bSJens Axboe */ 9853a326a2cSIngo Molnar ssize_t 9863a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 987cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 9885274f052SJens Axboe { 9894f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 9908c34e2d6SJens Axboe struct inode *inode = mapping->host; 9917f3d4ee1SMiklos Szeredi struct splice_desc sd = { 9927f3d4ee1SMiklos Szeredi .total_len = len, 9937f3d4ee1SMiklos Szeredi .flags = flags, 9947f3d4ee1SMiklos Szeredi .pos = *ppos, 9957f3d4ee1SMiklos Szeredi .u.file = out, 9967f3d4ee1SMiklos Szeredi }; 9973a326a2cSIngo Molnar ssize_t ret; 9988c34e2d6SJens Axboe 99914da9200SJan Kara sb_start_write(inode->i_sb); 100014da9200SJan Kara 100161e0d47cSMiklos Szeredi pipe_lock(pipe); 1002eb443e5aSMiklos Szeredi 1003eb443e5aSMiklos Szeredi splice_from_pipe_begin(&sd); 1004eb443e5aSMiklos Szeredi do { 1005eb443e5aSMiklos Szeredi ret = splice_from_pipe_next(pipe, &sd); 1006eb443e5aSMiklos Szeredi if (ret <= 0) 1007eb443e5aSMiklos Szeredi break; 1008eb443e5aSMiklos Szeredi 1009eb443e5aSMiklos Szeredi mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD); 1010eb443e5aSMiklos Szeredi ret = file_remove_suid(out); 1011723590edSMiklos Szeredi if (!ret) { 1012c3b2da31SJosef Bacik ret = file_update_time(out); 1013c3b2da31SJosef Bacik if (!ret) 1014c3b2da31SJosef Bacik ret = splice_from_pipe_feed(pipe, &sd, 1015c3b2da31SJosef Bacik pipe_to_file); 1016723590edSMiklos Szeredi } 1017eb443e5aSMiklos Szeredi mutex_unlock(&inode->i_mutex); 1018eb443e5aSMiklos Szeredi } while (ret > 0); 1019eb443e5aSMiklos Szeredi splice_from_pipe_end(pipe, &sd); 1020eb443e5aSMiklos Szeredi 102161e0d47cSMiklos Szeredi pipe_unlock(pipe); 1022eb443e5aSMiklos Szeredi 1023eb443e5aSMiklos Szeredi if (sd.num_spliced) 1024eb443e5aSMiklos Szeredi ret = sd.num_spliced; 1025eb443e5aSMiklos Szeredi 1026a4514ebdSJens Axboe if (ret > 0) { 10277f3d4ee1SMiklos Szeredi int err; 10287f3d4ee1SMiklos Szeredi 1029148f948bSJan Kara err = generic_write_sync(out, *ppos, ret); 10304f6f0bd2SJens Axboe if (err) 10314f6f0bd2SJens Axboe ret = err; 1032148f948bSJan Kara else 1033148f948bSJan Kara *ppos += ret; 1034d0e1d66bSNamjae Jeon balance_dirty_pages_ratelimited(mapping); 1035a4514ebdSJens Axboe } 103614da9200SJan Kara sb_end_write(inode->i_sb); 10374f6f0bd2SJens Axboe 10384f6f0bd2SJens Axboe return ret; 10395274f052SJens Axboe } 10405274f052SJens Axboe 1041059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 1042059a8f37SJens Axboe 1043b2858d7dSMiklos Szeredi static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 1044b2858d7dSMiklos Szeredi struct splice_desc *sd) 10450b0a47f5SMiklos Szeredi { 1046b2858d7dSMiklos Szeredi int ret; 1047b2858d7dSMiklos Szeredi void *data; 1048b2858d7dSMiklos Szeredi 1049b2858d7dSMiklos Szeredi data = buf->ops->map(pipe, buf, 0); 1050b2858d7dSMiklos Szeredi ret = kernel_write(sd->u.file, data + buf->offset, sd->len, sd->pos); 1051b2858d7dSMiklos Szeredi buf->ops->unmap(pipe, buf, data); 1052b2858d7dSMiklos Szeredi 1053b2858d7dSMiklos Szeredi return ret; 10540b0a47f5SMiklos Szeredi } 10550b0a47f5SMiklos Szeredi 10560b0a47f5SMiklos Szeredi static ssize_t default_file_splice_write(struct pipe_inode_info *pipe, 10570b0a47f5SMiklos Szeredi struct file *out, loff_t *ppos, 10580b0a47f5SMiklos Szeredi size_t len, unsigned int flags) 10590b0a47f5SMiklos Szeredi { 1060b2858d7dSMiklos Szeredi ssize_t ret; 10610b0a47f5SMiklos Szeredi 1062b2858d7dSMiklos Szeredi ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf); 1063b2858d7dSMiklos Szeredi if (ret > 0) 1064b2858d7dSMiklos Szeredi *ppos += ret; 10650b0a47f5SMiklos Szeredi 1066b2858d7dSMiklos Szeredi return ret; 10670b0a47f5SMiklos Szeredi } 10680b0a47f5SMiklos Szeredi 106983f9135bSJens Axboe /** 107083f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 1071932cc6d4SJens Axboe * @pipe: pipe to splice from 107283f9135bSJens Axboe * @out: socket to write to 1073932cc6d4SJens Axboe * @ppos: position in @out 107483f9135bSJens Axboe * @len: number of bytes to splice 107583f9135bSJens Axboe * @flags: splice modifier flags 107683f9135bSJens Axboe * 1077932cc6d4SJens Axboe * Description: 107883f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 107983f9135bSJens Axboe * is involved. 108083f9135bSJens Axboe * 108183f9135bSJens Axboe */ 10823a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 1083cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 10845274f052SJens Axboe { 108500522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 10865274f052SJens Axboe } 10875274f052SJens Axboe 1088059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 1089a0f06780SJeff Garzik 109083f9135bSJens Axboe /* 109183f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 109283f9135bSJens Axboe */ 10933a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 1094cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 10955274f052SJens Axboe { 10960b0a47f5SMiklos Szeredi ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, 10970b0a47f5SMiklos Szeredi loff_t *, size_t, unsigned int); 10985274f052SJens Axboe int ret; 10995274f052SJens Axboe 110049570e9bSJens Axboe if (unlikely(!