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> 36174cd4b1SIngo Molnar #include <linux/sched/signal.h> 37174cd4b1SIngo Molnar 3806ae43f3SAl Viro #include "internal.h" 395274f052SJens Axboe 4083f9135bSJens Axboe /* 4183f9135bSJens Axboe * Attempt to steal a page from a pipe buffer. This should perhaps go into 4283f9135bSJens Axboe * a vm helper function, it's already simplified quite a bit by the 4383f9135bSJens Axboe * addition of remove_mapping(). If success is returned, the caller may 4483f9135bSJens Axboe * attempt to reuse this page for another destination. 4583f9135bSJens Axboe */ 46c928f642SChristoph Hellwig static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe, 475abc97aaSJens Axboe struct pipe_buffer *buf) 485abc97aaSJens Axboe { 495abc97aaSJens Axboe struct page *page = buf->page; 509e94cd4fSJens Axboe struct address_space *mapping; 515abc97aaSJens Axboe 529e0267c2SJens Axboe lock_page(page); 539e0267c2SJens Axboe 549e94cd4fSJens Axboe mapping = page_mapping(page); 559e94cd4fSJens Axboe if (mapping) { 565abc97aaSJens Axboe WARN_ON(!PageUptodate(page)); 575abc97aaSJens Axboe 58ad8d6f0aSJens Axboe /* 599e94cd4fSJens Axboe * At least for ext2 with nobh option, we need to wait on 609e94cd4fSJens Axboe * writeback completing on this page, since we'll remove it 619e94cd4fSJens Axboe * from the pagecache. Otherwise truncate wont wait on the 629e94cd4fSJens Axboe * page, allowing the disk blocks to be reused by someone else 639e94cd4fSJens Axboe * before we actually wrote our data to them. fs corruption 649e94cd4fSJens Axboe * ensues. 65ad8d6f0aSJens Axboe */ 66ad8d6f0aSJens Axboe wait_on_page_writeback(page); 67ad8d6f0aSJens Axboe 68266cf658SDavid Howells if (page_has_private(page) && 69266cf658SDavid Howells !try_to_release_page(page, GFP_KERNEL)) 70ca39d651SJens Axboe goto out_unlock; 714f6f0bd2SJens Axboe 729e94cd4fSJens Axboe /* 739e94cd4fSJens Axboe * If we succeeded in removing the mapping, set LRU flag 749e94cd4fSJens Axboe * and return good. 759e94cd4fSJens Axboe */ 769e94cd4fSJens Axboe if (remove_mapping(mapping, page)) { 771432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 78c928f642SChristoph Hellwig return true; 795abc97aaSJens Axboe } 809e94cd4fSJens Axboe } 819e94cd4fSJens Axboe 829e94cd4fSJens Axboe /* 839e94cd4fSJens Axboe * Raced with truncate or failed to remove page from current 849e94cd4fSJens Axboe * address space, unlock and return failure. 859e94cd4fSJens Axboe */ 86ca39d651SJens Axboe out_unlock: 879e94cd4fSJens Axboe unlock_page(page); 88c928f642SChristoph Hellwig return false; 899e94cd4fSJens Axboe } 905abc97aaSJens Axboe 9176ad4d11SJens Axboe static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, 925274f052SJens Axboe struct pipe_buffer *buf) 935274f052SJens Axboe { 9409cbfeafSKirill A. Shutemov put_page(buf->page); 951432873aSJens Axboe buf->flags &= ~PIPE_BUF_FLAG_LRU; 965274f052SJens Axboe } 975274f052SJens Axboe 980845718dSJens Axboe /* 990845718dSJens Axboe * Check whether the contents of buf is OK to access. Since the content 1000845718dSJens Axboe * is a page cache page, IO may be in flight. 1010845718dSJens Axboe */ 102cac36bb0SJens Axboe static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, 1035274f052SJens Axboe struct pipe_buffer *buf) 1045274f052SJens Axboe { 1055274f052SJens Axboe struct page *page = buf->page; 10649d0b21bSJens Axboe int err; 1075274f052SJens Axboe 1085274f052SJens Axboe if (!PageUptodate(page)) { 10949d0b21bSJens Axboe lock_page(page); 1105274f052SJens Axboe 11149d0b21bSJens Axboe /* 11249d0b21bSJens Axboe * Page got truncated/unhashed. This will cause a 0-byte 11373d62d83SIngo Molnar * splice, if this is the first page. 11449d0b21bSJens Axboe */ 1155274f052SJens Axboe if (!page->mapping) { 11649d0b21bSJens Axboe err = -ENODATA; 11749d0b21bSJens Axboe goto error; 1185274f052SJens Axboe } 1195274f052SJens Axboe 12049d0b21bSJens Axboe /* 12173d62d83SIngo Molnar * Uh oh, read-error from disk. 12249d0b21bSJens Axboe */ 12349d0b21bSJens Axboe if (!PageUptodate(page)) { 12449d0b21bSJens Axboe err = -EIO; 12549d0b21bSJens Axboe goto error; 12649d0b21bSJens Axboe } 12749d0b21bSJens Axboe 12849d0b21bSJens Axboe /* 129f84d7519SJens Axboe * Page is ok afterall, we are done. 13049d0b21bSJens Axboe */ 13149d0b21bSJens Axboe unlock_page(page); 13249d0b21bSJens Axboe } 13349d0b21bSJens Axboe 134f84d7519SJens Axboe return 0; 13549d0b21bSJens Axboe error: 13649d0b21bSJens Axboe unlock_page(page); 137f84d7519SJens Axboe return err; 13870524490SJens Axboe } 13970524490SJens Axboe 140708e3508SHugh Dickins const struct pipe_buf_operations page_cache_pipe_buf_ops = { 141cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1425274f052SJens Axboe .release = page_cache_pipe_buf_release, 143c928f642SChristoph Hellwig .try_steal = page_cache_pipe_buf_try_steal, 144f84d7519SJens Axboe .get = generic_pipe_buf_get, 1455274f052SJens Axboe }; 1465274f052SJens Axboe 147c928f642SChristoph Hellwig static bool user_page_pipe_buf_try_steal(struct pipe_inode_info *pipe, 148912d35f8SJens Axboe struct pipe_buffer *buf) 149912d35f8SJens Axboe { 1507afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 151c928f642SChristoph Hellwig return false; 1527afa6fd0SJens Axboe 1531432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 154c928f642SChristoph Hellwig return generic_pipe_buf_try_steal(pipe, buf); 155912d35f8SJens Axboe } 156912d35f8SJens Axboe 157d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 158912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 159c928f642SChristoph Hellwig .try_steal = user_page_pipe_buf_try_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(); 1660ddad21dSLinus Torvalds if (waitqueue_active(&pipe->rd_wait)) 1670ddad21dSLinus Torvalds wake_up_interruptible(&pipe->rd_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; 1868cefc107SDavid Howells unsigned int tail = pipe->tail; 1878cefc107SDavid Howells unsigned int head = pipe->head; 1888cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 1898924feffSAl Viro int ret = 0, page_nr = 0; 1905274f052SJens Axboe 191d6785d91SRabin Vincent if (!spd_pages) 192d6785d91SRabin Vincent return 0; 193d6785d91SRabin Vincent 1948924feffSAl Viro if (unlikely(!pipe->readers)) { 1955274f052SJens Axboe send_sig(SIGPIPE, current, 0); 1965274f052SJens Axboe ret = -EPIPE; 1978924feffSAl Viro goto out; 1985274f052SJens Axboe } 1995274f052SJens Axboe 2006718b6f8SDavid Howells while (!pipe_full(head, tail, pipe->max_usage)) { 2018cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[head & mask]; 2025274f052SJens Axboe 203912d35f8SJens Axboe buf->page = spd->pages[page_nr]; 204912d35f8SJens Axboe buf->offset = spd->partial[page_nr].offset; 205912d35f8SJens Axboe buf->len = spd->partial[page_nr].len; 206497f9625SJens Axboe buf->private = spd->partial[page_nr].private; 207912d35f8SJens Axboe buf->ops = spd->ops; 2085a81e6a1SMiklos Szeredi buf->flags = 0; 2097afa6fd0SJens Axboe 2108cefc107SDavid Howells head++; 2118cefc107SDavid Howells pipe->head = head; 212912d35f8SJens Axboe page_nr++; 213912d35f8SJens Axboe ret += buf->len; 214912d35f8SJens Axboe 215912d35f8SJens Axboe if (!--spd->nr_pages) 2165274f052SJens Axboe break; 2175274f052SJens Axboe } 2185274f052SJens Axboe 21929e35094SLinus Torvalds if (!ret) 22029e35094SLinus Torvalds ret = -EAGAIN; 22129e35094SLinus Torvalds 2228924feffSAl Viro out: 22300de00bdSJens Axboe while (page_nr < spd_pages) 224bbdfc2f7SJens Axboe spd->spd_release(spd, page_nr++); 2255274f052SJens Axboe 2265274f052SJens Axboe return ret; 2275274f052SJens Axboe } 2282b514574SHannes Frederic Sowa EXPORT_SYMBOL_GPL(splice_to_pipe); 2295274f052SJens Axboe 23079fddc4eSAl Viro ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf) 23179fddc4eSAl Viro { 2328cefc107SDavid Howells unsigned int head = pipe->head; 2338cefc107SDavid Howells unsigned int tail = pipe->tail; 2348cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 23579fddc4eSAl Viro int ret; 23679fddc4eSAl Viro 23779fddc4eSAl Viro if (unlikely(!pipe->readers)) { 23879fddc4eSAl Viro send_sig(SIGPIPE, current, 0); 23979fddc4eSAl Viro ret = -EPIPE; 2406718b6f8SDavid Howells } else if (pipe_full(head, tail, pipe->max_usage)) { 24179fddc4eSAl Viro ret = -EAGAIN; 24279fddc4eSAl Viro } else { 2438cefc107SDavid Howells pipe->bufs[head & mask] = *buf; 2448cefc107SDavid Howells pipe->head = head + 1; 24579fddc4eSAl Viro return buf->len; 24679fddc4eSAl Viro } 247a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 24879fddc4eSAl Viro return ret; 24979fddc4eSAl Viro } 25079fddc4eSAl Viro EXPORT_SYMBOL(add_to_pipe); 25179fddc4eSAl Viro 25235f3d14dSJens Axboe /* 25335f3d14dSJens Axboe * Check if we need to grow the arrays holding pages and partial page 25435f3d14dSJens Axboe * descriptions. 25535f3d14dSJens Axboe */ 256047fe360SEric Dumazet int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) 25735f3d14dSJens Axboe { 2586718b6f8SDavid Howells unsigned int max_usage = READ_ONCE(pipe->max_usage); 259047fe360SEric Dumazet 2608cefc107SDavid Howells spd->nr_pages_max = max_usage; 2618cefc107SDavid Howells if (max_usage <= PIPE_DEF_BUFFERS) 26235f3d14dSJens Axboe return 0; 26335f3d14dSJens Axboe 2648cefc107SDavid Howells spd->pages = kmalloc_array(max_usage, sizeof(struct page *), GFP_KERNEL); 2658cefc107SDavid Howells spd->partial = kmalloc_array(max_usage, sizeof(struct partial_page), 2666da2ec56SKees Cook GFP_KERNEL); 26735f3d14dSJens Axboe 26835f3d14dSJens Axboe if (spd->pages && spd->partial) 26935f3d14dSJens Axboe return 0; 27035f3d14dSJens Axboe 27135f3d14dSJens Axboe kfree(spd->pages); 27235f3d14dSJens Axboe kfree(spd->partial); 27335f3d14dSJens Axboe return -ENOMEM; 27435f3d14dSJens Axboe } 27535f3d14dSJens Axboe 276047fe360SEric Dumazet void splice_shrink_spd(struct splice_pipe_desc *spd) 27735f3d14dSJens Axboe { 278047fe360SEric Dumazet if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) 27935f3d14dSJens Axboe return; 28035f3d14dSJens Axboe 28135f3d14dSJens Axboe kfree(spd->pages); 28235f3d14dSJens Axboe kfree(spd->partial); 28335f3d14dSJens Axboe } 28435f3d14dSJens Axboe 28583f9135bSJens Axboe /** 28683f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 28783f9135bSJens Axboe * @in: file to splice from 288932cc6d4SJens Axboe * @ppos: position in @in 28983f9135bSJens Axboe * @pipe: pipe to splice to 29083f9135bSJens Axboe * @len: number of bytes to splice 29183f9135bSJens Axboe * @flags: splice modifier flags 29283f9135bSJens Axboe * 293932cc6d4SJens Axboe * Description: 294932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 29582c156f8SAl Viro * used as long as it has more or less sane ->read_iter(). 