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> 3476b021d0SAl Viro #include <linux/compat.h> 3506ae43f3SAl Viro #include "internal.h" 365274f052SJens Axboe 3783f9135bSJens Axboe /* 3883f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 3983f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 4083f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 4183f9135bSJens Axboe * attempt to reuse this page for another destination. 4283f9135bSJens Axboe */ 4376ad4d11SJens Axboe static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, 445abc97aaSJens Axboe struct pipe_buffer *buf) 455abc97aaSJens Axboe { 465abc97aaSJens Axboe struct page *page = buf->page; 479e94cd4fSJens Axboe struct address_space *mapping; 485abc97aaSJens Axboe 499e0267c2SJens Axboe lock_page(page); 509e0267c2SJens Axboe 519e94cd4fSJens Axboe mapping = page_mapping(page); 529e94cd4fSJens Axboe if (mapping) { 535abc97aaSJens Axboe WARN_ON(!PageUptodate(page)); 545abc97aaSJens Axboe 55ad8d6f0aSJens Axboe /* 569e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 579e94cd4fSJens Axboe * writeback completing on this page, since we'll remove it 589e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 599e94cd4fSJens Axboe * page, allowing the disk blocks to be reused by someone else 609e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 619e94cd4fSJens Axboe * ensues. 62ad8d6f0aSJens Axboe */ 63ad8d6f0aSJens Axboe wait_on_page_writeback(page); 64ad8d6f0aSJens Axboe 65266cf658SDavid Howells if (page_has_private(page) && 66266cf658SDavid Howells !try_to_release_page(page, GFP_KERNEL)) 67ca39d651SJens Axboe goto out_unlock; 684f6f0bd2SJens Axboe 699e94cd4fSJens Axboe /* 709e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 719e94cd4fSJens Axboe * and return good. 729e94cd4fSJens Axboe */ 739e94cd4fSJens Axboe if (remove_mapping(mapping, page)) { 741432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 755abc97aaSJens Axboe return 0; 765abc97aaSJens Axboe } 779e94cd4fSJens Axboe } 789e94cd4fSJens Axboe 799e94cd4fSJens Axboe /* 809e94cd4fSJens Axboe * Raced with truncate or failed to remove page from current 819e94cd4fSJens Axboe * address space, unlock and return failure. 829e94cd4fSJens Axboe */ 83ca39d651SJens Axboe out_unlock: 849e94cd4fSJens Axboe unlock_page(page); 859e94cd4fSJens Axboe return 1; 869e94cd4fSJens Axboe } 875abc97aaSJens Axboe 8876ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 895274f052SJens Axboe struct pipe_buffer *buf) 905274f052SJens Axboe { 915274f052SJens Axboe page_cache_release(buf->page); 921432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 935274f052SJens Axboe } 945274f052SJens Axboe 950845718dSJens Axboe /* 960845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 970845718dSJens Axboe * is a page cache page, IO may be in flight. 980845718dSJens Axboe */ 99cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 1005274f052SJens Axboe struct pipe_buffer *buf) 1015274f052SJens Axboe { 1025274f052SJens Axboe struct page *page = buf->page; 10349d0b21bSJens Axboe int err; 1045274f052SJens Axboe 1055274f052SJens Axboe if (!PageUptodate(page)) { 10649d0b21bSJens Axboe lock_page(page); 1075274f052SJens Axboe 10849d0b21bSJens Axboe /* 10949d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 11073d62d83SIngo Molnar * splice, if this is the first page. 11149d0b21bSJens Axboe */ 1125274f052SJens Axboe if (!page->mapping) { 11349d0b21bSJens Axboe err = -ENODATA; 11449d0b21bSJens Axboe goto error; 1155274f052SJens Axboe } 1165274f052SJens Axboe 11749d0b21bSJens Axboe /* 11873d62d83SIngo Molnar * Uh oh, read-error from disk. 11949d0b21bSJens Axboe */ 12049d0b21bSJens Axboe if (!PageUptodate(page)) { 12149d0b21bSJens Axboe err = -EIO; 12249d0b21bSJens Axboe goto error; 12349d0b21bSJens Axboe } 12449d0b21bSJens Axboe 12549d0b21bSJens Axboe /* 126f84d7519SJens Axboe * Page is ok afterall, we are done. 12749d0b21bSJens Axboe */ 12849d0b21bSJens Axboe unlock_page(page); 12949d0b21bSJens Axboe } 13049d0b21bSJens Axboe 131f84d7519SJens Axboe return 0; 13249d0b21bSJens Axboe error: 13349d0b21bSJens Axboe unlock_page(page); 134f84d7519SJens Axboe return err; 13570524490SJens Axboe } 13670524490SJens Axboe 137708e3508SHugh Dickins const struct pipe_buf_operations page_cache_pipe_buf_ops = { 1385274f052SJens Axboe .can_merge = 0, 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, 157cac36bb0SJens Axboe .confirm = generic_pipe_buf_confirm, 158912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 159912d35f8SJens Axboe .steal = user_page_pipe_buf_steal, 160f84d7519SJens Axboe .get = generic_pipe_buf_get, 161912d35f8SJens Axboe }; 162912d35f8SJens Axboe 163825cdcb1SNamhyung Kim static void wakeup_pipe_readers(struct pipe_inode_info *pipe) 164825cdcb1SNamhyung Kim { 165825cdcb1SNamhyung Kim smp_mb(); 166825cdcb1SNamhyung Kim if (waitqueue_active(&pipe->wait)) 167825cdcb1SNamhyung Kim wake_up_interruptible(&pipe->wait); 168825cdcb1SNamhyung Kim kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 169825cdcb1SNamhyung Kim } 170825cdcb1SNamhyung Kim 171932cc6d4SJens Axboe /** 172932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 173932cc6d4SJens Axboe * @pipe: pipe to fill 174932cc6d4SJens Axboe * @spd: data to fill 175932cc6d4SJens Axboe * 176932cc6d4SJens Axboe * Description: 17779685b8dSRandy Dunlap * @spd contains a map of pages and len/offset tuples, along with 178932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 179932cc6d4SJens Axboe * function will link that data to the pipe. 180932cc6d4SJens Axboe * 18183f9135bSJens Axboe */ 182d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 183912d35f8SJens Axboe struct splice_pipe_desc *spd) 1845274f052SJens Axboe { 18500de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 186912d35f8SJens Axboe int ret, do_wakeup, page_nr; 1875274f052SJens Axboe 1885274f052SJens Axboe ret = 0; 1895274f052SJens Axboe do_wakeup = 0; 190912d35f8SJens Axboe page_nr = 0; 1915274f052SJens Axboe 19261e0d47cSMiklos Szeredi pipe_lock(pipe); 1935274f052SJens Axboe 1945274f052SJens Axboe for (;;) { 1953a326a2cSIngo Molnar if (!pipe->readers) { 1965274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1975274f052SJens Axboe if (!ret) 1985274f052SJens Axboe ret = -EPIPE; 1995274f052SJens Axboe break; 2005274f052SJens Axboe } 2015274f052SJens Axboe 20235f3d14dSJens Axboe if (pipe->nrbufs < pipe->buffers) { 20335f3d14dSJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); 2043a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 2055274f052SJens Axboe 206912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 207912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 208912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 209497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 210912d35f8SJens Axboe buf->ops = spd->ops; 2117afa6fd0SJens Axboe if (spd->flags & SPLICE_F_GIFT) 2127afa6fd0SJens Axboe buf->flags |= PIPE_BUF_FLAG_GIFT; 2137afa6fd0SJens Axboe 2146f767b04SJens Axboe pipe->nrbufs++; 215912d35f8SJens Axboe page_nr++; 216912d35f8SJens Axboe ret += buf->len; 217912d35f8SJens Axboe 2186447a3cfSAl Viro if (pipe->files) 2195274f052SJens Axboe do_wakeup = 1; 2205274f052SJens Axboe 221912d35f8SJens Axboe if (!--spd->nr_pages) 2225274f052SJens Axboe break; 22335f3d14dSJens Axboe if (pipe->nrbufs < pipe->buffers) 2245274f052SJens Axboe continue; 2255274f052SJens Axboe 2265274f052SJens Axboe break; 2275274f052SJens Axboe } 2285274f052SJens Axboe 229912d35f8SJens Axboe if (spd->flags & SPLICE_F_NONBLOCK) { 23029e35094SLinus Torvalds if (!ret) 23129e35094SLinus Torvalds ret = -EAGAIN; 23229e35094SLinus Torvalds break; 23329e35094SLinus Torvalds } 23429e35094SLinus Torvalds 2355274f052SJens Axboe if (signal_pending(current)) { 2365274f052SJens Axboe if (!ret) 2375274f052SJens Axboe ret = -ERESTARTSYS; 2385274f052SJens Axboe break; 2395274f052SJens Axboe } 2405274f052SJens Axboe 2415274f052SJens Axboe if (do_wakeup) { 242c0bd1f65SJens Axboe smp_mb(); 2433a326a2cSIngo Molnar if (waitqueue_active(&pipe->wait)) 2443a326a2cSIngo Molnar wake_up_interruptible_sync(&pipe->wait); 2453a326a2cSIngo Molnar kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2465274f052SJens Axboe do_wakeup = 0; 2475274f052SJens Axboe } 2485274f052SJens Axboe 2493a326a2cSIngo Molnar pipe->waiting_writers++; 2503a326a2cSIngo Molnar pipe_wait(pipe); 2513a326a2cSIngo Molnar pipe->waiting_writers--; 2525274f052SJens Axboe } 2535274f052SJens Axboe 25461e0d47cSMiklos Szeredi pipe_unlock(pipe); 2555274f052SJens Axboe 256825cdcb1SNamhyung Kim if (do_wakeup) 257825cdcb1SNamhyung Kim wakeup_pipe_readers(pipe); 2585274f052SJens Axboe 25900de00bdSJens Axboe while (page_nr < spd_pages) 260bbdfc2f7SJens Axboe spd->spd_release(spd, page_nr++); 2615274f052SJens Axboe 2625274f052SJens Axboe return ret; 2635274f052SJens Axboe } 2645274f052SJens Axboe 265708e3508SHugh Dickins void spd_release_page(struct splice_pipe_desc *spd, unsigned int i) 266bbdfc2f7SJens Axboe { 267bbdfc2f7SJens Axboe page_cache_release(spd->pages[i]); 268bbdfc2f7SJens Axboe } 269bbdfc2f7SJens Axboe 27035f3d14dSJens Axboe /* 27135f3d14dSJens Axboe * Check if we need to grow the arrays holding pages and partial page 27235f3d14dSJens Axboe * descriptions. 27335f3d14dSJens Axboe */ 274047fe360SEric Dumazet int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) 27535f3d14dSJens Axboe { 276047fe360SEric Dumazet unsigned int buffers = ACCESS_ONCE(pipe->buffers); 277047fe360SEric Dumazet 278047fe360SEric Dumazet spd->nr_pages_max = buffers; 279047fe360SEric Dumazet if (buffers <= PIPE_DEF_BUFFERS) 28035f3d14dSJens Axboe return 0; 28135f3d14dSJens Axboe 282047fe360SEric Dumazet spd->pages = kmalloc(buffers * sizeof(struct page *), GFP_KERNEL); 283047fe360SEric Dumazet spd->partial = kmalloc(buffers * sizeof(struct partial_page), GFP_KERNEL); 28435f3d14dSJens Axboe 28535f3d14dSJens Axboe if (spd->pages && spd->partial) 28635f3d14dSJens Axboe return 0; 28735f3d14dSJens Axboe 28835f3d14dSJens Axboe kfree(spd->pages); 28935f3d14dSJens Axboe kfree(spd->partial); 29035f3d14dSJens Axboe return -ENOMEM; 29135f3d14dSJens Axboe } 29235f3d14dSJens Axboe 293047fe360SEric Dumazet void splice_shrink_spd(struct splice_pipe_desc *spd) 29435f3d14dSJens Axboe { 295047fe360SEric Dumazet if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) 29635f3d14dSJens Axboe return; 29735f3d14dSJens Axboe 29835f3d14dSJens Axboe kfree(spd->pages); 29935f3d14dSJens Axboe kfree(spd->partial); 30035f3d14dSJens Axboe } 30135f3d14dSJens Axboe 3023a326a2cSIngo Molnar static int 303cbb7e577SJens Axboe __generic_file_splice_read(struct file *in, loff_t *ppos, 304cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 305cbb7e577SJens Axboe unsigned int flags) 3065274f052SJens Axboe { 3075274f052SJens Axboe struct address_space *mapping = in->f_mapping; 308d8983910SFengguang Wu unsigned int loff, nr_pages, req_pages; 30935f3d14dSJens Axboe struct page *pages[PIPE_DEF_BUFFERS]; 31035f3d14dSJens Axboe struct partial_page partial[PIPE_DEF_BUFFERS]; 3115274f052SJens Axboe struct page *page; 31291ad66efSJens Axboe pgoff_t index, end_index; 31391ad66efSJens Axboe loff_t isize; 314eb20796bSJens Axboe int error, page_nr; 315912d35f8SJens Axboe struct splice_pipe_desc spd = { 316912d35f8SJens Axboe .pages = pages, 317912d35f8SJens Axboe .partial = partial, 318047fe360SEric Dumazet .nr_pages_max = PIPE_DEF_BUFFERS, 319912d35f8SJens Axboe .flags = flags, 320912d35f8SJens Axboe .ops = &page_cache_pipe_buf_ops, 321bbdfc2f7SJens Axboe .spd_release = spd_release_page, 322912d35f8SJens Axboe }; 3235274f052SJens Axboe 32435f3d14dSJens Axboe if (splice_grow_spd(pipe, &spd)) 32535f3d14dSJens Axboe return -ENOMEM; 32635f3d14dSJens Axboe 327cbb7e577SJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 328912d35f8SJens Axboe loff = *ppos & ~PAGE_CACHE_MASK; 329d8983910SFengguang Wu req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 330047fe360SEric Dumazet nr_pages = min(req_pages, spd.nr_pages_max); 3315274f052SJens Axboe 3325274f052SJens Axboe /* 333eb20796bSJens Axboe * Lookup the (hopefully) full range of pages we need. 33482aa5d61SJens Axboe */ 33535f3d14dSJens Axboe spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, spd.pages); 336431a4820SFengguang Wu index += spd.nr_pages; 337eb20796bSJens Axboe 3385274f052SJens Axboe /* 339eb20796bSJens Axboe * If find_get_pages_contig() returned fewer pages than we needed, 340431a4820SFengguang Wu * readahead/allocate the rest and fill in the holes. 