(out->f_mode & FMODE_WRITE))) 11015274f052SJens Axboe return -EBADF; 11025274f052SJens Axboe 1103efc968d4SLinus Torvalds if (unlikely(out->f_flags & O_APPEND)) 1104efc968d4SLinus Torvalds return -EINVAL; 1105efc968d4SLinus Torvalds 1106cbb7e577SJens Axboe ret = rw_verify_area(WRITE, out, ppos, len); 11075274f052SJens Axboe if (unlikely(ret < 0)) 11085274f052SJens Axboe return ret; 11095274f052SJens Axboe 1110cc56f7deSChangli Gao if (out->f_op && out->f_op->splice_write) 11110b0a47f5SMiklos Szeredi splice_write = out->f_op->splice_write; 1112cc56f7deSChangli Gao else 11130b0a47f5SMiklos Szeredi splice_write = default_file_splice_write; 11140b0a47f5SMiklos Szeredi 11150b0a47f5SMiklos Szeredi return splice_write(pipe, out, ppos, len, flags); 11165274f052SJens Axboe } 11175274f052SJens Axboe 111883f9135bSJens Axboe /* 111983f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 112083f9135bSJens Axboe */ 1121cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 1122cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 1123cbb7e577SJens Axboe unsigned int flags) 11245274f052SJens Axboe { 11256818173bSMiklos Szeredi ssize_t (*splice_read)(struct file *, loff_t *, 11266818173bSMiklos Szeredi struct pipe_inode_info *, size_t, unsigned int); 11275274f052SJens Axboe int ret; 11285274f052SJens Axboe 112949570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 11305274f052SJens Axboe return -EBADF; 11315274f052SJens Axboe 1132cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 11335274f052SJens Axboe if (unlikely(ret < 0)) 11345274f052SJens Axboe return ret; 11355274f052SJens Axboe 1136cc56f7deSChangli Gao if (in->f_op && in->f_op->splice_read) 11376818173bSMiklos Szeredi splice_read = in->f_op->splice_read; 1138cc56f7deSChangli Gao else 11396818173bSMiklos Szeredi splice_read = default_file_splice_read; 11406818173bSMiklos Szeredi 11416818173bSMiklos Szeredi return splice_read(in, ppos, pipe, len, flags); 11425274f052SJens Axboe } 11435274f052SJens Axboe 1144932cc6d4SJens Axboe /** 1145932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 1146932cc6d4SJens Axboe * @in: file to splice from 1147932cc6d4SJens Axboe * @sd: actor information on where to splice to 1148932cc6d4SJens Axboe * @actor: handles the data splicing 1149932cc6d4SJens Axboe * 1150932cc6d4SJens Axboe * Description: 1151932cc6d4SJens Axboe * This is a special case helper to splice directly between two 1152932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 1153932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 1154932cc6d4SJens Axboe * that process. 1155932cc6d4SJens Axboe * 1156c66ab6faSJens Axboe */ 1157c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 1158c66ab6faSJens Axboe splice_direct_actor *actor) 1159b92ce558SJens Axboe { 1160b92ce558SJens Axboe struct pipe_inode_info *pipe; 1161b92ce558SJens Axboe long ret, bytes; 1162b92ce558SJens Axboe umode_t i_mode; 1163c66ab6faSJens Axboe size_t len; 1164c66ab6faSJens Axboe int i, flags; 1165b92ce558SJens Axboe 1166b92ce558SJens Axboe /* 1167b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 1168b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 1169b92ce558SJens Axboe * piped splicing for that! 1170b92ce558SJens Axboe */ 11710f7fc9e4SJosef "Jeff" Sipek i_mode = in->f_path.dentry->d_inode->i_mode; 1172b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 1173b92ce558SJens Axboe return -EINVAL; 1174b92ce558SJens Axboe 1175b92ce558SJens Axboe /* 1176b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 1177b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 1178b92ce558SJens Axboe */ 1179b92ce558SJens Axboe pipe = current->splice_pipe; 118049570e9bSJens Axboe if (unlikely(!pipe)) { 1181b92ce558SJens Axboe pipe = alloc_pipe_info(NULL); 1182b92ce558SJens Axboe if (!pipe) 1183b92ce558SJens Axboe return -ENOMEM; 1184b92ce558SJens Axboe 1185b92ce558SJens Axboe /* 1186b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 118700522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 1188b92ce558SJens Axboe * PIPE_READERS appropriately. 1189b92ce558SJens Axboe */ 1190b92ce558SJens Axboe pipe->readers = 1; 1191b92ce558SJens Axboe 1192b92ce558SJens Axboe current->splice_pipe = pipe; 1193b92ce558SJens Axboe } 1194b92ce558SJens Axboe 1195b92ce558SJens Axboe /* 119673d62d83SIngo Molnar * Do the splice. 1197b92ce558SJens Axboe */ 1198b92ce558SJens Axboe ret = 0; 1199b92ce558SJens Axboe bytes = 0; 1200c66ab6faSJens Axboe len = sd->total_len; 1201c66ab6faSJens Axboe flags = sd->flags; 1202c66ab6faSJens Axboe 1203c66ab6faSJens Axboe /* 1204c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 1205c66ab6faSJens Axboe */ 1206c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 1207b92ce558SJens Axboe 1208b92ce558SJens Axboe while (len) { 120951a92c0fSJens Axboe size_t read_len; 1210a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 1211b92ce558SJens Axboe 1212bcd4f3acSJens Axboe ret = do_splice_to(in, &pos, pipe, len, flags); 121351a92c0fSJens Axboe if (unlikely(ret <= 0)) 1214b92ce558SJens Axboe goto out_release; 1215b92ce558SJens Axboe 1216b92ce558SJens Axboe read_len = ret; 1217c66ab6faSJens Axboe sd->total_len = read_len; 1218b92ce558SJens Axboe 1219b92ce558SJens Axboe /* 1220b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1221b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1222b92ce558SJens Axboe * could get stuck data in the internal pipe: 1223b92ce558SJens Axboe */ 1224c66ab6faSJens Axboe ret = actor(pipe, sd); 1225a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 1226a82c53a0STom Zanussi sd->pos = prev_pos; 1227b92ce558SJens Axboe goto out_release; 1228a82c53a0STom Zanussi } 1229b92ce558SJens Axboe 1230b92ce558SJens Axboe bytes += ret; 1231b92ce558SJens Axboe len -= ret; 1232bcd4f3acSJens Axboe sd->pos = pos; 1233b92ce558SJens Axboe 1234a82c53a0STom Zanussi if (ret < read_len) { 1235a82c53a0STom Zanussi sd->pos = prev_pos + ret; 123651a92c0fSJens Axboe goto out_release; 1237b92ce558SJens Axboe } 1238a82c53a0STom Zanussi } 1239b92ce558SJens Axboe 12409e97198dSJens Axboe done: 1241b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 12429e97198dSJens Axboe file_accessed(in); 1243b92ce558SJens