1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 25274f052SJens Axboe /* 35274f052SJens Axboe * "splice": joining two ropes together by interweaving their strands. 45274f052SJens Axboe * 55274f052SJens Axboe * This is the "extended pipe" functionality, where a pipe is used as 65274f052SJens Axboe * an arbitrary in-memory buffer. Think of a pipe as a small kernel 75274f052SJens Axboe * buffer that you can use to transfer data from one end to the other. 85274f052SJens Axboe * 95274f052SJens Axboe * The traditional unix read/write is extended with a "splice()" operation 105274f052SJens Axboe * that transfers data buffers to or from a pipe buffer. 115274f052SJens Axboe * 125274f052SJens Axboe * Named by Larry McVoy, original implementation from Linus, extended by 13c2058e06SJens Axboe * Jens to support splicing to files, network, direct splicing, etc and 14c2058e06SJens Axboe * fixing lots of bugs. 155274f052SJens Axboe * 160fe23479SJens Axboe * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> 17c2058e06SJens Axboe * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> 18c2058e06SJens Axboe * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> 195274f052SJens Axboe * 205274f052SJens Axboe */ 21be297968SChristoph Hellwig #include <linux/bvec.h> 225274f052SJens Axboe #include <linux/fs.h> 235274f052SJens Axboe #include <linux/file.h> 245274f052SJens Axboe #include <linux/pagemap.h> 25d6b29d7cSJens Axboe #include <linux/splice.h> 2608e552c6SKAMEZAWA Hiroyuki #include <linux/memcontrol.h> 275274f052SJens Axboe #include <linux/mm_inline.h> 285abc97aaSJens Axboe #include <linux/swap.h> 294f6f0bd2SJens Axboe #include <linux/writeback.h> 30630d9c47SPaul Gortmaker #include <linux/export.h> 314f6f0bd2SJens Axboe #include <linux/syscalls.h> 32912d35f8SJens Axboe #include <linux/uio.h> 3329ce2058SJames Morris #include <linux/security.h> 345a0e3ad6STejun Heo #include <linux/gfp.h> 3535f9c09fSEric Dumazet #include <linux/socket.h> 3676b021d0SAl Viro #include <linux/compat.h> 37174cd4b1SIngo Molnar #include <linux/sched/signal.h> 38174cd4b1SIngo Molnar 3906ae43f3SAl Viro #include "internal.h" 405274f052SJens Axboe 4183f9135bSJens Axboe /* 4283f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 4383f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 4483f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 4583f9135bSJens Axboe * attempt to reuse this page for another destination. 4683f9135bSJens Axboe */ 47c928f642SChristoph Hellwig static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe, 485abc97aaSJens Axboe struct pipe_buffer *buf) 495abc97aaSJens Axboe { 505abc97aaSJens Axboe struct page *page = buf->page; 519e94cd4fSJens Axboe struct address_space *mapping; 525abc97aaSJens Axboe 539e0267c2SJens Axboe lock_page(page); 549e0267c2SJens Axboe 559e94cd4fSJens Axboe mapping = page_mapping(page); 569e94cd4fSJens Axboe if (mapping) { 575abc97aaSJens Axboe WARN_ON(!PageUptodate(page)); 585abc97aaSJens Axboe 59ad8d6f0aSJens Axboe /* 609e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 619e94cd4fSJens Axboe * writeback completing on this page, since we'll remove it 629e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 639e94cd4fSJens Axboe * page, allowing the disk blocks to be reused by someone else 649e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 659e94cd4fSJens Axboe * ensues. 66ad8d6f0aSJens Axboe */ 67ad8d6f0aSJens Axboe wait_on_page_writeback(page); 68ad8d6f0aSJens Axboe 69266cf658SDavid Howells if (page_has_private(page) && 70266cf658SDavid Howells !try_to_release_page(page, GFP_KERNEL)) 71ca39d651SJens Axboe goto out_unlock; 724f6f0bd2SJens Axboe 739e94cd4fSJens Axboe /* 749e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 759e94cd4fSJens Axboe * and return good. 769e94cd4fSJens Axboe */ 779e94cd4fSJens Axboe if (remove_mapping(mapping, page)) { 781432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 79c928f642SChristoph Hellwig return true; 805abc97aaSJens Axboe } 819e94cd4fSJens Axboe } 829e94cd4fSJens Axboe 839e94cd4fSJens Axboe /* 849e94cd4fSJens Axboe * Raced with truncate or failed to remove page from current 859e94cd4fSJens Axboe * address space, unlock and return failure. 869e94cd4fSJens Axboe */ 87ca39d651SJens Axboe out_unlock: 889e94cd4fSJens Axboe unlock_page(page); 89c928f642SChristoph Hellwig return false; 909e94cd4fSJens Axboe } 915abc97aaSJens Axboe 9276ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 935274f052SJens Axboe struct pipe_buffer *buf) 945274f052SJens Axboe { 9509cbfeafSKirill A. Shutemov put_page(buf->page); 961432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 975274f052SJens Axboe } 985274f052SJens Axboe 990845718dSJens Axboe /* 1000845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 1010845718dSJens Axboe * is a page cache page, IO may be in flight. 1020845718dSJens Axboe */ 103cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 1045274f052SJens Axboe struct pipe_buffer *buf) 1055274f052SJens Axboe { 1065274f052SJens Axboe struct page *page = buf->page; 10749d0b21bSJens Axboe int err; 1085274f052SJens Axboe 1095274f052SJens Axboe if (!PageUptodate(page)) { 11049d0b21bSJens Axboe lock_page(page); 1115274f052SJens Axboe 11249d0b21bSJens Axboe /* 11349d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 11473d62d83SIngo Molnar * splice, if this is the first page. 11549d0b21bSJens Axboe */ 1165274f052SJens Axboe if (!page->mapping) { 11749d0b21bSJens Axboe err = -ENODATA; 11849d0b21bSJens Axboe goto error; 1195274f052SJens Axboe } 1205274f052SJens Axboe 12149d0b21bSJens Axboe /* 12273d62d83SIngo Molnar * Uh oh, read-error from disk. 12349d0b21bSJens Axboe */ 12449d0b21bSJens Axboe if (!PageUptodate(page)) { 12549d0b21bSJens Axboe err = -EIO; 12649d0b21bSJens Axboe goto error; 12749d0b21bSJens Axboe } 12849d0b21bSJens Axboe 12949d0b21bSJens Axboe /* 130f84d7519SJens Axboe * Page is ok afterall, we are done. 13149d0b21bSJens Axboe */ 13249d0b21bSJens Axboe unlock_page(page); 13349d0b21bSJens Axboe } 13449d0b21bSJens Axboe 135f84d7519SJens Axboe return 0; 13649d0b21bSJens Axboe error: 13749d0b21bSJens Axboe unlock_page(page); 138f84d7519SJens Axboe return err; 13970524490SJens Axboe } 14070524490SJens Axboe 141708e3508SHugh Dickins const struct pipe_buf_operations page_cache_pipe_buf_ops = { 142cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1435274f052SJens Axboe .release = page_cache_pipe_buf_release, 144c928f642SChristoph Hellwig .try_steal = page_cache_pipe_buf_try_steal, 145f84d7519SJens Axboe .get = generic_pipe_buf_get, 1465274f052SJens Axboe }; 1475274f052SJens Axboe 148c928f642SChristoph Hellwig static bool user_page_pipe_buf_try_steal(struct pipe_inode_info *pipe, 149912d35f8SJens Axboe struct pipe_buffer *buf) 150912d35f8SJens Axboe { 1517afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 152c928f642SChristoph Hellwig return false; 1537afa6fd0SJens Axboe 1541432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 155c928f642SChristoph Hellwig return generic_pipe_buf_try_steal(pipe, buf); 156912d35f8SJens Axboe } 157912d35f8SJens Axboe 158d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 159912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 160c928f642SChristoph Hellwig .try_steal = user_page_pipe_buf_try_steal, 161f84d7519SJens Axboe .get = generic_pipe_buf_get, 162912d35f8SJens Axboe }; 163912d35f8SJens Axboe 164825cdcb1SNamhyung Kim static void wakeup_pipe_readers(struct pipe_inode_info *pipe) 165825cdcb1SNamhyung Kim { 166825cdcb1SNamhyung Kim smp_mb(); 1670ddad21dSLinus Torvalds if (waitqueue_active(&pipe->rd_wait)) 1680ddad21dSLinus Torvalds wake_up_interruptible(&pipe->rd_wait); 169825cdcb1SNamhyung Kim kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 170825cdcb1SNamhyung Kim } 171825cdcb1SNamhyung Kim 172932cc6d4SJens Axboe /** 173932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 174932cc6d4SJens Axboe * @pipe: pipe to fill 175932cc6d4SJens Axboe * @spd: data to fill 176932cc6d4SJens Axboe * 177932cc6d4SJens Axboe * Description: 17879685b8dSRandy Dunlap * @spd contains a map of pages and len/offset tuples, along with 179932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 180932cc6d4SJens Axboe * function will link that data to the pipe. 181932cc6d4SJens Axboe * 18283f9135bSJens Axboe */ 183d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 184912d35f8SJens Axboe struct splice_pipe_desc *spd) 1855274f052SJens Axboe { 18600de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 1878cefc107SDavid Howells unsigned int tail = pipe->tail; 1888cefc107SDavid Howells unsigned int head = pipe->head; 1898cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 1908924feffSAl Viro int ret = 0, page_nr = 0; 1915274f052SJens Axboe 192d6785d91SRabin Vincent if (!spd_pages) 193d6785d91SRabin Vincent return 0; 194d6785d91SRabin Vincent 1958924feffSAl Viro if (unlikely(!pipe->readers)) { 1965274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1975274f052SJens Axboe ret = -EPIPE; 1988924feffSAl Viro goto out; 1995274f052SJens Axboe } 2005274f052SJens Axboe 2016718b6f8SDavid Howells while (!pipe_full(head, tail, pipe->max_usage)) { 2028cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[head & mask]; 2035274f052SJens Axboe 204912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 205912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 206912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 207497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 208912d35f8SJens Axboe buf->ops = spd->ops; 2095a81e6a1SMiklos Szeredi buf->flags = 0; 2107afa6fd0SJens Axboe 2118cefc107SDavid Howells head++; 2128cefc107SDavid Howells pipe->head = head; 213912d35f8SJens Axboe page_nr++; 214912d35f8SJens Axboe ret += buf->len; 215912d35f8SJens Axboe 216912d35f8SJens Axboe if (!