341eb20796bSJens Axboe */ 342431a4820SFengguang Wu if (spd.nr_pages < nr_pages) 343cf914a7dSRusty Russell page_cache_sync_readahead(mapping, &in->f_ra, in, 344cf914a7dSRusty Russell index, req_pages - spd.nr_pages); 345431a4820SFengguang Wu 346932cc6d4SJens Axboe error = 0; 347eb20796bSJens Axboe while (spd.nr_pages < nr_pages) { 348eb20796bSJens Axboe /* 349eb20796bSJens Axboe * Page could be there, find_get_pages_contig() breaks on 350eb20796bSJens Axboe * the first hole. 3515274f052SJens Axboe */ 3527480a904SJens Axboe page = find_get_page(mapping, index); 3537480a904SJens Axboe if (!page) { 354e27dedd8SJens Axboe /* 355eb20796bSJens Axboe * page didn't exist, allocate one. 3567480a904SJens Axboe */ 3577480a904SJens Axboe page = page_cache_alloc_cold(mapping); 3585274f052SJens Axboe if (!page) 3595274f052SJens Axboe break; 3605274f052SJens Axboe 3617480a904SJens Axboe error = add_to_page_cache_lru(page, mapping, index, 3620ae0b5d0SNick Piggin GFP_KERNEL); 3635274f052SJens Axboe if (unlikely(error)) { 3645274f052SJens Axboe page_cache_release(page); 365a0548871SJens Axboe if (error == -EEXIST) 366a0548871SJens Axboe continue; 3675274f052SJens Axboe break; 3685274f052SJens Axboe } 369eb20796bSJens Axboe /* 370eb20796bSJens Axboe * add_to_page_cache() locks the page, unlock it 371eb20796bSJens Axboe * to avoid convoluting the logic below even more. 372eb20796bSJens Axboe */ 373eb20796bSJens Axboe unlock_page(page); 3745274f052SJens Axboe } 3757480a904SJens Axboe 37635f3d14dSJens Axboe spd.pages[spd.nr_pages++] = page; 377eb20796bSJens Axboe index++; 378eb20796bSJens Axboe } 379eb20796bSJens Axboe 380eb20796bSJens Axboe /* 381eb20796bSJens Axboe * Now loop over the map and see if we need to start IO on any 382eb20796bSJens Axboe * pages, fill in the partial map, etc. 383eb20796bSJens Axboe */ 384eb20796bSJens Axboe index = *ppos >> PAGE_CACHE_SHIFT; 385eb20796bSJens Axboe nr_pages = spd.nr_pages; 386eb20796bSJens Axboe spd.nr_pages = 0; 387eb20796bSJens Axboe for (page_nr = 0; page_nr < nr_pages; page_nr++) { 388eb20796bSJens Axboe unsigned int this_len; 389eb20796bSJens Axboe 390eb20796bSJens Axboe if (!len) 391eb20796bSJens Axboe break; 392eb20796bSJens Axboe 393eb20796bSJens Axboe /* 394eb20796bSJens Axboe * this_len is the max we'll use from this page 395eb20796bSJens Axboe */ 396eb20796bSJens Axboe this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); 39735f3d14dSJens Axboe page = spd.pages[page_nr]; 398eb20796bSJens Axboe 399a08a166fSFengguang Wu if (PageReadahead(page)) 400cf914a7dSRusty Russell page_cache_async_readahead(mapping, &in->f_ra, in, 401d8983910SFengguang Wu page, index, req_pages - page_nr); 402a08a166fSFengguang Wu 4037480a904SJens Axboe /* 4047480a904SJens Axboe * If the page isn't uptodate, we may need to start io on it 4057480a904SJens Axboe */ 4067480a904SJens Axboe if (!PageUptodate(page)) { 4077480a904SJens Axboe lock_page(page); 4087480a904SJens Axboe 4097480a904SJens Axboe /* 41032502b84SMiklos Szeredi * Page was truncated, or invalidated by the 41132502b84SMiklos Szeredi * filesystem. Redo the find/create, but this time the 41232502b84SMiklos Szeredi * page is kept locked, so there's no chance of another 41332502b84SMiklos Szeredi * race with truncate/invalidate. 4147480a904SJens Axboe */ 4157480a904SJens Axboe if (!page->mapping) { 4167480a904SJens Axboe unlock_page(page); 41732502b84SMiklos Szeredi page = find_or_create_page(mapping, index, 41832502b84SMiklos Szeredi mapping_gfp_mask(mapping)); 41932502b84SMiklos Szeredi 42032502b84SMiklos Szeredi if (!page) { 42132502b84SMiklos Szeredi error = -ENOMEM; 4227480a904SJens Axboe break; 4237480a904SJens Axboe } 42435f3d14dSJens Axboe page_cache_release(spd.pages[page_nr]); 42535f3d14dSJens Axboe spd.pages[page_nr] = page; 42632502b84SMiklos Szeredi } 4277480a904SJens Axboe /* 4287480a904SJens Axboe * page was already under io and is now done, great 4297480a904SJens Axboe */ 4307480a904SJens Axboe if (PageUptodate(page)) { 4317480a904SJens Axboe unlock_page(page); 4327480a904SJens Axboe goto fill_it; 4337480a904SJens Axboe } 4347480a904SJens Axboe 4357480a904SJens Axboe /* 4367480a904SJens Axboe * need to read in the page 4377480a904SJens Axboe */ 4387480a904SJens Axboe error = mapping->a_ops->readpage(in, page); 4397480a904SJens Axboe if (unlikely(error)) { 440eb20796bSJens Axboe /* 441eb20796bSJens Axboe * We really should re-lookup the page here, 442eb20796bSJens Axboe * but it complicates things a lot. Instead 443eb20796bSJens Axboe * lets just do what we already stored, and 444eb20796bSJens Axboe * we'll get it the next time we are called. 445eb20796bSJens Axboe */ 4467480a904SJens Axboe if (error == AOP_TRUNCATED_PAGE) 447eb20796bSJens Axboe error = 0; 448eb20796bSJens Axboe 4497480a904SJens Axboe break; 4507480a904SJens Axboe } 451620a324bSJens Axboe } 452620a324bSJens Axboe fill_it: 45391ad66efSJens Axboe /* 454620a324bSJens Axboe * i_size must be checked after PageUptodate. 45591ad66efSJens Axboe */ 45691ad66efSJens Axboe isize = i_size_read(mapping->host); 45791ad66efSJens Axboe end_index = (isize - 1) >> PAGE_CACHE_SHIFT; 458eb20796bSJens Axboe if (unlikely(!isize || index > end_index)) 45991ad66efSJens Axboe break; 46091ad66efSJens Axboe 46191ad66efSJens Axboe /* 46291ad66efSJens Axboe * if this is the last page, see if we need to shrink 46391ad66efSJens Axboe * the length and stop 46491ad66efSJens Axboe */ 46591ad66efSJens Axboe if (end_index == index) { 466475ecadeSHugh Dickins unsigned int plen; 467475ecadeSHugh Dickins 468475ecadeSHugh Dickins /* 469475ecadeSHugh Dickins * max good bytes in this page 470475ecadeSHugh Dickins */ 471475ecadeSHugh Dickins plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; 472475ecadeSHugh Dickins if (plen <= loff) 47391ad66efSJens Axboe break; 474475ecadeSHugh Dickins 47591ad66efSJens Axboe /* 47691ad66efSJens Axboe * force quit after adding this page 47791ad66efSJens Axboe */ 478475ecadeSHugh Dickins this_len = min(this_len, plen - loff); 479eb20796bSJens Axboe len = this_len; 48091ad66efSJens Axboe } 481620a324bSJens Axboe 48235f3d14dSJens Axboe spd.partial[page_nr].offset = loff; 48335f3d14dSJens Axboe spd.partial[page_nr].len = this_len; 48482aa5d61SJens Axboe len -= this_len; 48591ad66efSJens Axboe loff = 0; 486eb20796bSJens Axboe spd.nr_pages++; 487eb20796bSJens Axboe index++; 4885274f052SJens Axboe } 4895274f052SJens Axboe 490eb20796bSJens Axboe /* 491475ecadeSHugh Dickins * Release any pages at the end, if we quit early. 'page_nr' is how far 492eb20796bSJens Axboe * we got, 'nr_pages' is how many pages are in the map. 493eb20796bSJens Axboe */ 494eb20796bSJens Axboe while (page_nr < nr_pages) 49535f3d14dSJens Axboe page_cache_release(spd.pages[page_nr++]); 496f4e6b498SFengguang Wu in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT; 497eb20796bSJens Axboe 498912d35f8SJens Axboe if (spd.nr_pages) 49935f3d14dSJens Axboe error = splice_to_pipe(pipe, &spd); 50016c523ddSJens Axboe 501047fe360SEric Dumazet splice_shrink_spd(&spd); 5027480a904SJens Axboe return error; 5035274f052SJens Axboe } 5045274f052SJens Axboe 50583f9135bSJens Axboe /** 50683f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 50783f9135bSJens Axboe * @in: file to splice from 508932cc6d4SJens Axboe * @ppos: position in @in 50983f9135bSJens Axboe * @pipe: pipe to splice to 51083f9135bSJens Axboe * @len: number of bytes to splice 51183f9135bSJens Axboe * @flags: splice modifier flags 51283f9135bSJens Axboe * 513932cc6d4SJens Axboe * Description: 514932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 515932cc6d4SJens Axboe * used as long as the address_space operations for the source implements 516932cc6d4SJens Axboe * a readpage() hook. 517932cc6d4SJens Axboe * 51883f9135bSJens Axboe */ 519cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 520cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 521cbb7e577SJens Axboe unsigned int flags) 5225274f052SJens Axboe { 523d366d398SJens Axboe loff_t isize, left; 5248191ecd1SJens Axboe int ret; 525d366d398SJens Axboe 526d366d398SJens Axboe isize = i_size_read(in->f_mapping->host); 527d366d398SJens Axboe if (unlikely(*ppos >= isize)) 528d366d398SJens Axboe return 0; 529d366d398SJens Axboe 530d366d398SJens Axboe left = isize - *ppos; 531d366d398SJens Axboe if (unlikely(left < len)) 532d366d398SJens Axboe len = left; 5335274f052SJens Axboe 534cbb7e577SJens Axboe ret = __generic_file_splice_read(in, ppos, pipe, len, flags); 535723590edSMiklos Szeredi if (ret > 0) { 536cbb7e577SJens Axboe *ppos += ret; 537723590edSMiklos Szeredi file_accessed(in); 538723590edSMiklos Szeredi } 5395274f052SJens Axboe 5405274f052SJens Axboe return ret; 5415274f052SJens Axboe } 542059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 543059a8f37SJens Axboe 5446818173bSMiklos Szeredi static const struct pipe_buf_operations default_pipe_buf_ops = { 5456818173bSMiklos Szeredi .can_merge = 0, 5466818173bSMiklos Szeredi .confirm = generic_pipe_buf_confirm, 5476818173bSMiklos Szeredi .release = generic_pipe_buf_release, 5486818173bSMiklos Szeredi .steal = generic_pipe_buf_steal, 5496818173bSMiklos Szeredi .get = generic_pipe_buf_get, 5506818173bSMiklos Szeredi }; 5516818173bSMiklos Szeredi 55228a625cbSMiklos Szeredi static int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe, 55328a625cbSMiklos Szeredi struct pipe_buffer *buf) 55428a625cbSMiklos Szeredi { 55528a625cbSMiklos Szeredi return 1; 55628a625cbSMiklos Szeredi } 