Axboe return bytes; 1244b92ce558SJens Axboe 1245b92ce558SJens Axboe out_release: 1246b92ce558SJens Axboe /* 1247b92ce558SJens Axboe * If we did an incomplete transfer we must release 1248b92ce558SJens Axboe * the pipe buffers in question: 1249b92ce558SJens Axboe */ 125035f3d14dSJens Axboe for (i = 0; i < pipe->buffers; i++) { 1251b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1252b92ce558SJens Axboe 1253b92ce558SJens Axboe if (buf->ops) { 1254b92ce558SJens Axboe buf->ops->release(pipe, buf); 1255b92ce558SJens Axboe buf->ops = NULL; 1256b92ce558SJens Axboe } 1257b92ce558SJens Axboe } 1258b92ce558SJens Axboe 12599e97198dSJens Axboe if (!bytes) 12609e97198dSJens Axboe bytes = ret; 1261b92ce558SJens Axboe 12629e97198dSJens Axboe goto done; 1263c66ab6faSJens Axboe } 1264c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1265c66ab6faSJens Axboe 1266c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1267c66ab6faSJens Axboe struct splice_desc *sd) 1268c66ab6faSJens Axboe { 12696a14b90bSJens Axboe struct file *file = sd->u.file; 1270c66ab6faSJens Axboe 12712cb4b05eSChangli Gao return do_splice_from(pipe, file, &file->f_pos, sd->total_len, 12722cb4b05eSChangli Gao sd->flags); 1273c66ab6faSJens Axboe } 1274c66ab6faSJens Axboe 1275932cc6d4SJens Axboe /** 1276932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1277932cc6d4SJens Axboe * @in: file to splice from 1278932cc6d4SJens Axboe * @ppos: input file offset 1279932cc6d4SJens Axboe * @out: file to splice to 1280932cc6d4SJens Axboe * @len: number of bytes to splice 1281932cc6d4SJens Axboe * @flags: splice modifier flags 1282932cc6d4SJens Axboe * 1283932cc6d4SJens Axboe * Description: 1284932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1285932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1286932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1287932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1288932cc6d4SJens Axboe * 1289932cc6d4SJens Axboe */ 1290c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 1291c66ab6faSJens Axboe size_t len, unsigned int flags) 1292c66ab6faSJens Axboe { 1293c66ab6faSJens Axboe struct splice_desc sd = { 1294c66ab6faSJens Axboe .len = len, 1295c66ab6faSJens Axboe .total_len = len, 1296c66ab6faSJens Axboe .flags = flags, 1297c66ab6faSJens Axboe .pos = *ppos, 12986a14b90bSJens Axboe .u.file = out, 1299c66ab6faSJens Axboe }; 130051a92c0fSJens Axboe long ret; 1301c66ab6faSJens Axboe 1302c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 130351a92c0fSJens Axboe if (ret > 0) 1304a82c53a0STom Zanussi *ppos = sd.pos; 130551a92c0fSJens Axboe 1306c66ab6faSJens Axboe return ret; 1307b92ce558SJens Axboe } 1308b92ce558SJens Axboe 13097c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 13107c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 13117c77f0b3SMiklos Szeredi size_t len, unsigned int flags); 1312ddac0d39SJens Axboe 1313ddac0d39SJens Axboe /* 131483f9135bSJens Axboe * Determine where to splice to/from. 131583f9135bSJens Axboe */ 1316529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1317529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1318529565dcSIngo Molnar size_t len, unsigned int flags) 13195274f052SJens Axboe { 13207c77f0b3SMiklos Szeredi struct pipe_inode_info *ipipe; 13217c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe; 1322cbb7e577SJens Axboe loff_t offset, *off; 1323a4514ebdSJens Axboe long ret; 13245274f052SJens Axboe 132571993e62SLinus Torvalds ipipe = get_pipe_info(in); 132671993e62SLinus Torvalds opipe = get_pipe_info(out); 13277c77f0b3SMiklos Szeredi 13287c77f0b3SMiklos Szeredi if (ipipe && opipe) { 13297c77f0b3SMiklos Szeredi if (off_in || off_out) 13307c77f0b3SMiklos Szeredi return -ESPIPE; 13317c77f0b3SMiklos Szeredi 13327c77f0b3SMiklos Szeredi if (!(in->f_mode & FMODE_READ)) 13337c77f0b3SMiklos Szeredi return -EBADF; 13347c77f0b3SMiklos Szeredi 13357c77f0b3SMiklos Szeredi if (!(out->f_mode & FMODE_WRITE)) 13367c77f0b3SMiklos Szeredi return -EBADF; 13377c77f0b3SMiklos Szeredi 13387c77f0b3SMiklos Szeredi /* Splicing to self would be fun, but... */ 13397c77f0b3SMiklos Szeredi if (ipipe == opipe) 13407c77f0b3SMiklos Szeredi return -EINVAL; 13417c77f0b3SMiklos Szeredi 13427c77f0b3SMiklos Szeredi return splice_pipe_to_pipe(ipipe, opipe, len, flags); 13437c77f0b3SMiklos Szeredi } 13447c77f0b3SMiklos Szeredi 13457c77f0b3SMiklos Szeredi if (ipipe) { 1346529565dcSIngo Molnar if (off_in) 1347529565dcSIngo Molnar return -ESPIPE; 1348b92ce558SJens Axboe if (off_out) { 134919c9a49bSChangli Gao if (!(out->f_mode & FMODE_PWRITE)) 1350b92ce558SJens Axboe return -EINVAL; 1351cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1352b92ce558SJens Axboe return -EFAULT; 1353cbb7e577SJens Axboe off = &offset; 1354cbb7e577SJens Axboe } else 1355cbb7e577SJens Axboe off = &out->f_pos; 1356529565dcSIngo Molnar 13577c77f0b3SMiklos Szeredi ret = do_splice_from(ipipe, out, off, len, flags); 1358a4514ebdSJens Axboe 1359a4514ebdSJens Axboe if (off_out && copy_to_user(off_out, off, sizeof(loff_t))) 1360a4514ebdSJens Axboe ret = -EFAULT; 1361a4514ebdSJens Axboe 1362a4514ebdSJens Axboe return ret; 1363529565dcSIngo Molnar } 13645274f052SJens Axboe 13657c77f0b3SMiklos Szeredi if (opipe) { 1366529565dcSIngo Molnar if (off_out) 1367529565dcSIngo Molnar return -ESPIPE; 1368b92ce558SJens Axboe if (off_in) { 136919c9a49bSChangli Gao if (!