--spd->nr_pages) 2175274f052SJens Axboe break; 2185274f052SJens Axboe } 2195274f052SJens Axboe 22029e35094SLinus Torvalds if (!ret) 22129e35094SLinus Torvalds ret = -EAGAIN; 22229e35094SLinus Torvalds 2238924feffSAl Viro out: 22400de00bdSJens Axboe while (page_nr < spd_pages) 225bbdfc2f7SJens Axboe spd->spd_release(spd, page_nr++); 2265274f052SJens Axboe 2275274f052SJens Axboe return ret; 2285274f052SJens Axboe } 2292b514574SHannes Frederic Sowa EXPORT_SYMBOL_GPL(splice_to_pipe); 2305274f052SJens Axboe 23179fddc4eSAl Viro ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf) 23279fddc4eSAl Viro { 2338cefc107SDavid Howells unsigned int head = pipe->head; 2348cefc107SDavid Howells unsigned int tail = pipe->tail; 2358cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 23679fddc4eSAl Viro int ret; 23779fddc4eSAl Viro 23879fddc4eSAl Viro if (unlikely(!pipe->readers)) { 23979fddc4eSAl Viro send_sig(SIGPIPE, current, 0); 24079fddc4eSAl Viro ret = -EPIPE; 2416718b6f8SDavid Howells } else if (pipe_full(head, tail, pipe->max_usage)) { 24279fddc4eSAl Viro ret = -EAGAIN; 24379fddc4eSAl Viro } else { 2448cefc107SDavid Howells pipe->bufs[head & mask] = *buf; 2458cefc107SDavid Howells pipe->head = head + 1; 24679fddc4eSAl Viro return buf->len; 24779fddc4eSAl Viro } 248a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 24979fddc4eSAl Viro return ret; 25079fddc4eSAl Viro } 25179fddc4eSAl Viro EXPORT_SYMBOL(add_to_pipe); 25279fddc4eSAl Viro 25335f3d14dSJens Axboe /* 25435f3d14dSJens Axboe * Check if we need to grow the arrays holding pages and partial page 25535f3d14dSJens Axboe * descriptions. 25635f3d14dSJens Axboe */ 257047fe360SEric Dumazet int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) 25835f3d14dSJens Axboe { 2596718b6f8SDavid Howells unsigned int max_usage = READ_ONCE(pipe->max_usage); 260047fe360SEric Dumazet 2618cefc107SDavid Howells spd->nr_pages_max = max_usage; 2628cefc107SDavid Howells if (max_usage <= PIPE_DEF_BUFFERS) 26335f3d14dSJens Axboe return 0; 26435f3d14dSJens Axboe 2658cefc107SDavid Howells spd->pages = kmalloc_array(max_usage, sizeof(struct page *), GFP_KERNEL); 2668cefc107SDavid Howells spd->partial = kmalloc_array(max_usage, sizeof(struct partial_page), 2676da2ec56SKees Cook GFP_KERNEL); 26835f3d14dSJens Axboe 26935f3d14dSJens Axboe if (spd->pages && spd->partial) 27035f3d14dSJens Axboe return 0; 27135f3d14dSJens Axboe 27235f3d14dSJens Axboe kfree(spd->pages); 27335f3d14dSJens Axboe kfree(spd->partial); 27435f3d14dSJens Axboe return -ENOMEM; 27535f3d14dSJens Axboe } 27635f3d14dSJens Axboe 277047fe360SEric Dumazet void splice_shrink_spd(struct splice_pipe_desc *spd) 27835f3d14dSJens Axboe { 279047fe360SEric Dumazet if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) 28035f3d14dSJens Axboe return; 28135f3d14dSJens Axboe 28235f3d14dSJens Axboe kfree(spd->pages); 28335f3d14dSJens Axboe kfree(spd->partial); 28435f3d14dSJens Axboe } 28535f3d14dSJens Axboe 28683f9135bSJens Axboe /** 28783f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 28883f9135bSJens Axboe * @in: file to splice from 289932cc6d4SJens Axboe * @ppos: position in @in 29083f9135bSJens Axboe * @pipe: pipe to splice to 29183f9135bSJens Axboe * @len: number of bytes to splice 29283f9135bSJens Axboe * @flags: splice modifier flags 29383f9135bSJens Axboe * 294932cc6d4SJens Axboe * Description: 295932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 29682c156f8SAl Viro * used as long as it has more or less sane ->read_iter(). 297932cc6d4SJens Axboe * 29883f9135bSJens Axboe */ 299cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 300cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 301cbb7e577SJens Axboe unsigned int flags) 3025274f052SJens Axboe { 30382c156f8SAl Viro struct iov_iter to; 30482c156f8SAl Viro struct kiocb kiocb; 3058cefc107SDavid Howells unsigned int i_head; 3068cefc107SDavid Howells int ret; 307be64f884SBoaz Harrosh 308aa563d7bSDavid Howells iov_iter_pipe(&to, READ, pipe, len); 3098cefc107SDavid Howells i_head = to.head; 31082c156f8SAl Viro init_sync_kiocb(&kiocb, in); 31182c156f8SAl Viro kiocb.ki_pos = *ppos; 312bb7462b6SMiklos Szeredi ret = call_read_iter(in, &kiocb, &to); 313723590edSMiklos Szeredi if (ret > 0) { 31482c156f8SAl Viro *ppos = kiocb.ki_pos; 315723590edSMiklos Szeredi file_accessed(in); 31682c156f8SAl Viro } else if (ret < 0) { 3178cefc107SDavid Howells to.head = i_head; 31882c156f8SAl Viro to.iov_offset = 0; 31982c156f8SAl Viro iov_iter_advance(&to, 0); /* to free what was emitted */ 32082c156f8SAl Viro /* 32182c156f8SAl Viro * callers of ->splice_read() expect -EAGAIN on 32282c156f8SAl Viro * "can't put anything in there", rather than -EFAULT. 32382c156f8SAl Viro */ 32482c156f8SAl Viro if (ret == -EFAULT) 32582c156f8SAl Viro ret = -EAGAIN; 326723590edSMiklos Szeredi } 3275274f052SJens Axboe 3285274f052SJens Axboe return ret; 3295274f052SJens Axboe } 330059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 331059a8f37SJens Axboe 332241699cdSAl Viro const struct pipe_buf_operations default_pipe_buf_ops = { 3336818173bSMiklos Szeredi .release = generic_pipe_buf_release, 334c928f642SChristoph Hellwig .try_steal = generic_pipe_buf_try_steal, 3356818173bSMiklos Szeredi .get = generic_pipe_buf_get, 3366818173bSMiklos Szeredi }; 3376818173bSMiklos Szeredi 33828a625cbSMiklos Szeredi /* Pipe buffer operations for a socket and similar. */ 33928a625cbSMiklos Szeredi const struct pipe_buf_operations nosteal_pipe_buf_ops = { 34028a625cbSMiklos Szeredi .release = generic_pipe_buf_release, 34128a625cbSMiklos Szeredi .get = generic_pipe_buf_get, 34228a625cbSMiklos Szeredi }; 34328a625cbSMiklos Szeredi EXPORT_SYMBOL(nosteal_pipe_buf_ops); 34428a625cbSMiklos Szeredi 345523ac9afSAl Viro static ssize_t kernel_readv(struct file *file, const struct kvec *vec, 3466818173bSMiklos Szeredi unsigned long vlen, loff_t offset) 3476818173bSMiklos Szeredi { 3486818173bSMiklos Szeredi mm_segment_t old_fs; 3496818173bSMiklos Szeredi loff_t pos = offset; 3506818173bSMiklos Szeredi ssize_t res; 3516818173bSMiklos Szeredi 3526818173bSMiklos Szeredi old_fs = get_fs(); 353736706beSLinus Torvalds set_fs(KERNEL_DS); 3546818173bSMiklos Szeredi /* The cast to a user pointer is valid due to the set_fs() */ 355793b80efSChristoph Hellwig res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos, 0); 3566818173bSMiklos Szeredi set_fs(old_fs); 3576818173bSMiklos Szeredi 3586818173bSMiklos Szeredi return res; 3596818173bSMiklos Szeredi } 3606818173bSMiklos Szeredi 36182c156f8SAl Viro static ssize_t default_file_splice_read(struct file *in, loff_t *ppos, 3626818173bSMiklos Szeredi struct pipe_inode_info *pipe, size_t len, 3636818173bSMiklos Szeredi unsigned int flags) 3646818173bSMiklos Szeredi { 365523ac9afSAl Viro struct kvec *vec, __vec[PIPE_DEF_BUFFERS]; 366523ac9afSAl Viro struct iov_iter to; 367523ac9afSAl Viro struct page **pages; 3686818173bSMiklos Szeredi unsigned int nr_pages; 3698cefc107SDavid Howells unsigned int mask; 37013c0f52bSAl Viro size_t offset, base, copied = 0; 3716818173bSMiklos Szeredi ssize_t res; 3726818173bSMiklos Szeredi int i; 3736818173bSMiklos Szeredi 3746718b6f8SDavid Howells if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 375523ac9afSAl Viro return -EAGAIN; 376523ac9afSAl Viro 377523ac9afSAl Viro /* 378523ac9afSAl Viro * Try to keep page boundaries matching to source pagecache ones - 379523ac9afSAl Viro * it probably won't be much help, but... 380523ac9afSAl Viro */ 381523ac9afSAl Viro offset = *ppos & ~PAGE_MASK; 382523ac9afSAl Viro 383aa563d7bSDavid Howells iov_iter_pipe(&to, READ, pipe, len + offset); 384523ac9afSAl Viro 38513c0f52bSAl Viro res = iov_iter_get_pages_alloc(&to, &pages, len + offset, &base); 386523ac9afSAl Viro if (res <= 0) 38735f3d14dSJens Axboe return -ENOMEM; 38835f3d14dSJens Axboe 38913c0f52bSAl Viro nr_pages = DIV_ROUND_UP(res + base, PAGE_SIZE); 390523ac9afSAl Viro 39135f3d14dSJens Axboe vec = __vec; 392523ac9afSAl Viro if (nr_pages > PIPE_DEF_BUFFERS) { 3936da2ec56SKees Cook vec = kmalloc_array(nr_pages, sizeof(struct kvec), GFP_KERNEL); 394523ac9afSAl Viro if (unlikely(!vec)) { 395523ac9afSAl Viro res = -ENOMEM; 396523ac9afSAl Viro goto out; 397523ac9afSAl Viro } 39835f3d14dSJens Axboe } 39935f3d14dSJens Axboe 4008cefc107SDavid Howells mask = pipe->ring_size - 1; 4018cefc107SDavid Howells pipe->bufs[to.head & mask].offset = offset; 4028cefc107SDavid Howells pipe->bufs[to.head & mask].len -= offset; 4036818173bSMiklos Szeredi 404523ac9afSAl Viro for (i = 0; i < nr_pages; i++) { 405523ac9afSAl Viro size_t this_len = min_t(size_t, len, PAGE_SIZE - offset); 406523ac9afSAl Viro vec[i].iov_base = page_address(pages[i]) + offset; 4076818173bSMiklos Szeredi vec[i].iov_len = this_len; 4086818173bSMiklos Szeredi len -= this_len; 4096818173bSMiklos Szeredi offset = 0; 4106818173bSMiklos Szeredi } 4116818173bSMiklos Szeredi 412523ac9afSAl Viro res = kernel_readv(in, vec, nr_pages, *ppos); 413523ac9afSAl Viro if (res > 0) { 414523ac9afSAl Viro copied = res; 4156818173bSMiklos Szeredi *ppos += res; 416523ac9afSAl Viro } 4176818173bSMiklos Szeredi 41835f3d14dSJens Axboe if (vec != __vec) 41935f3d14dSJens Axboe kfree(vec); 420523ac9afSAl Viro out: 421523ac9afSAl Viro for (i = 0; i < nr_pages; i++) 422523ac9afSAl Viro put_page(pages[i]); 423523ac9afSAl Viro kvfree(pages); 424523ac9afSAl Viro iov_iter_advance(&to, copied); /* truncates and discards */ 4256818173bSMiklos Szeredi return res; 4266818173bSMiklos Szeredi } 4276818173bSMiklos Szeredi 4285274f052SJens Axboe /* 4294f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 430016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 4315274f052SJens Axboe */ 43276ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 4335274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 4345274f052SJens Axboe { 4356a14b90bSJens Axboe struct file *file = sd->u.file; 4365274f052SJens Axboe loff_t pos = sd->pos; 437a8adbe37SMichał Mirosław int more; 4385274f052SJens Axboe 