15274f052SJens Axboe /* 25274f052SJens Axboe * "splice": joining two ropes together by interweaving their strands. 35274f052SJens Axboe * 45274f052SJens Axboe * This is the "extended pipe" functionality, where a pipe is used as 55274f052SJens Axboe * an arbitrary in-memory buffer. Think of a pipe as a small kernel 65274f052SJens Axboe * buffer that you can use to transfer data from one end to the other. 75274f052SJens Axboe * 85274f052SJens Axboe * The traditional unix read/write is extended with a "splice()" operation 95274f052SJens Axboe * that transfers data buffers to or from a pipe buffer. 105274f052SJens Axboe * 115274f052SJens Axboe * Named by Larry McVoy, original implementation from Linus, extended by 12c2058e06SJens Axboe * Jens to support splicing to files, network, direct splicing, etc and 13c2058e06SJens Axboe * fixing lots of bugs. 145274f052SJens Axboe * 150fe23479SJens Axboe * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> 16c2058e06SJens Axboe * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> 17c2058e06SJens Axboe * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> 185274f052SJens Axboe * 195274f052SJens Axboe */ 20be297968SChristoph Hellwig #include <linux/bvec.h> 215274f052SJens Axboe #include <linux/fs.h> 225274f052SJens Axboe #include <linux/file.h> 235274f052SJens Axboe #include <linux/pagemap.h> 24d6b29d7cSJens Axboe #include <linux/splice.h> 2508e552c6SKAMEZAWA Hiroyuki #include <linux/memcontrol.h> 265274f052SJens Axboe #include <linux/mm_inline.h> 275abc97aaSJens Axboe #include <linux/swap.h> 284f6f0bd2SJens Axboe #include <linux/writeback.h> 29630d9c47SPaul Gortmaker #include <linux/export.h> 304f6f0bd2SJens Axboe #include <linux/syscalls.h> 31912d35f8SJens Axboe #include <linux/uio.h> 3229ce2058SJames Morris #include <linux/security.h> 335a0e3ad6STejun Heo #include <linux/gfp.h> 3435f9c09fSEric Dumazet #include <linux/socket.h> 3576b021d0SAl Viro #include <linux/compat.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 */ 4676ad4d11SJens Axboe static int page_cache_pipe_buf_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; 785abc97aaSJens Axboe return 0; 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); 889e94cd4fSJens Axboe return 1; 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 = { 1415274f052SJens Axboe .can_merge = 0, 142cac36bb0SJens Axboe .confirm = page_cache_pipe_buf_confirm, 1435274f052SJens Axboe .release = page_cache_pipe_buf_release, 1445abc97aaSJens Axboe .steal = page_cache_pipe_buf_steal, 145f84d7519SJens Axboe .get = generic_pipe_buf_get, 1465274f052SJens Axboe }; 1475274f052SJens Axboe 148912d35f8SJens Axboe static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, 149912d35f8SJens Axboe struct pipe_buffer *buf) 150912d35f8SJens Axboe { 1517afa6fd0SJens Axboe if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) 152912d35f8SJens Axboe return 1; 1537afa6fd0SJens Axboe 1541432873aSJens Axboe buf->flags |= PIPE_BUF_FLAG_LRU; 155330ab716SJens Axboe return generic_pipe_buf_steal(pipe, buf); 156912d35f8SJens Axboe } 157912d35f8SJens Axboe 158d4c3cca9SEric Dumazet static const struct pipe_buf_operations user_page_pipe_buf_ops = { 159912d35f8SJens Axboe .can_merge = 0, 160cac36bb0SJens Axboe .confirm = generic_pipe_buf_confirm, 161912d35f8SJens Axboe .release = page_cache_pipe_buf_release, 162912d35f8SJens Axboe .steal = user_page_pipe_buf_steal, 163f84d7519SJens Axboe .get = generic_pipe_buf_get, 164912d35f8SJens Axboe }; 165912d35f8SJens Axboe 166825cdcb1SNamhyung Kim static void wakeup_pipe_readers(struct pipe_inode_info *pipe) 167825cdcb1SNamhyung Kim { 168825cdcb1SNamhyung Kim smp_mb(); 169825cdcb1SNamhyung Kim if (waitqueue_active(&pipe->wait)) 170825cdcb1SNamhyung Kim wake_up_interruptible(&pipe->wait); 171825cdcb1SNamhyung Kim kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 172825cdcb1SNamhyung Kim } 173825cdcb1SNamhyung Kim 174932cc6d4SJens Axboe /** 175932cc6d4SJens Axboe * splice_to_pipe - fill passed data into a pipe 176932cc6d4SJens Axboe * @pipe: pipe to fill 177932cc6d4SJens Axboe * @spd: data to fill 178932cc6d4SJens Axboe * 179932cc6d4SJens Axboe * Description: 18079685b8dSRandy Dunlap * @spd contains a map of pages and len/offset tuples, along with 181932cc6d4SJens Axboe * the struct pipe_buf_operations associated with these pages. This 182932cc6d4SJens Axboe * function will link that data to the pipe. 183932cc6d4SJens Axboe * 18483f9135bSJens Axboe */ 185d6b29d7cSJens Axboe ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 186912d35f8SJens Axboe struct splice_pipe_desc *spd) 1875274f052SJens Axboe { 18800de00bdSJens Axboe unsigned int spd_pages = spd->nr_pages; 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 2008924feffSAl Viro while (pipe->nrbufs < pipe->buffers) { 20135f3d14dSJens Axboe int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); 2023a326a2cSIngo Molnar struct pipe_buffer *buf = pipe->bufs + newbuf; 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 2116f767b04SJens Axboe pipe->nrbufs++; 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 { 23279fddc4eSAl Viro int ret; 23379fddc4eSAl Viro 23479fddc4eSAl Viro if (unlikely(!pipe->readers)) { 23579fddc4eSAl Viro send_sig(SIGPIPE, current, 0); 23679fddc4eSAl Viro ret = -EPIPE; 23779fddc4eSAl Viro } else if (pipe->nrbufs == pipe->buffers) { 23879fddc4eSAl Viro ret = -EAGAIN; 23979fddc4eSAl Viro } else { 24079fddc4eSAl Viro int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); 24179fddc4eSAl Viro pipe->bufs[newbuf] = *buf; 24279fddc4eSAl Viro pipe->nrbufs++; 24379fddc4eSAl Viro return buf->len; 24479fddc4eSAl Viro } 245a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 24679fddc4eSAl Viro return ret; 24779fddc4eSAl Viro } 24879fddc4eSAl Viro EXPORT_SYMBOL(add_to_pipe); 24979fddc4eSAl Viro 25035f3d14dSJens Axboe /* 25135f3d14dSJens Axboe * Check if we need to grow the arrays holding pages and partial page 25235f3d14dSJens Axboe * descriptions. 25335f3d14dSJens Axboe */ 254047fe360SEric Dumazet int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) 25535f3d14dSJens Axboe { 256047fe360SEric Dumazet unsigned int buffers = ACCESS_ONCE(pipe->buffers); 257047fe360SEric Dumazet 258047fe360SEric Dumazet spd->nr_pages_max = buffers; 259047fe360SEric Dumazet if (buffers <= PIPE_DEF_BUFFERS) 26035f3d14dSJens Axboe return 0; 26135f3d14dSJens Axboe 262047fe360SEric Dumazet spd->pages = kmalloc(buffers * sizeof(struct page *), GFP_KERNEL); 263047fe360SEric Dumazet spd->partial = kmalloc(buffers * sizeof(struct partial_page), GFP_KERNEL); 26435f3d14dSJens Axboe 26535f3d14dSJens Axboe if (spd->pages && spd->partial) 26635f3d14dSJens Axboe return 0; 26735f3d14dSJens Axboe 26835f3d14dSJens Axboe kfree(spd->pages); 26935f3d14dSJens Axboe kfree(spd->partial); 27035f3d14dSJens Axboe return -ENOMEM; 27135f3d14dSJens Axboe } 27235f3d14dSJens Axboe 273047fe360SEric Dumazet void splice_shrink_spd(struct splice_pipe_desc *spd) 27435f3d14dSJens Axboe { 275047fe360SEric Dumazet if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) 27635f3d14dSJens Axboe return; 27735f3d14dSJens Axboe 27835f3d14dSJens Axboe kfree(spd->pages); 27935f3d14dSJens Axboe kfree(spd->partial); 28035f3d14dSJens Axboe } 28135f3d14dSJens Axboe 28283f9135bSJens Axboe /** 28383f9135bSJens Axboe * generic_file_splice_read - splice data from file to a pipe 28483f9135bSJens Axboe * @in: file to splice from 285932cc6d4SJens Axboe * @ppos: position in @in 28683f9135bSJens Axboe * @pipe: pipe to splice to 28783f9135bSJens Axboe * @len: number of bytes to splice 28883f9135bSJens Axboe * @flags: splice modifier flags 28983f9135bSJens Axboe * 290932cc6d4SJens Axboe * Description: 291932cc6d4SJens Axboe * Will read pages from given file and fill them into a pipe. Can be 29282c156f8SAl Viro * used as long as it has more or less sane ->read_iter(). 293932cc6d4SJens Axboe * 29483f9135bSJens Axboe */ 295cbb7e577SJens Axboe ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 296cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 297cbb7e577SJens Axboe unsigned int flags) 2985274f052SJens Axboe { 29982c156f8SAl Viro struct iov_iter to; 30082c156f8SAl Viro struct kiocb kiocb; 30182c156f8SAl Viro int idx, ret; 302be64f884SBoaz Harrosh 30382c156f8SAl Viro iov_iter_pipe(&to, ITER_PIPE | READ, pipe, len); 30482c156f8SAl Viro idx = to.idx; 30582c156f8SAl Viro init_sync_kiocb(&kiocb, in); 30682c156f8SAl Viro kiocb.ki_pos = *ppos; 307bb7462b6SMiklos Szeredi ret = call_read_iter(in, &kiocb, &to); 308723590edSMiklos Szeredi if (ret > 0) { 30982c156f8SAl Viro *ppos = kiocb.ki_pos; 310723590edSMiklos Szeredi file_accessed(in); 31182c156f8SAl Viro } else if (ret < 0) { 31282c156f8SAl Viro to.idx = idx; 31382c156f8SAl Viro to.iov_offset = 0; 31482c156f8SAl Viro iov_iter_advance(&to, 0); /* to free what was emitted */ 31582c156f8SAl Viro /* 31682c156f8SAl Viro * callers of ->splice_read() expect -EAGAIN on 31782c156f8SAl Viro * "can't put anything in there", rather than -EFAULT. 