55728a625cbSMiklos Szeredi 55828a625cbSMiklos Szeredi /* Pipe buffer operations for a socket and similar. */ 55928a625cbSMiklos Szeredi const struct pipe_buf_operations nosteal_pipe_buf_ops = { 56028a625cbSMiklos Szeredi .can_merge = 0, 56128a625cbSMiklos Szeredi .confirm = generic_pipe_buf_confirm, 56228a625cbSMiklos Szeredi .release = generic_pipe_buf_release, 56328a625cbSMiklos Szeredi .steal = generic_pipe_buf_nosteal, 56428a625cbSMiklos Szeredi .get = generic_pipe_buf_get, 56528a625cbSMiklos Szeredi }; 56628a625cbSMiklos Szeredi EXPORT_SYMBOL(nosteal_pipe_buf_ops); 56728a625cbSMiklos Szeredi 5686818173bSMiklos Szeredi static ssize_t kernel_readv(struct file *file, const struct iovec *vec, 5696818173bSMiklos Szeredi unsigned long vlen, loff_t offset) 5706818173bSMiklos Szeredi { 5716818173bSMiklos Szeredi mm_segment_t old_fs; 5726818173bSMiklos Szeredi loff_t pos = offset; 5736818173bSMiklos Szeredi ssize_t res; 5746818173bSMiklos Szeredi 5756818173bSMiklos Szeredi old_fs = get_fs(); 5766818173bSMiklos Szeredi set_fs(get_ds()); 5776818173bSMiklos Szeredi /* The cast to a user pointer is valid due to the set_fs() */ 5786818173bSMiklos Szeredi res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos); 5796818173bSMiklos Szeredi set_fs(old_fs); 5806818173bSMiklos Szeredi 5816818173bSMiklos Szeredi return res; 5826818173bSMiklos Szeredi } 5836818173bSMiklos Szeredi 5847bb307e8SAl Viro ssize_t kernel_write(struct file *file, const char *buf, size_t count, 585b2858d7dSMiklos Szeredi loff_t pos) 5860b0a47f5SMiklos Szeredi { 5870b0a47f5SMiklos Szeredi mm_segment_t old_fs; 5880b0a47f5SMiklos Szeredi ssize_t res; 5890b0a47f5SMiklos Szeredi 5900b0a47f5SMiklos Szeredi old_fs = get_fs(); 5910b0a47f5SMiklos Szeredi set_fs(get_ds()); 5920b0a47f5SMiklos Szeredi /* The cast to a user pointer is valid due to the set_fs() */ 5937bb307e8SAl Viro res = vfs_write(file, (__force const char __user *)buf, count, &pos); 5940b0a47f5SMiklos Szeredi set_fs(old_fs); 5950b0a47f5SMiklos Szeredi 5960b0a47f5SMiklos Szeredi return res; 5970b0a47f5SMiklos Szeredi } 5987bb307e8SAl Viro EXPORT_SYMBOL(kernel_write); 5990b0a47f5SMiklos Szeredi 6006818173bSMiklos Szeredi ssize_t default_file_splice_read(struct file *in, loff_t *ppos, 6016818173bSMiklos Szeredi struct pipe_inode_info *pipe, size_t len, 6026818173bSMiklos Szeredi unsigned int flags) 6036818173bSMiklos Szeredi { 6046818173bSMiklos Szeredi unsigned int nr_pages; 6056818173bSMiklos Szeredi unsigned int nr_freed; 6066818173bSMiklos Szeredi size_t offset; 60735f3d14dSJens Axboe struct page *pages[PIPE_DEF_BUFFERS]; 60835f3d14dSJens Axboe struct partial_page partial[PIPE_DEF_BUFFERS]; 60935f3d14dSJens Axboe struct iovec *vec, __vec[PIPE_DEF_BUFFERS]; 6106818173bSMiklos Szeredi ssize_t res; 6116818173bSMiklos Szeredi size_t this_len; 6126818173bSMiklos Szeredi int error; 6136818173bSMiklos Szeredi int i; 6146818173bSMiklos Szeredi struct splice_pipe_desc spd = { 6156818173bSMiklos Szeredi .pages = pages, 6166818173bSMiklos Szeredi .partial = partial, 617047fe360SEric Dumazet .nr_pages_max = PIPE_DEF_BUFFERS, 6186818173bSMiklos Szeredi .flags = flags, 6196818173bSMiklos Szeredi .ops = &default_pipe_buf_ops, 6206818173bSMiklos Szeredi .spd_release = spd_release_page, 6216818173bSMiklos Szeredi }; 6226818173bSMiklos Szeredi 62335f3d14dSJens Axboe if (splice_grow_spd(pipe, &spd)) 62435f3d14dSJens Axboe return -ENOMEM; 62535f3d14dSJens Axboe 62635f3d14dSJens Axboe res = -ENOMEM; 62735f3d14dSJens Axboe vec = __vec; 628047fe360SEric Dumazet if (spd.nr_pages_max > PIPE_DEF_BUFFERS) { 629047fe360SEric Dumazet vec = kmalloc(spd.nr_pages_max * sizeof(struct iovec), GFP_KERNEL); 63035f3d14dSJens Axboe if (!vec) 63135f3d14dSJens Axboe goto shrink_ret; 63235f3d14dSJens Axboe } 63335f3d14dSJens Axboe 6346818173bSMiklos Szeredi offset = *ppos & ~PAGE_CACHE_MASK; 6356818173bSMiklos Szeredi nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 6366818173bSMiklos Szeredi 637047fe360SEric Dumazet for (i = 0; i < nr_pages && i < spd.nr_pages_max && len; i++) { 6386818173bSMiklos Szeredi struct page *page; 6396818173bSMiklos Szeredi 6404f231228SJens Axboe page = alloc_page(GFP_USER); 6416818173bSMiklos Szeredi error = -ENOMEM; 6426818173bSMiklos Szeredi if (!page) 6436818173bSMiklos Szeredi goto err; 6446818173bSMiklos Szeredi 6456818173bSMiklos Szeredi this_len = min_t(size_t, len, PAGE_CACHE_SIZE - offset); 6464f231228SJens Axboe vec[i].iov_base = (void __user *) page_address(page); 6476818173bSMiklos Szeredi vec[i].iov_len = this_len; 64835f3d14dSJens Axboe spd.pages[i] = page; 6496818173bSMiklos Szeredi spd.nr_pages++; 6506818173bSMiklos Szeredi len -= this_len; 6516818173bSMiklos Szeredi offset = 0; 6526818173bSMiklos Szeredi } 6536818173bSMiklos Szeredi 6546818173bSMiklos Szeredi res = kernel_readv(in, vec, spd.nr_pages, *ppos); 65577f6bf57SAndrew Morton if (res < 0) { 65677f6bf57SAndrew Morton error = res; 6576818173bSMiklos Szeredi goto err; 65877f6bf57SAndrew Morton } 6596818173bSMiklos Szeredi 6606818173bSMiklos Szeredi error = 0; 6616818173bSMiklos Szeredi if (!res) 6626818173bSMiklos Szeredi goto err; 6636818173bSMiklos Szeredi 6646818173bSMiklos Szeredi nr_freed = 0; 6656818173bSMiklos Szeredi for (i = 0; i < spd.nr_pages; i++) { 6666818173bSMiklos Szeredi this_len = min_t(size_t, vec[i].iov_len, res); 66735f3d14dSJens Axboe spd.partial[i].offset = 0; 66835f3d14dSJens Axboe spd.partial[i].len = this_len; 6696818173bSMiklos Szeredi if (!this_len) { 67035f3d14dSJens Axboe __free_page(spd.pages[i]); 67135f3d14dSJens Axboe spd.pages[i] = NULL; 6726818173bSMiklos Szeredi nr_freed++; 6736818173bSMiklos Szeredi } 6746818173bSMiklos Szeredi res -= this_len; 6756818173bSMiklos Szeredi } 6766818173bSMiklos Szeredi spd.nr_pages -= nr_freed; 6776818173bSMiklos Szeredi 6786818173bSMiklos Szeredi res = splice_to_pipe(pipe, &spd); 6796818173bSMiklos Szeredi if (res > 0) 6806818173bSMiklos Szeredi *ppos += res; 6816818173bSMiklos Szeredi 68235f3d14dSJens Axboe shrink_ret: 68335f3d14dSJens Axboe if (vec != __vec) 68435f3d14dSJens Axboe kfree(vec); 685047fe360SEric Dumazet splice_shrink_spd(&spd); 6866818173bSMiklos Szeredi return res; 6876818173bSMiklos Szeredi 6886818173bSMiklos Szeredi err: 6894f231228SJens Axboe for (i = 0; i < spd.nr_pages; i++) 69035f3d14dSJens Axboe __free_page(spd.pages[i]); 6914f231228SJens Axboe 69235f3d14dSJens Axboe res = error; 69335f3d14dSJens Axboe goto shrink_ret; 6946818173bSMiklos Szeredi } 6956818173bSMiklos Szeredi EXPORT_SYMBOL(default_file_splice_read); 6966818173bSMiklos Szeredi 6975274f052SJens Axboe /* 6984f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 699016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 7005274f052SJens Axboe */ 70176ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 7025274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 7035274f052SJens Axboe { 7046a14b90bSJens Axboe struct file *file = sd->u.file; 7055274f052SJens Axboe loff_t pos = sd->pos; 706a8adbe37SMichał Mirosław int more; 7075274f052SJens Axboe 70872c2d531SAl Viro if (!likely(file->f_op->sendpage)) 709a8adbe37SMichał Mirosław return -EINVAL; 710a8adbe37SMichał Mirosław 71135f9c09fSEric Dumazet more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; 712ae62ca7bSEric Dumazet 713ae62ca7bSEric Dumazet if (sd->len < sd->total_len && pipe->nrbufs > 1) 71435f9c09fSEric Dumazet more |= MSG_SENDPAGE_NOTLAST; 715ae62ca7bSEric Dumazet 716a8adbe37SMichał Mirosław return file->f_op->sendpage(file, buf->page, buf->offset, 717f84d7519SJens Axboe sd->len, &pos, more); 7185274f052SJens Axboe } 7195274f052SJens Axboe 7205274f052SJens Axboe /* 7215274f052SJens Axboe * This is a little more tricky than the file -> pipe splicing. There are 7225274f052SJens Axboe * basically three cases: 7235274f052SJens Axboe * 7245274f052SJens Axboe * - Destination page already exists in the address space and there 7255274f052SJens Axboe * are users of it. For that case we have no other option that 7265274f052SJens Axboe * copying the data. Tough luck. 7275274f052SJens Axboe * - Destination page already exists in the address space, but there 7285274f052SJens Axboe * are no users of it. Make sure it's uptodate, then drop it. Fall 7295274f052SJens Axboe * through to last case. 7305274f052SJens Axboe * - Destination page does not exist, we can add the pipe page to 7315274f052SJens Axboe * the page cache and avoid the copy. 7325274f052SJens Axboe * 73383f9135bSJens Axboe * If asked to move pages to the output file (SPLICE_F_MOVE is set in 73483f9135bSJens Axboe * sd->flags), we attempt to migrate pages from the pipe to the output 73583f9135bSJens Axboe * file address space page cache. This is possible if no one else has 73683f9135bSJens Axboe * the pipe page referenced outside of the pipe and page cache. If 73783f9135bSJens Axboe * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create 73883f9135bSJens Axboe * a new page in the output file page cache and fill/dirty that. 7395274f052SJens Axboe */ 740328eaabaSMiklos Szeredi int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 7415274f052SJens Axboe struct splice_desc *sd) 7425274f052SJens Axboe { 7436a14b90bSJens Axboe struct file *file = sd->u.file; 7445274f052SJens Axboe struct address_space *mapping = file->f_mapping; 745016b661eSJens Axboe unsigned int offset, this_len; 7465274f052SJens Axboe struct page *page; 747afddba49SNick Piggin void *fsdata; 7483e7ee3e7SJens Axboe int ret; 7495274f052SJens Axboe 7505274f052SJens Axboe offset = sd->pos & ~PAGE_CACHE_MASK; 7515274f052SJens Axboe 752016b661eSJens Axboe this_len = sd->len; 753016b661eSJens Axboe if (this_len + offset > PAGE_CACHE_SIZE) 754016b661eSJens Axboe this_len = PAGE_CACHE_SIZE - offset; 755016b661eSJens Axboe 756afddba49SNick Piggin ret = pagecache_write_begin(file, mapping, sd->pos, this_len, 757afddba49SNick Piggin AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); 7589e0267c2SJens Axboe if (unlikely(ret)) 759afddba49SNick Piggin goto out; 7605274f052SJens Axboe 7610568b409SJens Axboe if (buf->page != page) { 762fbb32750SAl Viro char *src = kmap_atomic(buf->page); 763e8e3c3d6SCong Wang char *dst = kmap_atomic(page); 7645abc97aaSJens Axboe 765016b661eSJens Axboe memcpy(dst + offset, src + buf->offset, this_len); 7665274f052SJens Axboe flush_dcache_page(page); 767e8e3c3d6SCong Wang kunmap_atomic(dst); 768fbb32750SAl Viro kunmap_atomic(src); 7695abc97aaSJens Axboe } 770afddba49SNick Piggin ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, 771afddba49SNick Piggin page, fsdata); 7720568b409SJens Axboe out: 7735274f052SJens Axboe return ret; 7745274f052SJens Axboe } 775328eaabaSMiklos Szeredi EXPORT_SYMBOL(pipe_to_file); 7765274f052SJens Axboe 777b3c2d2ddSMiklos Szeredi static void wakeup_pipe_writers(struct pipe_inode_info *pipe) 778b3c2d2ddSMiklos Szeredi { 779b3c2d2ddSMiklos Szeredi smp_mb(); 780b3c2d2ddSMiklos Szeredi if (waitqueue_active(&pipe->wait)) 781b3c2d2ddSMiklos Szeredi wake_up_interruptible(&pipe->wait); 782b3c2d2ddSMiklos Szeredi kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 783b3c2d2ddSMiklos Szeredi } 784b3c2d2ddSMiklos Szeredi 785b3c2d2ddSMiklos Szeredi /** 786b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed - feed available data from a pipe to a file 787b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 788b3c2d2ddSMiklos Szeredi * @sd: information to @actor 789b3c2d2ddSMiklos Szeredi * @actor: handler that splices the data 790b3c2d2ddSMiklos Szeredi * 791b3c2d2ddSMiklos Szeredi * Description: 792b3c2d2ddSMiklos Szeredi * This function loops over the pipe and calls @actor to do the 793b3c2d2ddSMiklos Szeredi * actual moving of a single struct pipe_buffer to the desired 794b3c2d2ddSMiklos Szeredi * destination. It returns when there's no more buffers left in 795b3c2d2ddSMiklos Szeredi * the pipe or if the requested number of bytes (@sd->total_len) 796b3c2d2ddSMiklos Szeredi * have been copied. It returns a positive number (one) if the 797b3c2d2ddSMiklos Szeredi * pipe needs to be filled with more data, zero if the required 798b3c2d2ddSMiklos Szeredi * number of bytes have been copied and -errno on error. 