43972c2d531SAl Viro if (!likely(file->f_op->sendpage)) 440a8adbe37SMichał Mirosław return -EINVAL; 441a8adbe37SMichał Mirosław 44235f9c09fSEric Dumazet more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; 443ae62ca7bSEric Dumazet 4448cefc107SDavid Howells if (sd->len < sd->total_len && 4458cefc107SDavid Howells pipe_occupancy(pipe->head, pipe->tail) > 1) 44635f9c09fSEric Dumazet more |= MSG_SENDPAGE_NOTLAST; 447ae62ca7bSEric Dumazet 448a8adbe37SMichał Mirosław return file->f_op->sendpage(file, buf->page, buf->offset, 449f84d7519SJens Axboe sd->len, &pos, more); 4505274f052SJens Axboe } 4515274f052SJens Axboe 452b3c2d2ddSMiklos Szeredi static void wakeup_pipe_writers(struct pipe_inode_info *pipe) 453b3c2d2ddSMiklos Szeredi { 454b3c2d2ddSMiklos Szeredi smp_mb(); 4550ddad21dSLinus Torvalds if (waitqueue_active(&pipe->wr_wait)) 4560ddad21dSLinus Torvalds wake_up_interruptible(&pipe->wr_wait); 457b3c2d2ddSMiklos Szeredi kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 458b3c2d2ddSMiklos Szeredi } 459b3c2d2ddSMiklos Szeredi 460b3c2d2ddSMiklos Szeredi /** 461b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed - feed available data from a pipe to a file 462b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 463b3c2d2ddSMiklos Szeredi * @sd: information to @actor 464b3c2d2ddSMiklos Szeredi * @actor: handler that splices the data 465b3c2d2ddSMiklos Szeredi * 466b3c2d2ddSMiklos Szeredi * Description: 467b3c2d2ddSMiklos Szeredi * This function loops over the pipe and calls @actor to do the 468b3c2d2ddSMiklos Szeredi * actual moving of a single struct pipe_buffer to the desired 469b3c2d2ddSMiklos Szeredi * destination. It returns when there's no more buffers left in 470b3c2d2ddSMiklos Szeredi * the pipe or if the requested number of bytes (@sd->total_len) 471b3c2d2ddSMiklos Szeredi * have been copied. It returns a positive number (one) if the 472b3c2d2ddSMiklos Szeredi * pipe needs to be filled with more data, zero if the required 473b3c2d2ddSMiklos Szeredi * number of bytes have been copied and -errno on error. 474b3c2d2ddSMiklos Szeredi * 475b3c2d2ddSMiklos Szeredi * This, together with splice_from_pipe_{begin,end,next}, may be 476b3c2d2ddSMiklos Szeredi * used to implement the functionality of __splice_from_pipe() when 477b3c2d2ddSMiklos Szeredi * locking is required around copying the pipe buffers to the 478b3c2d2ddSMiklos Szeredi * destination. 479b3c2d2ddSMiklos Szeredi */ 48096f9bc8fSAl Viro static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, 481b3c2d2ddSMiklos Szeredi splice_actor *actor) 482b3c2d2ddSMiklos Szeredi { 4838cefc107SDavid Howells unsigned int head = pipe->head; 4848cefc107SDavid Howells unsigned int tail = pipe->tail; 4858cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 486b3c2d2ddSMiklos Szeredi int ret; 487b3c2d2ddSMiklos Szeredi 488ec057595SLinus Torvalds while (!pipe_empty(head, tail)) { 4898cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 490b3c2d2ddSMiklos Szeredi 491b3c2d2ddSMiklos Szeredi sd->len = buf->len; 492b3c2d2ddSMiklos Szeredi if (sd->len > sd->total_len) 493b3c2d2ddSMiklos Szeredi sd->len = sd->total_len; 494b3c2d2ddSMiklos Szeredi 495fba597dbSMiklos Szeredi ret = pipe_buf_confirm(pipe, buf); 496a8adbe37SMichał Mirosław if (unlikely(ret)) { 497b3c2d2ddSMiklos Szeredi if (ret == -ENODATA) 498b3c2d2ddSMiklos Szeredi ret = 0; 499b3c2d2ddSMiklos Szeredi return ret; 500b3c2d2ddSMiklos Szeredi } 501a8adbe37SMichał Mirosław 502a8adbe37SMichał Mirosław ret = actor(pipe, buf, sd); 503a8adbe37SMichał Mirosław if (ret <= 0) 504a8adbe37SMichał Mirosław return ret; 505a8adbe37SMichał Mirosław 506b3c2d2ddSMiklos Szeredi buf->offset += ret; 507b3c2d2ddSMiklos Szeredi buf->len -= ret; 508b3c2d2ddSMiklos Szeredi 509b3c2d2ddSMiklos Szeredi sd->num_spliced += ret; 510b3c2d2ddSMiklos Szeredi sd->len -= ret; 511b3c2d2ddSMiklos Szeredi sd->pos += ret; 512b3c2d2ddSMiklos Szeredi sd->total_len -= ret; 513b3c2d2ddSMiklos Szeredi 514b3c2d2ddSMiklos Szeredi if (!buf->len) { 515a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 5168cefc107SDavid Howells tail++; 5178cefc107SDavid Howells pipe->tail = tail; 5186447a3cfSAl Viro if (pipe->files) 519b3c2d2ddSMiklos Szeredi sd->need_wakeup = true; 520b3c2d2ddSMiklos Szeredi } 521b3c2d2ddSMiklos Szeredi 522b3c2d2ddSMiklos Szeredi if (!sd->total_len) 523b3c2d2ddSMiklos Szeredi return 0; 524b3c2d2ddSMiklos Szeredi } 525b3c2d2ddSMiklos Szeredi 526b3c2d2ddSMiklos Szeredi return 1; 527b3c2d2ddSMiklos Szeredi } 528b3c2d2ddSMiklos Szeredi 529b3c2d2ddSMiklos Szeredi /** 530b3c2d2ddSMiklos Szeredi * splice_from_pipe_next - wait for some data to splice from 531b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 532b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 533b3c2d2ddSMiklos Szeredi * 534b3c2d2ddSMiklos Szeredi * Description: 535b3c2d2ddSMiklos Szeredi * This function will wait for some data and return a positive 536b3c2d2ddSMiklos Szeredi * value (one) if pipe buffers are available. It will return zero 537b3c2d2ddSMiklos Szeredi * or -errno if no more data needs to be spliced. 538b3c2d2ddSMiklos Szeredi */ 53996f9bc8fSAl Viro static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) 540b3c2d2ddSMiklos Szeredi { 541c725bfceSJan Kara /* 542c725bfceSJan Kara * Check for signal early to make process killable when there are 543c725bfceSJan Kara * always buffers available 544c725bfceSJan Kara */ 545c725bfceSJan Kara if (signal_pending(current)) 546c725bfceSJan Kara return -ERESTARTSYS; 547c725bfceSJan Kara 5488cefc107SDavid Howells while (pipe_empty(pipe->head, pipe->tail)) { 549b3c2d2ddSMiklos Szeredi if (!pipe->writers) 550b3c2d2ddSMiklos Szeredi return 0; 551b3c2d2ddSMiklos Szeredi 552a28c8b9dSLinus Torvalds if (sd->num_spliced) 553b3c2d2ddSMiklos Szeredi return 0; 554b3c2d2ddSMiklos Szeredi 555b3c2d2ddSMiklos Szeredi if (sd->flags & SPLICE_F_NONBLOCK) 556b3c2d2ddSMiklos Szeredi return -EAGAIN; 557b3c2d2ddSMiklos Szeredi 558b3c2d2ddSMiklos Szeredi if (signal_pending(current)) 559b3c2d2ddSMiklos Szeredi return -ERESTARTSYS; 560b3c2d2ddSMiklos Szeredi 561b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) { 562b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 563b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 564b3c2d2ddSMiklos Szeredi } 565b3c2d2ddSMiklos Szeredi 566b3c2d2ddSMiklos Szeredi pipe_wait(pipe); 567b3c2d2ddSMiklos Szeredi } 568b3c2d2ddSMiklos Szeredi 569b3c2d2ddSMiklos Szeredi return 1; 570b3c2d2ddSMiklos Szeredi } 571b3c2d2ddSMiklos Szeredi 572b3c2d2ddSMiklos Szeredi /** 573b3c2d2ddSMiklos Szeredi * splice_from_pipe_begin - start splicing from pipe 574b80901bbSRandy Dunlap * @sd: information about the splice operation 575b3c2d2ddSMiklos Szeredi * 576b3c2d2ddSMiklos Szeredi * Description: 577b3c2d2ddSMiklos Szeredi * This function should be called before a loop containing 578b3c2d2ddSMiklos Szeredi * splice_from_pipe_next() and splice_from_pipe_feed() to 579b3c2d2ddSMiklos Szeredi * initialize the necessary fields of @sd. 580b3c2d2ddSMiklos Szeredi */ 58196f9bc8fSAl Viro static void splice_from_pipe_begin(struct splice_desc *sd) 582b3c2d2ddSMiklos Szeredi { 583b3c2d2ddSMiklos Szeredi sd->num_spliced = 0; 584b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 585b3c2d2ddSMiklos Szeredi } 586b3c2d2ddSMiklos Szeredi 587b3c2d2ddSMiklos Szeredi /** 588b3c2d2ddSMiklos Szeredi * splice_from_pipe_end - finish splicing from pipe 589b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 590b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 591b3c2d2ddSMiklos Szeredi * 592b3c2d2ddSMiklos Szeredi * Description: 593b3c2d2ddSMiklos Szeredi * This function will wake up pipe writers if necessary. It should 594b3c2d2ddSMiklos Szeredi * be called after a loop containing splice_from_pipe_next() and 595b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed(). 596b3c2d2ddSMiklos Szeredi */ 59796f9bc8fSAl Viro static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) 598b3c2d2ddSMiklos Szeredi { 599b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) 600b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 601b3c2d2ddSMiklos Szeredi } 602b3c2d2ddSMiklos Szeredi 603932cc6d4SJens Axboe /** 604932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 605932cc6d4SJens Axboe * @pipe: pipe to splice from 606932cc6d4SJens Axboe * @sd: information to @actor 607932cc6d4SJens Axboe * @actor: handler that splices the data 608932cc6d4SJens Axboe * 609932cc6d4SJens Axboe * Description: 610932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 611932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 612932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 613932cc6d4SJens Axboe * pipe_to_user. 614932cc6d4SJens Axboe * 61583f9135bSJens Axboe */ 616c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 617c66ab6faSJens Axboe splice_actor *actor) 6185274f052SJens Axboe { 619b3c2d2ddSMiklos Szeredi int ret; 6205274f052SJens Axboe 621b3c2d2ddSMiklos Szeredi splice_from_pipe_begin(sd); 622b3c2d2ddSMiklos Szeredi do { 623c2489e07SJan Kara cond_resched(); 624b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_next(pipe, sd); 625b3c2d2ddSMiklos Szeredi if (ret > 0) 626b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_feed(pipe, sd, actor); 627b3c2d2ddSMiklos Szeredi } while (ret > 0); 628b3c2d2ddSMiklos Szeredi splice_from_pipe_end(pipe, sd); 6295274f052SJens Axboe 630b3c2d2ddSMiklos Szeredi return sd->num_spliced ? sd->num_spliced : ret; 6315274f052SJens Axboe } 63240bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 6335274f052SJens Axboe 634932cc6d4SJens Axboe /** 635932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 636932cc6d4SJens Axboe * @pipe: pipe to splice from 637932cc6d4SJens Axboe * @out: file to splice to 638932cc6d4SJens Axboe * @ppos: position in @out 639932cc6d4SJens Axboe * @len: how many bytes to splice 640932cc6d4SJens Axboe * @flags: splice modifier