31882c156f8SAl Viro */ 31982c156f8SAl Viro if (ret == -EFAULT) 32082c156f8SAl Viro ret = -EAGAIN; 321723590edSMiklos Szeredi } 3225274f052SJens Axboe 3235274f052SJens Axboe return ret; 3245274f052SJens Axboe } 325059a8f37SJens Axboe EXPORT_SYMBOL(generic_file_splice_read); 326059a8f37SJens Axboe 327241699cdSAl Viro const struct pipe_buf_operations default_pipe_buf_ops = { 3286818173bSMiklos Szeredi .can_merge = 0, 3296818173bSMiklos Szeredi .confirm = generic_pipe_buf_confirm, 3306818173bSMiklos Szeredi .release = generic_pipe_buf_release, 3316818173bSMiklos Szeredi .steal = generic_pipe_buf_steal, 3326818173bSMiklos Szeredi .get = generic_pipe_buf_get, 3336818173bSMiklos Szeredi }; 3346818173bSMiklos Szeredi 33528a625cbSMiklos Szeredi static int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe, 33628a625cbSMiklos Szeredi struct pipe_buffer *buf) 33728a625cbSMiklos Szeredi { 33828a625cbSMiklos Szeredi return 1; 33928a625cbSMiklos Szeredi } 34028a625cbSMiklos Szeredi 34128a625cbSMiklos Szeredi /* Pipe buffer operations for a socket and similar. */ 34228a625cbSMiklos Szeredi const struct pipe_buf_operations nosteal_pipe_buf_ops = { 34328a625cbSMiklos Szeredi .can_merge = 0, 34428a625cbSMiklos Szeredi .confirm = generic_pipe_buf_confirm, 34528a625cbSMiklos Szeredi .release = generic_pipe_buf_release, 34628a625cbSMiklos Szeredi .steal = generic_pipe_buf_nosteal, 34728a625cbSMiklos Szeredi .get = generic_pipe_buf_get, 34828a625cbSMiklos Szeredi }; 34928a625cbSMiklos Szeredi EXPORT_SYMBOL(nosteal_pipe_buf_ops); 35028a625cbSMiklos Szeredi 351523ac9afSAl Viro static ssize_t kernel_readv(struct file *file, const struct kvec *vec, 3526818173bSMiklos Szeredi unsigned long vlen, loff_t offset) 3536818173bSMiklos Szeredi { 3546818173bSMiklos Szeredi mm_segment_t old_fs; 3556818173bSMiklos Szeredi loff_t pos = offset; 3566818173bSMiklos Szeredi ssize_t res; 3576818173bSMiklos Szeredi 3586818173bSMiklos Szeredi old_fs = get_fs(); 3596818173bSMiklos Szeredi set_fs(get_ds()); 3606818173bSMiklos Szeredi /* The cast to a user pointer is valid due to the set_fs() */ 361793b80efSChristoph Hellwig res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos, 0); 3626818173bSMiklos Szeredi set_fs(old_fs); 3636818173bSMiklos Szeredi 3646818173bSMiklos Szeredi return res; 3656818173bSMiklos Szeredi } 3666818173bSMiklos Szeredi 3677bb307e8SAl Viro ssize_t kernel_write(struct file *file, const char *buf, size_t count, 368b2858d7dSMiklos Szeredi loff_t pos) 3690b0a47f5SMiklos Szeredi { 3700b0a47f5SMiklos Szeredi mm_segment_t old_fs; 3710b0a47f5SMiklos Szeredi ssize_t res; 3720b0a47f5SMiklos Szeredi 3730b0a47f5SMiklos Szeredi old_fs = get_fs(); 3740b0a47f5SMiklos Szeredi set_fs(get_ds()); 3750b0a47f5SMiklos Szeredi /* The cast to a user pointer is valid due to the set_fs() */ 3767bb307e8SAl Viro res = vfs_write(file, (__force const char __user *)buf, count, &pos); 3770b0a47f5SMiklos Szeredi set_fs(old_fs); 3780b0a47f5SMiklos Szeredi 3790b0a47f5SMiklos Szeredi return res; 3800b0a47f5SMiklos Szeredi } 3817bb307e8SAl Viro EXPORT_SYMBOL(kernel_write); 3820b0a47f5SMiklos Szeredi 38382c156f8SAl Viro static ssize_t default_file_splice_read(struct file *in, loff_t *ppos, 3846818173bSMiklos Szeredi struct pipe_inode_info *pipe, size_t len, 3856818173bSMiklos Szeredi unsigned int flags) 3866818173bSMiklos Szeredi { 387523ac9afSAl Viro struct kvec *vec, __vec[PIPE_DEF_BUFFERS]; 388523ac9afSAl Viro struct iov_iter to; 389523ac9afSAl Viro struct page **pages; 3906818173bSMiklos Szeredi unsigned int nr_pages; 39113c0f52bSAl Viro size_t offset, base, copied = 0; 3926818173bSMiklos Szeredi ssize_t res; 3936818173bSMiklos Szeredi int i; 3946818173bSMiklos Szeredi 395523ac9afSAl Viro if (pipe->nrbufs == pipe->buffers) 396523ac9afSAl Viro return -EAGAIN; 397523ac9afSAl Viro 398523ac9afSAl Viro /* 399523ac9afSAl Viro * Try to keep page boundaries matching to source pagecache ones - 400523ac9afSAl Viro * it probably won't be much help, but... 401523ac9afSAl Viro */ 402523ac9afSAl Viro offset = *ppos & ~PAGE_MASK; 403523ac9afSAl Viro 404523ac9afSAl Viro iov_iter_pipe(&to, ITER_PIPE | READ, pipe, len + offset); 405523ac9afSAl Viro 40613c0f52bSAl Viro res = iov_iter_get_pages_alloc(&to, &pages, len + offset, &base); 407523ac9afSAl Viro if (res <= 0) 40835f3d14dSJens Axboe return -ENOMEM; 40935f3d14dSJens Axboe 41013c0f52bSAl Viro nr_pages = DIV_ROUND_UP(res + base, PAGE_SIZE); 411523ac9afSAl Viro 41235f3d14dSJens Axboe vec = __vec; 413523ac9afSAl Viro if (nr_pages > PIPE_DEF_BUFFERS) { 414523ac9afSAl Viro vec = kmalloc(nr_pages * sizeof(struct kvec), GFP_KERNEL); 415523ac9afSAl Viro if (unlikely(!vec)) { 416523ac9afSAl Viro res = -ENOMEM; 417523ac9afSAl Viro goto out; 418523ac9afSAl Viro } 41935f3d14dSJens Axboe } 42035f3d14dSJens Axboe 421523ac9afSAl Viro pipe->bufs[to.idx].offset = offset; 422523ac9afSAl Viro pipe->bufs[to.idx].len -= offset; 4236818173bSMiklos Szeredi 424523ac9afSAl Viro for (i = 0; i < nr_pages; i++) { 425523ac9afSAl Viro size_t this_len = min_t(size_t, len, PAGE_SIZE - offset); 426523ac9afSAl Viro vec[i].iov_base = page_address(pages[i]) + offset; 4276818173bSMiklos Szeredi vec[i].iov_len = this_len; 4286818173bSMiklos Szeredi len -= this_len; 4296818173bSMiklos Szeredi offset = 0; 4306818173bSMiklos Szeredi } 4316818173bSMiklos Szeredi 432523ac9afSAl Viro res = kernel_readv(in, vec, nr_pages, *ppos); 433523ac9afSAl Viro if (res > 0) { 434523ac9afSAl Viro copied = res; 4356818173bSMiklos Szeredi *ppos += res; 436523ac9afSAl Viro } 4376818173bSMiklos Szeredi 43835f3d14dSJens Axboe if (vec != __vec) 43935f3d14dSJens Axboe kfree(vec); 440523ac9afSAl Viro out: 441523ac9afSAl Viro for (i = 0; i < nr_pages; i++) 442523ac9afSAl Viro put_page(pages[i]); 443523ac9afSAl Viro kvfree(pages); 444523ac9afSAl Viro iov_iter_advance(&to, copied); /* truncates and discards */ 4456818173bSMiklos Szeredi return res; 4466818173bSMiklos Szeredi } 4476818173bSMiklos Szeredi 4485274f052SJens Axboe /* 4494f6f0bd2SJens Axboe * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' 450016b661eSJens Axboe * using sendpage(). Return the number of bytes sent. 4515274f052SJens Axboe */ 45276ad4d11SJens Axboe static int pipe_to_sendpage(struct pipe_inode_info *pipe, 4535274f052SJens Axboe struct pipe_buffer *buf, struct splice_desc *sd) 4545274f052SJens Axboe { 4556a14b90bSJens Axboe struct file *file = sd->u.file; 4565274f052SJens Axboe loff_t pos = sd->pos; 457a8adbe37SMichał Mirosław int more; 4585274f052SJens Axboe 45972c2d531SAl Viro if (!likely(file->f_op->sendpage)) 460a8adbe37SMichał Mirosław return -EINVAL; 461a8adbe37SMichał Mirosław 46235f9c09fSEric Dumazet more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; 463ae62ca7bSEric Dumazet 464ae62ca7bSEric Dumazet if (sd->len < sd->total_len && pipe->nrbufs > 1) 46535f9c09fSEric Dumazet more |= MSG_SENDPAGE_NOTLAST; 466ae62ca7bSEric Dumazet 467a8adbe37SMichał Mirosław return file->f_op->sendpage(file, buf->page, buf->offset, 468f84d7519SJens Axboe sd->len, &pos, more); 4695274f052SJens Axboe } 4705274f052SJens Axboe 471b3c2d2ddSMiklos Szeredi static void wakeup_pipe_writers(struct pipe_inode_info *pipe) 472b3c2d2ddSMiklos Szeredi { 473b3c2d2ddSMiklos Szeredi smp_mb(); 474b3c2d2ddSMiklos Szeredi if (waitqueue_active(&pipe->wait)) 475b3c2d2ddSMiklos Szeredi wake_up_interruptible(&pipe->wait); 476b3c2d2ddSMiklos Szeredi kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); 477b3c2d2ddSMiklos Szeredi } 478b3c2d2ddSMiklos Szeredi 479b3c2d2ddSMiklos Szeredi /** 480b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed - feed available data from a pipe to a file 481b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 482b3c2d2ddSMiklos Szeredi * @sd: information to @actor 483b3c2d2ddSMiklos Szeredi * @actor: handler that splices the data 484b3c2d2ddSMiklos Szeredi * 485b3c2d2ddSMiklos Szeredi * Description: 486b3c2d2ddSMiklos Szeredi * This function loops over the pipe and calls @actor to do the 487b3c2d2ddSMiklos Szeredi * actual moving of a single struct pipe_buffer to the desired 488b3c2d2ddSMiklos Szeredi * destination. It returns when there's no more buffers left in 489b3c2d2ddSMiklos Szeredi * the pipe or if the requested number of bytes (@sd->total_len) 490b3c2d2ddSMiklos Szeredi * have been copied. It returns a positive number (one) if the 491b3c2d2ddSMiklos Szeredi * pipe needs to be filled with more data, zero if the required 492b3c2d2ddSMiklos Szeredi * number of bytes have been copied and -errno on error. 493b3c2d2ddSMiklos Szeredi * 494b3c2d2ddSMiklos Szeredi * This, together with splice_from_pipe_{begin,end,next}, may be 495b3c2d2ddSMiklos Szeredi * used to implement the functionality of __splice_from_pipe() when 496b3c2d2ddSMiklos Szeredi * locking is required around copying the pipe buffers to the 497b3c2d2ddSMiklos Szeredi * destination. 498b3c2d2ddSMiklos Szeredi */ 49996f9bc8fSAl Viro static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, 500b3c2d2ddSMiklos Szeredi splice_actor *actor) 501b3c2d2ddSMiklos Szeredi { 502b3c2d2ddSMiklos Szeredi int ret; 503b3c2d2ddSMiklos Szeredi 504b3c2d2ddSMiklos Szeredi while (pipe->nrbufs) { 505b3c2d2ddSMiklos Szeredi struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 506b3c2d2ddSMiklos Szeredi 507b3c2d2ddSMiklos Szeredi sd->len = buf->len; 508b3c2d2ddSMiklos Szeredi if (sd->len > sd->total_len) 509b3c2d2ddSMiklos Szeredi sd->len = sd->total_len; 510b3c2d2ddSMiklos Szeredi 511fba597dbSMiklos Szeredi ret = pipe_buf_confirm(pipe, buf); 512a8adbe37SMichał Mirosław if (unlikely(ret)) { 513b3c2d2ddSMiklos Szeredi if (ret == -ENODATA) 514b3c2d2ddSMiklos