(in->f_mode & FMODE_PREAD)) 1370b92ce558SJens Axboe return -EINVAL; 1371cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1372b92ce558SJens Axboe return -EFAULT; 1373cbb7e577SJens Axboe off = &offset; 1374cbb7e577SJens Axboe } else 1375cbb7e577SJens Axboe off = &in->f_pos; 1376529565dcSIngo Molnar 13777c77f0b3SMiklos Szeredi ret = do_splice_to(in, off, opipe, len, flags); 1378a4514ebdSJens Axboe 1379a4514ebdSJens Axboe if (off_in && copy_to_user(off_in, off, sizeof(loff_t))) 1380a4514ebdSJens Axboe ret = -EFAULT; 1381a4514ebdSJens Axboe 1382a4514ebdSJens Axboe return ret; 1383529565dcSIngo Molnar } 13845274f052SJens Axboe 13855274f052SJens Axboe return -EINVAL; 13865274f052SJens Axboe } 13875274f052SJens Axboe 1388912d35f8SJens Axboe /* 1389912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1390912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1391912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1392912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1393912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1394912d35f8SJens Axboe */ 1395912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1396912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 1397bd1a68b5SEric Dumazet struct partial_page *partial, bool aligned, 139835f3d14dSJens Axboe unsigned int pipe_buffers) 1399912d35f8SJens Axboe { 1400912d35f8SJens Axboe int buffers = 0, error = 0; 1401912d35f8SJens Axboe 1402912d35f8SJens Axboe while (nr_vecs) { 1403912d35f8SJens Axboe unsigned long off, npages; 140475723957SLinus Torvalds struct iovec entry; 1405912d35f8SJens Axboe void __user *base; 1406912d35f8SJens Axboe size_t len; 1407912d35f8SJens Axboe int i; 1408912d35f8SJens Axboe 140975723957SLinus Torvalds error = -EFAULT; 1410bc40d73cSNick Piggin if (copy_from_user(&entry, iov, sizeof(entry))) 1411912d35f8SJens Axboe break; 141275723957SLinus Torvalds 141375723957SLinus Torvalds base = entry.iov_base; 141475723957SLinus Torvalds len = entry.iov_len; 1415912d35f8SJens Axboe 1416912d35f8SJens Axboe /* 1417912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1418912d35f8SJens Axboe */ 141975723957SLinus Torvalds error = 0; 1420912d35f8SJens Axboe if (unlikely(!len)) 1421912d35f8SJens Axboe break; 1422912d35f8SJens Axboe error = -EFAULT; 1423712a30e6SBastian Blank if (!access_ok(VERIFY_READ, base, len)) 1424912d35f8SJens Axboe break; 1425912d35f8SJens Axboe 1426912d35f8SJens Axboe /* 1427912d35f8SJens Axboe * Get this base offset and number of pages, then map 1428912d35f8SJens Axboe * in the user pages. 1429912d35f8SJens Axboe */ 1430912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 14317afa6fd0SJens Axboe 14327afa6fd0SJens Axboe /* 14337afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 14347afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 14357afa6fd0SJens Axboe */ 14367afa6fd0SJens Axboe error = -EINVAL; 14377afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 14387afa6fd0SJens Axboe break; 14397afa6fd0SJens Axboe 1440912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 144135f3d14dSJens Axboe if (npages > pipe_buffers - buffers) 144235f3d14dSJens Axboe npages = pipe_buffers - buffers; 1443912d35f8SJens Axboe 1444bc40d73cSNick Piggin error = get_user_pages_fast((unsigned long)base, npages, 1445bc40d73cSNick Piggin 0, &pages[buffers]); 1446912d35f8SJens Axboe 1447912d35f8SJens Axboe if (unlikely(error <= 0)) 1448912d35f8SJens Axboe break; 1449912d35f8SJens Axboe 1450912d35f8SJens Axboe /* 1451912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1452912d35f8SJens Axboe */ 1453912d35f8SJens Axboe for (i = 0; i < error; i++) { 14547591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1455912d35f8SJens Axboe 1456912d35f8SJens Axboe partial[buffers].offset = off; 1457912d35f8SJens Axboe partial[buffers].len = plen; 1458912d35f8SJens Axboe 1459912d35f8SJens Axboe off = 0; 1460912d35f8SJens Axboe len -= plen; 1461912d35f8SJens Axboe buffers++; 1462912d35f8SJens Axboe } 1463912d35f8SJens Axboe 1464912d35f8SJens Axboe /* 1465912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1466912d35f8SJens Axboe * means we have to move some of this into a pipe to 1467912d35f8SJens Axboe * be able to continue. 1468912d35f8SJens Axboe */ 1469912d35f8SJens Axboe if (len) 1470912d35f8SJens Axboe break; 1471912d35f8SJens Axboe 1472912d35f8SJens Axboe /* 1473912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1474912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1475912d35f8SJens Axboe * room for. 1476912d35f8SJens Axboe */ 147735f3d14dSJens Axboe if (error < npages || buffers == pipe_buffers) 1478912d35f8SJens Axboe break; 1479912d35f8SJens Axboe 1480912d35f8SJens Axboe nr_vecs--; 1481912d35f8SJens Axboe iov++; 1482912d35f8SJens Axboe } 1483912d35f8SJens Axboe 1484912d35f8SJens Axboe if (buffers) 1485912d35f8SJens Axboe return buffers; 1486912d35f8SJens Axboe 1487912d35f8SJens Axboe return error; 1488912d35f8SJens Axboe } 1489912d35f8SJens Axboe 14906a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 14916a14b90bSJens Axboe struct splice_desc *sd) 14926a14b90bSJens Axboe { 14936a14b90bSJens Axboe char *src; 14946a14b90bSJens Axboe int ret; 14956a14b90bSJens Axboe 14966a14b90bSJens Axboe /* 14976a14b90bSJens Axboe * See if we can use the atomic maps, by prefaulting in the 14986a14b90bSJens Axboe * pages and doing an atomic copy 14996a14b90bSJens Axboe */ 15006a14b90bSJens Axboe if (!fault_in_pages_writeable(sd->u.userptr, sd->len)) { 15016a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 1); 15026a14b90bSJens Axboe ret = __copy_to_user_inatomic(sd->u.userptr, src + buf->offset, 15036a14b90bSJens Axboe sd->len); 15046a14b90bSJens Axboe buf->ops->unmap(pipe, buf, src); 15056a14b90bSJens Axboe if (!ret) { 15066a14b90bSJens Axboe ret = sd->len; 15076a14b90bSJens Axboe goto out; 15086a14b90bSJens Axboe } 15096a14b90bSJens Axboe } 15106a14b90bSJens Axboe 15116a14b90bSJens Axboe /* 15126a14b90bSJens Axboe * No dice, use slow non-atomic map and copy 15136a14b90bSJens Axboe */ 15146a14b90bSJens Axboe src = buf->ops->map(pipe, buf, 0); 15156a14b90bSJens Axboe 15166a14b90bSJens Axboe ret = sd->len; 15176a14b90bSJens Axboe if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len)) 15186a14b90bSJens Axboe ret = -EFAULT; 15196a14b90bSJens Axboe 15206866bef4SJens Axboe buf->ops->unmap(pipe, buf, src); 15216a14b90bSJens Axboe out: 15226a14b90bSJens Axboe if (ret > 0) 15236a14b90bSJens Axboe sd->u.userptr += ret; 15246a14b90bSJens Axboe return ret; 15256a14b90bSJens Axboe } 15266a14b90bSJens Axboe 15276a14b90bSJens Axboe /* 15286a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 15296a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 15306a14b90bSJens Axboe */ 15316a14b90bSJens Axboe static long vmsplice_to_user(struct file *file, const struct iovec __user *iov, 15326a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 15336a14b90bSJens Axboe { 15346a14b90bSJens Axboe struct pipe_inode_info *pipe; 15356a14b90bSJens Axboe struct splice_desc sd; 15366a14b90bSJens Axboe ssize_t size; 15376a14b90bSJens Axboe int error; 15386a14b90bSJens Axboe long ret; 15396a14b90bSJens Axboe 154071993e62SLinus Torvalds pipe = get_pipe_info(file); 15416a14b90bSJens Axboe if (!pipe) 15426a14b90bSJens Axboe return -EBADF; 15436a14b90bSJens Axboe 154461e0d47cSMiklos Szeredi pipe_lock(pipe); 15456a14b90bSJens Axboe 15466a14b90bSJens Axboe error = ret = 0; 15476a14b90bSJens Axboe while (nr_segs) { 15486a14b90bSJens Axboe void __user *base; 15496a14b90bSJens Axboe size_t len; 15506a14b90bSJens Axboe 15516a14b90bSJens Axboe /* 15526a14b90bSJens Axboe * Get user address base and length for this iovec. 15536a14b90bSJens Axboe */ 15546a14b90bSJens Axboe error = get_user(base, &iov->iov_base); 15556a14b90bSJens Axboe if (unlikely(error)) 15566a14b90bSJens Axboe break; 15576a14b90bSJens Axboe error = get_user(len, &iov->iov_len); 15586a14b90bSJens Axboe if (unlikely(error)) 15596a14b90bSJens Axboe break; 15606a14b90bSJens Axboe 15616a14b90bSJens Axboe /* 15626a14b90bSJens Axboe * Sanity check this iovec. 0 read succeeds. 15636a14b90bSJens Axboe */ 15646a14b90bSJens Axboe if (unlikely(!len)) 15656a14b90bSJens Axboe break; 15666a14b90bSJens Axboe if (unlikely(!base)) { 15676a14b90bSJens Axboe error = -EFAULT; 15686a14b90bSJens Axboe break; 15696a14b90bSJens Axboe } 15706a14b90bSJens Axboe 15718811930dSJens Axboe if (unlikely(!access_ok(VERIFY_WRITE, base, len))) { 15728811930dSJens Axboe error = -EFAULT; 15738811930dSJens Axboe break; 15748811930dSJens Axboe } 15758811930dSJens Axboe 15766a14b90bSJens Axboe sd.len = 0; 15776a14b90bSJens Axboe sd.total_len = len; 15786a14b90bSJens Axboe sd.flags = flags; 15796a14b90bSJens Axboe sd.u.userptr = base; 15806a14b90bSJens Axboe sd.pos = 0; 15816a14b90bSJens Axboe 15826a14b90bSJens Axboe size = __splice_from_pipe(pipe, &sd, pipe_to_user); 15836a14b90bSJens Axboe if (size < 0) { 15846a14b90bSJens Axboe if (!ret) 15856a14b90bSJens Axboe ret = size; 15866a14b90bSJens Axboe 15876a14b90bSJens Axboe break; 15886a14b90bSJens Axboe } 15896a14b90bSJens Axboe 15906a14b90bSJens Axboe ret += size; 15916a14b90bSJens Axboe 15926a14b90bSJens Axboe if (size < len) 15936a14b90bSJens Axboe break; 15946a14b90bSJens Axboe 15956a14b90bSJens Axboe nr_segs--; 15966a14b90bSJens Axboe iov++; 15976a14b90bSJens Axboe } 15986a14b90bSJens Axboe 159961e0d47cSMiklos Szeredi pipe_unlock(pipe); 16006a14b90bSJens Axboe 16016a14b90bSJens Axboe if (!ret) 16026a14b90bSJens Axboe ret = error; 16036a14b90bSJens Axboe 16046a14b90bSJens Axboe return ret; 16056a14b90bSJens Axboe } 16066a14b90bSJens Axboe 1607912d35f8SJens Axboe /* 1608912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1609912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1610912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1611912d35f8SJens Axboe */ 16126a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1613912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1614912d35f8SJens Axboe { 1615ddac0d39SJens Axboe struct pipe_inode_info *pipe; 161635f3d14dSJens Axboe struct page *pages[PIPE_DEF_BUFFERS]; 161735f3d14dSJens Axboe struct partial_page partial[PIPE_DEF_BUFFERS]; 1618912d35f8SJens Axboe struct splice_pipe_desc spd = { 1619912d35f8SJens Axboe .pages = pages, 1620912d35f8SJens Axboe .partial = partial, 1621047fe360SEric Dumazet .nr_pages_max = PIPE_DEF_BUFFERS, 1622912d35f8SJens Axboe .flags = flags, 1623912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1624bbdfc2f7SJens Axboe .spd_release = spd_release_page, 1625912d35f8SJens Axboe }; 162635f3d14dSJens Axboe long ret; 1627912d35f8SJens Axboe 162871993e62SLinus Torvalds pipe = get_pipe_info(file); 1629ddac0d39SJens Axboe if (!pipe) 1630912d35f8SJens Axboe return -EBADF; 1631912d35f8SJens Axboe 163235f3d14dSJens Axboe if (splice_grow_spd(pipe, &spd)) 163335f3d14dSJens Axboe return -ENOMEM; 1634912d35f8SJens Axboe 163535f3d14dSJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, spd.pages, 1636bd1a68b5SEric Dumazet spd.partial, false, 1637047fe360SEric Dumazet spd.nr_pages_max); 163835f3d14dSJens Axboe if (spd.nr_pages <= 0) 163935f3d14dSJens Axboe ret = spd.nr_pages; 164035f3d14dSJens Axboe else 164135f3d14dSJens Axboe ret = splice_to_pipe(pipe, &spd); 164235f3d14dSJens Axboe 1643047fe360SEric Dumazet splice_shrink_spd(&spd); 164435f3d14dSJens Axboe return ret; 1645912d35f8SJens Axboe } 1646912d35f8SJens Axboe 16476a14b90bSJens Axboe /* 16486a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 16496a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 16506a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 16516a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 16526a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 16536a14b90bSJens Axboe * solutions for that: 16546a14b90bSJens Axboe * 16556a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 16566a14b90bSJens Axboe * do a regular read() on the buffer anyway. 