flags 641932cc6d4SJens Axboe * @actor: handler that splices the data 642932cc6d4SJens Axboe * 643932cc6d4SJens Axboe * Description: 6442933970bSMiklos Szeredi * See __splice_from_pipe. This function locks the pipe inode, 645932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 646932cc6d4SJens Axboe * 647932cc6d4SJens Axboe */ 6486da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 6496da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 6506da61809SMark Fasheh splice_actor *actor) 6516da61809SMark Fasheh { 6526da61809SMark Fasheh ssize_t ret; 653c66ab6faSJens Axboe struct splice_desc sd = { 654c66ab6faSJens Axboe .total_len = len, 655c66ab6faSJens Axboe .flags = flags, 656c66ab6faSJens Axboe .pos = *ppos, 6576a14b90bSJens Axboe .u.file = out, 658c66ab6faSJens Axboe }; 6596da61809SMark Fasheh 66061e0d47cSMiklos Szeredi pipe_lock(pipe); 661c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 66261e0d47cSMiklos Szeredi pipe_unlock(pipe); 6636da61809SMark Fasheh 6646da61809SMark Fasheh return ret; 6656da61809SMark Fasheh } 6666da61809SMark Fasheh 6676da61809SMark Fasheh /** 6688d020765SAl Viro * iter_file_splice_write - splice data from a pipe to a file 6698d020765SAl Viro * @pipe: pipe info 6708d020765SAl Viro * @out: file to write to 6718d020765SAl Viro * @ppos: position in @out 6728d020765SAl Viro * @len: number of bytes to splice 6738d020765SAl Viro * @flags: splice modifier flags 6748d020765SAl Viro * 6758d020765SAl Viro * Description: 6768d020765SAl Viro * Will either move or copy pages (determined by @flags options) from 6778d020765SAl Viro * the given pipe inode to the given file. 6788d020765SAl Viro * This one is ->write_iter-based. 6798d020765SAl Viro * 6808d020765SAl Viro */ 6818d020765SAl Viro ssize_t 6828d020765SAl Viro iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 6838d020765SAl Viro loff_t *ppos, size_t len, unsigned int flags) 6848d020765SAl Viro { 6858d020765SAl Viro struct splice_desc sd = { 6868d020765SAl Viro .total_len = len, 6878d020765SAl Viro .flags = flags, 6888d020765SAl Viro .pos = *ppos, 6898d020765SAl Viro .u.file = out, 6908d020765SAl Viro }; 6916718b6f8SDavid Howells int nbufs = pipe->max_usage; 6928d020765SAl Viro struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec), 6938d020765SAl Viro GFP_KERNEL); 6948d020765SAl Viro ssize_t ret; 6958d020765SAl Viro 6968d020765SAl Viro if (unlikely(!array)) 6978d020765SAl Viro return -ENOMEM; 6988d020765SAl Viro 6998d020765SAl Viro pipe_lock(pipe); 7008d020765SAl Viro 7018d020765SAl Viro splice_from_pipe_begin(&sd); 7028d020765SAl Viro while (sd.total_len) { 7038d020765SAl Viro struct iov_iter from; 704ec057595SLinus Torvalds unsigned int head, tail, mask; 7058d020765SAl Viro size_t left; 7068cefc107SDavid Howells int n; 7078d020765SAl Viro 7088d020765SAl Viro ret = splice_from_pipe_next(pipe, &sd); 7098d020765SAl Viro if (ret <= 0) 7108d020765SAl Viro break; 7118d020765SAl Viro 7126718b6f8SDavid Howells if (unlikely(nbufs < pipe->max_usage)) { 7138d020765SAl Viro kfree(array); 7146718b6f8SDavid Howells nbufs = pipe->max_usage; 7158d020765SAl Viro array = kcalloc(nbufs, sizeof(struct bio_vec), 7168d020765SAl Viro GFP_KERNEL); 7178d020765SAl Viro if (!array) { 7188d020765SAl Viro ret = -ENOMEM; 7198d020765SAl Viro break; 7208d020765SAl Viro } 7218d020765SAl Viro } 7228d020765SAl Viro 723ec057595SLinus Torvalds head = pipe->head; 724ec057595SLinus Torvalds tail = pipe->tail; 725ec057595SLinus Torvalds mask = pipe->ring_size - 1; 726ec057595SLinus Torvalds 7278d020765SAl Viro /* build the vector */ 7288d020765SAl Viro left = sd.total_len; 7298cefc107SDavid Howells for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++, n++) { 7308cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 7318d020765SAl Viro size_t this_len = buf->len; 7328d020765SAl Viro 7338d020765SAl Viro if (this_len > left) 7348d020765SAl Viro this_len = left; 7358d020765SAl Viro 736fba597dbSMiklos Szeredi ret = pipe_buf_confirm(pipe, buf); 7378d020765SAl Viro if (unlikely(ret)) { 7388d020765SAl Viro if (ret == -ENODATA) 7398d020765SAl Viro ret = 0; 7408d020765SAl Viro goto done; 7418d020765SAl Viro } 7428d020765SAl Viro 7438d020765SAl Viro array[n].bv_page = buf->page; 7448d020765SAl Viro array[n].bv_len = this_len; 7458d020765SAl Viro array[n].bv_offset = buf->offset; 7468d020765SAl Viro left -= this_len; 7478d020765SAl Viro } 7488d020765SAl Viro 749aa563d7bSDavid Howells iov_iter_bvec(&from, WRITE, array, n, sd.total_len - left); 750abbb6589SChristoph Hellwig ret = vfs_iter_write(out, &from, &sd.pos, 0); 7518d020765SAl Viro if (ret <= 0) 7528d020765SAl Viro break; 7538d020765SAl Viro 7548d020765SAl Viro sd.num_spliced += ret; 7558d020765SAl Viro sd.total_len -= ret; 756dbe4e192SChristoph Hellwig *ppos = sd.pos; 7578d020765SAl Viro 7588d020765SAl Viro /* dismiss the fully eaten buffers, adjust the partial one */ 7598cefc107SDavid Howells tail = pipe->tail; 7608d020765SAl Viro while (ret) { 7618cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 7628d020765SAl Viro if (ret >= buf->len) { 7638d020765SAl Viro ret -= buf->len; 7648d020765SAl Viro buf->len = 0; 765a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 7668cefc107SDavid Howells tail++; 7678cefc107SDavid Howells pipe->tail = tail; 7688d020765SAl Viro if (pipe->files) 7698d020765SAl Viro sd.need_wakeup = true; 7708d020765SAl Viro } else { 7718d020765SAl Viro buf->offset += ret; 7728d020765SAl Viro buf->len -= ret; 7738d020765SAl Viro ret = 0; 7748d020765SAl Viro } 7758d020765SAl Viro } 7768d020765SAl Viro } 7778d020765SAl Viro done: 7788d020765SAl Viro kfree(array); 7798d020765SAl Viro splice_from_pipe_end(pipe, &sd); 7808d020765SAl Viro 7818d020765SAl Viro pipe_unlock(pipe); 7828d020765SAl Viro 7838d020765SAl Viro if (sd.num_spliced) 7848d020765SAl Viro ret = sd.num_spliced; 7858d020765SAl Viro 7868d020765SAl Viro return ret; 7878d020765SAl Viro } 7888d020765SAl Viro 7898d020765SAl Viro EXPORT_SYMBOL(iter_file_splice_write); 7908d020765SAl Viro 791b2858d7dSMiklos Szeredi static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 792b2858d7dSMiklos Szeredi struct splice_desc *sd) 7930b0a47f5SMiklos Szeredi { 794b2858d7dSMiklos Szeredi int ret; 795b2858d7dSMiklos Szeredi void *data; 79606ae43f3SAl Viro loff_t tmp = sd->pos; 797b2858d7dSMiklos Szeredi 798fbb32750SAl Viro data = kmap(buf->page); 79906ae43f3SAl Viro ret = __kernel_write(sd->u.file, data + buf->offset, sd->len, &tmp); 800fbb32750SAl Viro kunmap(buf->page); 801b2858d7dSMiklos Szeredi 802b2858d7dSMiklos Szeredi return ret; 8030b0a47f5SMiklos Szeredi } 8040b0a47f5SMiklos Szeredi 8050b0a47f5SMiklos Szeredi static ssize_t default_file_splice_write(struct pipe_inode_info *pipe, 8060b0a47f5SMiklos Szeredi struct file *out, loff_t *ppos, 8070b0a47f5SMiklos Szeredi size_t len, unsigned int flags) 8080b0a47f5SMiklos Szeredi { 809b2858d7dSMiklos Szeredi ssize_t ret; 8100b0a47f5SMiklos Szeredi 811b2858d7dSMiklos Szeredi ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf); 812b2858d7dSMiklos Szeredi if (ret > 0) 813b2858d7dSMiklos Szeredi *ppos += ret; 8140b0a47f5SMiklos Szeredi 815b2858d7dSMiklos Szeredi return ret; 8160b0a47f5SMiklos Szeredi } 8170b0a47f5SMiklos Szeredi 81883f9135bSJens Axboe /** 81983f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 820932cc6d4SJens Axboe * @pipe: pipe to splice from 82183f9135bSJens Axboe * @out: socket to write to 822932cc6d4SJens Axboe * @ppos: position in @out 82383f9135bSJens Axboe * @len: number of bytes to splice 82483f9135bSJens Axboe * @flags: splice modifier flags 82583f9135bSJens Axboe * 826932cc6d4SJens Axboe * Description: 82783f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 82883f9135bSJens Axboe * is involved. 82983f9135bSJens Axboe * 83083f9135bSJens Axboe */ 8313a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 832cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8335274f052SJens Axboe { 83400522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8355274f052SJens Axboe } 8365274f052SJens Axboe 837059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 838a0f06780SJeff Garzik 83983f9135bSJens Axboe /* 84083f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 84183f9135bSJens Axboe */ 8423a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 843cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8445274f052SJens Axboe { 84572c2d531SAl Viro if (out->f_op->splice_write) 84600c285d0SChristoph Hellwig return out->f_op->splice_write(pipe, out, ppos, len, flags); 84700c285d0SChristoph Hellwig return default_file_splice_write(pipe, out, ppos, len, flags); 8485274f052SJens Axboe } 8495274f052SJens Axboe 85083f9135bSJens Axboe /* 85183f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 85283f9135bSJens Axboe */ 853cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 854cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 855cbb7e577SJens Axboe unsigned int flags) 8565274f052SJens Axboe { 8575274f052SJens Axboe int ret; 8585274f052SJens Axboe 85949570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 8605274f052SJens Axboe return -EBADF; 8615274f052SJens Axboe 862cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 8635274f052SJens Axboe if (unlikely(ret < 0)) 8645274f052SJens Axboe return ret; 8655274f052SJens Axboe 86603cc0789SAl Viro if (unlikely(len > MAX_RW_COUNT)) 86703cc0789SAl Viro len = MAX_RW_COUNT; 86803cc0789SAl Viro 86972c2d531SAl Viro if (in->f_op->splice_read) 8702bc01060SChristoph Hellwig return in->f_op->splice_read(in, ppos, pipe, len, flags); 8712bc01060SChristoph Hellwig return default_file_splice_read(in, ppos, pipe, len, flags); 8725274f052SJens Axboe } 8735274f052SJens Axboe 874932cc6d4SJens Axboe /** 875932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 876932cc6d4SJens Axboe * @in: file to splice from 877932cc6d4SJens Axboe * @sd: actor information on where to splice to 878932cc6d4SJens Axboe * @actor: handles the data splicing 879932cc6d4SJens Axboe * 880932cc6d4SJens Axboe * Description: 881932cc6d4SJens Axboe * This is a special case helper to splice directly between two 882932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 883932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 884932cc6d4SJens Axboe * that process. 