296932cc6d4SJens Axboe * 29783f9135bSJens Axboe */ 298cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 299cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 300cbb7e577SJens Axboe unsigned int flags) 3015274f052SJens Axboe { 30282c156f8SAl Viro struct iov_iter to; 30382c156f8SAl Viro struct kiocb kiocb; 3048cefc107SDavid Howells unsigned int i_head; 3058cefc107SDavid Howells int ret; 306be64f884SBoaz Harrosh 307aa563d7bSDavid Howells iov_iter_pipe(&to, READ, pipe, len); 3088cefc107SDavid Howells i_head = to.head; 30982c156f8SAl Viro init_sync_kiocb(&kiocb, in); 31082c156f8SAl Viro kiocb.ki_pos = *ppos; 311bb7462b6SMiklos Szeredi ret = call_read_iter(in, &kiocb, &to); 312723590edSMiklos Szeredi if (ret > 0) { 31382c156f8SAl Viro *ppos = kiocb.ki_pos; 314723590edSMiklos Szeredi file_accessed(in); 31582c156f8SAl Viro } else if (ret < 0) { 3168cefc107SDavid Howells to.head = i_head; 31782c156f8SAl Viro to.iov_offset = 0; 31882c156f8SAl Viro iov_iter_advance(&to, 0); /* to free what was emitted */ 31982c156f8SAl Viro /* 32082c156f8SAl Viro * callers of ->splice_read() expect -EAGAIN on 32182c156f8SAl Viro * "can't put anything in there", rather than -EFAULT. 32282c156f8SAl Viro */ 32382c156f8SAl Viro if (ret == -EFAULT) 32482c156f8SAl Viro ret = -EAGAIN; 325723590edSMiklos Szeredi } 3265274f052SJens Axboe 3275274f052SJens Axboe return ret; 3285274f052SJens Axboe } 329059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 330059a8f37SJens Axboe 331241699cdSAl Viro const struct pipe_buf_operations default_pipe_buf_ops = { 3326818173bSMiklos Szeredi .release = generic_pipe_buf_release, 333c928f642SChristoph Hellwig .try_steal = generic_pipe_buf_try_steal, 3346818173bSMiklos Szeredi .get = generic_pipe_buf_get, 3356818173bSMiklos Szeredi }; 3366818173bSMiklos Szeredi 33728a625cbSMiklos Szeredi /* Pipe buffer operations for a socket and similar. */ 33828a625cbSMiklos Szeredi const struct pipe_buf_operations nosteal_pipe_buf_ops = { 33928a625cbSMiklos Szeredi .release = generic_pipe_buf_release, 34028a625cbSMiklos Szeredi .get = generic_pipe_buf_get, 34128a625cbSMiklos Szeredi }; 34228a625cbSMiklos Szeredi EXPORT_SYMBOL(nosteal_pipe_buf_ops); 34328a625cbSMiklos Szeredi 344523ac9afSAl Viro static ssize_t kernel_readv(struct file *file, const struct kvec *vec, 3456818173bSMiklos Szeredi unsigned long vlen, loff_t offset) 3466818173bSMiklos Szeredi { 3476818173bSMiklos Szeredi mm_segment_t old_fs; 3486818173bSMiklos Szeredi loff_t pos = offset; 3496818173bSMiklos Szeredi ssize_t res; 3506818173bSMiklos Szeredi 3516818173bSMiklos Szeredi old_fs = get_fs(); 352736706beSLinus Torvalds set_fs(KERNEL_DS); 3536818173bSMiklos Szeredi /* The cast to a user pointer is valid due to the set_fs() */ 354793b80efSChristoph Hellwig res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos, 0); 3556818173bSMiklos Szeredi set_fs(old_fs); 3566818173bSMiklos Szeredi 3576818173bSMiklos Szeredi return res; 3586818173bSMiklos Szeredi } 3596818173bSMiklos Szeredi 36082c156f8SAl Viro static ssize_t default_file_splice_read(struct file *in, loff_t *ppos, 3616818173bSMiklos Szeredi struct pipe_inode_info *pipe, size_t len, 3626818173bSMiklos Szeredi unsigned int flags) 3636818173bSMiklos Szeredi { 364523ac9afSAl Viro struct kvec *vec, __vec[PIPE_DEF_BUFFERS]; 365523ac9afSAl Viro struct iov_iter to; 366523ac9afSAl Viro struct page **pages; 3676818173bSMiklos Szeredi unsigned int nr_pages; 3688cefc107SDavid Howells unsigned int mask; 36913c0f52bSAl Viro size_t offset, base, copied = 0; 3706818173bSMiklos Szeredi ssize_t res; 3716818173bSMiklos Szeredi int i; 3726818173bSMiklos Szeredi 3736718b6f8SDavid Howells if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 374523ac9afSAl Viro return -EAGAIN; 375523ac9afSAl Viro 376523ac9afSAl Viro /* 377523ac9afSAl Viro * Try to keep page boundaries matching to source pagecache ones - 378523ac9afSAl Viro * it probably won't be much help, but... 379523ac9afSAl Viro */ 380523ac9afSAl Viro offset = *ppos & ~PAGE_MASK; 381523ac9afSAl Viro 382aa563d7bSDavid Howells iov_iter_pipe(&to, READ, pipe, len + offset); 383523ac9afSAl Viro 38413c0f52bSAl Viro res = iov_iter_get_pages_alloc(&to, &pages, len + offset, &base); 385523ac9afSAl Viro if (res <= 0) 38635f3d14dSJens Axboe return -ENOMEM; 38735f3d14dSJens Axboe 38813c0f52bSAl Viro nr_pages = DIV_ROUND_UP(res + base, PAGE_SIZE); 389523ac9afSAl Viro 39035f3d14dSJens Axboe vec = __vec; 391523ac9afSAl Viro if (nr_pages > PIPE_DEF_BUFFERS) { 3926da2ec56SKees Cook vec = kmalloc_array(nr_pages, sizeof(struct kvec), GFP_KERNEL); 393523ac9afSAl Viro if (unlikely(!vec)) { 394523ac9afSAl Viro res = -ENOMEM; 395523ac9afSAl Viro goto out; 396523ac9afSAl Viro } 39735f3d14dSJens Axboe } 39835f3d14dSJens Axboe 3998cefc107SDavid Howells mask = pipe->ring_size - 1; 4008cefc107SDavid Howells pipe->bufs[to.head & mask].offset = offset; 4018cefc107SDavid Howells pipe->bufs[to.head & mask].len -= offset; 4026818173bSMiklos Szeredi 403523ac9afSAl Viro for (i = 0; i < nr_pages; i++) { 404523ac9afSAl Viro size_t this_len = min_t(size_t, len, PAGE_SIZE - offset); 405523ac9afSAl Viro vec[i].iov_base = page_address(pages[i]) + offset; 4066818173bSMiklos Szeredi vec[i].iov_len = this_len; 4076818173bSMiklos Szeredi len -= this_len; 4086818173bSMiklos Szeredi offset = 0; 4096818173bSMiklos Szeredi } 4106818173bSMiklos Szeredi 411523ac9afSAl Viro res = kernel_readv(in, vec, nr_pages, *ppos); 412523ac9afSAl Viro if (res > 0) { 413523ac9afSAl Viro copied = res; 4146818173bSMiklos Szeredi *ppos += res; 415523ac9afSAl Viro } 4166818173bSMiklos Szeredi 41735f3d14dSJens Axboe if (vec != __vec) 41835f3d14dSJens Axboe kfree(vec); 419523ac9afSAl Viro out: 420523ac9afSAl Viro for (i = 0; i < nr_pages; i++) 421523ac9afSAl Viro put_page(pages[i]); 422523ac9afSAl Viro kvfree(pages); 423523ac9afSAl Viro iov_iter_advance(&to, copied); /* truncates and discards */ 4246818173bSMiklos Szeredi return res; 4256818173bSMiklos Szeredi } 4266818173bSMiklos Szeredi 4275274f052SJens Axboe /* 4284f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 429016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 4305274f052SJens Axboe */ 43176ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 4325274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 4335274f052SJens Axboe { 4346a14b90bSJens Axboe struct file *file = sd->u.file; 4355274f052SJens Axboe loff_t pos = sd->pos; 436a8adbe37SMichał Mirosław int more; 4375274f052SJens Axboe 43872c2d531SAl Viro if (!likely(file->f_op->sendpage)) 439a8adbe37SMichał Mirosław return -EINVAL; 440a8adbe37SMichał Mirosław 44135f9c09fSEric Dumazet more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; 442ae62ca7bSEric Dumazet 4438cefc107SDavid Howells if (sd->len < sd->total_len && 4448cefc107SDavid Howells pipe_occupancy(pipe->head, pipe->tail) > 1) 44535f9c09fSEric Dumazet more |= MSG_SENDPAGE_NOTLAST; 446ae62ca7bSEric Dumazet 447a8adbe37SMichał Mirosław return file->f_op->sendpage(file, buf->page, buf->offset, 448f84d7519SJens Axboe sd->len, &pos, more); 4495274f052SJens Axboe } 4505274f052SJens Axboe 451b3c2d2ddSMiklos Szeredi static void wakeup_pipe_writers(struct pipe_inode_info *pipe) 452b3c2d2ddSMiklos Szeredi { 453b3c2d2ddSMiklos Szeredi smp_mb(); 4540ddad21dSLinus Torvalds if (waitqueue_active(&pipe->wr_wait)) 4550ddad21dSLinus Torvalds wake_up_interruptible(&pipe->wr_wait); 456b3c2d2ddSMiklos Szeredi kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 457b3c2d2ddSMiklos Szeredi } 458b3c2d2ddSMiklos Szeredi 459b3c2d2ddSMiklos Szeredi /** 460b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed - feed available data from a pipe to a file 461b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 462b3c2d2ddSMiklos Szeredi * @sd: information to @actor 463b3c2d2ddSMiklos Szeredi * @actor: handler that splices the data 464b3c2d2ddSMiklos Szeredi * 465b3c2d2ddSMiklos Szeredi * Description: 466b3c2d2ddSMiklos Szeredi * This function loops over the pipe and calls @actor to do the 467b3c2d2ddSMiklos Szeredi * actual moving of a single struct pipe_buffer to the desired 468b3c2d2ddSMiklos Szeredi * destination. It returns when there's no more buffers left in 469b3c2d2ddSMiklos Szeredi * the pipe or if the requested number of bytes (@sd->total_len) 470b3c2d2ddSMiklos Szeredi * have been copied. It returns a positive number (one) if the 471b3c2d2ddSMiklos Szeredi * pipe needs to be filled with more data, zero if the required 472b3c2d2ddSMiklos Szeredi * number of bytes have been copied and -errno on error. 473b3c2d2ddSMiklos Szeredi * 474b3c2d2ddSMiklos Szeredi * This, together with splice_from_pipe_{begin,end,next}, may be 475b3c2d2ddSMiklos Szeredi * used to implement the functionality of __splice_from_pipe() when 476b3c2d2ddSMiklos Szeredi * locking is required around copying the pipe buffers to the 477b3c2d2ddSMiklos Szeredi * destination. 