16576a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 16586a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 16596a14b90bSJens Axboe * 16606a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 16616a14b90bSJens Axboe * 16626a14b90bSJens Axboe */ 1663836f92adSHeiko Carstens SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, iov, 1664836f92adSHeiko Carstens unsigned long, nr_segs, unsigned int, flags) 1665912d35f8SJens Axboe { 16662903ff01SAl Viro struct fd f; 1667912d35f8SJens Axboe long error; 1668912d35f8SJens Axboe 16696a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 16706a14b90bSJens Axboe return -EINVAL; 16716a14b90bSJens Axboe else if (unlikely(!nr_segs)) 16726a14b90bSJens Axboe return 0; 16736a14b90bSJens Axboe 1674912d35f8SJens Axboe error = -EBADF; 16752903ff01SAl Viro f = fdget(fd); 16762903ff01SAl Viro if (f.file) { 16772903ff01SAl Viro if (f.file->f_mode & FMODE_WRITE) 16782903ff01SAl Viro error = vmsplice_to_pipe(f.file, iov, nr_segs, flags); 16792903ff01SAl Viro else if (f.file->f_mode & FMODE_READ) 16802903ff01SAl Viro error = vmsplice_to_user(f.file, iov, nr_segs, flags); 1681912d35f8SJens Axboe 16822903ff01SAl Viro fdput(f); 1683912d35f8SJens Axboe } 1684912d35f8SJens Axboe 1685912d35f8SJens Axboe return error; 1686912d35f8SJens Axboe } 1687912d35f8SJens Axboe 1688836f92adSHeiko Carstens SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, 1689836f92adSHeiko Carstens int, fd_out, loff_t __user *, off_out, 1690836f92adSHeiko Carstens size_t, len, unsigned int, flags) 16915274f052SJens Axboe { 16922903ff01SAl Viro struct fd in, out; 16935274f052SJens Axboe long error; 16945274f052SJens Axboe 16955274f052SJens Axboe if (unlikely(!len)) 16965274f052SJens Axboe return 0; 16975274f052SJens Axboe 16985274f052SJens Axboe error = -EBADF; 16992903ff01SAl Viro in = fdget(fd_in); 17002903ff01SAl Viro if (in.file) { 17012903ff01SAl Viro if (in.file->f_mode & FMODE_READ) { 17022903ff01SAl Viro out = fdget(fd_out); 17032903ff01SAl Viro if (out.file) { 17042903ff01SAl Viro if (out.file->f_mode & FMODE_WRITE) 17052903ff01SAl Viro error = do_splice(in.file, off_in, 17062903ff01SAl Viro out.file, off_out, 1707529565dcSIngo Molnar len, flags); 17082903ff01SAl Viro fdput(out); 17095274f052SJens Axboe } 17105274f052SJens Axboe } 17112903ff01SAl Viro fdput(in); 17125274f052SJens Axboe } 17135274f052SJens Axboe return error; 17145274f052SJens Axboe } 171570524490SJens Axboe 171670524490SJens Axboe /* 1717aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1718aadd06e5SJens Axboe * return an appropriate error. 1719aadd06e5SJens Axboe */ 17207c77f0b3SMiklos Szeredi static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1721aadd06e5SJens Axboe { 1722aadd06e5SJens Axboe int ret; 1723aadd06e5SJens Axboe 1724aadd06e5SJens Axboe /* 1725aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1726aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1727aadd06e5SJens Axboe */ 1728aadd06e5SJens Axboe if (pipe->nrbufs) 1729aadd06e5SJens Axboe return 0; 1730aadd06e5SJens Axboe 1731aadd06e5SJens Axboe ret = 0; 173261e0d47cSMiklos Szeredi pipe_lock(pipe); 1733aadd06e5SJens Axboe 1734aadd06e5SJens Axboe while (!pipe->nrbufs) { 1735aadd06e5SJens Axboe if (signal_pending(current)) { 1736aadd06e5SJens Axboe ret = -ERESTARTSYS; 1737aadd06e5SJens Axboe break; 1738aadd06e5SJens Axboe } 1739aadd06e5SJens Axboe if (!pipe->writers) 1740aadd06e5SJens Axboe break; 1741aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1742aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1743aadd06e5SJens Axboe ret = -EAGAIN; 1744aadd06e5SJens Axboe break; 1745aadd06e5SJens Axboe } 1746aadd06e5SJens Axboe } 1747aadd06e5SJens Axboe pipe_wait(pipe); 1748aadd06e5SJens Axboe } 1749aadd06e5SJens Axboe 175061e0d47cSMiklos Szeredi pipe_unlock(pipe); 1751aadd06e5SJens Axboe return ret; 1752aadd06e5SJens Axboe } 1753aadd06e5SJens Axboe 1754aadd06e5SJens Axboe /* 1755aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1756aadd06e5SJens Axboe * return an appropriate error. 1757aadd06e5SJens Axboe */ 17587c77f0b3SMiklos Szeredi static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1759aadd06e5SJens Axboe { 1760aadd06e5SJens Axboe int ret; 1761aadd06e5SJens Axboe 1762aadd06e5SJens Axboe /* 1763aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1764aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1765aadd06e5SJens Axboe */ 176635f3d14dSJens Axboe if (pipe->nrbufs < pipe->buffers) 1767aadd06e5SJens Axboe return 0; 1768aadd06e5SJens Axboe 1769aadd06e5SJens Axboe ret = 0; 177061e0d47cSMiklos Szeredi pipe_lock(pipe); 1771aadd06e5SJens Axboe 177235f3d14dSJens Axboe while (pipe->nrbufs >= pipe->buffers) { 1773aadd06e5SJens Axboe if (!pipe->readers) { 1774aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1775aadd06e5SJens Axboe ret = -EPIPE; 1776aadd06e5SJens Axboe break; 1777aadd06e5SJens Axboe } 1778aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1779aadd06e5SJens Axboe ret = -EAGAIN; 1780aadd06e5SJens Axboe break; 1781aadd06e5SJens Axboe } 1782aadd06e5SJens Axboe if (signal_pending(current)) { 1783aadd06e5SJens Axboe ret = -ERESTARTSYS; 1784aadd06e5SJens Axboe break; 1785aadd06e5SJens Axboe } 1786aadd06e5SJens Axboe pipe->waiting_writers++; 1787aadd06e5SJens Axboe pipe_wait(pipe); 1788aadd06e5SJens Axboe pipe->waiting_writers--; 1789aadd06e5SJens Axboe } 1790aadd06e5SJens Axboe 179161e0d47cSMiklos Szeredi pipe_unlock(pipe); 1792aadd06e5SJens Axboe return ret; 1793aadd06e5SJens Axboe } 1794aadd06e5SJens Axboe 1795aadd06e5SJens Axboe /* 17967c77f0b3SMiklos Szeredi * Splice contents of ipipe to opipe. 