Szeredi ret = 0; 515b3c2d2ddSMiklos Szeredi return ret; 516b3c2d2ddSMiklos Szeredi } 517a8adbe37SMichał Mirosław 518a8adbe37SMichał Mirosław ret = actor(pipe, buf, sd); 519a8adbe37SMichał Mirosław if (ret <= 0) 520a8adbe37SMichał Mirosław return ret; 521a8adbe37SMichał Mirosław 522b3c2d2ddSMiklos Szeredi buf->offset += ret; 523b3c2d2ddSMiklos Szeredi buf->len -= ret; 524b3c2d2ddSMiklos Szeredi 525b3c2d2ddSMiklos Szeredi sd->num_spliced += ret; 526b3c2d2ddSMiklos Szeredi sd->len -= ret; 527b3c2d2ddSMiklos Szeredi sd->pos += ret; 528b3c2d2ddSMiklos Szeredi sd->total_len -= ret; 529b3c2d2ddSMiklos Szeredi 530b3c2d2ddSMiklos Szeredi if (!buf->len) { 531a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 53235f3d14dSJens Axboe pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); 533b3c2d2ddSMiklos Szeredi pipe->nrbufs--; 5346447a3cfSAl Viro if (pipe->files) 535b3c2d2ddSMiklos Szeredi sd->need_wakeup = true; 536b3c2d2ddSMiklos Szeredi } 537b3c2d2ddSMiklos Szeredi 538b3c2d2ddSMiklos Szeredi if (!sd->total_len) 539b3c2d2ddSMiklos Szeredi return 0; 540b3c2d2ddSMiklos Szeredi } 541b3c2d2ddSMiklos Szeredi 542b3c2d2ddSMiklos Szeredi return 1; 543b3c2d2ddSMiklos Szeredi } 544b3c2d2ddSMiklos Szeredi 545b3c2d2ddSMiklos Szeredi /** 546b3c2d2ddSMiklos Szeredi * splice_from_pipe_next - wait for some data to splice from 547b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 548b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 549b3c2d2ddSMiklos Szeredi * 550b3c2d2ddSMiklos Szeredi * Description: 551b3c2d2ddSMiklos Szeredi * This function will wait for some data and return a positive 552b3c2d2ddSMiklos Szeredi * value (one) if pipe buffers are available. It will return zero 553b3c2d2ddSMiklos Szeredi * or -errno if no more data needs to be spliced. 554b3c2d2ddSMiklos Szeredi */ 55596f9bc8fSAl Viro static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) 556b3c2d2ddSMiklos Szeredi { 557c725bfceSJan Kara /* 558c725bfceSJan Kara * Check for signal early to make process killable when there are 559c725bfceSJan Kara * always buffers available 560c725bfceSJan Kara */ 561c725bfceSJan Kara if (signal_pending(current)) 562c725bfceSJan Kara return -ERESTARTSYS; 563c725bfceSJan Kara 564b3c2d2ddSMiklos Szeredi while (!pipe->nrbufs) { 565b3c2d2ddSMiklos Szeredi if (!pipe->writers) 566b3c2d2ddSMiklos Szeredi return 0; 567b3c2d2ddSMiklos Szeredi 568b3c2d2ddSMiklos Szeredi if (!pipe->waiting_writers && 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 582b3c2d2ddSMiklos Szeredi pipe_wait(pipe); 583b3c2d2ddSMiklos Szeredi } 584b3c2d2ddSMiklos Szeredi 585b3c2d2ddSMiklos Szeredi return 1; 586b3c2d2ddSMiklos Szeredi } 587b3c2d2ddSMiklos Szeredi 588b3c2d2ddSMiklos Szeredi /** 589b3c2d2ddSMiklos Szeredi * splice_from_pipe_begin - start splicing from pipe 590b80901bbSRandy Dunlap * @sd: information about the splice operation 591b3c2d2ddSMiklos Szeredi * 592b3c2d2ddSMiklos Szeredi * Description: 593b3c2d2ddSMiklos Szeredi * This function should be called before a loop containing 594b3c2d2ddSMiklos Szeredi * splice_from_pipe_next() and splice_from_pipe_feed() to 595b3c2d2ddSMiklos Szeredi * initialize the necessary fields of @sd. 596b3c2d2ddSMiklos Szeredi */ 59796f9bc8fSAl Viro static void splice_from_pipe_begin(struct splice_desc *sd) 598b3c2d2ddSMiklos Szeredi { 599b3c2d2ddSMiklos Szeredi sd->num_spliced = 0; 600b3c2d2ddSMiklos Szeredi sd->need_wakeup = false; 601b3c2d2ddSMiklos Szeredi } 602b3c2d2ddSMiklos Szeredi 603b3c2d2ddSMiklos Szeredi /** 604b3c2d2ddSMiklos Szeredi * splice_from_pipe_end - finish splicing from pipe 605b3c2d2ddSMiklos Szeredi * @pipe: pipe to splice from 606b3c2d2ddSMiklos Szeredi * @sd: information about the splice operation 607b3c2d2ddSMiklos Szeredi * 608b3c2d2ddSMiklos Szeredi * Description: 609b3c2d2ddSMiklos Szeredi * This function will wake up pipe writers if necessary. It should 610b3c2d2ddSMiklos Szeredi * be called after a loop containing splice_from_pipe_next() and 611b3c2d2ddSMiklos Szeredi * splice_from_pipe_feed(). 