478b3c2d2ddSMiklos Szeredi */ 47996f9bc8fSAl Viro static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, 480b3c2d2ddSMiklos Szeredi splice_actor *actor) 481b3c2d2ddSMiklos Szeredi { 4828cefc107SDavid Howells unsigned int head = pipe->head; 4838cefc107SDavid Howells unsigned int tail = pipe->tail; 4848cefc107SDavid Howells unsigned int mask = pipe->ring_size - 1; 485b3c2d2ddSMiklos Szeredi int ret; 486b3c2d2ddSMiklos Szeredi 487ec057595SLinus Torvalds while (!pipe_empty(head, tail)) { 4888cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 489b3c2d2ddSMiklos Szeredi 490b3c2d2ddSMiklos Szeredi sd->len = buf->len; 491b3c2d2ddSMiklos Szeredi if (sd->len > sd->total_len) 492b3c2d2ddSMiklos Szeredi sd->len = sd->total_len; 493b3c2d2ddSMiklos Szeredi 494fba597dbSMiklos Szeredi ret = pipe_buf_confirm(pipe, buf); 495a8adbe37SMichał Mirosław if (unlikely(ret)) { 496b3c2d2ddSMiklos Szeredi if (ret == -ENODATA) 497b3c2d2ddSMiklos Szeredi ret = 0; 498b3c2d2ddSMiklos Szeredi return ret; 499b3c2d2ddSMiklos Szeredi } 500a8adbe37SMichał Mirosław 501a8adbe37SMichał Mirosław ret = actor(pipe, buf, sd); 502a8adbe37SMichał Mirosław if (ret <= 0) 503a8adbe37SMichał Mirosław return ret; 504a8adbe37SMichał Mirosław 505b3c2d2ddSMiklos Szeredi buf->offset += ret; 506b3c2d2ddSMiklos Szeredi buf->len -= ret; 507b3c2d2ddSMiklos Szeredi 508b3c2d2ddSMiklos Szeredi sd->num_spliced += ret; 509b3c2d2ddSMiklos Szeredi sd->len -= ret; 510b3c2d2ddSMiklos Szeredi sd->pos += ret; 511b3c2d2ddSMiklos Szeredi sd->total_len -= ret; 512b3c2d2ddSMiklos Szeredi 513b3c2d2ddSMiklos Szeredi if (!buf->len) { 514a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 5158cefc107SDavid Howells tail++; 5168cefc107SDavid Howells pipe->tail = tail; 5176447a3cfSAl Viro if (pipe->files) 518b3c2d2ddSMiklos Szeredi sd->need_wakeup = true; 519b3c2d2ddSMiklos Szeredi } 520b3c2d2ddSMiklos Szeredi 521b3c2d2ddSMiklos Szeredi if (!sd->total_len) 522b3c2d2ddSMiklos Szeredi return 0; 523b3c2d2ddSMiklos Szeredi } 524b3c2d2ddSMiklos Szeredi 525b3c2d2ddSMiklos Szeredi return 1; 526b3c2d2ddSMiklos Szeredi } 527b3c2d2ddSMiklos Szeredi 528d1a819a2SLinus Torvalds /* We know we have a pipe buffer, but maybe it's empty? */ 529d1a819a2SLinus Torvalds static inline bool eat_empty_buffer(struct pipe_inode_info *pipe) 530d1a819a2SLinus Torvalds { 531d1a819a2SLinus Torvalds unsigned int tail = pipe->tail; 532d1a819a2SLinus Torvalds unsigned int mask = pipe->ring_size - 1; 533d1a819a2SLinus Torvalds struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 534d1a819a2SLinus Torvalds 535d1a819a2SLinus Torvalds if (unlikely(!buf->len)) { 536d1a819a2SLinus Torvalds pipe_buf_release(pipe, buf); 537d1a819a2SLinus Torvalds pipe->tail = tail+1; 538d1a819a2SLinus Torvalds return true; 539d1a819a2SLinus Torvalds } 540d1a819a2SLinus Torvalds 541d1a819a2SLinus Torvalds return false; 542d1a819a2SLinus Torvalds } 543d1a819a2SLinus Torvalds 544b3c2d2ddSMiklos Szeredi /** 545b3c2d2ddSMiklos Szeredi * splice_from_pipe_next - wait for some data to splice from 546b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 547b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 548b3c2d2ddSMiklos Szeredi * 549b3c2d2ddSMiklos Szeredi * Description: 550b3c2d2ddSMiklos Szeredi * This function will wait for some data and return a positive 551b3c2d2ddSMiklos Szeredi * value (one) if pipe buffers are available. It will return zero 552b3c2d2ddSMiklos Szeredi * or -errno if no more data needs to be spliced. 553b3c2d2ddSMiklos Szeredi */ 55496f9bc8fSAl Viro static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) 555b3c2d2ddSMiklos Szeredi { 556c725bfceSJan Kara /* 557c725bfceSJan Kara * Check for signal early to make process killable when there are 558c725bfceSJan Kara * always buffers available 559c725bfceSJan Kara */ 560c725bfceSJan Kara if (signal_pending(current)) 561c725bfceSJan Kara return -ERESTARTSYS; 562c725bfceSJan Kara 563d1a819a2SLinus Torvalds repeat: 5648cefc107SDavid Howells while (pipe_empty(pipe->head, pipe->tail)) { 565b3c2d2ddSMiklos Szeredi if (!pipe->writers) 566b3c2d2ddSMiklos Szeredi return 0; 567b3c2d2ddSMiklos Szeredi 568a28c8b9dSLinus Torvalds if (sd->num_spliced) 569b3c2d2ddSMiklos Szeredi return 0; 570b3c2d2ddSMiklos Szeredi 571b3c2d2ddSMiklos Szeredi if (sd->flags & SPLICE_F_NONBLOCK) 572b3c2d2ddSMiklos Szeredi return -EAGAIN; 573b3c2d2ddSMiklos Szeredi 574b3c2d2ddSMiklos Szeredi if (signal_pending(current)) 575b3c2d2ddSMiklos Szeredi return -ERESTARTSYS; 576b3c2d2ddSMiklos Szeredi 577b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) { 578b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 579b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 580b3c2d2ddSMiklos Szeredi } 581b3c2d2ddSMiklos Szeredi 582472e5b05SLinus Torvalds pipe_wait_readable(pipe); 583b3c2d2ddSMiklos Szeredi } 584b3c2d2ddSMiklos Szeredi 585d1a819a2SLinus Torvalds if (eat_empty_buffer(pipe)) 586d1a819a2SLinus Torvalds goto repeat; 587d1a819a2SLinus Torvalds 588b3c2d2ddSMiklos Szeredi return 1; 589b3c2d2ddSMiklos Szeredi } 590b3c2d2ddSMiklos Szeredi 591b3c2d2ddSMiklos Szeredi /** 592b3c2d2ddSMiklos Szeredi * splice_from_pipe_begin - start splicing from pipe 593b80901bbSRandy Dunlap * @sd: information about the splice operation 594b3c2d2ddSMiklos Szeredi * 595b3c2d2ddSMiklos Szeredi * Description: 596b3c2d2ddSMiklos Szeredi * This function should be called before a loop containing 597b3c2d2ddSMiklos Szeredi * splice_from_pipe_next() and splice_from_pipe_feed() to 598b3c2d2ddSMiklos Szeredi * initialize the necessary fields of @sd. 599b3c2d2ddSMiklos Szeredi */ 60096f9bc8fSAl Viro static void splice_from_pipe_begin(struct splice_desc *sd) 601b3c2d2ddSMiklos Szeredi { 602b3c2d2ddSMiklos Szeredi sd->num_spliced = 0; 603b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 604b3c2d2ddSMiklos Szeredi } 605b3c2d2ddSMiklos Szeredi 606b3c2d2ddSMiklos Szeredi /** 607b3c2d2ddSMiklos Szeredi * splice_from_pipe_end - finish splicing from pipe 608b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 609b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 610b3c2d2ddSMiklos Szeredi * 611b3c2d2ddSMiklos Szeredi * Description: 612b3c2d2ddSMiklos Szeredi * This function will wake up pipe writers if necessary. It should 613b3c2d2ddSMiklos Szeredi * be called after a loop containing splice_from_pipe_next() and 614b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed(). 615b3c2d2ddSMiklos Szeredi */ 61696f9bc8fSAl Viro static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) 617b3c2d2ddSMiklos Szeredi { 618b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) 619b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 620b3c2d2ddSMiklos Szeredi } 621b3c2d2ddSMiklos Szeredi 622932cc6d4SJens Axboe /** 623932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 624932cc6d4SJens Axboe * @pipe: pipe to splice from 625932cc6d4SJens Axboe * @sd: information to @actor 626932cc6d4SJens Axboe * @actor: handler that splices the data 627932cc6d4SJens Axboe * 628932cc6d4SJens Axboe * Description: 629932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 630932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 631932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 632932cc6d4SJens Axboe * pipe_to_user. 633932cc6d4SJens Axboe * 63483f9135bSJens Axboe */ 635c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 636c66ab6faSJens Axboe splice_actor *actor) 6375274f052SJens Axboe { 638b3c2d2ddSMiklos Szeredi int ret; 6395274f052SJens Axboe 640b3c2d2ddSMiklos Szeredi splice_from_pipe_begin(sd); 641b3c2d2ddSMiklos Szeredi do { 642c2489e07SJan Kara cond_resched(); 643b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_next(pipe, sd); 644b3c2d2ddSMiklos Szeredi if (ret > 0) 645b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_feed(pipe, sd, actor); 646b3c2d2ddSMiklos Szeredi } while (ret > 0); 647b3c2d2ddSMiklos Szeredi splice_from_pipe_end(pipe, sd); 6485274f052SJens Axboe 649b3c2d2ddSMiklos Szeredi return sd->num_spliced ? sd->num_spliced : ret; 6505274f052SJens Axboe } 65140bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 6525274f052SJens Axboe 653932cc6d4SJens Axboe /** 654932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 655932cc6d4SJens Axboe * @pipe: pipe to splice from 656932cc6d4SJens Axboe * @out: file to splice to 657932cc6d4SJens Axboe * @ppos: position in @out 658932cc6d4SJens Axboe * @len: how many bytes to splice 659932cc6d4SJens Axboe * @flags: splice modifier flags 660932cc6d4SJens Axboe * @actor: handler that splices the data 661932cc6d4SJens Axboe * 662932cc6d4SJens Axboe * Description: 6632933970bSMiklos Szeredi * See __splice_from_pipe. This function locks the pipe inode, 664932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 665932cc6d4SJens Axboe * 666932cc6d4SJens Axboe */ 6676da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 6686da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 6696da61809SMark Fasheh splice_actor *actor) 6706da61809SMark Fasheh { 6716da61809SMark Fasheh ssize_t ret; 672c66ab6faSJens Axboe struct splice_desc sd = { 673c66ab6faSJens Axboe .total_len = len, 674c66ab6faSJens Axboe .flags = flags, 675c66ab6faSJens Axboe .pos = *ppos, 6766a14b90bSJens Axboe .u.file = out, 677c66ab6faSJens Axboe }; 6786da61809SMark Fasheh 67961e0d47cSMiklos Szeredi pipe_lock(pipe); 680c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 68161e0d47cSMiklos Szeredi pipe_unlock(pipe); 6826da61809SMark Fasheh 6836da61809SMark Fasheh return ret; 6846da61809SMark Fasheh } 6856da61809SMark Fasheh 6866da61809SMark Fasheh /** 6878d020765SAl Viro * iter_file_splice_write - splice data from a pipe to a file 6888d020765SAl Viro * @pipe: pipe info 6898d020765SAl Viro * @out: file to write to 6908d020765SAl Viro * @ppos: position in @out 6918d020765SAl Viro * @len: number of bytes to splice 6928d020765SAl Viro * @flags: splice modifier flags 6938d020765SAl Viro * 6948d020765SAl Viro * Description: 6958d020765SAl Viro * Will either move or copy pages (determined by @flags options) from 6968d020765SAl Viro * the given pipe inode to the given file. 6978d020765SAl Viro * This one is ->write_iter-based. 