17977c77f0b3SMiklos Szeredi */ 17987c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 17997c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 18007c77f0b3SMiklos Szeredi size_t len, unsigned int flags) 18017c77f0b3SMiklos Szeredi { 18027c77f0b3SMiklos Szeredi struct pipe_buffer *ibuf, *obuf; 18037c77f0b3SMiklos Szeredi int ret = 0, nbuf; 18047c77f0b3SMiklos Szeredi bool input_wakeup = false; 18057c77f0b3SMiklos Szeredi 18067c77f0b3SMiklos Szeredi 18077c77f0b3SMiklos Szeredi retry: 18087c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 18097c77f0b3SMiklos Szeredi if (ret) 18107c77f0b3SMiklos Szeredi return ret; 18117c77f0b3SMiklos Szeredi 18127c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 18137c77f0b3SMiklos Szeredi if (ret) 18147c77f0b3SMiklos Szeredi return ret; 18157c77f0b3SMiklos Szeredi 18167c77f0b3SMiklos Szeredi /* 18177c77f0b3SMiklos Szeredi * Potential ABBA deadlock, work around it by ordering lock 18187c77f0b3SMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 18197c77f0b3SMiklos Szeredi * could deadlock (one doing tee from A -> B, the other from B -> A). 18207c77f0b3SMiklos Szeredi */ 18217c77f0b3SMiklos Szeredi pipe_double_lock(ipipe, opipe); 18227c77f0b3SMiklos Szeredi 18237c77f0b3SMiklos Szeredi do { 18247c77f0b3SMiklos Szeredi if (!opipe->readers) { 18257c77f0b3SMiklos Szeredi send_sig(SIGPIPE, current, 0); 18267c77f0b3SMiklos Szeredi if (!ret) 18277c77f0b3SMiklos Szeredi ret = -EPIPE; 18287c77f0b3SMiklos Szeredi break; 18297c77f0b3SMiklos Szeredi } 18307c77f0b3SMiklos Szeredi 18317c77f0b3SMiklos Szeredi if (!ipipe->nrbufs && !ipipe->writers) 18327c77f0b3SMiklos Szeredi break; 18337c77f0b3SMiklos Szeredi 18347c77f0b3SMiklos Szeredi /* 18357c77f0b3SMiklos Szeredi * Cannot make any progress, because either the input 18367c77f0b3SMiklos Szeredi * pipe is empty or the output pipe is full. 18377c77f0b3SMiklos Szeredi */ 183835f3d14dSJens Axboe if (!ipipe->nrbufs || opipe->nrbufs >= opipe->buffers) { 18397c77f0b3SMiklos Szeredi /* Already processed some buffers, break */ 18407c77f0b3SMiklos Szeredi if (ret) 18417c77f0b3SMiklos Szeredi break; 18427c77f0b3SMiklos Szeredi 18437c77f0b3SMiklos Szeredi if (flags & SPLICE_F_NONBLOCK) { 18447c77f0b3SMiklos Szeredi ret = -EAGAIN; 18457c77f0b3SMiklos Szeredi break; 18467c77f0b3SMiklos Szeredi } 18477c77f0b3SMiklos Szeredi 18487c77f0b3SMiklos Szeredi /* 18497c77f0b3SMiklos Szeredi * We raced with another reader/writer and haven't 18507c77f0b3SMiklos Szeredi * managed to process any buffers. A zero return 18517c77f0b3SMiklos Szeredi * value means EOF, so retry instead. 18527c77f0b3SMiklos Szeredi */ 18537c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 18547c77f0b3SMiklos Szeredi pipe_unlock(opipe); 18557c77f0b3SMiklos Szeredi goto retry; 18567c77f0b3SMiklos Szeredi } 18577c77f0b3SMiklos Szeredi 18587c77f0b3SMiklos Szeredi ibuf = ipipe->bufs + ipipe->curbuf; 185935f3d14dSJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (opipe->buffers - 1); 18607c77f0b3SMiklos Szeredi obuf = opipe->bufs + nbuf; 18617c77f0b3SMiklos Szeredi 18627c77f0b3SMiklos Szeredi if (len >= ibuf->len) { 18637c77f0b3SMiklos Szeredi /* 18647c77f0b3SMiklos Szeredi * Simply move the whole buffer from ipipe to opipe 18657c77f0b3SMiklos Szeredi */ 18667c77f0b3SMiklos Szeredi *obuf = *ibuf; 18677c77f0b3SMiklos Szeredi ibuf->ops = NULL; 18687c77f0b3SMiklos Szeredi opipe->nrbufs++; 186935f3d14dSJens Axboe ipipe->curbuf = (ipipe->curbuf + 1) & (ipipe->buffers - 1); 18707c77f0b3SMiklos Szeredi ipipe->nrbufs--; 18717c77f0b3SMiklos Szeredi input_wakeup = true; 18727c77f0b3SMiklos Szeredi } else { 18737c77f0b3SMiklos Szeredi /* 18747c77f0b3SMiklos Szeredi * Get a reference to this pipe buffer, 18757c77f0b3SMiklos Szeredi * so we can copy the contents over. 18767c77f0b3SMiklos Szeredi */ 18777c77f0b3SMiklos Szeredi ibuf->ops->get(ipipe, ibuf); 18787c77f0b3SMiklos Szeredi *obuf = *ibuf; 18797c77f0b3SMiklos Szeredi 18807c77f0b3SMiklos Szeredi /* 18817c77f0b3SMiklos Szeredi * Don't inherit the gift flag, we need to 18827c77f0b3SMiklos Szeredi * prevent multiple steals of this page. 18837c77f0b3SMiklos Szeredi */ 18847c77f0b3SMiklos Szeredi obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 18857c77f0b3SMiklos Szeredi 18867c77f0b3SMiklos Szeredi obuf->len = len; 18877c77f0b3SMiklos Szeredi opipe->nrbufs++; 18887c77f0b3SMiklos Szeredi ibuf->offset += obuf->len; 18897c77f0b3SMiklos Szeredi ibuf->len -= obuf->len; 18907c77f0b3SMiklos Szeredi } 18917c77f0b3SMiklos Szeredi ret += obuf->len; 18927c77f0b3SMiklos Szeredi len -= obuf->len; 18937c77f0b3SMiklos Szeredi } while (len); 18947c77f0b3SMiklos Szeredi 18957c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 18967c77f0b3SMiklos Szeredi pipe_unlock(opipe); 18977c77f0b3SMiklos Szeredi 18987c77f0b3SMiklos Szeredi /* 18997c77f0b3SMiklos Szeredi * If we put data in the output pipe, wakeup any potential readers. 19007c77f0b3SMiklos Szeredi */ 1901825cdcb1SNamhyung Kim if (ret > 0) 1902825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 1903825cdcb1SNamhyung Kim 19047c77f0b3SMiklos Szeredi if (input_wakeup) 19057c77f0b3SMiklos Szeredi wakeup_pipe_writers(ipipe); 19067c77f0b3SMiklos Szeredi 19077c77f0b3SMiklos Szeredi return ret; 19087c77f0b3SMiklos Szeredi } 19097c77f0b3SMiklos Szeredi 19107c77f0b3SMiklos Szeredi /* 191170524490SJens Axboe * Link contents of ipipe to opipe. 