885932cc6d4SJens Axboe * 886c66ab6faSJens Axboe */ 887c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 888c66ab6faSJens Axboe splice_direct_actor *actor) 889b92ce558SJens Axboe { 890b92ce558SJens Axboe struct pipe_inode_info *pipe; 891b92ce558SJens Axboe long ret, bytes; 892b92ce558SJens Axboe umode_t i_mode; 893c66ab6faSJens Axboe size_t len; 8940ff28d9fSChristophe Leroy int i, flags, more; 895b92ce558SJens Axboe 896b92ce558SJens Axboe /* 897b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 898b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 899b92ce558SJens Axboe * piped splicing for that! 900b92ce558SJens Axboe */ 901496ad9aaSAl Viro i_mode = file_inode(in)->i_mode; 902b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 903b92ce558SJens Axboe return -EINVAL; 904b92ce558SJens Axboe 905b92ce558SJens Axboe /* 906b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 907b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 908b92ce558SJens Axboe */ 909b92ce558SJens Axboe pipe = current->splice_pipe; 91049570e9bSJens Axboe if (unlikely(!pipe)) { 9117bee130eSAl Viro pipe = alloc_pipe_info(); 912b92ce558SJens Axboe if (!pipe) 913b92ce558SJens Axboe return -ENOMEM; 914b92ce558SJens Axboe 915b92ce558SJens Axboe /* 916b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 91700522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 918b92ce558SJens Axboe * PIPE_READERS appropriately. 919b92ce558SJens Axboe */ 920b92ce558SJens Axboe pipe->readers = 1; 921b92ce558SJens Axboe 922b92ce558SJens Axboe current->splice_pipe = pipe; 923b92ce558SJens Axboe } 924b92ce558SJens Axboe 925b92ce558SJens Axboe /* 92673d62d83SIngo Molnar * Do the splice. 927b92ce558SJens Axboe */ 928b92ce558SJens Axboe ret = 0; 929b92ce558SJens Axboe bytes = 0; 930c66ab6faSJens Axboe len = sd->total_len; 931c66ab6faSJens Axboe flags = sd->flags; 932c66ab6faSJens Axboe 933c66ab6faSJens Axboe /* 934c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 935c66ab6faSJens Axboe */ 936c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 9370ff28d9fSChristophe Leroy more = sd->flags & SPLICE_F_MORE; 938b92ce558SJens Axboe 9398cefc107SDavid Howells WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail)); 94017614445SDarrick J. Wong 941b92ce558SJens Axboe while (len) { 9428cefc107SDavid Howells unsigned int p_space; 94351a92c0fSJens Axboe size_t read_len; 944a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 945b92ce558SJens Axboe 94617614445SDarrick J. Wong /* Don't try to read more the pipe has space for. */ 9476718b6f8SDavid Howells p_space = pipe->max_usage - 9488cefc107SDavid Howells pipe_occupancy(pipe->head, pipe->tail); 9498cefc107SDavid Howells read_len = min_t(size_t, len, p_space << PAGE_SHIFT); 95017614445SDarrick J. Wong ret = do_splice_to(in, &pos, pipe, read_len, flags); 95151a92c0fSJens Axboe if (unlikely(ret <= 0)) 952b92ce558SJens Axboe goto out_release; 953b92ce558SJens Axboe 954b92ce558SJens Axboe read_len = ret; 955c66ab6faSJens Axboe sd->total_len = read_len; 956b92ce558SJens Axboe 957b92ce558SJens Axboe /* 9580ff28d9fSChristophe Leroy * If more data is pending, set SPLICE_F_MORE 9590ff28d9fSChristophe Leroy * If this is the last data and SPLICE_F_MORE was not set 9600ff28d9fSChristophe Leroy * initially, clears it. 9610ff28d9fSChristophe Leroy */ 9620ff28d9fSChristophe Leroy if (read_len < len) 9630ff28d9fSChristophe Leroy sd->flags |= SPLICE_F_MORE; 9640ff28d9fSChristophe Leroy else if (!more) 9650ff28d9fSChristophe Leroy sd->flags &= ~SPLICE_F_MORE; 9660ff28d9fSChristophe Leroy /* 967b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 968b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 969b92ce558SJens Axboe * could get stuck data in the internal pipe: 970b92ce558SJens Axboe */ 971c66ab6faSJens Axboe ret = actor(pipe, sd); 972a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 973a82c53a0STom Zanussi sd->pos = prev_pos; 974b92ce558SJens Axboe goto out_release; 975a82c53a0STom Zanussi } 976b92ce558SJens Axboe 977b92ce558SJens Axboe bytes += ret; 978b92ce558SJens Axboe len -= ret; 979bcd4f3acSJens Axboe sd->pos = pos; 980b92ce558SJens Axboe 981a82c53a0STom Zanussi if (ret < read_len) { 982a82c53a0STom Zanussi sd->pos = prev_pos + ret; 98351a92c0fSJens Axboe goto out_release; 984b92ce558SJens Axboe } 985a82c53a0STom Zanussi } 986b92ce558SJens Axboe 9879e97198dSJens Axboe done: 9888cefc107SDavid Howells pipe->tail = pipe->head = 0; 9899e97198dSJens Axboe file_accessed(in); 990b92ce558SJens Axboe return bytes; 991b92ce558SJens Axboe 992b92ce558SJens Axboe out_release: 993b92ce558SJens Axboe /* 994b92ce558SJens Axboe * If we did an incomplete transfer we must release 995b92ce558SJens Axboe * the pipe buffers in question: 996b92ce558SJens Axboe */ 9978cefc107SDavid Howells for (i = 0; i < pipe->ring_size; i++) { 9988cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[i]; 999b92ce558SJens Axboe 1000a779638cSMiklos Szeredi if (buf->ops) 1001a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 1002b92ce558SJens Axboe } 1003b92ce558SJens Axboe 10049e97198dSJens Axboe if (!bytes) 10059e97198dSJens Axboe bytes = ret; 1006b92ce558SJens Axboe 10079e97198dSJens Axboe goto done; 1008c66ab6faSJens Axboe } 1009c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1010c66ab6faSJens Axboe 1011c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1012c66ab6faSJens Axboe struct splice_desc *sd) 1013c66ab6faSJens Axboe { 10146a14b90bSJens Axboe struct file *file = sd->u.file; 1015c66ab6faSJens Axboe 10167995bd28SAl Viro return do_splice_from(pipe, file, sd->opos, sd->total_len, 10172cb4b05eSChangli Gao sd->flags); 1018c66ab6faSJens Axboe } 1019c66ab6faSJens Axboe 1020932cc6d4SJens Axboe /** 1021932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1022932cc6d4SJens Axboe * @in: file to splice from 1023932cc6d4SJens Axboe * @ppos: input file offset 1024932cc6d4SJens Axboe * @out: file to splice to 1025acdb37c3SRandy Dunlap * @opos: output file offset 1026932cc6d4SJens Axboe * @len: number of bytes to splice 1027932cc6d4SJens Axboe * @flags: splice modifier flags 1028932cc6d4SJens Axboe * 1029932cc6d4SJens Axboe * Description: 1030932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1031932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1032932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1033932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1034932cc6d4SJens Axboe * 1035932cc6d4SJens Axboe */ 1036c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 10377995bd28SAl Viro loff_t *opos, size_t len, unsigned int flags) 1038c66ab6faSJens Axboe { 1039c66ab6faSJens Axboe struct splice_desc sd = { 1040c66ab6faSJens Axboe .len = len, 1041c66ab6faSJens Axboe .total_len = len, 1042c66ab6faSJens Axboe .flags = flags, 1043c66ab6faSJens Axboe .pos = *ppos, 10446a14b90bSJens Axboe .u.file = out, 10457995bd28SAl Viro .opos = opos, 1046c66ab6faSJens Axboe }; 104751a92c0fSJens Axboe long ret; 1048c66ab6faSJens Axboe 104918c67cb9SAl Viro if (unlikely(!(out->f_mode & FMODE_WRITE))) 105018c67cb9SAl Viro return -EBADF; 105118c67cb9SAl Viro 105218c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 105318c67cb9SAl Viro return -EINVAL; 105418c67cb9SAl Viro 105518c67cb9SAl Viro ret = rw_verify_area(WRITE, out, opos, len); 105618c67cb9SAl Viro if (unlikely(ret < 0)) 105718c67cb9SAl Viro return ret; 105818c67cb9SAl Viro 1059c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 106051a92c0fSJens Axboe if (ret > 0) 1061a82c53a0STom Zanussi *ppos = sd.pos; 106251a92c0fSJens Axboe 1063c66ab6faSJens Axboe return ret; 1064b92ce558SJens Axboe } 10651c118596SMiklos Szeredi EXPORT_SYMBOL(do_splice_direct); 1066b92ce558SJens Axboe 10678924feffSAl Viro static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) 10688924feffSAl Viro { 106952bce911SLinus Torvalds for (;;) { 107052bce911SLinus Torvalds if (unlikely(!pipe->readers)) { 107152bce911SLinus Torvalds send_sig(SIGPIPE, current, 0); 107252bce911SLinus Torvalds return -EPIPE; 107352bce911SLinus Torvalds } 10746718b6f8SDavid Howells if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 107552bce911SLinus Torvalds return 0; 10768924feffSAl Viro if (flags & SPLICE_F_NONBLOCK) 10778924feffSAl Viro return -EAGAIN; 10788924feffSAl Viro if (signal_pending(current)) 10798924feffSAl Viro return -ERESTARTSYS; 10808924feffSAl Viro pipe_wait(pipe); 10818924feffSAl Viro } 10828924feffSAl Viro } 10838924feffSAl Viro 10847c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 10857c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 10867c77f0b3SMiklos Szeredi size_t len, unsigned int flags); 1087ddac0d39SJens Axboe 1088ddac0d39SJens Axboe /* 108983f9135bSJens Axboe * Determine where to splice to/from. 109083f9135bSJens Axboe */ 1091444ebb57SPavel Begunkov long do_splice(struct file *in, loff_t __user *off_in, 1092529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1093529565dcSIngo Molnar size_t len, unsigned int flags) 10945274f052SJens Axboe { 10957c77f0b3SMiklos Szeredi struct pipe_inode_info *ipipe; 10967c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe; 10977995bd28SAl Viro loff_t offset; 1098a4514ebdSJens Axboe long ret; 10995274f052SJens Axboe 110071993e62SLinus Torvalds ipipe = get_pipe_info(in); 110171993e62SLinus Torvalds opipe = get_pipe_info(out); 11027c77f0b3SMiklos Szeredi 11037c77f0b3SMiklos Szeredi if (ipipe && opipe) { 11047c77f0b3SMiklos Szeredi if (off_in || off_out) 11057c77f0b3SMiklos Szeredi return -ESPIPE; 11067c77f0b3SMiklos Szeredi 11077c77f0b3SMiklos Szeredi if (!