6988d020765SAl Viro * 6998d020765SAl Viro */ 7008d020765SAl Viro ssize_t 7018d020765SAl Viro iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 7028d020765SAl Viro loff_t *ppos, size_t len, unsigned int flags) 7038d020765SAl Viro { 7048d020765SAl Viro struct splice_desc sd = { 7058d020765SAl Viro .total_len = len, 7068d020765SAl Viro .flags = flags, 7078d020765SAl Viro .pos = *ppos, 7088d020765SAl Viro .u.file = out, 7098d020765SAl Viro }; 7106718b6f8SDavid Howells int nbufs = pipe->max_usage; 7118d020765SAl Viro struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec), 7128d020765SAl Viro GFP_KERNEL); 7138d020765SAl Viro ssize_t ret; 7148d020765SAl Viro 7158d020765SAl Viro if (unlikely(!array)) 7168d020765SAl Viro return -ENOMEM; 7178d020765SAl Viro 7188d020765SAl Viro pipe_lock(pipe); 7198d020765SAl Viro 7208d020765SAl Viro splice_from_pipe_begin(&sd); 7218d020765SAl Viro while (sd.total_len) { 7228d020765SAl Viro struct iov_iter from; 723ec057595SLinus Torvalds unsigned int head, tail, mask; 7248d020765SAl Viro size_t left; 7258cefc107SDavid Howells int n; 7268d020765SAl Viro 7278d020765SAl Viro ret = splice_from_pipe_next(pipe, &sd); 7288d020765SAl Viro if (ret <= 0) 7298d020765SAl Viro break; 7308d020765SAl Viro 7316718b6f8SDavid Howells if (unlikely(nbufs < pipe->max_usage)) { 7328d020765SAl Viro kfree(array); 7336718b6f8SDavid Howells nbufs = pipe->max_usage; 7348d020765SAl Viro array = kcalloc(nbufs, sizeof(struct bio_vec), 7358d020765SAl Viro GFP_KERNEL); 7368d020765SAl Viro if (!array) { 7378d020765SAl Viro ret = -ENOMEM; 7388d020765SAl Viro break; 7398d020765SAl Viro } 7408d020765SAl Viro } 7418d020765SAl Viro 742ec057595SLinus Torvalds head = pipe->head; 743ec057595SLinus Torvalds tail = pipe->tail; 744ec057595SLinus Torvalds mask = pipe->ring_size - 1; 745ec057595SLinus Torvalds 7468d020765SAl Viro /* build the vector */ 7478d020765SAl Viro left = sd.total_len; 7488cefc107SDavid Howells for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++, n++) { 7498cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 7508d020765SAl Viro size_t this_len = buf->len; 7518d020765SAl Viro 7528d020765SAl Viro if (this_len > left) 7538d020765SAl Viro this_len = left; 7548d020765SAl Viro 755fba597dbSMiklos Szeredi ret = pipe_buf_confirm(pipe, buf); 7568d020765SAl Viro if (unlikely(ret)) { 7578d020765SAl Viro if (ret == -ENODATA) 7588d020765SAl Viro ret = 0; 7598d020765SAl Viro goto done; 7608d020765SAl Viro } 7618d020765SAl Viro 7628d020765SAl Viro array[n].bv_page = buf->page; 7638d020765SAl Viro array[n].bv_len = this_len; 7648d020765SAl Viro array[n].bv_offset = buf->offset; 7658d020765SAl Viro left -= this_len; 7668d020765SAl Viro } 7678d020765SAl Viro 768aa563d7bSDavid Howells iov_iter_bvec(&from, WRITE, array, n, sd.total_len - left); 769abbb6589SChristoph Hellwig ret = vfs_iter_write(out, &from, &sd.pos, 0); 7708d020765SAl Viro if (ret <= 0) 7718d020765SAl Viro break; 7728d020765SAl Viro 7738d020765SAl Viro sd.num_spliced += ret; 7748d020765SAl Viro sd.total_len -= ret; 775dbe4e192SChristoph Hellwig *ppos = sd.pos; 7768d020765SAl Viro 7778d020765SAl Viro /* dismiss the fully eaten buffers, adjust the partial one */ 7788cefc107SDavid Howells tail = pipe->tail; 7798d020765SAl Viro while (ret) { 7808cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[tail & mask]; 7818d020765SAl Viro if (ret >= buf->len) { 7828d020765SAl Viro ret -= buf->len; 7838d020765SAl Viro buf->len = 0; 784a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 7858cefc107SDavid Howells tail++; 7868cefc107SDavid Howells pipe->tail = tail; 7878d020765SAl Viro if (pipe->files) 7888d020765SAl Viro sd.need_wakeup = true; 7898d020765SAl Viro } else { 7908d020765SAl Viro buf->offset += ret; 7918d020765SAl Viro buf->len -= ret; 7928d020765SAl Viro ret = 0; 7938d020765SAl Viro } 7948d020765SAl Viro } 7958d020765SAl Viro } 7968d020765SAl Viro done: 7978d020765SAl Viro kfree(array); 7988d020765SAl Viro splice_from_pipe_end(pipe, &sd); 7998d020765SAl Viro 8008d020765SAl Viro pipe_unlock(pipe); 8018d020765SAl Viro 8028d020765SAl Viro if (sd.num_spliced) 8038d020765SAl Viro ret = sd.num_spliced; 8048d020765SAl Viro 8058d020765SAl Viro return ret; 8068d020765SAl Viro } 8078d020765SAl Viro 8088d020765SAl Viro EXPORT_SYMBOL(iter_file_splice_write); 8098d020765SAl Viro 810b2858d7dSMiklos Szeredi static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 811b2858d7dSMiklos Szeredi struct splice_desc *sd) 8120b0a47f5SMiklos Szeredi { 813b2858d7dSMiklos Szeredi int ret; 814b2858d7dSMiklos Szeredi void *data; 81506ae43f3SAl Viro loff_t tmp = sd->pos; 816b2858d7dSMiklos Szeredi 817fbb32750SAl Viro data = kmap(buf->page); 81806ae43f3SAl Viro ret = __kernel_write(sd->u.file, data + buf->offset, sd->len, &tmp); 819fbb32750SAl Viro kunmap(buf->page); 820b2858d7dSMiklos Szeredi 821b2858d7dSMiklos Szeredi return ret; 8220b0a47f5SMiklos Szeredi } 8230b0a47f5SMiklos Szeredi 8240b0a47f5SMiklos Szeredi static ssize_t default_file_splice_write(struct pipe_inode_info *pipe, 8250b0a47f5SMiklos Szeredi struct file *out, loff_t *ppos, 8260b0a47f5SMiklos Szeredi size_t len, unsigned int flags) 8270b0a47f5SMiklos Szeredi { 828b2858d7dSMiklos Szeredi ssize_t ret; 8290b0a47f5SMiklos Szeredi 830b2858d7dSMiklos Szeredi ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf); 831b2858d7dSMiklos Szeredi if (ret > 0) 832b2858d7dSMiklos Szeredi *ppos += ret; 8330b0a47f5SMiklos Szeredi 834b2858d7dSMiklos Szeredi return ret; 8350b0a47f5SMiklos Szeredi } 8360b0a47f5SMiklos Szeredi 83783f9135bSJens Axboe /** 83883f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 839932cc6d4SJens Axboe * @pipe: pipe to splice from 84083f9135bSJens Axboe * @out: socket to write to 841932cc6d4SJens Axboe * @ppos: position in @out 84283f9135bSJens Axboe * @len: number of bytes to splice 84383f9135bSJens Axboe * @flags: splice modifier flags 84483f9135bSJens Axboe * 845932cc6d4SJens Axboe * Description: 84683f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 84783f9135bSJens Axboe * is involved. 84883f9135bSJens Axboe * 84983f9135bSJens Axboe */ 8503a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 851cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8525274f052SJens Axboe { 85300522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8545274f052SJens Axboe } 8555274f052SJens Axboe 856059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 857a0f06780SJeff Garzik 85883f9135bSJens Axboe /* 85983f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 86083f9135bSJens Axboe */ 8613a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 862cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8635274f052SJens Axboe { 86472c2d531SAl Viro if (out->f_op->splice_write) 86500c285d0SChristoph Hellwig return out->f_op->splice_write(pipe, out, ppos, len, flags); 86600c285d0SChristoph Hellwig return default_file_splice_write(pipe, out, ppos, len, flags); 8675274f052SJens Axboe } 8685274f052SJens Axboe 86983f9135bSJens Axboe /* 87083f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 87183f9135bSJens Axboe */ 872cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 873cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 874cbb7e577SJens Axboe unsigned int flags) 8755274f052SJens Axboe { 8765274f052SJens Axboe int ret; 8775274f052SJens Axboe 87849570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 8795274f052SJens Axboe return -EBADF; 8805274f052SJens Axboe 881cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 8825274f052SJens Axboe if (unlikely(ret < 0)) 8835274f052SJens Axboe return ret; 8845274f052SJens Axboe 88503cc0789SAl Viro if (unlikely(len > MAX_RW_COUNT)) 88603cc0789SAl Viro len = MAX_RW_COUNT; 88703cc0789SAl Viro 88872c2d531SAl Viro if (in->f_op->splice_read) 8892bc01060SChristoph Hellwig return in->f_op->splice_read(in, ppos, pipe, len, flags); 8902bc01060SChristoph Hellwig return default_file_splice_read(in, ppos, pipe, len, flags); 8915274f052SJens Axboe } 8925274f052SJens Axboe 893932cc6d4SJens Axboe /** 894932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 895932cc6d4SJens Axboe * @in: file to splice from 896932cc6d4SJens Axboe * @sd: actor information on where to splice to 897932cc6d4SJens Axboe * @actor: handles the data splicing 898932cc6d4SJens Axboe * 899932cc6d4SJens Axboe * Description: 900932cc6d4SJens Axboe * This is a special case helper to splice directly between two 901932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 902932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 903932cc6d4SJens Axboe * that process. 