612b3c2d2ddSMiklos Szeredi */ 61396f9bc8fSAl Viro static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) 614b3c2d2ddSMiklos Szeredi { 615b3c2d2ddSMiklos Szeredi if (sd->need_wakeup) 616b3c2d2ddSMiklos Szeredi wakeup_pipe_writers(pipe); 617b3c2d2ddSMiklos Szeredi } 618b3c2d2ddSMiklos Szeredi 619932cc6d4SJens Axboe /** 620932cc6d4SJens Axboe * __splice_from_pipe - splice data from a pipe to given actor 621932cc6d4SJens Axboe * @pipe: pipe to splice from 622932cc6d4SJens Axboe * @sd: information to @actor 623932cc6d4SJens Axboe * @actor: handler that splices the data 624932cc6d4SJens Axboe * 625932cc6d4SJens Axboe * Description: 626932cc6d4SJens Axboe * This function does little more than loop over the pipe and call 627932cc6d4SJens Axboe * @actor to do the actual moving of a single struct pipe_buffer to 628932cc6d4SJens Axboe * the desired destination. See pipe_to_file, pipe_to_sendpage, or 629932cc6d4SJens Axboe * pipe_to_user. 630932cc6d4SJens Axboe * 63183f9135bSJens Axboe */ 632c66ab6faSJens Axboe ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, 633c66ab6faSJens Axboe splice_actor *actor) 6345274f052SJens Axboe { 635b3c2d2ddSMiklos Szeredi int ret; 6365274f052SJens Axboe 637b3c2d2ddSMiklos Szeredi splice_from_pipe_begin(sd); 638b3c2d2ddSMiklos Szeredi do { 639c2489e07SJan Kara cond_resched(); 640b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_next(pipe, sd); 641b3c2d2ddSMiklos Szeredi if (ret > 0) 642b3c2d2ddSMiklos Szeredi ret = splice_from_pipe_feed(pipe, sd, actor); 643b3c2d2ddSMiklos Szeredi } while (ret > 0); 644b3c2d2ddSMiklos Szeredi splice_from_pipe_end(pipe, sd); 6455274f052SJens Axboe 646b3c2d2ddSMiklos Szeredi return sd->num_spliced ? sd->num_spliced : ret; 6475274f052SJens Axboe } 64840bee44eSMark Fasheh EXPORT_SYMBOL(__splice_from_pipe); 6495274f052SJens Axboe 650932cc6d4SJens Axboe /** 651932cc6d4SJens Axboe * splice_from_pipe - splice data from a pipe to a file 652932cc6d4SJens Axboe * @pipe: pipe to splice from 653932cc6d4SJens Axboe * @out: file to splice to 654932cc6d4SJens Axboe * @ppos: position in @out 655932cc6d4SJens Axboe * @len: how many bytes to splice 656932cc6d4SJens Axboe * @flags: splice modifier flags 657932cc6d4SJens Axboe * @actor: handler that splices the data 658932cc6d4SJens Axboe * 659932cc6d4SJens Axboe * Description: 6602933970bSMiklos Szeredi * See __splice_from_pipe. This function locks the pipe inode, 661932cc6d4SJens Axboe * otherwise it's identical to __splice_from_pipe(). 662932cc6d4SJens Axboe * 663932cc6d4SJens Axboe */ 6646da61809SMark Fasheh ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, 6656da61809SMark Fasheh loff_t *ppos, size_t len, unsigned int flags, 6666da61809SMark Fasheh splice_actor *actor) 6676da61809SMark Fasheh { 6686da61809SMark Fasheh ssize_t ret; 669c66ab6faSJens Axboe struct splice_desc sd = { 670c66ab6faSJens Axboe .total_len = len, 671c66ab6faSJens Axboe .flags = flags, 672c66ab6faSJens Axboe .pos = *ppos, 6736a14b90bSJens Axboe .u.file = out, 674c66ab6faSJens Axboe }; 6756da61809SMark Fasheh 67661e0d47cSMiklos Szeredi pipe_lock(pipe); 677c66ab6faSJens Axboe ret = __splice_from_pipe(pipe, &sd, actor); 67861e0d47cSMiklos Szeredi pipe_unlock(pipe); 6796da61809SMark Fasheh 6806da61809SMark Fasheh return ret; 6816da61809SMark Fasheh } 6826da61809SMark Fasheh 6836da61809SMark Fasheh /** 6848d020765SAl Viro * iter_file_splice_write - splice data from a pipe to a file 6858d020765SAl Viro * @pipe: pipe info 6868d020765SAl Viro * @out: file to write to 6878d020765SAl Viro * @ppos: position in @out 6888d020765SAl Viro * @len: number of bytes to splice 6898d020765SAl Viro * @flags: splice modifier flags 6908d020765SAl Viro * 6918d020765SAl Viro * Description: 6928d020765SAl Viro * Will either move or copy pages (determined by @flags options) from 6938d020765SAl Viro * the given pipe inode to the given file. 6948d020765SAl Viro * This one is ->write_iter-based. 6958d020765SAl Viro * 6968d020765SAl Viro */ 6978d020765SAl Viro ssize_t 6988d020765SAl Viro iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 6998d020765SAl Viro loff_t *ppos, size_t len, unsigned int flags) 7008d020765SAl Viro { 7018d020765SAl Viro struct splice_desc sd = { 7028d020765SAl Viro .total_len = len, 7038d020765SAl Viro .flags = flags, 7048d020765SAl Viro .pos = *ppos, 7058d020765SAl Viro .u.file = out, 7068d020765SAl Viro }; 7078d020765SAl Viro int nbufs = pipe->buffers; 7088d020765SAl Viro struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec), 7098d020765SAl Viro GFP_KERNEL); 7108d020765SAl Viro ssize_t ret; 7118d020765SAl Viro 7128d020765SAl Viro if (unlikely(!array)) 7138d020765SAl Viro return -ENOMEM; 7148d020765SAl Viro 7158d020765SAl Viro pipe_lock(pipe); 7168d020765SAl Viro 7178d020765SAl Viro splice_from_pipe_begin(&sd); 7188d020765SAl Viro while (sd.total_len) { 7198d020765SAl Viro struct iov_iter from; 7208d020765SAl Viro size_t left; 7218d020765SAl Viro int n, idx; 7228d020765SAl Viro 7238d020765SAl Viro ret = splice_from_pipe_next(pipe, &sd); 7248d020765SAl Viro if (ret <= 0) 7258d020765SAl Viro break; 7268d020765SAl Viro 7278d020765SAl Viro if (unlikely(nbufs < pipe->buffers)) { 7288d020765SAl Viro kfree(array); 7298d020765SAl Viro nbufs = pipe->buffers; 7308d020765SAl Viro array = kcalloc(nbufs, sizeof(struct bio_vec), 7318d020765SAl Viro GFP_KERNEL); 7328d020765SAl Viro if (!array) { 7338d020765SAl Viro ret = -ENOMEM; 7348d020765SAl Viro break; 7358d020765SAl Viro } 7368d020765SAl Viro } 7378d020765SAl Viro 7388d020765SAl Viro /* build the vector */ 7398d020765SAl Viro left = sd.total_len; 7408d020765SAl Viro for (n = 0, idx = pipe->curbuf; left && n < pipe->nrbufs; n++, idx++) { 7418d020765SAl Viro struct pipe_buffer *buf = pipe->bufs + idx; 7428d020765SAl Viro size_t this_len = buf->len; 7438d020765SAl Viro 7448d020765SAl Viro if (this_len > left) 7458d020765SAl Viro this_len = left; 7468d020765SAl Viro 7478d020765SAl Viro if (idx == pipe->buffers - 1) 7488d020765SAl Viro idx = -1; 7498d020765SAl Viro 750fba597dbSMiklos Szeredi ret = pipe_buf_confirm(pipe, buf); 7518d020765SAl Viro if (unlikely(ret)) { 7528d020765SAl Viro if (ret == -ENODATA) 7538d020765SAl Viro ret = 0; 7548d020765SAl Viro goto done; 7558d020765SAl Viro } 7568d020765SAl Viro 7578d020765SAl Viro array[n].bv_page = buf->page; 7588d020765SAl Viro array[n].bv_len = this_len; 7598d020765SAl Viro array[n].bv_offset = buf->offset; 7608d020765SAl Viro left -= this_len; 7618d020765SAl Viro } 7628d020765SAl Viro 76305afcb77SAl Viro iov_iter_bvec(&from, ITER_BVEC | WRITE, array, n, 76405afcb77SAl Viro sd.total_len - left); 765abbb6589SChristoph Hellwig ret = vfs_iter_write(out, &from, &sd.pos, 0); 7668d020765SAl Viro if (ret <= 0) 7678d020765SAl Viro break; 7688d020765SAl Viro 7698d020765SAl Viro sd.num_spliced += ret; 7708d020765SAl Viro sd.total_len -= ret; 771dbe4e192SChristoph Hellwig *ppos = sd.pos; 7728d020765SAl Viro 7738d020765SAl Viro /* dismiss the fully eaten buffers, adjust the partial one */ 7748d020765SAl Viro while (ret) { 7758d020765SAl Viro struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; 7768d020765SAl Viro if (ret >= buf->len) { 7778d020765SAl Viro ret -= buf->len; 7788d020765SAl Viro buf->len = 0; 779a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 7808d020765SAl Viro pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); 7818d020765SAl Viro pipe->nrbufs--; 7828d020765SAl Viro if (pipe->files) 7838d020765SAl Viro sd.need_wakeup = true; 7848d020765SAl Viro } else { 7858d020765SAl Viro buf->offset += ret; 7868d020765SAl Viro buf->len -= ret; 7878d020765SAl Viro ret = 0; 7888d020765SAl Viro } 7898d020765SAl Viro } 7908d020765SAl Viro } 7918d020765SAl Viro done: 7928d020765SAl Viro kfree(array); 7938d020765SAl Viro splice_from_pipe_end(pipe, &sd); 7948d020765SAl Viro 7958d020765SAl Viro pipe_unlock(pipe); 7968d020765SAl Viro 7978d020765SAl Viro if (sd.num_spliced) 7988d020765SAl Viro ret = sd.num_spliced; 7998d020765SAl Viro 8008d020765SAl Viro return ret; 8018d020765SAl Viro } 8028d020765SAl Viro 8038d020765SAl Viro EXPORT_SYMBOL(iter_file_splice_write); 8048d020765SAl Viro 805b2858d7dSMiklos Szeredi static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 806b2858d7dSMiklos Szeredi struct splice_desc *sd) 8070b0a47f5SMiklos Szeredi { 808b2858d7dSMiklos Szeredi int ret; 809b2858d7dSMiklos Szeredi void *data; 81006ae43f3SAl Viro loff_t tmp = sd->pos; 811b2858d7dSMiklos Szeredi 812fbb32750SAl Viro data = kmap(buf->page); 81306ae43f3SAl Viro ret = __kernel_write(sd->u.file, data + buf->offset, sd->len, &tmp); 814fbb32750SAl Viro kunmap(buf->page); 815b2858d7dSMiklos Szeredi 816b2858d7dSMiklos Szeredi return ret; 8170b0a47f5SMiklos Szeredi } 8180b0a47f5SMiklos Szeredi 8190b0a47f5SMiklos Szeredi static ssize_t default_file_splice_write(struct pipe_inode_info *pipe, 8200b0a47f5SMiklos Szeredi struct file *out, loff_t *ppos, 8210b0a47f5SMiklos Szeredi size_t len, unsigned int flags) 8220b0a47f5SMiklos Szeredi { 823b2858d7dSMiklos Szeredi ssize_t ret; 8240b0a47f5SMiklos Szeredi 825b2858d7dSMiklos Szeredi ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf); 826b2858d7dSMiklos Szeredi if (ret > 0) 827b2858d7dSMiklos Szeredi *ppos += ret; 8280b0a47f5SMiklos Szeredi 829b2858d7dSMiklos Szeredi return ret; 8300b0a47f5SMiklos Szeredi } 8310b0a47f5SMiklos Szeredi 83283f9135bSJens Axboe /** 83383f9135bSJens Axboe * generic_splice_sendpage - splice data from a pipe to a socket 834932cc6d4SJens Axboe * @pipe: pipe to splice from 83583f9135bSJens Axboe * @out: socket to write to 836932cc6d4SJens Axboe * @ppos: position in @out 83783f9135bSJens Axboe * @len: number of bytes to splice 83883f9135bSJens Axboe * @flags: splice modifier flags 83983f9135bSJens Axboe * 840932cc6d4SJens Axboe * Description: 84183f9135bSJens Axboe * Will send @len bytes from the pipe to a network socket. No data copying 84283f9135bSJens Axboe * is involved. 