(in->f_mode & FMODE_READ)) 11087c77f0b3SMiklos Szeredi return -EBADF; 11097c77f0b3SMiklos Szeredi 11107c77f0b3SMiklos Szeredi if (!(out->f_mode & FMODE_WRITE)) 11117c77f0b3SMiklos Szeredi return -EBADF; 11127c77f0b3SMiklos Szeredi 11137c77f0b3SMiklos Szeredi /* Splicing to self would be fun, but... */ 11147c77f0b3SMiklos Szeredi if (ipipe == opipe) 11157c77f0b3SMiklos Szeredi return -EINVAL; 11167c77f0b3SMiklos Szeredi 1117ee5e0011SSlavomir Kaslev if ((in->f_flags | out->f_flags) & O_NONBLOCK) 1118ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1119ee5e0011SSlavomir Kaslev 11207c77f0b3SMiklos Szeredi return splice_pipe_to_pipe(ipipe, opipe, len, flags); 11217c77f0b3SMiklos Szeredi } 11227c77f0b3SMiklos Szeredi 11237c77f0b3SMiklos Szeredi if (ipipe) { 1124529565dcSIngo Molnar if (off_in) 1125529565dcSIngo Molnar return -ESPIPE; 1126b92ce558SJens Axboe if (off_out) { 112719c9a49bSChangli Gao if (!(out->f_mode & FMODE_PWRITE)) 1128b92ce558SJens Axboe return -EINVAL; 1129cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1130b92ce558SJens Axboe return -EFAULT; 11317995bd28SAl Viro } else { 11327995bd28SAl Viro offset = out->f_pos; 11337995bd28SAl Viro } 1134529565dcSIngo Molnar 113518c67cb9SAl Viro if (unlikely(!(out->f_mode & FMODE_WRITE))) 113618c67cb9SAl Viro return -EBADF; 113718c67cb9SAl Viro 113818c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 113918c67cb9SAl Viro return -EINVAL; 114018c67cb9SAl Viro 114118c67cb9SAl Viro ret = rw_verify_area(WRITE, out, &offset, len); 114218c67cb9SAl Viro if (unlikely(ret < 0)) 114318c67cb9SAl Viro return ret; 114418c67cb9SAl Viro 1145ee5e0011SSlavomir Kaslev if (in->f_flags & O_NONBLOCK) 1146ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1147ee5e0011SSlavomir Kaslev 1148500368f7SAl Viro file_start_write(out); 11497995bd28SAl Viro ret = do_splice_from(ipipe, out, &offset, len, flags); 1150500368f7SAl Viro file_end_write(out); 1151a4514ebdSJens Axboe 11527995bd28SAl Viro if (!off_out) 11537995bd28SAl Viro out->f_pos = offset; 11547995bd28SAl Viro else if (copy_to_user(off_out, &offset, sizeof(loff_t))) 1155a4514ebdSJens Axboe ret = -EFAULT; 1156a4514ebdSJens Axboe 1157a4514ebdSJens Axboe return ret; 1158529565dcSIngo Molnar } 11595274f052SJens Axboe 11607c77f0b3SMiklos Szeredi if (opipe) { 1161529565dcSIngo Molnar if (off_out) 1162529565dcSIngo Molnar return -ESPIPE; 1163b92ce558SJens Axboe if (off_in) { 116419c9a49bSChangli Gao if (!(in->f_mode & FMODE_PREAD)) 1165b92ce558SJens Axboe return -EINVAL; 1166cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1167b92ce558SJens Axboe return -EFAULT; 11687995bd28SAl Viro } else { 11697995bd28SAl Viro offset = in->f_pos; 11707995bd28SAl Viro } 1171529565dcSIngo Molnar 1172ee5e0011SSlavomir Kaslev if (out->f_flags & O_NONBLOCK) 1173ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1174ee5e0011SSlavomir Kaslev 11758924feffSAl Viro pipe_lock(opipe); 11768924feffSAl Viro ret = wait_for_space(opipe, flags); 11773253d9d0SDarrick J. Wong if (!ret) { 11786a965666SLinus Torvalds unsigned int p_space; 11793253d9d0SDarrick J. Wong 11803253d9d0SDarrick J. Wong /* Don't try to read more the pipe has space for. */ 11816a965666SLinus Torvalds p_space = opipe->max_usage - pipe_occupancy(opipe->head, opipe->tail); 11826a965666SLinus Torvalds len = min_t(size_t, len, p_space << PAGE_SHIFT); 11833253d9d0SDarrick J. Wong 11847995bd28SAl Viro ret = do_splice_to(in, &offset, opipe, len, flags); 11853253d9d0SDarrick J. Wong } 11868924feffSAl Viro pipe_unlock(opipe); 11878924feffSAl Viro if (ret > 0) 11888924feffSAl Viro wakeup_pipe_readers(opipe); 11897995bd28SAl Viro if (!off_in) 11907995bd28SAl Viro in->f_pos = offset; 11917995bd28SAl Viro else if (copy_to_user(off_in, &offset, sizeof(loff_t))) 1192a4514ebdSJens Axboe ret = -EFAULT; 1193a4514ebdSJens Axboe 1194a4514ebdSJens Axboe return ret; 1195529565dcSIngo Molnar } 11965274f052SJens Axboe 11975274f052SJens Axboe return -EINVAL; 11985274f052SJens Axboe } 11995274f052SJens Axboe 120079fddc4eSAl Viro static int iter_to_pipe(struct iov_iter *from, 120179fddc4eSAl Viro struct pipe_inode_info *pipe, 120279fddc4eSAl Viro unsigned flags) 1203912d35f8SJens Axboe { 120479fddc4eSAl Viro struct pipe_buffer buf = { 120579fddc4eSAl Viro .ops = &user_page_pipe_buf_ops, 120679fddc4eSAl Viro .flags = flags 120779fddc4eSAl Viro }; 120879fddc4eSAl Viro size_t total = 0; 120979fddc4eSAl Viro int ret = 0; 121079fddc4eSAl Viro bool failed = false; 121179fddc4eSAl Viro 121279fddc4eSAl Viro while (iov_iter_count(from) && !failed) { 121379fddc4eSAl Viro struct page *pages[16]; 1214db85a9ebSAl Viro ssize_t copied; 1215db85a9ebSAl Viro size_t start; 121679fddc4eSAl Viro int n; 1217912d35f8SJens Axboe 121879fddc4eSAl Viro copied = iov_iter_get_pages(from, pages, ~0UL, 16, &start); 121979fddc4eSAl Viro if (copied <= 0) { 122079fddc4eSAl Viro ret = copied; 122179fddc4eSAl Viro break; 122279fddc4eSAl Viro } 1223912d35f8SJens Axboe 122479fddc4eSAl Viro for (n = 0; copied; n++, start = 0) { 1225db85a9ebSAl Viro int size = min_t(int, copied, PAGE_SIZE - start); 122679fddc4eSAl Viro if (!failed) { 122779fddc4eSAl Viro buf.page = pages[n]; 122879fddc4eSAl Viro buf.offset = start; 122979fddc4eSAl Viro buf.len = size; 123079fddc4eSAl Viro ret = add_to_pipe(pipe, &buf); 123179fddc4eSAl Viro if (unlikely(ret < 0)) { 123279fddc4eSAl Viro failed = true; 123379fddc4eSAl Viro } else { 123479fddc4eSAl Viro iov_iter_advance(from, ret); 123579fddc4eSAl Viro total += ret; 123679fddc4eSAl Viro } 123779fddc4eSAl Viro } else { 123879fddc4eSAl Viro put_page(pages[n]); 123979fddc4eSAl Viro } 1240db85a9ebSAl Viro copied -= size; 1241912d35f8SJens Axboe } 1242912d35f8SJens Axboe } 124379fddc4eSAl Viro return total ? total : ret; 1244912d35f8SJens Axboe } 1245912d35f8SJens Axboe 12466a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 12476a14b90bSJens Axboe struct splice_desc *sd) 12486a14b90bSJens Axboe { 12496130f531SAl Viro int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data); 12506130f531SAl Viro return n == sd->len ? n : -EFAULT; 12516a14b90bSJens Axboe } 12526a14b90bSJens Axboe 12536a14b90bSJens Axboe /* 12546a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 12556a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 12566a14b90bSJens Axboe */ 125787a3002aSAl Viro static long vmsplice_to_user(struct file *file, struct iov_iter *iter, 125887a3002aSAl Viro unsigned int flags) 12596a14b90bSJens Axboe { 126087a3002aSAl Viro struct pipe_inode_info *pipe = get_pipe_info(file); 126187a3002aSAl Viro struct splice_desc sd = { 126287a3002aSAl Viro .total_len = iov_iter_count(iter), 126387a3002aSAl Viro .flags = flags, 126487a3002aSAl Viro .u.data = iter 126587a3002aSAl Viro }; 126687a3002aSAl Viro long ret = 0; 12676a14b90bSJens Axboe 12686a14b90bSJens Axboe if (!pipe) 12696a14b90bSJens Axboe return -EBADF; 12706a14b90bSJens Axboe 1271345995faSAl Viro if (sd.total_len) { 12726130f531SAl Viro pipe_lock(pipe); 12736130f531SAl Viro ret = __splice_from_pipe(pipe, &sd, pipe_to_user); 127461e0d47cSMiklos Szeredi pipe_unlock(pipe); 1275345995faSAl Viro } 12766a14b90bSJens Axboe 12776a14b90bSJens Axboe return ret; 12786a14b90bSJens Axboe } 12796a14b90bSJens Axboe 1280912d35f8SJens Axboe /* 1281912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1282912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1283912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1284912d35f8SJens Axboe */ 128587a3002aSAl Viro static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter, 128687a3002aSAl Viro unsigned int flags) 1287912d35f8SJens Axboe { 1288ddac0d39SJens Axboe struct pipe_inode_info *pipe; 128987a3002aSAl Viro long ret = 0; 129079fddc4eSAl Viro unsigned buf_flag = 0; 129179fddc4eSAl Viro 129279fddc4eSAl Viro if (flags & SPLICE_F_GIFT) 129379fddc4eSAl Viro buf_flag = PIPE_BUF_FLAG_GIFT; 1294912d35f8SJens Axboe 129571993e62SLinus Torvalds pipe = get_pipe_info(file); 1296ddac0d39SJens Axboe if (!pipe) 1297912d35f8SJens Axboe return -EBADF; 1298912d35f8SJens Axboe 12998924feffSAl Viro pipe_lock(pipe); 13008924feffSAl Viro ret = wait_for_space(pipe, flags); 130179fddc4eSAl Viro if (!ret) 130287a3002aSAl Viro ret = iter_to_pipe(iter, pipe, buf_flag); 13038924feffSAl Viro pipe_unlock(pipe); 13048924feffSAl Viro if (ret > 0) 13058924feffSAl Viro wakeup_pipe_readers(pipe); 130635f3d14dSJens Axboe return ret; 1307912d35f8SJens Axboe } 1308912d35f8SJens Axboe 130987a3002aSAl Viro static int vmsplice_type(struct fd f, int *type) 131087a3002aSAl Viro { 131187a3002aSAl Viro if (!f.file) 131287a3002aSAl Viro return -EBADF; 131387a3002aSAl Viro if (f.file->f_mode & FMODE_WRITE) { 131487a3002aSAl Viro *type = WRITE; 131587a3002aSAl Viro } else if (f.file->f_mode & FMODE_READ) { 131687a3002aSAl Viro *type = READ; 131787a3002aSAl Viro } else { 131887a3002aSAl Viro fdput(f); 131987a3002aSAl Viro return -EBADF; 132087a3002aSAl Viro } 132187a3002aSAl Viro return 0; 132287a3002aSAl Viro } 132387a3002aSAl Viro 13246a14b90bSJens Axboe /* 13256a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 13266a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 13276a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 13286a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 13296a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 13306a14b90bSJens Axboe * solutions for that: 13316a14b90bSJens Axboe * 13326a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 13336a14b90bSJens Axboe * do a regular read() on the buffer anyway. 