191270524490SJens Axboe */ 191370524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 191470524490SJens Axboe struct pipe_inode_info *opipe, 191570524490SJens Axboe size_t len, unsigned int flags) 191670524490SJens Axboe { 191770524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1918aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 191970524490SJens Axboe 192070524490SJens Axboe /* 192170524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 192261e0d47cSMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 192370524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 192470524490SJens Axboe */ 192561e0d47cSMiklos Szeredi pipe_double_lock(ipipe, opipe); 192670524490SJens Axboe 1927aadd06e5SJens Axboe do { 192870524490SJens Axboe if (!opipe->readers) { 192970524490SJens Axboe send_sig(SIGPIPE, current, 0); 193070524490SJens Axboe if (!ret) 193170524490SJens Axboe ret = -EPIPE; 193270524490SJens Axboe break; 193370524490SJens Axboe } 193470524490SJens Axboe 193570524490SJens Axboe /* 1936aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1937aadd06e5SJens Axboe * output room, break. 193870524490SJens Axboe */ 193935f3d14dSJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= opipe->buffers) 1940aadd06e5SJens Axboe break; 1941aadd06e5SJens Axboe 194235f3d14dSJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (ipipe->buffers-1)); 194335f3d14dSJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (opipe->buffers - 1); 194470524490SJens Axboe 194570524490SJens Axboe /* 194670524490SJens Axboe * Get a reference to this pipe buffer, 194770524490SJens Axboe * so we can copy the contents over. 194870524490SJens Axboe */ 194970524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 195070524490SJens Axboe 195170524490SJens Axboe obuf = opipe->bufs + nbuf; 195270524490SJens Axboe *obuf = *ibuf; 195370524490SJens Axboe 19547afa6fd0SJens Axboe /* 19557afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 19567afa6fd0SJens Axboe * prevent multiple steals of this page. 19577afa6fd0SJens Axboe */ 19587afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 19597afa6fd0SJens Axboe 196070524490SJens Axboe if (obuf->len > len) 196170524490SJens Axboe obuf->len = len; 196270524490SJens Axboe 196370524490SJens Axboe opipe->nrbufs++; 196470524490SJens Axboe ret += obuf->len; 196570524490SJens Axboe len -= obuf->len; 1966aadd06e5SJens Axboe i++; 1967aadd06e5SJens Axboe } while (len); 196870524490SJens Axboe 196902cf01aeSJens Axboe /* 197002cf01aeSJens Axboe * return EAGAIN if we have the potential of some data in the 197102cf01aeSJens Axboe * future, otherwise just return 0 197202cf01aeSJens Axboe */ 197302cf01aeSJens Axboe if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) 197402cf01aeSJens Axboe ret = -EAGAIN; 197502cf01aeSJens Axboe 197661e0d47cSMiklos Szeredi pipe_unlock(ipipe); 197761e0d47cSMiklos Szeredi pipe_unlock(opipe); 197870524490SJens Axboe 1979aadd06e5SJens Axboe /* 1980aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1981aadd06e5SJens Axboe */ 1982825cdcb1SNamhyung Kim if (ret > 0) 1983825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 198470524490SJens Axboe 198570524490SJens Axboe return ret; 198670524490SJens Axboe } 198770524490SJens Axboe 198870524490SJens Axboe /* 198970524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 199070524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 199170524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 199270524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 199370524490SJens Axboe */ 199470524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 199570524490SJens Axboe unsigned int flags) 199670524490SJens Axboe { 199771993e62SLinus Torvalds struct pipe_inode_info *ipipe = get_pipe_info(in); 199871993e62SLinus Torvalds struct pipe_inode_info *opipe = get_pipe_info(out); 1999aadd06e5SJens Axboe int ret = -EINVAL; 200070524490SJens Axboe 200170524490SJens Axboe /* 2002aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 2003aadd06e5SJens Axboe * copying the data. 200470524490SJens Axboe */ 2005aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 2006aadd06e5SJens Axboe /* 2007aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 2008aadd06e5SJens Axboe * ordering doesn't really matter. 2009aadd06e5SJens Axboe */ 20107c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 2011aadd06e5SJens Axboe if (!ret) { 20127c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 201302cf01aeSJens Axboe if (!ret) 2014aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 2015aadd06e5SJens Axboe } 2016aadd06e5SJens Axboe } 201770524490SJens Axboe 2018aadd06e5SJens Axboe return ret; 201970524490SJens Axboe } 202070524490SJens Axboe 2021836f92adSHeiko Carstens SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) 202270524490SJens Axboe { 20232903ff01SAl Viro struct fd in; 20242903ff01SAl Viro int error; 202570524490SJens Axboe 202670524490SJens Axboe if (unlikely(!len)) 202770524490SJens Axboe return 0; 202870524490SJens Axboe 202970524490SJens Axboe error = -EBADF; 20302903ff01SAl Viro in = fdget(fdin); 20312903ff01SAl Viro if (in.file) { 20322903ff01SAl Viro if (in.file->f_mode & FMODE_READ) { 20332903ff01SAl Viro struct fd out = fdget(fdout); 20342903ff01SAl Viro if (out.file) { 20352903ff01SAl Viro if (out.file->f_mode & FMODE_WRITE) 20362903ff01SAl Viro error = do_tee(in.file, out.file, 20372903ff01SAl Viro len, flags); 20382903ff01SAl Viro fdput(out); 203970524490SJens Axboe } 204070524490SJens Axboe } 20412903ff01SAl Viro fdput(in); 204270524490SJens Axboe } 204370524490SJens Axboe 204470524490SJens Axboe return error; 204570524490SJens Axboe } 2046