799b3c2d2ddSMiklos Szeredi * 800b3c2d2ddSMiklos Szeredi * This, together with splice_from_pipe_{begin,end,next}, may be 801b3c2d2ddSMiklos Szeredi * used to implement the functionality of __splice_from_pipe() when 802b3c2d2ddSMiklos Szeredi * locking is required around copying the pipe buffers to the 803b3c2d2ddSMiklos Szeredi * destination. 804b3c2d2ddSMiklos Szeredi */ 805b3c2d2ddSMiklos Szeredi int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, 806b3c2d2ddSMiklos Szeredi splice_actor *actor) 807b3c2d2ddSMiklos Szeredi { 808b3c2d2ddSMiklos Szeredi int ret; 809b3c2d2ddSMiklos Szeredi 810b3c2d2ddSMiklos Szeredi while (pipe->nrbufs) { 811b3c2d2ddSMiklos Szeredi struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 812b3c2d2ddSMiklos Szeredi const struct pipe_buf_operations *ops = buf->ops; 813b3c2d2ddSMiklos Szeredi 814b3c2d2ddSMiklos Szeredi sd->len = buf->len; 815b3c2d2ddSMiklos Szeredi if (sd->len > sd->total_len) 816b3c2d2ddSMiklos Szeredi sd->len = sd->total_len; 817b3c2d2ddSMiklos Szeredi 818a8adbe37SMichał Mirosław ret = buf->ops->confirm(pipe, buf); 819a8adbe37SMichał Mirosław if (unlikely(ret)) { 820b3c2d2ddSMiklos Szeredi if (ret == -ENODATA) 821b3c2d2ddSMiklos Szeredi ret = 0; 822b3c2d2ddSMiklos Szeredi return ret; 823b3c2d2ddSMiklos Szeredi } 824a8adbe37SMichał Mirosław 825a8adbe37SMichał Mirosław ret = actor(pipe, buf, sd); 826a8adbe37SMichał Mirosław if (ret <= 0) 827a8adbe37SMichał Mirosław return ret; 828a8adbe37SMichał Mirosław 829b3c2d2ddSMiklos Szeredi buf->offset += ret; 830b3c2d2ddSMiklos Szeredi buf->len -= ret; 831b3c2d2ddSMiklos Szeredi 832b3c2d2ddSMiklos Szeredi sd->num_spliced += ret; 833b3c2d2ddSMiklos Szeredi sd->len -= ret; 834b3c2d2ddSMiklos Szeredi sd->pos += ret; 835b3c2d2ddSMiklos Szeredi sd->total_len -= ret; 836b3c2d2ddSMiklos Szeredi 837b3c2d2ddSMiklos Szeredi if (!buf->len) { 838b3c2d2ddSMiklos Szeredi buf->ops = NULL; 839b3c2d2ddSMiklos Szeredi ops->release(pipe, buf); 84035f3d14dSJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); 841b3c2d2ddSMiklos Szeredi pipe->nrbufs--; 8426447a3cfSAl Viro if (pipe->files) 843b3c2d2ddSMiklos Szeredi sd->need_wakeup = true; 844b3c2d2ddSMiklos Szeredi } 845b3c2d2ddSMiklos Szeredi 846b3c2d2ddSMiklos Szeredi if (!sd->total_len) 847b3c2d2ddSMiklos Szeredi return 0; 848b3c2d2ddSMiklos Szeredi } 849b3c2d2ddSMiklos Szeredi 850b3c2d2ddSMiklos Szeredi return 1; 851b3c2d2ddSMiklos Szeredi } 852b3c2d2ddSMiklos Szeredi EXPORT_SYMBOL(splice_from_pipe_feed); 853b3c2d2ddSMiklos Szeredi 854b3c2d2ddSMiklos Szeredi /** 855b3c2d2ddSMiklos Szeredi * splice_from_pipe_next - wait for some data to splice from 856b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 857b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 858b3c2d2ddSMiklos Szeredi * 859b3c2d2ddSMiklos Szeredi * Description: 860b3c2d2ddSMiklos Szeredi * This function will wait for some data and return a positive 861b3c2d2ddSMiklos Szeredi * value (one) if pipe buffers are available. It will return zero 862b3c2d2ddSMiklos Szeredi * or -errno if no more data needs to be spliced. 863b3c2d2ddSMiklos Szeredi */ 864b3c2d2ddSMiklos Szeredi int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) 865b3c2d2ddSMiklos Szeredi { 866b3c2d2ddSMiklos Szeredi while (!pipe->nrbufs) { 867b3c2d2ddSMiklos Szeredi if (!pipe->writers) 868b3c2d2ddSMiklos Szeredi return 0; 869b3c2d2ddSMiklos Szeredi 870b3c2d2ddSMiklos Szeredi if (!pipe->waiting_writers && sd->num_spliced) 871b3c2d2ddSMiklos Szeredi return 0; 872b3c2d2ddSMiklos Szeredi 873b3c2d2ddSMiklos Szeredi if (sd->flags & SPLICE_F_NONBLOCK) 874b3c2d2ddSMiklos Szeredi return -EAGAIN; 875b3c2d2ddSMiklos Szeredi 876b3c2d2ddSMiklos Szeredi if (signal_pending(current)) 877b3c2d2ddSMiklos Szeredi return -ERESTARTSYS; 878b3c2d2ddSMiklos Szeredi 879b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) { 880b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 881b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 882b3c2d2ddSMiklos Szeredi } 883b3c2d2ddSMiklos Szeredi 884b3c2d2ddSMiklos Szeredi pipe_wait(pipe); 885b3c2d2ddSMiklos Szeredi } 886b3c2d2ddSMiklos Szeredi 887b3c2d2ddSMiklos Szeredi return 1; 888b3c2d2ddSMiklos Szeredi } 889b3c2d2ddSMiklos Szeredi EXPORT_SYMBOL(splice_from_pipe_next); 890b3c2d2ddSMiklos Szeredi 891b3c2d2ddSMiklos Szeredi /** 892b3c2d2ddSMiklos Szeredi * splice_from_pipe_begin - start splicing from pipe 893b80901bbSRandy Dunlap * @sd: information about the splice operation 894b3c2d2ddSMiklos Szeredi * 895b3c2d2ddSMiklos Szeredi * Description: 896b3c2d2ddSMiklos Szeredi * This function should be called before a loop containing 897b3c2d2ddSMiklos Szeredi * splice_from_pipe_next() and splice_from_pipe_feed() to 898b3c2d2ddSMiklos Szeredi * initialize the necessary fields of @sd. 899b3c2d2ddSMiklos Szeredi */ 900b3c2d2ddSMiklos Szeredi void splice_from_pipe_begin(struct splice_desc *sd) 901b3c2d2ddSMiklos Szeredi { 902b3c2d2ddSMiklos Szeredi sd->num_spliced = 0; 903b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 904b3c2d2ddSMiklos Szeredi } 905b3c2d2ddSMiklos Szeredi EXPORT_SYMBOL(splice_from_pipe_begin); 906b3c2d2ddSMiklos Szeredi 907b3c2d2ddSMiklos Szeredi /** 908b3c2d2ddSMiklos Szeredi * splice_from_pipe_end - finish splicing from pipe 909b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 910b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 911b3c2d2ddSMiklos Szeredi * 912b3c2d2ddSMiklos Szeredi * Description: 913b3c2d2ddSMiklos Szeredi * This function will wake up pipe writers if necessary. It should 914b3c2d2ddSMiklos Szeredi * be called after a loop containing splice_from_pipe_next() and 915b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed(). 916b3c2d2ddSMiklos Szeredi */ 917b3c2d2ddSMiklos Szeredi void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) 918b3c2d2ddSMiklos Szeredi { 919b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) 920b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 921b3c2d2ddSMiklos Szeredi } 922b3c2d2ddSMiklos Szeredi EXPORT_SYMBOL(splice_from_pipe_end); 923b3c2d2ddSMiklos Szeredi 924932cc6d4SJens Axboe /** 925932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 926932cc6d4SJens Axboe * @pipe: pipe to splice from 927932cc6d4SJens Axboe * @sd: information to @actor 928932cc6d4SJens Axboe * @actor: handler that splices the data 929932cc6d4SJens Axboe * 930932cc6d4SJens Axboe * Description: 931932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 932932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 933932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 934932cc6d4SJens Axboe * pipe_to_user. 935932cc6d4SJens Axboe * 93683f9135bSJens Axboe */ 937c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 938c66ab6faSJens Axboe splice_actor *actor) 9395274f052SJens Axboe { 940b3c2d2ddSMiklos Szeredi int ret; 9415274f052SJens Axboe 942b3c2d2ddSMiklos Szeredi splice_from_pipe_begin(sd); 943b3c2d2ddSMiklos Szeredi do { 944b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_next(pipe, sd); 945b3c2d2ddSMiklos Szeredi if (ret > 0) 946b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_feed(pipe, sd, actor); 947b3c2d2ddSMiklos Szeredi } while (ret > 0); 948b3c2d2ddSMiklos Szeredi splice_from_pipe_end(pipe, sd); 9495274f052SJens Axboe 950b3c2d2ddSMiklos Szeredi return sd->num_spliced ? sd->num_spliced : ret; 9515274f052SJens Axboe } 95240bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 9535274f052SJens Axboe 954932cc6d4SJens Axboe /** 955932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 956932cc6d4SJens Axboe * @pipe: pipe to splice from 957932cc6d4SJens Axboe * @out: file to splice to 958932cc6d4SJens Axboe * @ppos: position in @out 959932cc6d4SJens Axboe * @len: how many bytes to splice 960932cc6d4SJens Axboe * @flags: splice modifier flags 961932cc6d4SJens Axboe * @actor: handler that splices the data 962932cc6d4SJens Axboe * 963932cc6d4SJens Axboe * Description: 9642933970bSMiklos Szeredi * See __splice_from_pipe. This function locks the pipe inode, 965932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 966932cc6d4SJens Axboe * 967932cc6d4SJens Axboe */ 9686da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 9696da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 9706da61809SMark Fasheh splice_actor *actor) 9716da61809SMark Fasheh { 9726da61809SMark Fasheh ssize_t ret; 973c66ab6faSJens Axboe struct splice_desc sd = { 974c66ab6faSJens Axboe .total_len = len, 975c66ab6faSJens Axboe .flags = flags, 976c66ab6faSJens Axboe .pos = *ppos, 9776a14b90bSJens Axboe .u.file = out, 978c66ab6faSJens Axboe }; 9796da61809SMark Fasheh 98061e0d47cSMiklos Szeredi pipe_lock(pipe); 981c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 98261e0d47cSMiklos Szeredi pipe_unlock(pipe); 9836da61809SMark Fasheh 9846da61809SMark Fasheh return ret; 9856da61809SMark Fasheh } 9866da61809SMark Fasheh 9876da61809SMark Fasheh /** 98883f9135bSJens Axboe * generic_file_splice_write - splice data from a pipe to a file 9893a326a2cSIngo Molnar * @pipe: pipe info 99083f9135bSJens Axboe * @out: file to write to 991932cc6d4SJens Axboe * @ppos: position in @out 99283f9135bSJens Axboe * @len: number of bytes to splice 99383f9135bSJens Axboe * @flags: splice modifier flags 99483f9135bSJens Axboe * 995932cc6d4SJens Axboe * Description: 99683f9135bSJens Axboe * Will either move or copy pages (determined by @flags options) from 99783f9135bSJens Axboe * the given pipe inode to the given file. 99883f9135bSJens Axboe * 99983f9135bSJens Axboe */ 10003a326a2cSIngo Molnar ssize_t 10013a326a2cSIngo Molnar generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 1002cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 10035274f052SJens Axboe { 10044f6f0bd2SJens Axboe struct address_space *mapping = out->f_mapping; 10058c34e2d6SJens Axboe struct inode *inode = mapping->host; 