904932cc6d4SJens Axboe * 905c66ab6faSJens Axboe */ 906c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 907c66ab6faSJens Axboe splice_direct_actor *actor) 908b92ce558SJens Axboe { 909b92ce558SJens Axboe struct pipe_inode_info *pipe; 910b92ce558SJens Axboe long ret, bytes; 911b92ce558SJens Axboe umode_t i_mode; 912c66ab6faSJens Axboe size_t len; 9130ff28d9fSChristophe Leroy int i, flags, more; 914b92ce558SJens Axboe 915b92ce558SJens Axboe /* 916b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 917b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 918b92ce558SJens Axboe * piped splicing for that! 919b92ce558SJens Axboe */ 920496ad9aaSAl Viro i_mode = file_inode(in)->i_mode; 921b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 922b92ce558SJens Axboe return -EINVAL; 923b92ce558SJens Axboe 924b92ce558SJens Axboe /* 925b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 926b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 927b92ce558SJens Axboe */ 928b92ce558SJens Axboe pipe = current->splice_pipe; 92949570e9bSJens Axboe if (unlikely(!pipe)) { 9307bee130eSAl Viro pipe = alloc_pipe_info(); 931b92ce558SJens Axboe if (!pipe) 932b92ce558SJens Axboe return -ENOMEM; 933b92ce558SJens Axboe 934b92ce558SJens Axboe /* 935b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 93600522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 937b92ce558SJens Axboe * PIPE_READERS appropriately. 938b92ce558SJens Axboe */ 939b92ce558SJens Axboe pipe->readers = 1; 940b92ce558SJens Axboe 941b92ce558SJens Axboe current->splice_pipe = pipe; 942b92ce558SJens Axboe } 943b92ce558SJens Axboe 944b92ce558SJens Axboe /* 94573d62d83SIngo Molnar * Do the splice. 946b92ce558SJens Axboe */ 947b92ce558SJens Axboe ret = 0; 948b92ce558SJens Axboe bytes = 0; 949c66ab6faSJens Axboe len = sd->total_len; 950c66ab6faSJens Axboe flags = sd->flags; 951c66ab6faSJens Axboe 952c66ab6faSJens Axboe /* 953c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 954c66ab6faSJens Axboe */ 955c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 9560ff28d9fSChristophe Leroy more = sd->flags & SPLICE_F_MORE; 957b92ce558SJens Axboe 9588cefc107SDavid Howells WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail)); 95917614445SDarrick J. Wong 960b92ce558SJens Axboe while (len) { 9618cefc107SDavid Howells unsigned int p_space; 96251a92c0fSJens Axboe size_t read_len; 963a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 964b92ce558SJens Axboe 96517614445SDarrick J. Wong /* Don't try to read more the pipe has space for. */ 9666718b6f8SDavid Howells p_space = pipe->max_usage - 9678cefc107SDavid Howells pipe_occupancy(pipe->head, pipe->tail); 9688cefc107SDavid Howells read_len = min_t(size_t, len, p_space << PAGE_SHIFT); 96917614445SDarrick J. Wong ret = do_splice_to(in, &pos, pipe, read_len, flags); 97051a92c0fSJens Axboe if (unlikely(ret <= 0)) 971b92ce558SJens Axboe goto out_release; 972b92ce558SJens Axboe 973b92ce558SJens Axboe read_len = ret; 974c66ab6faSJens Axboe sd->total_len = read_len; 975b92ce558SJens Axboe 976b92ce558SJens Axboe /* 9770ff28d9fSChristophe Leroy * If more data is pending, set SPLICE_F_MORE 9780ff28d9fSChristophe Leroy * If this is the last data and SPLICE_F_MORE was not set 9790ff28d9fSChristophe Leroy * initially, clears it. 9800ff28d9fSChristophe Leroy */ 9810ff28d9fSChristophe Leroy if (read_len < len) 9820ff28d9fSChristophe Leroy sd->flags |= SPLICE_F_MORE; 9830ff28d9fSChristophe Leroy else if (!more) 9840ff28d9fSChristophe Leroy sd->flags &= ~SPLICE_F_MORE; 9850ff28d9fSChristophe Leroy /* 986b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 987b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 988b92ce558SJens Axboe * could get stuck data in the internal pipe: 989b92ce558SJens Axboe */ 990c66ab6faSJens Axboe ret = actor(pipe, sd); 991a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 992a82c53a0STom Zanussi sd->pos = prev_pos; 993b92ce558SJens Axboe goto out_release; 994a82c53a0STom Zanussi } 995b92ce558SJens Axboe 996b92ce558SJens Axboe bytes += ret; 997b92ce558SJens Axboe len -= ret; 998bcd4f3acSJens Axboe sd->pos = pos; 999b92ce558SJens Axboe 1000a82c53a0STom Zanussi if (ret < read_len) { 1001a82c53a0STom Zanussi sd->pos = prev_pos + ret; 100251a92c0fSJens Axboe goto out_release; 1003b92ce558SJens Axboe } 1004a82c53a0STom Zanussi } 1005b92ce558SJens Axboe 10069e97198dSJens Axboe done: 10078cefc107SDavid Howells pipe->tail = pipe->head = 0; 10089e97198dSJens Axboe file_accessed(in); 1009b92ce558SJens Axboe return bytes; 1010b92ce558SJens Axboe 1011b92ce558SJens Axboe out_release: 1012b92ce558SJens Axboe /* 1013b92ce558SJens Axboe * If we did an incomplete transfer we must release 1014b92ce558SJens Axboe * the pipe buffers in question: 1015b92ce558SJens Axboe */ 10168cefc107SDavid Howells for (i = 0; i < pipe->ring_size; i++) { 10178cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[i]; 1018b92ce558SJens Axboe 1019a779638cSMiklos Szeredi if (buf->ops) 1020a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 1021b92ce558SJens Axboe } 1022b92ce558SJens Axboe 10239e97198dSJens Axboe if (!bytes) 10249e97198dSJens Axboe bytes = ret; 1025b92ce558SJens Axboe 10269e97198dSJens Axboe goto done; 1027c66ab6faSJens Axboe } 1028c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1029c66ab6faSJens Axboe 1030c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1031c66ab6faSJens Axboe struct splice_desc *sd) 1032c66ab6faSJens Axboe { 10336a14b90bSJens Axboe struct file *file = sd->u.file; 1034c66ab6faSJens Axboe 10357995bd28SAl Viro return do_splice_from(pipe, file, sd->opos, sd->total_len, 10362cb4b05eSChangli Gao sd->flags); 1037c66ab6faSJens Axboe } 1038c66ab6faSJens Axboe 1039932cc6d4SJens Axboe /** 1040932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1041932cc6d4SJens Axboe * @in: file to splice from 1042932cc6d4SJens Axboe * @ppos: input file offset 1043932cc6d4SJens Axboe * @out: file to splice to 1044acdb37c3SRandy Dunlap * @opos: output file offset 1045932cc6d4SJens Axboe * @len: number of bytes to splice 1046932cc6d4SJens Axboe * @flags: splice modifier flags 1047932cc6d4SJens Axboe * 1048932cc6d4SJens Axboe * Description: 1049932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1050932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1051932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1052932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1053932cc6d4SJens Axboe * 1054932cc6d4SJens Axboe */ 1055c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 10567995bd28SAl Viro loff_t *opos, size_t len, unsigned int flags) 1057c66ab6faSJens Axboe { 1058c66ab6faSJens Axboe struct splice_desc sd = { 1059c66ab6faSJens Axboe .len = len, 1060c66ab6faSJens Axboe .total_len = len, 1061c66ab6faSJens Axboe .flags = flags, 1062c66ab6faSJens Axboe .pos = *ppos, 10636a14b90bSJens Axboe .u.file = out, 10647995bd28SAl Viro .opos = opos, 1065c66ab6faSJens Axboe }; 106651a92c0fSJens Axboe long ret; 1067c66ab6faSJens Axboe 106818c67cb9SAl Viro if (unlikely(!(out->f_mode & FMODE_WRITE))) 106918c67cb9SAl Viro return -EBADF; 107018c67cb9SAl Viro 107118c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 107218c67cb9SAl Viro return -EINVAL; 107318c67cb9SAl Viro 107418c67cb9SAl Viro ret = rw_verify_area(WRITE, out, opos, len); 107518c67cb9SAl Viro if (unlikely(ret < 0)) 107618c67cb9SAl Viro return ret; 107718c67cb9SAl Viro 1078c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 107951a92c0fSJens Axboe if (ret > 0) 1080a82c53a0STom Zanussi *ppos = sd.pos; 108151a92c0fSJens Axboe 1082c66ab6faSJens Axboe return ret; 1083b92ce558SJens Axboe } 10841c118596SMiklos Szeredi EXPORT_SYMBOL(do_splice_direct); 1085b92ce558SJens Axboe 10868924feffSAl Viro static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) 10878924feffSAl Viro { 108852bce911SLinus Torvalds for (;;) { 108952bce911SLinus Torvalds if (unlikely(!pipe->readers)) { 109052bce911SLinus Torvalds send_sig(SIGPIPE, current, 0); 109152bce911SLinus Torvalds return -EPIPE; 109252bce911SLinus Torvalds } 10936718b6f8SDavid Howells if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 109452bce911SLinus Torvalds return 0; 10958924feffSAl Viro if (flags & SPLICE_F_NONBLOCK) 10968924feffSAl Viro return -EAGAIN; 10978924feffSAl Viro if (signal_pending(current)) 10988924feffSAl Viro return -ERESTARTSYS; 1099472e5b05SLinus Torvalds pipe_wait_writable(pipe); 11008924feffSAl Viro } 11018924feffSAl Viro } 11028924feffSAl Viro 11037c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 11047c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 11057c77f0b3SMiklos Szeredi size_t len, unsigned int flags); 1106ddac0d39SJens Axboe 1107ddac0d39SJens Axboe /* 110883f9135bSJens Axboe * Determine where to splice to/from. 110983f9135bSJens Axboe */ 1110ee6e00c8SJens Axboe long do_splice(struct file *in, loff_t *off_in, struct file *out, 1111ee6e00c8SJens Axboe loff_t *off_out, size_t len, unsigned int flags) 11125274f052SJens Axboe { 11137c77f0b3SMiklos Szeredi struct pipe_inode_info *ipipe; 11147c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe; 11157995bd28SAl Viro loff_t offset; 1116a4514ebdSJens Axboe long ret; 11175274f052SJens Axboe 111890da2e3fSPavel Begunkov if (unlikely(!(in->f_mode & FMODE_READ) || 111990da2e3fSPavel Begunkov !(out->f_mode & FMODE_WRITE))) 112090da2e3fSPavel Begunkov return -EBADF; 112190da2e3fSPavel Begunkov 1122c73be61cSDavid Howells ipipe = get_pipe_info(in, true); 1123c73be61cSDavid Howells opipe = get_pipe_info(out, true); 11247c77f0b3SMiklos Szeredi 11257c77f0b3SMiklos Szeredi if (ipipe && opipe) { 11267c77f0b3SMiklos Szeredi if (off_in || off_out) 11277c77f0b3SMiklos Szeredi return -ESPIPE; 11287c77f0b3SMiklos Szeredi 11297c77f0b3SMiklos Szeredi /* Splicing to self would be fun, but... */ 11307c77f0b3SMiklos Szeredi if (ipipe == opipe) 11317c77f0b3SMiklos Szeredi return -EINVAL; 11327c77f0b3SMiklos Szeredi 1133ee5e0011SSlavomir Kaslev if ((in->f_flags | out->f_flags) & O_NONBLOCK) 1134ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1135ee5e0011SSlavomir Kaslev 11367c77f0b3SMiklos Szeredi return splice_pipe_to_pipe(ipipe, opipe, len, flags); 11377c77f0b3SMiklos Szeredi } 11387c77f0b3SMiklos Szeredi 11397c77f0b3SMiklos Szeredi if (ipipe) { 1140529565dcSIngo Molnar if (off_in) 1141529565dcSIngo Molnar return -ESPIPE; 1142b92ce558SJens Axboe if (off_out) { 114319c9a49bSChangli Gao if (!