13346a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 13356a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 13366a14b90bSJens Axboe * 13376a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 13386a14b90bSJens Axboe * 13396a14b90bSJens Axboe */ 134087a3002aSAl Viro static long do_vmsplice(struct file *f, struct iov_iter *iter, unsigned int flags) 1341912d35f8SJens Axboe { 13423d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 13433d6ea290SAl Viro return -EINVAL; 134487a3002aSAl Viro 134587a3002aSAl Viro if (!iov_iter_count(iter)) 13466a14b90bSJens Axboe return 0; 13476a14b90bSJens Axboe 134887a3002aSAl Viro if (iov_iter_rw(iter) == WRITE) 134987a3002aSAl Viro return vmsplice_to_pipe(f, iter, flags); 135087a3002aSAl Viro else 135187a3002aSAl Viro return vmsplice_to_user(f, iter, flags); 1352912d35f8SJens Axboe } 1353912d35f8SJens Axboe 135487a3002aSAl Viro SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, uiov, 135530cfe4efSDominik Brodowski unsigned long, nr_segs, unsigned int, flags) 135630cfe4efSDominik Brodowski { 135787a3002aSAl Viro struct iovec iovstack[UIO_FASTIOV]; 135887a3002aSAl Viro struct iovec *iov = iovstack; 135987a3002aSAl Viro struct iov_iter iter; 136087e5e6daSJens Axboe ssize_t error; 136187a3002aSAl Viro struct fd f; 136287a3002aSAl Viro int type; 136387a3002aSAl Viro 136487a3002aSAl Viro f = fdget(fd); 136587a3002aSAl Viro error = vmsplice_type(f, &type); 136687a3002aSAl Viro if (error) 136787a3002aSAl Viro return error; 136887a3002aSAl Viro 136987a3002aSAl Viro error = import_iovec(type, uiov, nr_segs, 137087a3002aSAl Viro ARRAY_SIZE(iovstack), &iov, &iter); 137187e5e6daSJens Axboe if (error >= 0) { 137287a3002aSAl Viro error = do_vmsplice(f.file, &iter, flags); 137387a3002aSAl Viro kfree(iov); 137487a3002aSAl Viro } 137587a3002aSAl Viro fdput(f); 137687a3002aSAl Viro return error; 137730cfe4efSDominik Brodowski } 137830cfe4efSDominik Brodowski 137976b021d0SAl Viro #ifdef CONFIG_COMPAT 138076b021d0SAl Viro COMPAT_SYSCALL_DEFINE4(vmsplice, int, fd, const struct compat_iovec __user *, iov32, 138176b021d0SAl Viro unsigned int, nr_segs, unsigned int, flags) 138276b021d0SAl Viro { 138387a3002aSAl Viro struct iovec iovstack[UIO_FASTIOV]; 138487a3002aSAl Viro struct iovec *iov = iovstack; 138587a3002aSAl Viro struct iov_iter iter; 138687e5e6daSJens Axboe ssize_t error; 138787a3002aSAl Viro struct fd f; 138887a3002aSAl Viro int type; 138987a3002aSAl Viro 139087a3002aSAl Viro f = fdget(fd); 139187a3002aSAl Viro error = vmsplice_type(f, &type); 139287a3002aSAl Viro if (error) 139387a3002aSAl Viro return error; 139487a3002aSAl Viro 139587a3002aSAl Viro error = compat_import_iovec(type, iov32, nr_segs, 139687a3002aSAl Viro ARRAY_SIZE(iovstack), &iov, &iter); 139787e5e6daSJens Axboe if (error >= 0) { 139887a3002aSAl Viro error = do_vmsplice(f.file, &iter, flags); 139987a3002aSAl Viro kfree(iov); 140076b021d0SAl Viro } 140187a3002aSAl Viro fdput(f); 140287a3002aSAl Viro return error; 140376b021d0SAl Viro } 140476b021d0SAl Viro #endif 140576b021d0SAl Viro 1406836f92adSHeiko Carstens SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, 1407836f92adSHeiko Carstens int, fd_out, loff_t __user *, off_out, 1408836f92adSHeiko Carstens size_t, len, unsigned int, flags) 14095274f052SJens Axboe { 14102903ff01SAl Viro struct fd in, out; 14115274f052SJens Axboe long error; 14125274f052SJens Axboe 14135274f052SJens Axboe if (unlikely(!len)) 14145274f052SJens Axboe return 0; 14155274f052SJens Axboe 14163d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 14173d6ea290SAl Viro return -EINVAL; 14183d6ea290SAl Viro 14195274f052SJens Axboe error = -EBADF; 14202903ff01SAl Viro in = fdget(fd_in); 14212903ff01SAl Viro if (in.file) { 14222903ff01SAl Viro if (in.file->f_mode & FMODE_READ) { 14232903ff01SAl Viro out = fdget(fd_out); 14242903ff01SAl Viro if (out.file) { 14252903ff01SAl Viro if (out.file->f_mode & FMODE_WRITE) 14262903ff01SAl Viro error = do_splice(in.file, off_in, 14272903ff01SAl Viro out.file, off_out, 1428529565dcSIngo Molnar len, flags); 14292903ff01SAl Viro fdput(out); 14305274f052SJens Axboe } 14315274f052SJens Axboe } 14322903ff01SAl Viro fdput(in); 14335274f052SJens Axboe } 14345274f052SJens Axboe return error; 14355274f052SJens Axboe } 143670524490SJens Axboe 143770524490SJens Axboe /* 1438aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1439aadd06e5SJens Axboe * return an appropriate error. 1440aadd06e5SJens Axboe */ 14417c77f0b3SMiklos Szeredi static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1442aadd06e5SJens Axboe { 1443aadd06e5SJens Axboe int ret; 1444aadd06e5SJens Axboe 1445aadd06e5SJens Axboe /* 14468cefc107SDavid Howells * Check the pipe occupancy without the inode lock first. This function 1447aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1448aadd06e5SJens Axboe */ 14498cefc107SDavid Howells if (!pipe_empty(pipe->head, pipe->tail)) 1450aadd06e5SJens Axboe return 0; 1451aadd06e5SJens Axboe 1452aadd06e5SJens Axboe ret = 0; 145361e0d47cSMiklos Szeredi pipe_lock(pipe); 1454aadd06e5SJens Axboe 14558cefc107SDavid Howells while (pipe_empty(pipe->head, pipe->tail)) { 1456aadd06e5SJens Axboe if (signal_pending(current)) { 1457aadd06e5SJens Axboe ret = -ERESTARTSYS; 1458aadd06e5SJens Axboe break; 1459aadd06e5SJens Axboe } 1460aadd06e5SJens Axboe if (!pipe->writers) 1461aadd06e5SJens Axboe break; 1462aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1463aadd06e5SJens Axboe ret = -EAGAIN; 1464aadd06e5SJens Axboe break; 1465aadd06e5SJens Axboe } 1466aadd06e5SJens Axboe pipe_wait(pipe); 1467aadd06e5SJens Axboe } 1468aadd06e5SJens Axboe 146961e0d47cSMiklos Szeredi pipe_unlock(pipe); 1470aadd06e5SJens Axboe return ret; 1471aadd06e5SJens Axboe } 1472aadd06e5SJens Axboe 1473aadd06e5SJens Axboe /* 1474aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1475aadd06e5SJens Axboe * return an appropriate error. 1476aadd06e5SJens Axboe */ 14777c77f0b3SMiklos Szeredi static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1478aadd06e5SJens Axboe { 1479aadd06e5SJens Axboe int ret; 1480aadd06e5SJens Axboe 1481aadd06e5SJens Axboe /* 14828cefc107SDavid Howells * Check pipe occupancy without the inode lock first. This function 1483aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1484aadd06e5SJens Axboe */ 14856718b6f8SDavid Howells if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 1486aadd06e5SJens Axboe return 0; 1487aadd06e5SJens Axboe 1488aadd06e5SJens Axboe ret = 0; 148961e0d47cSMiklos Szeredi pipe_lock(pipe); 1490aadd06e5SJens Axboe 14916718b6f8SDavid Howells while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { 1492aadd06e5SJens Axboe if (!pipe->readers) { 1493aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1494aadd06e5SJens Axboe ret = -EPIPE; 1495aadd06e5SJens Axboe break; 1496aadd06e5SJens Axboe } 1497aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1498aadd06e5SJens Axboe ret = -EAGAIN; 1499aadd06e5SJens Axboe break; 1500aadd06e5SJens Axboe } 1501aadd06e5SJens Axboe if (signal_pending(current)) { 1502aadd06e5SJens Axboe ret = -ERESTARTSYS; 1503aadd06e5SJens Axboe break; 1504aadd06e5SJens Axboe } 1505aadd06e5SJens Axboe pipe_wait(pipe); 1506aadd06e5SJens Axboe } 1507aadd06e5SJens Axboe 150861e0d47cSMiklos Szeredi pipe_unlock(pipe); 1509aadd06e5SJens Axboe return ret; 1510aadd06e5SJens Axboe } 1511aadd06e5SJens Axboe 1512aadd06e5SJens Axboe /* 15137c77f0b3SMiklos Szeredi * Splice contents of ipipe to opipe. 15147c77f0b3SMiklos Szeredi */ 15157c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 15167c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 15177c77f0b3SMiklos Szeredi size_t len, unsigned int flags) 15187c77f0b3SMiklos Szeredi { 15197c77f0b3SMiklos Szeredi struct pipe_buffer *ibuf, *obuf; 15208cefc107SDavid Howells unsigned int i_head, o_head; 15218cefc107SDavid Howells unsigned int i_tail, o_tail; 15228cefc107SDavid Howells unsigned int i_mask, o_mask; 15238cefc107SDavid Howells int ret = 0; 15247c77f0b3SMiklos Szeredi bool input_wakeup = false; 15257c77f0b3SMiklos Szeredi 15267c77f0b3SMiklos Szeredi 15277c77f0b3SMiklos Szeredi retry: 15287c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 15297c77f0b3SMiklos Szeredi if (ret) 15307c77f0b3SMiklos Szeredi return ret; 15317c77f0b3SMiklos Szeredi 15327c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 15337c77f0b3SMiklos Szeredi if (ret) 15347c77f0b3SMiklos Szeredi return ret; 15357c77f0b3SMiklos Szeredi 15367c77f0b3SMiklos Szeredi /* 15377c77f0b3SMiklos Szeredi * Potential ABBA deadlock, work around it by ordering lock 15387c77f0b3SMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 15397c77f0b3SMiklos Szeredi * could deadlock (one doing tee from A -> B, the other from B -> A). 15407c77f0b3SMiklos Szeredi */ 15417c77f0b3SMiklos Szeredi pipe_double_lock(ipipe, opipe); 15427c77f0b3SMiklos Szeredi 15438cefc107SDavid Howells i_tail = ipipe->tail; 15448cefc107SDavid Howells i_mask = ipipe->ring_size - 1; 15458cefc107SDavid Howells o_head = opipe->head; 15468cefc107SDavid Howells o_mask = opipe->ring_size - 1; 15478cefc107SDavid Howells 15487c77f0b3SMiklos Szeredi do { 15498cefc107SDavid Howells size_t o_len; 15508cefc107SDavid Howells 15517c77f0b3SMiklos Szeredi if (!opipe->readers) { 15527c77f0b3SMiklos Szeredi send_sig(SIGPIPE, current, 0); 15537c77f0b3SMiklos Szeredi if (!ret) 15547c77f0b3SMiklos Szeredi ret = -EPIPE; 15557c77f0b3SMiklos Szeredi break; 15567c77f0b3SMiklos Szeredi } 15577c77f0b3SMiklos Szeredi 15588cefc107SDavid Howells i_head = ipipe->head; 15598cefc107SDavid Howells o_tail = opipe->tail; 15608cefc107SDavid Howells 15618cefc107SDavid Howells if (pipe_empty(i_head, i_tail) && !ipipe->writers) 15627c77f0b3SMiklos Szeredi break; 15637c77f0b3SMiklos Szeredi 15647c77f0b3SMiklos Szeredi /* 15657c77f0b3SMiklos Szeredi * Cannot make any progress, because either the input 15667c77f0b3SMiklos Szeredi * pipe is empty or the output pipe is full. 15677c77f0b3SMiklos Szeredi */ 15688cefc107SDavid Howells if (pipe_empty(i_head, i_tail) || 15696718b6f8SDavid Howells pipe_full(o_head, o_tail, opipe->max_usage)) { 15707c77f0b3SMiklos Szeredi /* Already processed some buffers, break */ 15717c77f0b3SMiklos Szeredi if (ret) 15727c77f0b3SMiklos Szeredi break; 15737c77f0b3SMiklos Szeredi 15747c77f0b3SMiklos Szeredi if (flags & SPLICE_F_NONBLOCK) { 15757c77f0b3SMiklos Szeredi ret = -EAGAIN; 15767c77f0b3SMiklos Szeredi break; 15777c77f0b3SMiklos Szeredi } 15787c77f0b3SMiklos Szeredi 15797c77f0b3SMiklos Szeredi /* 15807c77f0b3SMiklos Szeredi * We raced with another reader/writer and haven't 15817c77f0b3SMiklos Szeredi * managed to process any buffers. A zero return 15827c77f0b3SMiklos Szeredi * value means EOF, so retry instead. 