10067f3d4ee1SMiklos Szeredi struct splice_desc sd = { 10077f3d4ee1SMiklos Szeredi .total_len = len, 10087f3d4ee1SMiklos Szeredi .flags = flags, 10097f3d4ee1SMiklos Szeredi .pos = *ppos, 10107f3d4ee1SMiklos Szeredi .u.file = out, 10117f3d4ee1SMiklos Szeredi }; 10123a326a2cSIngo Molnar ssize_t ret; 10138c34e2d6SJens Axboe 101461e0d47cSMiklos Szeredi pipe_lock(pipe); 1015eb443e5aSMiklos Szeredi 1016eb443e5aSMiklos Szeredi splice_from_pipe_begin(&sd); 1017eb443e5aSMiklos Szeredi do { 1018eb443e5aSMiklos Szeredi ret = splice_from_pipe_next(pipe, &sd); 1019eb443e5aSMiklos Szeredi if (ret <= 0) 1020eb443e5aSMiklos Szeredi break; 1021eb443e5aSMiklos Szeredi 1022eb443e5aSMiklos Szeredi mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD); 1023eb443e5aSMiklos Szeredi ret = file_remove_suid(out); 1024723590edSMiklos Szeredi if (!ret) { 1025c3b2da31SJosef Bacik ret = file_update_time(out); 1026c3b2da31SJosef Bacik if (!ret) 1027c3b2da31SJosef Bacik ret = splice_from_pipe_feed(pipe, &sd, 1028c3b2da31SJosef Bacik pipe_to_file); 1029723590edSMiklos Szeredi } 1030eb443e5aSMiklos Szeredi mutex_unlock(&inode->i_mutex); 1031eb443e5aSMiklos Szeredi } while (ret > 0); 1032eb443e5aSMiklos Szeredi splice_from_pipe_end(pipe, &sd); 1033eb443e5aSMiklos Szeredi 103461e0d47cSMiklos Szeredi pipe_unlock(pipe); 1035eb443e5aSMiklos Szeredi 1036eb443e5aSMiklos Szeredi if (sd.num_spliced) 1037eb443e5aSMiklos Szeredi ret = sd.num_spliced; 1038eb443e5aSMiklos Szeredi 1039a4514ebdSJens Axboe if (ret > 0) { 10407f3d4ee1SMiklos Szeredi int err; 10417f3d4ee1SMiklos Szeredi 1042148f948bSJan Kara err = generic_write_sync(out, *ppos, ret); 10434f6f0bd2SJens Axboe if (err) 10444f6f0bd2SJens Axboe ret = err; 1045148f948bSJan Kara else 1046148f948bSJan Kara *ppos += ret; 1047d0e1d66bSNamjae Jeon balance_dirty_pages_ratelimited(mapping); 1048a4514ebdSJens Axboe } 10494f6f0bd2SJens Axboe 10504f6f0bd2SJens Axboe return ret; 10515274f052SJens Axboe } 10525274f052SJens Axboe 1053059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_write); 1054059a8f37SJens Axboe 1055b2858d7dSMiklos Szeredi static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 1056b2858d7dSMiklos Szeredi struct splice_desc *sd) 10570b0a47f5SMiklos Szeredi { 1058b2858d7dSMiklos Szeredi int ret; 1059b2858d7dSMiklos Szeredi void *data; 106006ae43f3SAl Viro loff_t tmp = sd->pos; 1061b2858d7dSMiklos Szeredi 1062fbb32750SAl Viro data = kmap(buf->page); 106306ae43f3SAl Viro ret = __kernel_write(sd->u.file, data + buf->offset, sd->len, &tmp); 1064fbb32750SAl Viro kunmap(buf->page); 1065b2858d7dSMiklos Szeredi 1066b2858d7dSMiklos Szeredi return ret; 10670b0a47f5SMiklos Szeredi } 10680b0a47f5SMiklos Szeredi 10690b0a47f5SMiklos Szeredi static ssize_t default_file_splice_write(struct pipe_inode_info *pipe, 10700b0a47f5SMiklos Szeredi struct file *out, loff_t *ppos, 10710b0a47f5SMiklos Szeredi size_t len, unsigned int flags) 10720b0a47f5SMiklos Szeredi { 1073b2858d7dSMiklos Szeredi ssize_t ret; 10740b0a47f5SMiklos Szeredi 1075b2858d7dSMiklos Szeredi ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf); 1076b2858d7dSMiklos Szeredi if (ret > 0) 1077b2858d7dSMiklos Szeredi *ppos += ret; 10780b0a47f5SMiklos Szeredi 1079b2858d7dSMiklos Szeredi return ret; 10800b0a47f5SMiklos Szeredi } 10810b0a47f5SMiklos Szeredi 108283f9135bSJens Axboe /** 108383f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 1084932cc6d4SJens Axboe * @pipe: pipe to splice from 108583f9135bSJens Axboe * @out: socket to write to 1086932cc6d4SJens Axboe * @ppos: position in @out 108783f9135bSJens Axboe * @len: number of bytes to splice 108883f9135bSJens Axboe * @flags: splice modifier flags 108983f9135bSJens Axboe * 1090932cc6d4SJens Axboe * Description: 109183f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 109283f9135bSJens Axboe * is involved. 109383f9135bSJens Axboe * 109483f9135bSJens Axboe */ 10953a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 1096cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 10975274f052SJens Axboe { 109800522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 10995274f052SJens Axboe } 11005274f052SJens Axboe 1101059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 1102a0f06780SJeff Garzik 110383f9135bSJens Axboe /* 110483f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 110583f9135bSJens Axboe */ 11063a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 1107cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 11085274f052SJens Axboe { 11090b0a47f5SMiklos Szeredi ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, 11100b0a47f5SMiklos Szeredi loff_t *, size_t, unsigned int); 11115274f052SJens Axboe 111272c2d531SAl Viro if (out->f_op->splice_write) 11130b0a47f5SMiklos Szeredi splice_write = out->f_op->splice_write; 1114cc56f7deSChangli Gao else 11150b0a47f5SMiklos Szeredi splice_write = default_file_splice_write; 11160b0a47f5SMiklos Szeredi 1117500368f7SAl Viro return splice_write(pipe, out, ppos, len, flags); 11185274f052SJens Axboe } 11195274f052SJens Axboe 112083f9135bSJens Axboe /* 112183f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 112283f9135bSJens Axboe */ 1123cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 1124cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 1125cbb7e577SJens Axboe unsigned int flags) 11265274f052SJens Axboe { 11276818173bSMiklos Szeredi ssize_t (*splice_read)(struct file *, loff_t *, 11286818173bSMiklos Szeredi struct pipe_inode_info *, size_t, unsigned int); 11295274f052SJens Axboe int ret; 11305274f052SJens Axboe 113149570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 11325274f052SJens Axboe return -EBADF; 11335274f052SJens Axboe 1134cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 11355274f052SJens Axboe if (unlikely(ret < 0)) 11365274f052SJens Axboe return ret; 11375274f052SJens Axboe 113872c2d531SAl Viro if (in->f_op->splice_read) 11396818173bSMiklos Szeredi splice_read = in->f_op->splice_read; 1140cc56f7deSChangli Gao else 11416818173bSMiklos Szeredi splice_read = default_file_splice_read; 11426818173bSMiklos Szeredi 11436818173bSMiklos Szeredi return splice_read(in, ppos, pipe, len, flags); 11445274f052SJens Axboe } 11455274f052SJens Axboe 1146932cc6d4SJens Axboe /** 1147932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 1148932cc6d4SJens Axboe * @in: file to splice from 1149932cc6d4SJens Axboe * @sd: actor information on where to splice to 1150932cc6d4SJens Axboe * @actor: handles the data splicing 1151932cc6d4SJens Axboe * 1152932cc6d4SJens Axboe * Description: 1153932cc6d4SJens Axboe * This is a special case helper to splice directly between two 1154932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 1155932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 1156932cc6d4SJens Axboe * that process. 1157932cc6d4SJens Axboe * 1158c66ab6faSJens Axboe */ 1159c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 1160c66ab6faSJens Axboe splice_direct_actor *actor) 1161b92ce558SJens Axboe { 1162b92ce558SJens Axboe struct pipe_inode_info *pipe; 1163b92ce558SJens Axboe long ret, bytes; 1164b92ce558SJens Axboe umode_t i_mode; 1165c66ab6faSJens Axboe size_t len; 1166c66ab6faSJens Axboe int i, flags; 1167b92ce558SJens Axboe 1168b92ce558SJens Axboe /* 1169b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 1170b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 1171b92ce558SJens Axboe * piped splicing for that! 1172b92ce558SJens Axboe */ 1173496ad9aaSAl Viro i_mode = file_inode(in)->i_mode; 1174b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 1175b92ce558SJens Axboe return -EINVAL; 1176b92ce558SJens Axboe 1177b92ce558SJens Axboe /* 1178b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 1179b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 1180b92ce558SJens Axboe */ 1181b92ce558SJens Axboe pipe = current->splice_pipe; 118249570e9bSJens Axboe if (unlikely(!pipe)) { 11837bee130eSAl Viro pipe = alloc_pipe_info(); 1184b92ce558SJens Axboe if (!pipe) 1185b92ce558SJens Axboe return -ENOMEM; 1186b92ce558SJens Axboe 1187b92ce558SJens Axboe /* 1188b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 118900522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 1190b92ce558SJens Axboe * PIPE_READERS appropriately. 1191b92ce558SJens Axboe */ 1192b92ce558SJens Axboe pipe->readers = 1; 1193b92ce558SJens Axboe 1194b92ce558SJens Axboe current->splice_pipe = pipe; 1195b92ce558SJens Axboe } 1196b92ce558SJens Axboe 1197b92ce558SJens Axboe /* 119873d62d83SIngo Molnar * Do the splice. 1199b92ce558SJens Axboe */ 1200b92ce558SJens Axboe ret = 0; 1201b92ce558SJens Axboe bytes = 0; 1202c66ab6faSJens Axboe len = sd->total_len; 1203c66ab6faSJens Axboe flags = sd->flags; 1204c66ab6faSJens Axboe 1205c66ab6faSJens Axboe /* 1206c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 1207c66ab6faSJens Axboe */ 1208c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 1209b92ce558SJens Axboe 1210b92ce558SJens Axboe while (len) { 121151a92c0fSJens Axboe size_t read_len; 1212a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 1213b92ce558SJens Axboe 1214bcd4f3acSJens Axboe ret = do_splice_to(in, &pos, pipe, len, flags); 121551a92c0fSJens Axboe if (unlikely(ret <= 0)) 1216b92ce558SJens Axboe goto out_release; 1217b92ce558SJens Axboe 1218b92ce558SJens Axboe read_len = ret; 1219c66ab6faSJens Axboe sd->total_len = read_len; 1220b92ce558SJens Axboe 1221b92ce558SJens Axboe /* 1222b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 1223b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 1224b92ce558SJens Axboe * could get stuck data in the internal pipe: 1225b92ce558SJens Axboe */ 1226c66ab6faSJens Axboe ret = actor(pipe, sd); 1227a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 1228a82c53a0STom Zanussi sd->pos = prev_pos; 1229b92ce558SJens Axboe goto out_release; 1230a82c53a0STom Zanussi } 1231b92ce558SJens Axboe 1232b92ce558SJens Axboe bytes += ret; 1233b92ce558SJens Axboe len -= ret; 1234bcd4f3acSJens Axboe sd->pos = pos; 1235b92ce558SJens Axboe 1236a82c53a0STom Zanussi if (ret < read_len) { 1237a82c53a0STom Zanussi sd->pos = prev_pos + ret; 123851a92c0fSJens Axboe goto out_release; 1239b92ce558SJens Axboe } 1240a82c53a0STom Zanussi } 1241b92ce558SJens Axboe 12429e97198dSJens Axboe done: 1243b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 12449e97198dSJens Axboe file_accessed(in); 1245b92ce558SJens Axboe return bytes; 1246b92ce558SJens Axboe 1247b92ce558SJens Axboe out_release: 1248b92ce558SJens Axboe /* 1249b92ce558SJens Axboe * If we did an incomplete transfer we must release 1250b92ce558SJens Axboe * the pipe buffers in question: 1251b92ce558SJens Axboe */ 125235f3d14dSJens Axboe for (i = 0; i < pipe->buffers; i++) { 1253b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1254b92ce558SJens Axboe 1255b92ce558SJens Axboe if (buf->ops) { 1256b92ce558SJens Axboe buf->ops->release(pipe, buf); 1257b92ce558SJens Axboe buf->ops = NULL; 1258b92ce558SJens Axboe } 1259b92ce558SJens Axboe } 1260b92ce558SJens Axboe 12619e97198dSJens