(out->f_mode & FMODE_PWRITE)) 1144b92ce558SJens Axboe return -EINVAL; 1145ee6e00c8SJens Axboe offset = *off_out; 11467995bd28SAl Viro } else { 11477995bd28SAl Viro offset = out->f_pos; 11487995bd28SAl Viro } 1149529565dcSIngo Molnar 115018c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 115118c67cb9SAl Viro return -EINVAL; 115218c67cb9SAl Viro 115318c67cb9SAl Viro ret = rw_verify_area(WRITE, out, &offset, len); 115418c67cb9SAl Viro if (unlikely(ret < 0)) 115518c67cb9SAl Viro return ret; 115618c67cb9SAl Viro 1157ee5e0011SSlavomir Kaslev if (in->f_flags & O_NONBLOCK) 1158ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1159ee5e0011SSlavomir Kaslev 1160500368f7SAl Viro file_start_write(out); 11617995bd28SAl Viro ret = do_splice_from(ipipe, out, &offset, len, flags); 1162500368f7SAl Viro file_end_write(out); 1163a4514ebdSJens Axboe 11647995bd28SAl Viro if (!off_out) 11657995bd28SAl Viro out->f_pos = offset; 1166ee6e00c8SJens Axboe else 1167ee6e00c8SJens Axboe *off_out = offset; 1168a4514ebdSJens Axboe 1169a4514ebdSJens Axboe return ret; 1170529565dcSIngo Molnar } 11715274f052SJens Axboe 11727c77f0b3SMiklos Szeredi if (opipe) { 1173529565dcSIngo Molnar if (off_out) 1174529565dcSIngo Molnar return -ESPIPE; 1175b92ce558SJens Axboe if (off_in) { 117619c9a49bSChangli Gao if (!(in->f_mode & FMODE_PREAD)) 1177b92ce558SJens Axboe return -EINVAL; 1178ee6e00c8SJens Axboe offset = *off_in; 11797995bd28SAl Viro } else { 11807995bd28SAl Viro offset = in->f_pos; 11817995bd28SAl Viro } 1182529565dcSIngo Molnar 1183ee5e0011SSlavomir Kaslev if (out->f_flags & O_NONBLOCK) 1184ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1185ee5e0011SSlavomir Kaslev 11868924feffSAl Viro pipe_lock(opipe); 11878924feffSAl Viro ret = wait_for_space(opipe, flags); 11883253d9d0SDarrick J. Wong if (!ret) { 11896a965666SLinus Torvalds unsigned int p_space; 11903253d9d0SDarrick J. Wong 11913253d9d0SDarrick J. Wong /* Don't try to read more the pipe has space for. */ 11926a965666SLinus Torvalds p_space = opipe->max_usage - pipe_occupancy(opipe->head, opipe->tail); 11936a965666SLinus Torvalds len = min_t(size_t, len, p_space << PAGE_SHIFT); 11943253d9d0SDarrick J. Wong 11957995bd28SAl Viro ret = do_splice_to(in, &offset, opipe, len, flags); 11963253d9d0SDarrick J. Wong } 11978924feffSAl Viro pipe_unlock(opipe); 11988924feffSAl Viro if (ret > 0) 11998924feffSAl Viro wakeup_pipe_readers(opipe); 12007995bd28SAl Viro if (!off_in) 12017995bd28SAl Viro in->f_pos = offset; 1202ee6e00c8SJens Axboe else 1203ee6e00c8SJens Axboe *off_in = offset; 1204a4514ebdSJens Axboe 1205a4514ebdSJens Axboe return ret; 1206529565dcSIngo Molnar } 12075274f052SJens Axboe 12085274f052SJens Axboe return -EINVAL; 12095274f052SJens Axboe } 12105274f052SJens Axboe 1211ee6e00c8SJens Axboe static long __do_splice(struct file *in, loff_t __user *off_in, 1212ee6e00c8SJens Axboe struct file *out, loff_t __user *off_out, 1213ee6e00c8SJens Axboe size_t len, unsigned int flags) 1214ee6e00c8SJens Axboe { 1215ee6e00c8SJens Axboe struct pipe_inode_info *ipipe; 1216ee6e00c8SJens Axboe struct pipe_inode_info *opipe; 1217ee6e00c8SJens Axboe loff_t offset, *__off_in = NULL, *__off_out = NULL; 1218ee6e00c8SJens Axboe long ret; 1219ee6e00c8SJens Axboe 1220ee6e00c8SJens Axboe ipipe = get_pipe_info(in, true); 1221ee6e00c8SJens Axboe opipe = get_pipe_info(out, true); 1222ee6e00c8SJens Axboe 1223ee6e00c8SJens Axboe if (ipipe && off_in) 1224ee6e00c8SJens Axboe return -ESPIPE; 1225ee6e00c8SJens Axboe if (opipe && off_out) 1226ee6e00c8SJens Axboe return -ESPIPE; 1227ee6e00c8SJens Axboe 1228ee6e00c8SJens Axboe if (off_out) { 1229ee6e00c8SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1230ee6e00c8SJens Axboe return -EFAULT; 1231ee6e00c8SJens Axboe __off_out = &offset; 1232ee6e00c8SJens Axboe } 1233ee6e00c8SJens Axboe if (off_in) { 1234ee6e00c8SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1235ee6e00c8SJens Axboe return -EFAULT; 1236ee6e00c8SJens Axboe __off_in = &offset; 1237ee6e00c8SJens Axboe } 1238ee6e00c8SJens Axboe 1239ee6e00c8SJens Axboe ret = do_splice(in, __off_in, out, __off_out, len, flags); 1240ee6e00c8SJens Axboe if (ret < 0) 1241ee6e00c8SJens Axboe return ret; 1242ee6e00c8SJens Axboe 1243ee6e00c8SJens Axboe if (__off_out && copy_to_user(off_out, __off_out, sizeof(loff_t))) 1244ee6e00c8SJens Axboe return -EFAULT; 1245ee6e00c8SJens Axboe if (__off_in && copy_to_user(off_in, __off_in, sizeof(loff_t))) 1246ee6e00c8SJens Axboe return -EFAULT; 1247ee6e00c8SJens Axboe 1248ee6e00c8SJens Axboe return ret; 1249ee6e00c8SJens Axboe } 1250ee6e00c8SJens Axboe 125179fddc4eSAl Viro static int iter_to_pipe(struct iov_iter *from, 125279fddc4eSAl Viro struct pipe_inode_info *pipe, 125379fddc4eSAl Viro unsigned flags) 1254912d35f8SJens Axboe { 125579fddc4eSAl Viro struct pipe_buffer buf = { 125679fddc4eSAl Viro .ops = &user_page_pipe_buf_ops, 125779fddc4eSAl Viro .flags = flags 125879fddc4eSAl Viro }; 125979fddc4eSAl Viro size_t total = 0; 126079fddc4eSAl Viro int ret = 0; 126179fddc4eSAl Viro bool failed = false; 126279fddc4eSAl Viro 126379fddc4eSAl Viro while (iov_iter_count(from) && !failed) { 126479fddc4eSAl Viro struct page *pages[16]; 1265db85a9ebSAl Viro ssize_t copied; 1266db85a9ebSAl Viro size_t start; 126779fddc4eSAl Viro int n; 1268912d35f8SJens Axboe 126979fddc4eSAl Viro copied = iov_iter_get_pages(from, pages, ~0UL, 16, &start); 127079fddc4eSAl Viro if (copied <= 0) { 127179fddc4eSAl Viro ret = copied; 127279fddc4eSAl Viro break; 127379fddc4eSAl Viro } 1274912d35f8SJens Axboe 127579fddc4eSAl Viro for (n = 0; copied; n++, start = 0) { 1276db85a9ebSAl Viro int size = min_t(int, copied, PAGE_SIZE - start); 127779fddc4eSAl Viro if (!failed) { 127879fddc4eSAl Viro buf.page = pages[n]; 127979fddc4eSAl Viro buf.offset = start; 128079fddc4eSAl Viro buf.len = size; 128179fddc4eSAl Viro ret = add_to_pipe(pipe, &buf); 128279fddc4eSAl Viro if (unlikely(ret < 0)) { 128379fddc4eSAl Viro failed = true; 128479fddc4eSAl Viro } else { 128579fddc4eSAl Viro iov_iter_advance(from, ret); 128679fddc4eSAl Viro total += ret; 128779fddc4eSAl Viro } 128879fddc4eSAl Viro } else { 128979fddc4eSAl Viro put_page(pages[n]); 129079fddc4eSAl Viro } 1291db85a9ebSAl Viro copied -= size; 1292912d35f8SJens Axboe } 1293912d35f8SJens Axboe } 129479fddc4eSAl Viro return total ? total : ret; 1295912d35f8SJens Axboe } 1296912d35f8SJens Axboe 12976a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 12986a14b90bSJens Axboe struct splice_desc *sd) 12996a14b90bSJens Axboe { 13006130f531SAl Viro int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data); 13016130f531SAl Viro return n == sd->len ? n : -EFAULT; 13026a14b90bSJens Axboe } 13036a14b90bSJens Axboe 13046a14b90bSJens Axboe /* 13056a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 13066a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 13076a14b90bSJens Axboe */ 130887a3002aSAl Viro static long vmsplice_to_user(struct file *file, struct iov_iter *iter, 130987a3002aSAl Viro unsigned int flags) 13106a14b90bSJens Axboe { 1311c73be61cSDavid Howells struct pipe_inode_info *pipe = get_pipe_info(file, true); 131287a3002aSAl Viro struct splice_desc sd = { 131387a3002aSAl Viro .total_len = iov_iter_count(iter), 131487a3002aSAl Viro .flags = flags, 131587a3002aSAl Viro .u.data = iter 131687a3002aSAl Viro }; 131787a3002aSAl Viro long ret = 0; 13186a14b90bSJens Axboe 13196a14b90bSJens Axboe if (!pipe) 13206a14b90bSJens Axboe return -EBADF; 13216a14b90bSJens Axboe 1322345995faSAl Viro if (sd.total_len) { 13236130f531SAl Viro pipe_lock(pipe); 13246130f531SAl Viro ret = __splice_from_pipe(pipe, &sd, pipe_to_user); 132561e0d47cSMiklos Szeredi pipe_unlock(pipe); 1326345995faSAl Viro } 13276a14b90bSJens Axboe 13286a14b90bSJens Axboe return ret; 13296a14b90bSJens Axboe } 13306a14b90bSJens Axboe 1331912d35f8SJens Axboe /* 1332912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1333912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1334912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1335912d35f8SJens Axboe */ 133687a3002aSAl Viro static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter, 133787a3002aSAl Viro unsigned int flags) 1338912d35f8SJens Axboe { 1339ddac0d39SJens Axboe struct pipe_inode_info *pipe; 134087a3002aSAl Viro long ret = 0; 134179fddc4eSAl Viro unsigned buf_flag = 0; 134279fddc4eSAl Viro 134379fddc4eSAl Viro if (flags & SPLICE_F_GIFT) 134479fddc4eSAl Viro buf_flag = PIPE_BUF_FLAG_GIFT; 1345912d35f8SJens Axboe 1346c73be61cSDavid Howells pipe = get_pipe_info(file, true); 1347ddac0d39SJens Axboe if (!pipe) 1348912d35f8SJens Axboe return -EBADF; 1349912d35f8SJens Axboe 13508924feffSAl Viro pipe_lock(pipe); 13518924feffSAl Viro ret = wait_for_space(pipe, flags); 135279fddc4eSAl Viro if (!ret) 135387a3002aSAl Viro ret = iter_to_pipe(iter, pipe, buf_flag); 13548924feffSAl Viro pipe_unlock(pipe); 13558924feffSAl Viro if (ret > 0) 13568924feffSAl Viro wakeup_pipe_readers(pipe); 135735f3d14dSJens Axboe return ret; 1358912d35f8SJens Axboe } 1359912d35f8SJens Axboe 136087a3002aSAl Viro static int vmsplice_type(struct fd f, int *type) 136187a3002aSAl Viro { 136287a3002aSAl Viro if (!f.file) 136387a3002aSAl Viro return -EBADF; 136487a3002aSAl Viro if (f.file->f_mode & FMODE_WRITE) { 136587a3002aSAl Viro *type = WRITE; 136687a3002aSAl Viro } else if (f.file->f_mode & FMODE_READ) { 136787a3002aSAl Viro *type = READ; 136887a3002aSAl Viro } else { 136987a3002aSAl Viro fdput(f); 137087a3002aSAl Viro return -EBADF; 137187a3002aSAl Viro } 137287a3002aSAl Viro return 0; 137387a3002aSAl Viro } 137487a3002aSAl Viro 13756a14b90bSJens Axboe /* 13766a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 13776a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 13786a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 13796a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 13806a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 13816a14b90bSJens Axboe * solutions for that: 13826a14b90bSJens Axboe * 13836a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 13846a14b90bSJens Axboe * do a regular read() on the buffer anyway. 