15837c77f0b3SMiklos Szeredi */ 15847c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 15857c77f0b3SMiklos Szeredi pipe_unlock(opipe); 15867c77f0b3SMiklos Szeredi goto retry; 15877c77f0b3SMiklos Szeredi } 15887c77f0b3SMiklos Szeredi 15898cefc107SDavid Howells ibuf = &ipipe->bufs[i_tail & i_mask]; 15908cefc107SDavid Howells obuf = &opipe->bufs[o_head & o_mask]; 15917c77f0b3SMiklos Szeredi 15927c77f0b3SMiklos Szeredi if (len >= ibuf->len) { 15937c77f0b3SMiklos Szeredi /* 15947c77f0b3SMiklos Szeredi * Simply move the whole buffer from ipipe to opipe 15957c77f0b3SMiklos Szeredi */ 15967c77f0b3SMiklos Szeredi *obuf = *ibuf; 15977c77f0b3SMiklos Szeredi ibuf->ops = NULL; 15988cefc107SDavid Howells i_tail++; 15998cefc107SDavid Howells ipipe->tail = i_tail; 16007c77f0b3SMiklos Szeredi input_wakeup = true; 16018cefc107SDavid Howells o_len = obuf->len; 16028cefc107SDavid Howells o_head++; 16038cefc107SDavid Howells opipe->head = o_head; 16047c77f0b3SMiklos Szeredi } else { 16057c77f0b3SMiklos Szeredi /* 16067c77f0b3SMiklos Szeredi * Get a reference to this pipe buffer, 16077c77f0b3SMiklos Szeredi * so we can copy the contents over. 16087c77f0b3SMiklos Szeredi */ 160915fab63eSMatthew Wilcox if (!pipe_buf_get(ipipe, ibuf)) { 161015fab63eSMatthew Wilcox if (ret == 0) 161115fab63eSMatthew Wilcox ret = -EFAULT; 161215fab63eSMatthew Wilcox break; 161315fab63eSMatthew Wilcox } 16147c77f0b3SMiklos Szeredi *obuf = *ibuf; 16157c77f0b3SMiklos Szeredi 16167c77f0b3SMiklos Szeredi /* 1617f6dd9755SChristoph Hellwig * Don't inherit the gift and merge flags, we need to 16187c77f0b3SMiklos Szeredi * prevent multiple steals of this page. 16197c77f0b3SMiklos Szeredi */ 16207c77f0b3SMiklos Szeredi obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1621f6dd9755SChristoph Hellwig obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; 1622a0ce2f0aSJann Horn 16237c77f0b3SMiklos Szeredi obuf->len = len; 16248cefc107SDavid Howells ibuf->offset += len; 16258cefc107SDavid Howells ibuf->len -= len; 16268cefc107SDavid Howells o_len = len; 16278cefc107SDavid Howells o_head++; 16288cefc107SDavid Howells opipe->head = o_head; 16297c77f0b3SMiklos Szeredi } 16308cefc107SDavid Howells ret += o_len; 16318cefc107SDavid Howells len -= o_len; 16327c77f0b3SMiklos Szeredi } while (len); 16337c77f0b3SMiklos Szeredi 16347c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 16357c77f0b3SMiklos Szeredi pipe_unlock(opipe); 16367c77f0b3SMiklos Szeredi 16377c77f0b3SMiklos Szeredi /* 16387c77f0b3SMiklos Szeredi * If we put data in the output pipe, wakeup any potential readers. 16397c77f0b3SMiklos Szeredi */ 1640825cdcb1SNamhyung Kim if (ret > 0) 1641825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 1642825cdcb1SNamhyung Kim 16437c77f0b3SMiklos Szeredi if (input_wakeup) 16447c77f0b3SMiklos Szeredi wakeup_pipe_writers(ipipe); 16457c77f0b3SMiklos Szeredi 16467c77f0b3SMiklos Szeredi return ret; 16477c77f0b3SMiklos Szeredi } 16487c77f0b3SMiklos Szeredi 16497c77f0b3SMiklos Szeredi /* 165070524490SJens Axboe * Link contents of ipipe to opipe. 165170524490SJens Axboe */ 165270524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 165370524490SJens Axboe struct pipe_inode_info *opipe, 165470524490SJens Axboe size_t len, unsigned int flags) 165570524490SJens Axboe { 165670524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 16578cefc107SDavid Howells unsigned int i_head, o_head; 16588cefc107SDavid Howells unsigned int i_tail, o_tail; 16598cefc107SDavid Howells unsigned int i_mask, o_mask; 16608cefc107SDavid Howells int ret = 0; 166170524490SJens Axboe 166270524490SJens Axboe /* 166370524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 166461e0d47cSMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 166570524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 166670524490SJens Axboe */ 166761e0d47cSMiklos Szeredi pipe_double_lock(ipipe, opipe); 166870524490SJens Axboe 16698cefc107SDavid Howells i_tail = ipipe->tail; 16708cefc107SDavid Howells i_mask = ipipe->ring_size - 1; 16718cefc107SDavid Howells o_head = opipe->head; 16728cefc107SDavid Howells o_mask = opipe->ring_size - 1; 16738cefc107SDavid Howells 1674aadd06e5SJens Axboe do { 167570524490SJens Axboe if (!opipe->readers) { 167670524490SJens Axboe send_sig(SIGPIPE, current, 0); 167770524490SJens Axboe if (!ret) 167870524490SJens Axboe ret = -EPIPE; 167970524490SJens Axboe break; 168070524490SJens Axboe } 168170524490SJens Axboe 16828cefc107SDavid Howells i_head = ipipe->head; 16838cefc107SDavid Howells o_tail = opipe->tail; 16848cefc107SDavid Howells 168570524490SJens Axboe /* 16868cefc107SDavid Howells * If we have iterated all input buffers or run out of 1687aadd06e5SJens Axboe * output room, break. 168870524490SJens Axboe */ 16898cefc107SDavid Howells if (pipe_empty(i_head, i_tail) || 16906718b6f8SDavid Howells pipe_full(o_head, o_tail, opipe->max_usage)) 1691aadd06e5SJens Axboe break; 1692aadd06e5SJens Axboe 16938cefc107SDavid Howells ibuf = &ipipe->bufs[i_tail & i_mask]; 16948cefc107SDavid Howells obuf = &opipe->bufs[o_head & o_mask]; 169570524490SJens Axboe 169670524490SJens Axboe /* 169770524490SJens Axboe * Get a reference to this pipe buffer, 169870524490SJens Axboe * so we can copy the contents over. 169970524490SJens Axboe */ 170015fab63eSMatthew Wilcox if (!pipe_buf_get(ipipe, ibuf)) { 170115fab63eSMatthew Wilcox if (ret == 0) 170215fab63eSMatthew Wilcox ret = -EFAULT; 170315fab63eSMatthew Wilcox break; 170415fab63eSMatthew Wilcox } 170570524490SJens Axboe 170670524490SJens Axboe *obuf = *ibuf; 170770524490SJens Axboe 17087afa6fd0SJens Axboe /* 1709f6dd9755SChristoph Hellwig * Don't inherit the gift and merge flag, we need to prevent 1710f6dd9755SChristoph Hellwig * multiple steals of this page. 17117afa6fd0SJens Axboe */ 17127afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1713f6dd9755SChristoph Hellwig obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; 1714a0ce2f0aSJann Horn 171570524490SJens Axboe if (obuf->len > len) 171670524490SJens Axboe obuf->len = len; 171770524490SJens Axboe ret += obuf->len; 171870524490SJens Axboe len -= obuf->len; 17198cefc107SDavid Howells 17208cefc107SDavid Howells o_head++; 17218cefc107SDavid Howells opipe->head = o_head; 17228cefc107SDavid Howells i_tail++; 1723aadd06e5SJens Axboe } while (len); 172470524490SJens Axboe 172561e0d47cSMiklos Szeredi pipe_unlock(ipipe); 172661e0d47cSMiklos Szeredi pipe_unlock(opipe); 172770524490SJens Axboe 1728aadd06e5SJens Axboe /* 1729aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1730aadd06e5SJens Axboe */ 1731825cdcb1SNamhyung Kim if (ret > 0) 1732825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 173370524490SJens Axboe 173470524490SJens Axboe return ret; 173570524490SJens Axboe } 173670524490SJens Axboe 173770524490SJens Axboe /* 173870524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 173970524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 174070524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 174170524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 174270524490SJens Axboe */ 174370524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 174470524490SJens Axboe unsigned int flags) 174570524490SJens Axboe { 174671993e62SLinus Torvalds struct pipe_inode_info *ipipe = get_pipe_info(in); 174771993e62SLinus Torvalds struct pipe_inode_info *opipe = get_pipe_info(out); 1748aadd06e5SJens Axboe int ret = -EINVAL; 174970524490SJens Axboe 175070524490SJens Axboe /* 1751aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1752aadd06e5SJens Axboe * copying the data. 175370524490SJens Axboe */ 1754aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1755ee5e0011SSlavomir Kaslev if ((in->f_flags | out->f_flags) & O_NONBLOCK) 1756ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1757ee5e0011SSlavomir Kaslev 1758aadd06e5SJens Axboe /* 1759aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1760aadd06e5SJens Axboe * ordering doesn't really matter. 1761aadd06e5SJens Axboe */ 17627c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 1763aadd06e5SJens Axboe if (!ret) { 17647c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 176502cf01aeSJens Axboe if (!ret) 1766aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1767aadd06e5SJens Axboe } 1768aadd06e5SJens Axboe } 176970524490SJens Axboe 1770aadd06e5SJens Axboe return ret; 177170524490SJens Axboe } 177270524490SJens Axboe 1773836f92adSHeiko Carstens SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) 177470524490SJens Axboe { 17752903ff01SAl Viro struct fd in; 17762903ff01SAl Viro int error; 177770524490SJens Axboe 17783d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 17793d6ea290SAl Viro return -EINVAL; 17803d6ea290SAl Viro 178170524490SJens Axboe if (unlikely(!len)) 178270524490SJens Axboe return 0; 178370524490SJens Axboe 178470524490SJens Axboe error = -EBADF; 17852903ff01SAl Viro in = fdget(fdin); 17862903ff01SAl Viro if (in.file) { 17872903ff01SAl Viro if (in.file->f_mode & FMODE_READ) { 17882903ff01SAl Viro struct fd out = fdget(fdout); 17892903ff01SAl Viro if (out.file) { 17902903ff01SAl Viro if (out.file->f_mode & FMODE_WRITE) 17912903ff01SAl Viro error = do_tee(in.file, out.file, 17922903ff01SAl Viro len, flags); 17932903ff01SAl Viro fdput(out); 179470524490SJens Axboe } 179570524490SJens Axboe } 17962903ff01SAl Viro fdput(in); 179770524490SJens Axboe } 179870524490SJens Axboe 179970524490SJens Axboe return error; 180070524490SJens Axboe } 1801