Axboe if (!bytes) 12629e97198dSJens Axboe bytes = ret; 1263b92ce558SJens Axboe 12649e97198dSJens Axboe goto done; 1265c66ab6faSJens Axboe } 1266c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1267c66ab6faSJens Axboe 1268c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1269c66ab6faSJens Axboe struct splice_desc *sd) 1270c66ab6faSJens Axboe { 12716a14b90bSJens Axboe struct file *file = sd->u.file; 1272c66ab6faSJens Axboe 12737995bd28SAl Viro return do_splice_from(pipe, file, sd->opos, sd->total_len, 12742cb4b05eSChangli Gao sd->flags); 1275c66ab6faSJens Axboe } 1276c66ab6faSJens Axboe 1277932cc6d4SJens Axboe /** 1278932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1279932cc6d4SJens Axboe * @in: file to splice from 1280932cc6d4SJens Axboe * @ppos: input file offset 1281932cc6d4SJens Axboe * @out: file to splice to 1282acdb37c3SRandy Dunlap * @opos: output file offset 1283932cc6d4SJens Axboe * @len: number of bytes to splice 1284932cc6d4SJens Axboe * @flags: splice modifier flags 1285932cc6d4SJens Axboe * 1286932cc6d4SJens Axboe * Description: 1287932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1288932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1289932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1290932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1291932cc6d4SJens Axboe * 1292932cc6d4SJens Axboe */ 1293c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 12947995bd28SAl Viro loff_t *opos, size_t len, unsigned int flags) 1295c66ab6faSJens Axboe { 1296c66ab6faSJens Axboe struct splice_desc sd = { 1297c66ab6faSJens Axboe .len = len, 1298c66ab6faSJens Axboe .total_len = len, 1299c66ab6faSJens Axboe .flags = flags, 1300c66ab6faSJens Axboe .pos = *ppos, 13016a14b90bSJens Axboe .u.file = out, 13027995bd28SAl Viro .opos = opos, 1303c66ab6faSJens Axboe }; 130451a92c0fSJens Axboe long ret; 1305c66ab6faSJens Axboe 130618c67cb9SAl Viro if (unlikely(!(out->f_mode & FMODE_WRITE))) 130718c67cb9SAl Viro return -EBADF; 130818c67cb9SAl Viro 130918c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 131018c67cb9SAl Viro return -EINVAL; 131118c67cb9SAl Viro 131218c67cb9SAl Viro ret = rw_verify_area(WRITE, out, opos, len); 131318c67cb9SAl Viro if (unlikely(ret < 0)) 131418c67cb9SAl Viro return ret; 131518c67cb9SAl Viro 1316c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 131751a92c0fSJens Axboe if (ret > 0) 1318a82c53a0STom Zanussi *ppos = sd.pos; 131951a92c0fSJens Axboe 1320c66ab6faSJens Axboe return ret; 1321b92ce558SJens Axboe } 1322b92ce558SJens Axboe 13237c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 13247c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 13257c77f0b3SMiklos Szeredi size_t len, unsigned int flags); 1326ddac0d39SJens Axboe 1327ddac0d39SJens Axboe /* 132883f9135bSJens Axboe * Determine where to splice to/from. 132983f9135bSJens Axboe */ 1330529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1331529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1332529565dcSIngo Molnar size_t len, unsigned int flags) 13335274f052SJens Axboe { 13347c77f0b3SMiklos Szeredi struct pipe_inode_info *ipipe; 13357c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe; 13367995bd28SAl Viro loff_t offset; 1337a4514ebdSJens Axboe long ret; 13385274f052SJens Axboe 133971993e62SLinus Torvalds ipipe = get_pipe_info(in); 134071993e62SLinus Torvalds opipe = get_pipe_info(out); 13417c77f0b3SMiklos Szeredi 13427c77f0b3SMiklos Szeredi if (ipipe && opipe) { 13437c77f0b3SMiklos Szeredi if (off_in || off_out) 13447c77f0b3SMiklos Szeredi return -ESPIPE; 13457c77f0b3SMiklos Szeredi 13467c77f0b3SMiklos Szeredi if (!(in->f_mode & FMODE_READ)) 13477c77f0b3SMiklos Szeredi return -EBADF; 13487c77f0b3SMiklos Szeredi 13497c77f0b3SMiklos Szeredi if (!(out->f_mode & FMODE_WRITE)) 13507c77f0b3SMiklos Szeredi return -EBADF; 13517c77f0b3SMiklos Szeredi 13527c77f0b3SMiklos Szeredi /* Splicing to self would be fun, but... */ 13537c77f0b3SMiklos Szeredi if (ipipe == opipe) 13547c77f0b3SMiklos Szeredi return -EINVAL; 13557c77f0b3SMiklos Szeredi 13567c77f0b3SMiklos Szeredi return splice_pipe_to_pipe(ipipe, opipe, len, flags); 13577c77f0b3SMiklos Szeredi } 13587c77f0b3SMiklos Szeredi 13597c77f0b3SMiklos Szeredi if (ipipe) { 1360529565dcSIngo Molnar if (off_in) 1361529565dcSIngo Molnar return -ESPIPE; 1362b92ce558SJens Axboe if (off_out) { 136319c9a49bSChangli Gao if (!(out->f_mode & FMODE_PWRITE)) 1364b92ce558SJens Axboe return -EINVAL; 1365cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1366b92ce558SJens Axboe return -EFAULT; 13677995bd28SAl Viro } else { 13687995bd28SAl Viro offset = out->f_pos; 13697995bd28SAl Viro } 1370529565dcSIngo Molnar 137118c67cb9SAl Viro if (unlikely(!(out->f_mode & FMODE_WRITE))) 137218c67cb9SAl Viro return -EBADF; 137318c67cb9SAl Viro 137418c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 137518c67cb9SAl Viro return -EINVAL; 137618c67cb9SAl Viro 137718c67cb9SAl Viro ret = rw_verify_area(WRITE, out, &offset, len); 137818c67cb9SAl Viro if (unlikely(ret < 0)) 137918c67cb9SAl Viro return ret; 138018c67cb9SAl Viro 1381500368f7SAl Viro file_start_write(out); 13827995bd28SAl Viro ret = do_splice_from(ipipe, out, &offset, len, flags); 1383500368f7SAl Viro file_end_write(out); 1384a4514ebdSJens Axboe 13857995bd28SAl Viro if (!off_out) 13867995bd28SAl Viro out->f_pos = offset; 13877995bd28SAl Viro else if (copy_to_user(off_out, &offset, sizeof(loff_t))) 1388a4514ebdSJens Axboe ret = -EFAULT; 1389a4514ebdSJens Axboe 1390a4514ebdSJens Axboe return ret; 1391529565dcSIngo Molnar } 13925274f052SJens Axboe 13937c77f0b3SMiklos Szeredi if (opipe) { 1394529565dcSIngo Molnar if (off_out) 1395529565dcSIngo Molnar return -ESPIPE; 1396b92ce558SJens Axboe if (off_in) { 139719c9a49bSChangli Gao if (!(in->f_mode & FMODE_PREAD)) 1398b92ce558SJens Axboe return -EINVAL; 1399cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1400b92ce558SJens Axboe return -EFAULT; 14017995bd28SAl Viro } else { 14027995bd28SAl Viro offset = in->f_pos; 14037995bd28SAl Viro } 1404529565dcSIngo Molnar 14057995bd28SAl Viro ret = do_splice_to(in, &offset, opipe, len, flags); 1406a4514ebdSJens Axboe 14077995bd28SAl Viro if (!off_in) 14087995bd28SAl Viro in->f_pos = offset; 14097995bd28SAl Viro else if (copy_to_user(off_in, &offset, sizeof(loff_t))) 1410a4514ebdSJens Axboe ret = -EFAULT; 1411a4514ebdSJens Axboe 1412a4514ebdSJens Axboe return ret; 1413529565dcSIngo Molnar } 14145274f052SJens Axboe 14155274f052SJens Axboe return -EINVAL; 14165274f052SJens Axboe } 14175274f052SJens Axboe 1418912d35f8SJens Axboe /* 1419912d35f8SJens Axboe * Map an iov into an array of pages and offset/length tupples. With the 1420912d35f8SJens Axboe * partial_page structure, we can map several non-contiguous ranges into 1421912d35f8SJens Axboe * our ones pages[] map instead of splitting that operation into pieces. 1422912d35f8SJens Axboe * Could easily be exported as a generic helper for other users, in which 1423912d35f8SJens Axboe * case one would probably want to add a 'max_nr_pages' parameter as well. 1424912d35f8SJens Axboe */ 1425912d35f8SJens Axboe static int get_iovec_page_array(const struct iovec __user *iov, 1426912d35f8SJens Axboe unsigned int nr_vecs, struct page **pages, 1427bd1a68b5SEric Dumazet struct partial_page *partial, bool aligned, 142835f3d14dSJens Axboe unsigned int pipe_buffers) 1429912d35f8SJens Axboe { 1430912d35f8SJens Axboe int buffers = 0, error = 0; 1431912d35f8SJens Axboe 1432912d35f8SJens Axboe while (nr_vecs) { 1433912d35f8SJens Axboe unsigned long off, npages; 143475723957SLinus Torvalds struct iovec entry; 1435912d35f8SJens Axboe void __user *base; 1436912d35f8SJens Axboe size_t len; 1437912d35f8SJens Axboe int i; 1438912d35f8SJens Axboe 143975723957SLinus Torvalds error = -EFAULT; 1440bc40d73cSNick Piggin if (copy_from_user(&entry, iov, sizeof(entry))) 1441912d35f8SJens Axboe break; 144275723957SLinus Torvalds 144375723957SLinus Torvalds base = entry.iov_base; 144475723957SLinus Torvalds len = entry.iov_len; 1445912d35f8SJens Axboe 1446912d35f8SJens Axboe /* 1447912d35f8SJens Axboe * Sanity check this iovec. 0 read succeeds. 1448912d35f8SJens Axboe */ 144975723957SLinus Torvalds error = 0; 1450912d35f8SJens Axboe if (unlikely(!len)) 1451912d35f8SJens Axboe break; 1452912d35f8SJens Axboe error = -EFAULT; 1453712a30e6SBastian Blank if (!access_ok(VERIFY_READ, base, len)) 1454912d35f8SJens Axboe break; 1455912d35f8SJens Axboe 1456912d35f8SJens Axboe /* 1457912d35f8SJens Axboe * Get this base offset and number of pages, then map 1458912d35f8SJens Axboe * in the user pages. 1459912d35f8SJens Axboe */ 1460912d35f8SJens Axboe off = (unsigned long) base & ~PAGE_MASK; 14617afa6fd0SJens Axboe 14627afa6fd0SJens Axboe /* 14637afa6fd0SJens Axboe * If asked for alignment, the offset must be zero and the 14647afa6fd0SJens Axboe * length a multiple of the PAGE_SIZE. 14657afa6fd0SJens Axboe */ 14667afa6fd0SJens Axboe error = -EINVAL; 14677afa6fd0SJens Axboe if (aligned && (off || len & ~PAGE_MASK)) 14687afa6fd0SJens Axboe break; 14697afa6fd0SJens Axboe 1470912d35f8SJens Axboe npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 147135f3d14dSJens Axboe if (npages > pipe_buffers - buffers) 147235f3d14dSJens Axboe npages = pipe_buffers - buffers; 1473912d35f8SJens Axboe 1474bc40d73cSNick Piggin error = get_user_pages_fast((unsigned long)base, npages, 1475bc40d73cSNick Piggin 0, &pages[buffers]); 1476912d35f8SJens Axboe 1477912d35f8SJens Axboe if (unlikely(error <= 0)) 1478912d35f8SJens Axboe break; 1479912d35f8SJens Axboe 1480912d35f8SJens Axboe /* 1481912d35f8SJens Axboe * Fill this contiguous range into the partial page map. 1482912d35f8SJens Axboe */ 1483912d35f8SJens Axboe for (i = 0; i < error; i++) { 14847591489aSJens Axboe const int plen = min_t(size_t, len, PAGE_SIZE - off); 1485912d35f8SJens Axboe 1486912d35f8SJens Axboe partial[buffers].offset = off; 1487912d35f8SJens Axboe partial[buffers].len = plen; 1488912d35f8SJens Axboe 1489912d35f8SJens Axboe off = 0; 1490912d35f8SJens Axboe len -= plen; 1491912d35f8SJens Axboe buffers++; 1492912d35f8SJens Axboe } 1493912d35f8SJens Axboe 1494912d35f8SJens Axboe /* 1495912d35f8SJens Axboe * We didn't complete this iov, stop here since it probably 1496912d35f8SJens Axboe * means we have to move some of this into a pipe to 1497912d35f8SJens Axboe * be able to continue. 