13856a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 13866a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 13876a14b90bSJens Axboe * 13886a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 13896a14b90bSJens Axboe * 13906a14b90bSJens Axboe */ 139187a3002aSAl Viro SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, uiov, 139230cfe4efSDominik Brodowski unsigned long, nr_segs, unsigned int, flags) 139330cfe4efSDominik Brodowski { 139487a3002aSAl Viro struct iovec iovstack[UIO_FASTIOV]; 139587a3002aSAl Viro struct iovec *iov = iovstack; 139687a3002aSAl Viro struct iov_iter iter; 139787e5e6daSJens Axboe ssize_t error; 139887a3002aSAl Viro struct fd f; 139987a3002aSAl Viro int type; 140087a3002aSAl Viro 1401598b3cecSChristoph Hellwig if (unlikely(flags & ~SPLICE_F_ALL)) 1402598b3cecSChristoph Hellwig return -EINVAL; 1403598b3cecSChristoph Hellwig 140487a3002aSAl Viro f = fdget(fd); 140587a3002aSAl Viro error = vmsplice_type(f, &type); 140687a3002aSAl Viro if (error) 140787a3002aSAl Viro return error; 140887a3002aSAl Viro 140987a3002aSAl Viro error = import_iovec(type, uiov, nr_segs, 141087a3002aSAl Viro ARRAY_SIZE(iovstack), &iov, &iter); 1411598b3cecSChristoph Hellwig if (error < 0) 1412598b3cecSChristoph Hellwig goto out_fdput; 1413598b3cecSChristoph Hellwig 1414598b3cecSChristoph Hellwig if (!iov_iter_count(&iter)) 1415598b3cecSChristoph Hellwig error = 0; 1416598b3cecSChristoph Hellwig else if (iov_iter_rw(&iter) == WRITE) 1417598b3cecSChristoph Hellwig error = vmsplice_to_pipe(f.file, &iter, flags); 1418598b3cecSChristoph Hellwig else 1419598b3cecSChristoph Hellwig error = vmsplice_to_user(f.file, &iter, flags); 1420598b3cecSChristoph Hellwig 142187a3002aSAl Viro kfree(iov); 1422598b3cecSChristoph Hellwig out_fdput: 142387a3002aSAl Viro fdput(f); 142487a3002aSAl Viro return error; 142530cfe4efSDominik Brodowski } 142630cfe4efSDominik Brodowski 1427836f92adSHeiko Carstens SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, 1428836f92adSHeiko Carstens int, fd_out, loff_t __user *, off_out, 1429836f92adSHeiko Carstens size_t, len, unsigned int, flags) 14305274f052SJens Axboe { 14312903ff01SAl Viro struct fd in, out; 14325274f052SJens Axboe long error; 14335274f052SJens Axboe 14345274f052SJens Axboe if (unlikely(!len)) 14355274f052SJens Axboe return 0; 14365274f052SJens Axboe 14373d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 14383d6ea290SAl Viro return -EINVAL; 14393d6ea290SAl Viro 14405274f052SJens Axboe error = -EBADF; 14412903ff01SAl Viro in = fdget(fd_in); 14422903ff01SAl Viro if (in.file) { 14432903ff01SAl Viro out = fdget(fd_out); 14442903ff01SAl Viro if (out.file) { 1445ee6e00c8SJens Axboe error = __do_splice(in.file, off_in, out.file, off_out, 1446529565dcSIngo Molnar len, flags); 14472903ff01SAl Viro fdput(out); 14485274f052SJens Axboe } 14492903ff01SAl Viro fdput(in); 14505274f052SJens Axboe } 14515274f052SJens Axboe return error; 14525274f052SJens Axboe } 145370524490SJens Axboe 145470524490SJens Axboe /* 1455aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1456aadd06e5SJens Axboe * return an appropriate error. 1457aadd06e5SJens Axboe */ 14587c77f0b3SMiklos Szeredi static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1459aadd06e5SJens Axboe { 1460aadd06e5SJens Axboe int ret; 1461aadd06e5SJens Axboe 1462aadd06e5SJens Axboe /* 14638cefc107SDavid Howells * Check the pipe occupancy without the inode lock first. This function 1464aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1465aadd06e5SJens Axboe */ 14668cefc107SDavid Howells if (!pipe_empty(pipe->head, pipe->tail)) 1467aadd06e5SJens Axboe return 0; 1468aadd06e5SJens Axboe 1469aadd06e5SJens Axboe ret = 0; 147061e0d47cSMiklos Szeredi pipe_lock(pipe); 1471aadd06e5SJens Axboe 14728cefc107SDavid Howells while (pipe_empty(pipe->head, pipe->tail)) { 1473aadd06e5SJens Axboe if (signal_pending(current)) { 1474aadd06e5SJens Axboe ret = -ERESTARTSYS; 1475aadd06e5SJens Axboe break; 1476aadd06e5SJens Axboe } 1477aadd06e5SJens Axboe if (!pipe->writers) 1478aadd06e5SJens Axboe break; 1479aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1480aadd06e5SJens Axboe ret = -EAGAIN; 1481aadd06e5SJens Axboe break; 1482aadd06e5SJens Axboe } 1483472e5b05SLinus Torvalds pipe_wait_readable(pipe); 1484aadd06e5SJens Axboe } 1485aadd06e5SJens Axboe 148661e0d47cSMiklos Szeredi pipe_unlock(pipe); 1487aadd06e5SJens Axboe return ret; 1488aadd06e5SJens Axboe } 1489aadd06e5SJens Axboe 1490aadd06e5SJens Axboe /* 1491aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1492aadd06e5SJens Axboe * return an appropriate error. 1493aadd06e5SJens Axboe */ 14947c77f0b3SMiklos Szeredi static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1495aadd06e5SJens Axboe { 1496aadd06e5SJens Axboe int ret; 1497aadd06e5SJens Axboe 1498aadd06e5SJens Axboe /* 14998cefc107SDavid Howells * Check pipe occupancy without the inode lock first. This function 1500aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1501aadd06e5SJens Axboe */ 1502566d1362STetsuo Handa if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 1503aadd06e5SJens Axboe return 0; 1504aadd06e5SJens Axboe 1505aadd06e5SJens Axboe ret = 0; 150661e0d47cSMiklos Szeredi pipe_lock(pipe); 1507aadd06e5SJens Axboe 15086718b6f8SDavid Howells while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { 1509aadd06e5SJens Axboe if (!pipe->readers) { 1510aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1511aadd06e5SJens Axboe ret = -EPIPE; 1512aadd06e5SJens Axboe break; 1513aadd06e5SJens Axboe } 1514aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1515aadd06e5SJens Axboe ret = -EAGAIN; 1516aadd06e5SJens Axboe break; 1517aadd06e5SJens Axboe } 1518aadd06e5SJens Axboe if (signal_pending(current)) { 1519aadd06e5SJens Axboe ret = -ERESTARTSYS; 1520aadd06e5SJens Axboe break; 1521aadd06e5SJens Axboe } 1522472e5b05SLinus Torvalds pipe_wait_writable(pipe); 1523aadd06e5SJens Axboe } 1524aadd06e5SJens Axboe 152561e0d47cSMiklos Szeredi pipe_unlock(pipe); 1526aadd06e5SJens Axboe return ret; 1527aadd06e5SJens Axboe } 1528aadd06e5SJens Axboe 1529aadd06e5SJens Axboe /* 15307c77f0b3SMiklos Szeredi * Splice contents of ipipe to opipe. 15317c77f0b3SMiklos Szeredi */ 15327c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 15337c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 15347c77f0b3SMiklos Szeredi size_t len, unsigned int flags) 15357c77f0b3SMiklos Szeredi { 15367c77f0b3SMiklos Szeredi struct pipe_buffer *ibuf, *obuf; 15378cefc107SDavid Howells unsigned int i_head, o_head; 15388cefc107SDavid Howells unsigned int i_tail, o_tail; 15398cefc107SDavid Howells unsigned int i_mask, o_mask; 15408cefc107SDavid Howells int ret = 0; 15417c77f0b3SMiklos Szeredi bool input_wakeup = false; 15427c77f0b3SMiklos Szeredi 15437c77f0b3SMiklos Szeredi 15447c77f0b3SMiklos Szeredi retry: 15457c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 15467c77f0b3SMiklos Szeredi if (ret) 15477c77f0b3SMiklos Szeredi return ret; 15487c77f0b3SMiklos Szeredi 15497c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 15507c77f0b3SMiklos Szeredi if (ret) 15517c77f0b3SMiklos Szeredi return ret; 15527c77f0b3SMiklos Szeredi 15537c77f0b3SMiklos Szeredi /* 15547c77f0b3SMiklos Szeredi * Potential ABBA deadlock, work around it by ordering lock 15557c77f0b3SMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 15567c77f0b3SMiklos Szeredi * could deadlock (one doing tee from A -> B, the other from B -> A). 15577c77f0b3SMiklos Szeredi */ 15587c77f0b3SMiklos Szeredi pipe_double_lock(ipipe, opipe); 15597c77f0b3SMiklos Szeredi 15608cefc107SDavid Howells i_tail = ipipe->tail; 15618cefc107SDavid Howells i_mask = ipipe->ring_size - 1; 15628cefc107SDavid Howells o_head = opipe->head; 15638cefc107SDavid Howells o_mask = opipe->ring_size - 1; 15648cefc107SDavid Howells 15657c77f0b3SMiklos Szeredi do { 15668cefc107SDavid Howells size_t o_len; 15678cefc107SDavid Howells 15687c77f0b3SMiklos Szeredi if (!opipe->readers) { 15697c77f0b3SMiklos Szeredi send_sig(SIGPIPE, current, 0); 15707c77f0b3SMiklos Szeredi if (!ret) 15717c77f0b3SMiklos Szeredi ret = -EPIPE; 15727c77f0b3SMiklos Szeredi break; 15737c77f0b3SMiklos Szeredi } 15747c77f0b3SMiklos Szeredi 15758cefc107SDavid Howells i_head = ipipe->head; 15768cefc107SDavid Howells o_tail = opipe->tail; 15778cefc107SDavid Howells 15788cefc107SDavid Howells if (pipe_empty(i_head, i_tail) && !ipipe->writers) 15797c77f0b3SMiklos Szeredi break; 15807c77f0b3SMiklos Szeredi 15817c77f0b3SMiklos Szeredi /* 15827c77f0b3SMiklos Szeredi * Cannot make any progress, because either the input 15837c77f0b3SMiklos Szeredi * pipe is empty or the output pipe is full. 15847c77f0b3SMiklos Szeredi */ 15858cefc107SDavid Howells if (pipe_empty(i_head, i_tail) || 15866718b6f8SDavid Howells pipe_full(o_head, o_tail, opipe->max_usage)) { 15877c77f0b3SMiklos Szeredi /* Already processed some buffers, break */ 15887c77f0b3SMiklos Szeredi if (ret) 15897c77f0b3SMiklos Szeredi break; 15907c77f0b3SMiklos Szeredi 15917c77f0b3SMiklos Szeredi if (flags & SPLICE_F_NONBLOCK) { 15927c77f0b3SMiklos Szeredi ret = -EAGAIN; 15937c77f0b3SMiklos Szeredi break; 15947c77f0b3SMiklos Szeredi } 15957c77f0b3SMiklos Szeredi 15967c77f0b3SMiklos Szeredi /* 15977c77f0b3SMiklos Szeredi * We raced with another reader/writer and haven't 15987c77f0b3SMiklos Szeredi * managed to process any buffers. A zero return 15997c77f0b3SMiklos Szeredi * value means EOF, so retry instead. 