1498912d35f8SJens Axboe */ 1499912d35f8SJens Axboe if (len) 1500912d35f8SJens Axboe break; 1501912d35f8SJens Axboe 1502912d35f8SJens Axboe /* 1503912d35f8SJens Axboe * Don't continue if we mapped fewer pages than we asked for, 1504912d35f8SJens Axboe * or if we mapped the max number of pages that we have 1505912d35f8SJens Axboe * room for. 1506912d35f8SJens Axboe */ 150735f3d14dSJens Axboe if (error < npages || buffers == pipe_buffers) 1508912d35f8SJens Axboe break; 1509912d35f8SJens Axboe 1510912d35f8SJens Axboe nr_vecs--; 1511912d35f8SJens Axboe iov++; 1512912d35f8SJens Axboe } 1513912d35f8SJens Axboe 1514912d35f8SJens Axboe if (buffers) 1515912d35f8SJens Axboe return buffers; 1516912d35f8SJens Axboe 1517912d35f8SJens Axboe return error; 1518912d35f8SJens Axboe } 1519912d35f8SJens Axboe 15206a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 15216a14b90bSJens Axboe struct splice_desc *sd) 15226a14b90bSJens Axboe { 15236130f531SAl Viro int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data); 15246130f531SAl Viro return n == sd->len ? n : -EFAULT; 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 */ 15316130f531SAl Viro static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov, 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 long ret; 15376130f531SAl Viro struct iovec iovstack[UIO_FASTIOV]; 15386130f531SAl Viro struct iovec *iov = iovstack; 15396130f531SAl Viro struct iov_iter iter; 15406130f531SAl Viro ssize_t count = 0; 15416a14b90bSJens Axboe 154271993e62SLinus Torvalds pipe = get_pipe_info(file); 15436a14b90bSJens Axboe if (!pipe) 15446a14b90bSJens Axboe return -EBADF; 15456a14b90bSJens Axboe 15466130f531SAl Viro ret = rw_copy_check_uvector(READ, uiov, nr_segs, 15476130f531SAl Viro ARRAY_SIZE(iovstack), iovstack, &iov); 15486130f531SAl Viro if (ret <= 0) 15496130f531SAl Viro return ret; 15506a14b90bSJens Axboe 15516130f531SAl Viro iov_iter_init(&iter, iov, nr_segs, count, 0); 15528811930dSJens Axboe 15536a14b90bSJens Axboe sd.len = 0; 15546130f531SAl Viro sd.total_len = count; 15556a14b90bSJens Axboe sd.flags = flags; 15566130f531SAl Viro sd.u.data = &iter; 15576a14b90bSJens Axboe sd.pos = 0; 15586a14b90bSJens Axboe 15596130f531SAl Viro pipe_lock(pipe); 15606130f531SAl Viro ret = __splice_from_pipe(pipe, &sd, pipe_to_user); 156161e0d47cSMiklos Szeredi pipe_unlock(pipe); 15626a14b90bSJens Axboe 15636130f531SAl Viro if (iov != iovstack) 15646130f531SAl Viro kfree(iov); 15656a14b90bSJens Axboe 15666a14b90bSJens Axboe return ret; 15676a14b90bSJens Axboe } 15686a14b90bSJens Axboe 1569912d35f8SJens Axboe /* 1570912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1571912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1572912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1573912d35f8SJens Axboe */ 15746a14b90bSJens Axboe static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, 1575912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1576912d35f8SJens Axboe { 1577ddac0d39SJens Axboe struct pipe_inode_info *pipe; 157835f3d14dSJens Axboe struct page *pages[PIPE_DEF_BUFFERS]; 157935f3d14dSJens Axboe struct partial_page partial[PIPE_DEF_BUFFERS]; 1580912d35f8SJens Axboe struct splice_pipe_desc spd = { 1581912d35f8SJens Axboe .pages = pages, 1582912d35f8SJens Axboe .partial = partial, 1583047fe360SEric Dumazet .nr_pages_max = PIPE_DEF_BUFFERS, 1584912d35f8SJens Axboe .flags = flags, 1585912d35f8SJens Axboe .ops = &user_page_pipe_buf_ops, 1586bbdfc2f7SJens Axboe .spd_release = spd_release_page, 1587912d35f8SJens Axboe }; 158835f3d14dSJens Axboe long ret; 1589912d35f8SJens Axboe 159071993e62SLinus Torvalds pipe = get_pipe_info(file); 1591ddac0d39SJens Axboe if (!pipe) 1592912d35f8SJens Axboe return -EBADF; 1593912d35f8SJens Axboe 159435f3d14dSJens Axboe if (splice_grow_spd(pipe, &spd)) 159535f3d14dSJens Axboe return -ENOMEM; 1596912d35f8SJens Axboe 159735f3d14dSJens Axboe spd.nr_pages = get_iovec_page_array(iov, nr_segs, spd.pages, 1598bd1a68b5SEric Dumazet spd.partial, false, 1599047fe360SEric Dumazet spd.nr_pages_max); 160035f3d14dSJens Axboe if (spd.nr_pages <= 0) 160135f3d14dSJens Axboe ret = spd.nr_pages; 160235f3d14dSJens Axboe else 160335f3d14dSJens Axboe ret = splice_to_pipe(pipe, &spd); 160435f3d14dSJens Axboe 1605047fe360SEric Dumazet splice_shrink_spd(&spd); 160635f3d14dSJens Axboe return ret; 1607912d35f8SJens Axboe } 1608912d35f8SJens Axboe 16096a14b90bSJens Axboe /* 16106a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 16116a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 16126a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 16136a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 16146a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 16156a14b90bSJens Axboe * solutions for that: 16166a14b90bSJens Axboe * 16176a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 16186a14b90bSJens Axboe * do a regular read() on the buffer anyway. 16196a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 16206a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 16216a14b90bSJens Axboe * 16226a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 16236a14b90bSJens Axboe * 16246a14b90bSJens Axboe */ 1625836f92adSHeiko Carstens SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, iov, 1626836f92adSHeiko Carstens unsigned long, nr_segs, unsigned int, flags) 1627912d35f8SJens Axboe { 16282903ff01SAl Viro struct fd f; 1629912d35f8SJens Axboe long error; 1630912d35f8SJens Axboe 16316a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 16326a14b90bSJens Axboe return -EINVAL; 16336a14b90bSJens Axboe else if (unlikely(!nr_segs)) 16346a14b90bSJens Axboe return 0; 16356a14b90bSJens Axboe 1636912d35f8SJens Axboe error = -EBADF; 16372903ff01SAl Viro f = fdget(fd); 16382903ff01SAl Viro if (f.file) { 16392903ff01SAl Viro if (f.file->f_mode & FMODE_WRITE) 16402903ff01SAl Viro error = vmsplice_to_pipe(f.file, iov, nr_segs, flags); 16412903ff01SAl Viro else if (f.file->f_mode & FMODE_READ) 16422903ff01SAl Viro error = vmsplice_to_user(f.file, iov, nr_segs, flags); 1643912d35f8SJens Axboe 16442903ff01SAl Viro fdput(f); 1645912d35f8SJens Axboe } 1646912d35f8SJens Axboe 1647912d35f8SJens Axboe return error; 1648912d35f8SJens Axboe } 1649912d35f8SJens Axboe 165076b021d0SAl Viro #ifdef CONFIG_COMPAT 165176b021d0SAl Viro COMPAT_SYSCALL_DEFINE4(vmsplice, int, fd, const struct compat_iovec __user *, iov32, 165276b021d0SAl Viro unsigned int, nr_segs, unsigned int, flags) 165376b021d0SAl Viro { 165476b021d0SAl Viro unsigned i; 165576b021d0SAl Viro struct iovec __user *iov; 165676b021d0SAl Viro if (nr_segs > UIO_MAXIOV) 165776b021d0SAl Viro return -EINVAL; 165876b021d0SAl Viro iov = compat_alloc_user_space(nr_segs * sizeof(struct iovec)); 165976b021d0SAl Viro for (i = 0; i < nr_segs; i++) { 166076b021d0SAl Viro struct compat_iovec v; 166176b021d0SAl Viro if (get_user(v.iov_base, &iov32[i].iov_base) || 166276b021d0SAl Viro get_user(v.iov_len, &iov32[i].iov_len) || 166376b021d0SAl Viro put_user(compat_ptr(v.iov_base), &iov[i].iov_base) || 166476b021d0SAl Viro put_user(v.iov_len, &iov[i].iov_len)) 166576b021d0SAl Viro return -EFAULT; 166676b021d0SAl Viro } 166776b021d0SAl Viro return sys_vmsplice(fd, iov, nr_segs, flags); 166876b021d0SAl Viro } 166976b021d0SAl Viro #endif 167076b021d0SAl Viro 1671836f92adSHeiko Carstens SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, 1672836f92adSHeiko Carstens int, fd_out, loff_t __user *, off_out, 1673836f92adSHeiko Carstens size_t, len, unsigned int, flags) 16745274f052SJens Axboe { 16752903ff01SAl Viro struct fd in, out; 16765274f052SJens Axboe long error; 16775274f052SJens Axboe 16785274f052SJens Axboe if (unlikely(!len)) 16795274f052SJens Axboe return 0; 16805274f052SJens Axboe 16815274f052SJens Axboe error = -EBADF; 16822903ff01SAl Viro in = fdget(fd_in); 16832903ff01SAl Viro if (in.file) { 16842903ff01SAl Viro if (in.file->f_mode & FMODE_READ) { 16852903ff01SAl Viro out = fdget(fd_out); 16862903ff01SAl Viro if (out.file) { 16872903ff01SAl Viro if (out.file->f_mode & FMODE_WRITE) 16882903ff01SAl Viro error = do_splice(in.file, off_in, 16892903ff01SAl Viro out.file, off_out, 1690529565dcSIngo Molnar len, flags); 16912903ff01SAl Viro fdput(out); 16925274f052SJens Axboe } 16935274f052SJens Axboe } 16942903ff01SAl Viro fdput(in); 16955274f052SJens Axboe } 16965274f052SJens Axboe return error; 16975274f052SJens Axboe } 169870524490SJens Axboe 169970524490SJens Axboe /* 1700aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1701aadd06e5SJens Axboe * return an appropriate error. 1702aadd06e5SJens Axboe */ 17037c77f0b3SMiklos Szeredi static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1704aadd06e5SJens Axboe { 1705aadd06e5SJens Axboe int ret; 1706aadd06e5SJens Axboe 1707aadd06e5SJens Axboe /* 1708aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1709aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1710aadd06e5SJens Axboe */ 1711aadd06e5SJens Axboe if (pipe->nrbufs) 1712aadd06e5SJens Axboe return 0; 1713aadd06e5SJens Axboe 1714aadd06e5SJens Axboe ret = 0; 171561e0d47cSMiklos Szeredi pipe_lock(pipe); 1716aadd06e5SJens Axboe 1717aadd06e5SJens Axboe while (!pipe->nrbufs) { 1718aadd06e5SJens Axboe if (signal_pending(current)) { 1719aadd06e5SJens Axboe ret = -ERESTARTSYS; 1720aadd06e5SJens Axboe break; 1721aadd06e5SJens Axboe } 1722aadd06e5SJens Axboe if (!pipe->writers) 1723aadd06e5SJens Axboe break; 1724aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1725aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1726aadd06e5SJens Axboe ret = -EAGAIN; 1727aadd06e5SJens Axboe break; 1728aadd06e5SJens Axboe } 1729aadd06e5SJens Axboe } 1730aadd06e5SJens Axboe pipe_wait(pipe); 1731aadd06e5SJens Axboe } 1732aadd06e5SJens Axboe 173361e0d47cSMiklos Szeredi pipe_unlock(pipe); 1734aadd06e5SJens Axboe return ret; 1735aadd06e5SJens Axboe } 1736aadd06e5SJens Axboe 1737aadd06e5SJens Axboe /* 1738aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1739aadd06e5SJens Axboe * return an appropriate error. 1740aadd06e5SJens Axboe */ 17417c77f0b3SMiklos Szeredi static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1742aadd06e5SJens Axboe { 1743aadd06e5SJens Axboe int ret; 1744aadd06e5SJens Axboe 1745aadd06e5SJens Axboe /* 1746aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1747aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1748aadd06e5SJens Axboe */ 174935f3d14dSJens Axboe if (pipe->nrbufs < pipe->buffers) 1750aadd06e5SJens Axboe return 0; 1751aadd06e5SJens Axboe 1752aadd06e5SJens Axboe ret = 0; 175361e0d47cSMiklos Szeredi pipe_lock(pipe); 1754aadd06e5SJens Axboe 175535f3d14dSJens Axboe while (pipe->nrbufs >= pipe->buffers) { 1756aadd06e5SJens Axboe if (!pipe->readers) { 1757aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1758aadd06e5SJens Axboe ret = -EPIPE; 1759aadd06e5SJens Axboe break; 1760aadd06e5SJens Axboe } 1761aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1762aadd06e5SJens Axboe ret = -EAGAIN; 1763aadd06e5SJens Axboe break; 1764aadd06e5SJens Axboe } 1765aadd06e5SJens Axboe if (signal_pending(current)) { 1766aadd06e5SJens Axboe ret = -ERESTARTSYS; 1767aadd06e5SJens Axboe break; 1768aadd06e5SJens Axboe } 1769aadd06e5SJens Axboe pipe->waiting_writers++; 1770aadd06e5SJens Axboe pipe_wait(pipe); 1771aadd06e5SJens Axboe pipe->waiting_writers--; 1772aadd06e5SJens Axboe } 1773aadd06e5SJens Axboe 177461e0d47cSMiklos Szeredi pipe_unlock(pipe); 1775aadd06e5SJens Axboe return ret; 1776aadd06e5SJens Axboe } 1777aadd06e5SJens Axboe 1778aadd06e5SJens Axboe /* 17797c77f0b3SMiklos Szeredi * Splice contents of ipipe to opipe. 17807c77f0b3SMiklos Szeredi */ 17817c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 17827c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 17837c77f0b3SMiklos Szeredi size_t len, unsigned int flags) 17847c77f0b3SMiklos Szeredi { 17857c77f0b3SMiklos Szeredi struct pipe_buffer *ibuf, *obuf; 17867c77f0b3SMiklos Szeredi int ret = 0, nbuf; 17877c77f0b3SMiklos Szeredi bool input_wakeup = false; 17887c77f0b3SMiklos Szeredi 17897c77f0b3SMiklos Szeredi 17907c77f0b3SMiklos Szeredi retry: 17917c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 17927c77f0b3SMiklos Szeredi if (ret) 17937c77f0b3SMiklos Szeredi return ret; 17947c77f0b3SMiklos Szeredi 17957c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 17967c77f0b3SMiklos Szeredi if (ret) 17977c77f0b3SMiklos Szeredi return ret; 17987c77f0b3SMiklos Szeredi 17997c77f0b3SMiklos Szeredi /* 18007c77f0b3SMiklos Szeredi * Potential ABBA deadlock, work around it by ordering lock 18017c77f0b3SMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 18027c77f0b3SMiklos Szeredi * could deadlock (one doing tee from A -> B, the other from B -> A). 18037c77f0b3SMiklos Szeredi */ 18047c77f0b3SMiklos Szeredi pipe_double_lock(ipipe, opipe); 18057c77f0b3SMiklos Szeredi 18067c77f0b3SMiklos Szeredi do { 18077c77f0b3SMiklos Szeredi if (!opipe->readers) { 18087c77f0b3SMiklos Szeredi send_sig(SIGPIPE, current, 0); 18097c77f0b3SMiklos Szeredi if (!ret) 18107c77f0b3SMiklos Szeredi ret = -EPIPE; 18117c77f0b3SMiklos Szeredi break; 18127c77f0b3SMiklos Szeredi } 18137c77f0b3SMiklos Szeredi 18147c77f0b3SMiklos Szeredi if (!ipipe->nrbufs && !ipipe->writers) 18157c77f0b3SMiklos Szeredi break; 18167c77f0b3SMiklos Szeredi 18177c77f0b3SMiklos Szeredi /* 18187c77f0b3SMiklos Szeredi * Cannot make any progress, because either the input 18197c77f0b3SMiklos Szeredi * pipe is empty or the output pipe is full. 18207c77f0b3SMiklos Szeredi */ 182135f3d14dSJens Axboe if (!ipipe->nrbufs || opipe->nrbufs >= opipe->buffers) { 18227c77f0b3SMiklos Szeredi /* Already processed some buffers, break */ 18237c77f0b3SMiklos Szeredi if (ret) 18247c77f0b3SMiklos Szeredi break; 18257c77f0b3SMiklos Szeredi 18267c77f0b3SMiklos Szeredi if (flags & SPLICE_F_NONBLOCK) { 18277c77f0b3SMiklos Szeredi ret = -EAGAIN; 18287c77f0b3SMiklos Szeredi break; 18297c77f0b3SMiklos Szeredi } 18307c77f0b3SMiklos Szeredi 18317c77f0b3SMiklos Szeredi /* 18327c77f0b3SMiklos Szeredi * We raced with another reader/writer and haven't 18337c77f0b3SMiklos Szeredi * managed to process any buffers. A zero return 18347c77f0b3SMiklos Szeredi * value means EOF, so retry instead. 18357c77f0b3SMiklos Szeredi */ 18367c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 18377c77f0b3SMiklos Szeredi pipe_unlock(opipe); 18387c77f0b3SMiklos Szeredi goto retry; 18397c77f0b3SMiklos Szeredi } 18407c77f0b3SMiklos Szeredi 18417c77f0b3SMiklos Szeredi ibuf = ipipe->bufs + ipipe->curbuf; 184235f3d14dSJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (opipe->buffers - 1); 18437c77f0b3SMiklos Szeredi obuf = opipe->bufs + nbuf; 18447c77f0b3SMiklos Szeredi 18457c77f0b3SMiklos Szeredi if (len >= ibuf->len) { 18467c77f0b3SMiklos Szeredi /* 18477c77f0b3SMiklos Szeredi * Simply move the whole buffer from ipipe to opipe 18487c77f0b3SMiklos Szeredi */ 18497c77f0b3SMiklos Szeredi *obuf = *ibuf; 18507c77f0b3SMiklos Szeredi ibuf->ops = NULL; 18517c77f0b3SMiklos Szeredi opipe->nrbufs++; 185235f3d14dSJens Axboe ipipe->curbuf = (ipipe->curbuf + 1) & (ipipe->buffers - 1); 18537c77f0b3SMiklos Szeredi ipipe->nrbufs--; 18547c77f0b3SMiklos Szeredi input_wakeup = true; 18557c77f0b3SMiklos Szeredi } else { 18567c77f0b3SMiklos Szeredi /* 18577c77f0b3SMiklos Szeredi * Get a reference to this pipe buffer, 18587c77f0b3SMiklos Szeredi * so we can copy the contents over. 18597c77f0b3SMiklos Szeredi */ 18607c77f0b3SMiklos Szeredi ibuf->ops->get(ipipe, ibuf); 18617c77f0b3SMiklos Szeredi *obuf = *ibuf; 18627c77f0b3SMiklos Szeredi 18637c77f0b3SMiklos Szeredi /* 18647c77f0b3SMiklos Szeredi * Don't inherit the gift flag, we need to 18657c77f0b3SMiklos Szeredi * prevent multiple steals of this page. 18667c77f0b3SMiklos Szeredi */ 18677c77f0b3SMiklos Szeredi obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 18687c77f0b3SMiklos Szeredi 18697c77f0b3SMiklos Szeredi obuf->len = len; 18707c77f0b3SMiklos Szeredi opipe->nrbufs++; 18717c77f0b3SMiklos Szeredi ibuf->offset += obuf->len; 18727c77f0b3SMiklos Szeredi ibuf->len -= obuf->len; 18737c77f0b3SMiklos Szeredi } 18747c77f0b3SMiklos Szeredi ret += obuf->len; 18757c77f0b3SMiklos Szeredi len -= obuf->len; 18767c77f0b3SMiklos Szeredi } while (len); 18777c77f0b3SMiklos Szeredi 18787c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 18797c77f0b3SMiklos Szeredi pipe_unlock(opipe); 18807c77f0b3SMiklos Szeredi 18817c77f0b3SMiklos Szeredi /* 18827c77f0b3SMiklos Szeredi * If we put data in the output pipe, wakeup any potential readers. 18837c77f0b3SMiklos Szeredi */ 1884825cdcb1SNamhyung Kim if (ret > 0) 1885825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 1886825cdcb1SNamhyung Kim 18877c77f0b3SMiklos Szeredi if (input_wakeup) 18887c77f0b3SMiklos Szeredi wakeup_pipe_writers(ipipe); 18897c77f0b3SMiklos Szeredi 18907c77f0b3SMiklos Szeredi return ret; 18917c77f0b3SMiklos Szeredi } 18927c77f0b3SMiklos Szeredi 18937c77f0b3SMiklos Szeredi /* 189470524490SJens Axboe * Link contents of ipipe to opipe. 189570524490SJens Axboe */ 189670524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 189770524490SJens Axboe struct pipe_inode_info *opipe, 189870524490SJens Axboe size_t len, unsigned int flags) 189970524490SJens Axboe { 190070524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1901aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 190270524490SJens Axboe 190370524490SJens Axboe /* 190470524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 190561e0d47cSMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 190670524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 190770524490SJens Axboe */ 190861e0d47cSMiklos Szeredi pipe_double_lock(ipipe, opipe); 190970524490SJens Axboe 1910aadd06e5SJens Axboe do { 191170524490SJens Axboe if (!opipe->readers) { 191270524490SJens Axboe send_sig(SIGPIPE, current, 0); 191370524490SJens Axboe if (!ret) 191470524490SJens Axboe ret = -EPIPE; 191570524490SJens Axboe break; 191670524490SJens Axboe } 191770524490SJens Axboe 191870524490SJens Axboe /* 1919aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1920aadd06e5SJens Axboe * output room, break. 192170524490SJens Axboe */ 192235f3d14dSJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= opipe->buffers) 1923aadd06e5SJens Axboe break; 1924aadd06e5SJens Axboe 192535f3d14dSJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (ipipe->buffers-1)); 192635f3d14dSJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (opipe->buffers - 1); 192770524490SJens Axboe 192870524490SJens Axboe /* 192970524490SJens Axboe * Get a reference to this pipe buffer, 193070524490SJens Axboe * so we can copy the contents over. 193170524490SJens Axboe */ 193270524490SJens Axboe ibuf->ops->get(ipipe, ibuf); 193370524490SJens Axboe 193470524490SJens Axboe obuf = opipe->bufs + nbuf; 193570524490SJens Axboe *obuf = *ibuf; 193670524490SJens Axboe 19377afa6fd0SJens Axboe /* 19387afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 19397afa6fd0SJens Axboe * prevent multiple steals of this page. 19407afa6fd0SJens Axboe */ 19417afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 19427afa6fd0SJens Axboe 194370524490SJens Axboe if (obuf->len > len) 194470524490SJens Axboe obuf->len = len; 194570524490SJens Axboe 194670524490SJens Axboe opipe->nrbufs++; 194770524490SJens Axboe ret += obuf->len; 194870524490SJens Axboe len -= obuf->len; 1949aadd06e5SJens Axboe i++; 1950aadd06e5SJens Axboe } while (len); 195170524490SJens Axboe 195202cf01aeSJens Axboe /* 195302cf01aeSJens Axboe * return EAGAIN if we have the potential of some data in the 195402cf01aeSJens Axboe * future, otherwise just return 0 195502cf01aeSJens Axboe */ 195602cf01aeSJens Axboe if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) 195702cf01aeSJens Axboe ret = -EAGAIN; 195802cf01aeSJens Axboe 195961e0d47cSMiklos Szeredi pipe_unlock(ipipe); 196061e0d47cSMiklos Szeredi pipe_unlock(opipe); 196170524490SJens Axboe 1962aadd06e5SJens Axboe /* 1963aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1964aadd06e5SJens Axboe */ 1965825cdcb1SNamhyung Kim if (ret > 0) 1966825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 196770524490SJens Axboe 196870524490SJens Axboe return ret; 196970524490SJens Axboe } 197070524490SJens Axboe 197170524490SJens Axboe /* 197270524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 197370524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 197470524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 197570524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 197670524490SJens Axboe */ 197770524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 197870524490SJens Axboe unsigned int flags) 197970524490SJens Axboe { 198071993e62SLinus Torvalds struct pipe_inode_info *ipipe = get_pipe_info(in); 198171993e62SLinus Torvalds struct pipe_inode_info *opipe = get_pipe_info(out); 1982aadd06e5SJens Axboe int ret = -EINVAL; 198370524490SJens Axboe 198470524490SJens Axboe /* 1985aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1986aadd06e5SJens Axboe * copying the data. 198770524490SJens Axboe */ 1988aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1989aadd06e5SJens Axboe /* 1990aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1991aadd06e5SJens Axboe * ordering doesn't really matter. 1992aadd06e5SJens Axboe */ 19937c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 1994aadd06e5SJens Axboe if (!ret) { 19957c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 199602cf01aeSJens Axboe if (!ret) 1997aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1998aadd06e5SJens Axboe } 1999aadd06e5SJens Axboe } 200070524490SJens Axboe 2001aadd06e5SJens Axboe return ret; 200270524490SJens Axboe } 200370524490SJens Axboe 2004836f92adSHeiko Carstens SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) 200570524490SJens Axboe { 20062903ff01SAl Viro struct fd in; 20072903ff01SAl Viro int error; 200870524490SJens Axboe 200970524490SJens Axboe if (unlikely(!len)) 201070524490SJens Axboe return 0; 201170524490SJens Axboe 201270524490SJens Axboe error = -EBADF; 20132903ff01SAl Viro in = fdget(fdin); 20142903ff01SAl Viro if (in.file) { 20152903ff01SAl Viro if (in.file->f_mode & FMODE_READ) { 20162903ff01SAl Viro struct fd out = fdget(fdout); 20172903ff01SAl Viro if (out.file) { 20182903ff01SAl Viro if (out.file->f_mode & FMODE_WRITE) 20192903ff01SAl Viro error = do_tee(in.file, out.file, 20202903ff01SAl Viro len, flags); 20212903ff01SAl Viro fdput(out); 202270524490SJens Axboe } 202370524490SJens Axboe } 20242903ff01SAl Viro fdput(in); 202570524490SJens Axboe } 202670524490SJens Axboe 202770524490SJens Axboe return error; 202870524490SJens Axboe } 2029