16007c77f0b3SMiklos Szeredi */ 16017c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 16027c77f0b3SMiklos Szeredi pipe_unlock(opipe); 16037c77f0b3SMiklos Szeredi goto retry; 16047c77f0b3SMiklos Szeredi } 16057c77f0b3SMiklos Szeredi 16068cefc107SDavid Howells ibuf = &ipipe->bufs[i_tail & i_mask]; 16078cefc107SDavid Howells obuf = &opipe->bufs[o_head & o_mask]; 16087c77f0b3SMiklos Szeredi 16097c77f0b3SMiklos Szeredi if (len >= ibuf->len) { 16107c77f0b3SMiklos Szeredi /* 16117c77f0b3SMiklos Szeredi * Simply move the whole buffer from ipipe to opipe 16127c77f0b3SMiklos Szeredi */ 16137c77f0b3SMiklos Szeredi *obuf = *ibuf; 16147c77f0b3SMiklos Szeredi ibuf->ops = NULL; 16158cefc107SDavid Howells i_tail++; 16168cefc107SDavid Howells ipipe->tail = i_tail; 16177c77f0b3SMiklos Szeredi input_wakeup = true; 16188cefc107SDavid Howells o_len = obuf->len; 16198cefc107SDavid Howells o_head++; 16208cefc107SDavid Howells opipe->head = o_head; 16217c77f0b3SMiklos Szeredi } else { 16227c77f0b3SMiklos Szeredi /* 16237c77f0b3SMiklos Szeredi * Get a reference to this pipe buffer, 16247c77f0b3SMiklos Szeredi * so we can copy the contents over. 16257c77f0b3SMiklos Szeredi */ 162615fab63eSMatthew Wilcox if (!pipe_buf_get(ipipe, ibuf)) { 162715fab63eSMatthew Wilcox if (ret == 0) 162815fab63eSMatthew Wilcox ret = -EFAULT; 162915fab63eSMatthew Wilcox break; 163015fab63eSMatthew Wilcox } 16317c77f0b3SMiklos Szeredi *obuf = *ibuf; 16327c77f0b3SMiklos Szeredi 16337c77f0b3SMiklos Szeredi /* 1634f6dd9755SChristoph Hellwig * Don't inherit the gift and merge flags, we need to 16357c77f0b3SMiklos Szeredi * prevent multiple steals of this page. 16367c77f0b3SMiklos Szeredi */ 16377c77f0b3SMiklos Szeredi obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1638f6dd9755SChristoph Hellwig obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; 1639a0ce2f0aSJann Horn 16407c77f0b3SMiklos Szeredi obuf->len = len; 16418cefc107SDavid Howells ibuf->offset += len; 16428cefc107SDavid Howells ibuf->len -= len; 16438cefc107SDavid Howells o_len = len; 16448cefc107SDavid Howells o_head++; 16458cefc107SDavid Howells opipe->head = o_head; 16467c77f0b3SMiklos Szeredi } 16478cefc107SDavid Howells ret += o_len; 16488cefc107SDavid Howells len -= o_len; 16497c77f0b3SMiklos Szeredi } while (len); 16507c77f0b3SMiklos Szeredi 16517c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 16527c77f0b3SMiklos Szeredi pipe_unlock(opipe); 16537c77f0b3SMiklos Szeredi 16547c77f0b3SMiklos Szeredi /* 16557c77f0b3SMiklos Szeredi * If we put data in the output pipe, wakeup any potential readers. 16567c77f0b3SMiklos Szeredi */ 1657825cdcb1SNamhyung Kim if (ret > 0) 1658825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 1659825cdcb1SNamhyung Kim 16607c77f0b3SMiklos Szeredi if (input_wakeup) 16617c77f0b3SMiklos Szeredi wakeup_pipe_writers(ipipe); 16627c77f0b3SMiklos Szeredi 16637c77f0b3SMiklos Szeredi return ret; 16647c77f0b3SMiklos Szeredi } 16657c77f0b3SMiklos Szeredi 16667c77f0b3SMiklos Szeredi /* 166770524490SJens Axboe * Link contents of ipipe to opipe. 166870524490SJens Axboe */ 166970524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 167070524490SJens Axboe struct pipe_inode_info *opipe, 167170524490SJens Axboe size_t len, unsigned int flags) 167270524490SJens Axboe { 167370524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 16748cefc107SDavid Howells unsigned int i_head, o_head; 16758cefc107SDavid Howells unsigned int i_tail, o_tail; 16768cefc107SDavid Howells unsigned int i_mask, o_mask; 16778cefc107SDavid Howells int ret = 0; 167870524490SJens Axboe 167970524490SJens Axboe /* 168070524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 168161e0d47cSMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 168270524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 168370524490SJens Axboe */ 168461e0d47cSMiklos Szeredi pipe_double_lock(ipipe, opipe); 168570524490SJens Axboe 16868cefc107SDavid Howells i_tail = ipipe->tail; 16878cefc107SDavid Howells i_mask = ipipe->ring_size - 1; 16888cefc107SDavid Howells o_head = opipe->head; 16898cefc107SDavid Howells o_mask = opipe->ring_size - 1; 16908cefc107SDavid Howells 1691aadd06e5SJens Axboe do { 169270524490SJens Axboe if (!opipe->readers) { 169370524490SJens Axboe send_sig(SIGPIPE, current, 0); 169470524490SJens Axboe if (!ret) 169570524490SJens Axboe ret = -EPIPE; 169670524490SJens Axboe break; 169770524490SJens Axboe } 169870524490SJens Axboe 16998cefc107SDavid Howells i_head = ipipe->head; 17008cefc107SDavid Howells o_tail = opipe->tail; 17018cefc107SDavid Howells 170270524490SJens Axboe /* 17038cefc107SDavid Howells * If we have iterated all input buffers or run out of 1704aadd06e5SJens Axboe * output room, break. 170570524490SJens Axboe */ 17068cefc107SDavid Howells if (pipe_empty(i_head, i_tail) || 17076718b6f8SDavid Howells pipe_full(o_head, o_tail, opipe->max_usage)) 1708aadd06e5SJens Axboe break; 1709aadd06e5SJens Axboe 17108cefc107SDavid Howells ibuf = &ipipe->bufs[i_tail & i_mask]; 17118cefc107SDavid Howells obuf = &opipe->bufs[o_head & o_mask]; 171270524490SJens Axboe 171370524490SJens Axboe /* 171470524490SJens Axboe * Get a reference to this pipe buffer, 171570524490SJens Axboe * so we can copy the contents over. 171670524490SJens Axboe */ 171715fab63eSMatthew Wilcox if (!pipe_buf_get(ipipe, ibuf)) { 171815fab63eSMatthew Wilcox if (ret == 0) 171915fab63eSMatthew Wilcox ret = -EFAULT; 172015fab63eSMatthew Wilcox break; 172115fab63eSMatthew Wilcox } 172270524490SJens Axboe 172370524490SJens Axboe *obuf = *ibuf; 172470524490SJens Axboe 17257afa6fd0SJens Axboe /* 1726f6dd9755SChristoph Hellwig * Don't inherit the gift and merge flag, we need to prevent 1727f6dd9755SChristoph Hellwig * multiple steals of this page. 17287afa6fd0SJens Axboe */ 17297afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1730f6dd9755SChristoph Hellwig obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; 1731a0ce2f0aSJann Horn 173270524490SJens Axboe if (obuf->len > len) 173370524490SJens Axboe obuf->len = len; 173470524490SJens Axboe ret += obuf->len; 173570524490SJens Axboe len -= obuf->len; 17368cefc107SDavid Howells 17378cefc107SDavid Howells o_head++; 17388cefc107SDavid Howells opipe->head = o_head; 17398cefc107SDavid Howells i_tail++; 1740aadd06e5SJens Axboe } while (len); 174170524490SJens Axboe 174261e0d47cSMiklos Szeredi pipe_unlock(ipipe); 174361e0d47cSMiklos Szeredi pipe_unlock(opipe); 174470524490SJens Axboe 1745aadd06e5SJens Axboe /* 1746aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1747aadd06e5SJens Axboe */ 1748825cdcb1SNamhyung Kim if (ret > 0) 1749825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 175070524490SJens Axboe 175170524490SJens Axboe return ret; 175270524490SJens Axboe } 175370524490SJens Axboe 175470524490SJens Axboe /* 175570524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 175670524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 175770524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 175870524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 175970524490SJens Axboe */ 17609dafdfc2SPavel Begunkov long do_tee(struct file *in, struct file *out, size_t len, unsigned int flags) 176170524490SJens Axboe { 1762c73be61cSDavid Howells struct pipe_inode_info *ipipe = get_pipe_info(in, true); 1763c73be61cSDavid Howells struct pipe_inode_info *opipe = get_pipe_info(out, true); 1764aadd06e5SJens Axboe int ret = -EINVAL; 176570524490SJens Axboe 176690da2e3fSPavel Begunkov if (unlikely(!(in->f_mode & FMODE_READ) || 176790da2e3fSPavel Begunkov !(out->f_mode & FMODE_WRITE))) 176890da2e3fSPavel Begunkov return -EBADF; 176990da2e3fSPavel Begunkov 177070524490SJens Axboe /* 1771aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1772aadd06e5SJens Axboe * copying the data. 177370524490SJens Axboe */ 1774aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1775ee5e0011SSlavomir Kaslev if ((in->f_flags | out->f_flags) & O_NONBLOCK) 1776ee5e0011SSlavomir Kaslev flags |= SPLICE_F_NONBLOCK; 1777ee5e0011SSlavomir Kaslev 1778aadd06e5SJens Axboe /* 1779aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1780aadd06e5SJens Axboe * ordering doesn't really matter. 1781aadd06e5SJens Axboe */ 17827c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 1783aadd06e5SJens Axboe if (!ret) { 17847c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 178502cf01aeSJens Axboe if (!ret) 1786aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1787aadd06e5SJens Axboe } 1788aadd06e5SJens Axboe } 178970524490SJens Axboe 1790aadd06e5SJens Axboe return ret; 179170524490SJens Axboe } 179270524490SJens Axboe 1793836f92adSHeiko Carstens SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) 179470524490SJens Axboe { 179590da2e3fSPavel Begunkov struct fd in, out; 17962903ff01SAl Viro int error; 179770524490SJens Axboe 17983d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 17993d6ea290SAl Viro return -EINVAL; 18003d6ea290SAl Viro 180170524490SJens Axboe if (unlikely(!len)) 180270524490SJens Axboe return 0; 180370524490SJens Axboe 180470524490SJens Axboe error = -EBADF; 18052903ff01SAl Viro in = fdget(fdin); 18062903ff01SAl Viro if (in.file) { 180790da2e3fSPavel Begunkov out = fdget(fdout); 18082903ff01SAl Viro if (out.file) { 180990da2e3fSPavel Begunkov error = do_tee(in.file, out.file, len, flags); 18102903ff01SAl Viro fdput(out); 181170524490SJens Axboe } 18122903ff01SAl Viro fdput(in); 181370524490SJens Axboe } 181470524490SJens Axboe 181570524490SJens Axboe return error; 181670524490SJens Axboe } 1817