84383f9135bSJens Axboe * 84483f9135bSJens Axboe */ 8453a326a2cSIngo Molnar ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, 846cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8475274f052SJens Axboe { 84800522fb4SJens Axboe return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); 8495274f052SJens Axboe } 8505274f052SJens Axboe 851059a8f37SJens Axboe EXPORT_SYMBOL(generic_splice_sendpage); 852a0f06780SJeff Garzik 85383f9135bSJens Axboe /* 85483f9135bSJens Axboe * Attempt to initiate a splice from pipe to file. 85583f9135bSJens Axboe */ 8563a326a2cSIngo Molnar static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 857cbb7e577SJens Axboe loff_t *ppos, size_t len, unsigned int flags) 8585274f052SJens Axboe { 8590b0a47f5SMiklos Szeredi ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, 8600b0a47f5SMiklos Szeredi loff_t *, size_t, unsigned int); 8615274f052SJens Axboe 86272c2d531SAl Viro if (out->f_op->splice_write) 8630b0a47f5SMiklos Szeredi splice_write = out->f_op->splice_write; 864cc56f7deSChangli Gao else 8650b0a47f5SMiklos Szeredi splice_write = default_file_splice_write; 8660b0a47f5SMiklos Szeredi 867500368f7SAl Viro return splice_write(pipe, out, ppos, len, flags); 8685274f052SJens Axboe } 8695274f052SJens Axboe 87083f9135bSJens Axboe /* 87183f9135bSJens Axboe * Attempt to initiate a splice from a file to a pipe. 87283f9135bSJens Axboe */ 873cbb7e577SJens Axboe static long do_splice_to(struct file *in, loff_t *ppos, 874cbb7e577SJens Axboe struct pipe_inode_info *pipe, size_t len, 875cbb7e577SJens Axboe unsigned int flags) 8765274f052SJens Axboe { 8776818173bSMiklos Szeredi ssize_t (*splice_read)(struct file *, loff_t *, 8786818173bSMiklos Szeredi struct pipe_inode_info *, size_t, unsigned int); 8795274f052SJens Axboe int ret; 8805274f052SJens Axboe 88149570e9bSJens Axboe if (unlikely(!(in->f_mode & FMODE_READ))) 8825274f052SJens Axboe return -EBADF; 8835274f052SJens Axboe 884cbb7e577SJens Axboe ret = rw_verify_area(READ, in, ppos, len); 8855274f052SJens Axboe if (unlikely(ret < 0)) 8865274f052SJens Axboe return ret; 8875274f052SJens Axboe 88803cc0789SAl Viro if (unlikely(len > MAX_RW_COUNT)) 88903cc0789SAl Viro len = MAX_RW_COUNT; 89003cc0789SAl Viro 89172c2d531SAl Viro if (in->f_op->splice_read) 8926818173bSMiklos Szeredi splice_read = in->f_op->splice_read; 893cc56f7deSChangli Gao else 8946818173bSMiklos Szeredi splice_read = default_file_splice_read; 8956818173bSMiklos Szeredi 8966818173bSMiklos Szeredi return splice_read(in, ppos, pipe, len, flags); 8975274f052SJens Axboe } 8985274f052SJens Axboe 899932cc6d4SJens Axboe /** 900932cc6d4SJens Axboe * splice_direct_to_actor - splices data directly between two non-pipes 901932cc6d4SJens Axboe * @in: file to splice from 902932cc6d4SJens Axboe * @sd: actor information on where to splice to 903932cc6d4SJens Axboe * @actor: handles the data splicing 904932cc6d4SJens Axboe * 905932cc6d4SJens Axboe * Description: 906932cc6d4SJens Axboe * This is a special case helper to splice directly between two 907932cc6d4SJens Axboe * points, without requiring an explicit pipe. Internally an allocated 908932cc6d4SJens Axboe * pipe is cached in the process, and reused during the lifetime of 909932cc6d4SJens Axboe * that process. 910932cc6d4SJens Axboe * 911c66ab6faSJens Axboe */ 912c66ab6faSJens Axboe ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 913c66ab6faSJens Axboe splice_direct_actor *actor) 914b92ce558SJens Axboe { 915b92ce558SJens Axboe struct pipe_inode_info *pipe; 916b92ce558SJens Axboe long ret, bytes; 917b92ce558SJens Axboe umode_t i_mode; 918c66ab6faSJens Axboe size_t len; 9190ff28d9fSChristophe Leroy int i, flags, more; 920b92ce558SJens Axboe 921b92ce558SJens Axboe /* 922b92ce558SJens Axboe * We require the input being a regular file, as we don't want to 923b92ce558SJens Axboe * randomly drop data for eg socket -> socket splicing. Use the 924b92ce558SJens Axboe * piped splicing for that! 925b92ce558SJens Axboe */ 926496ad9aaSAl Viro i_mode = file_inode(in)->i_mode; 927b92ce558SJens Axboe if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) 928b92ce558SJens Axboe return -EINVAL; 929b92ce558SJens Axboe 930b92ce558SJens Axboe /* 931b92ce558SJens Axboe * neither in nor out is a pipe, setup an internal pipe attached to 932b92ce558SJens Axboe * 'out' and transfer the wanted data from 'in' to 'out' through that 933b92ce558SJens Axboe */ 934b92ce558SJens Axboe pipe = current->splice_pipe; 93549570e9bSJens Axboe if (unlikely(!pipe)) { 9367bee130eSAl Viro pipe = alloc_pipe_info(); 937b92ce558SJens Axboe if (!pipe) 938b92ce558SJens Axboe return -ENOMEM; 939b92ce558SJens Axboe 940b92ce558SJens Axboe /* 941b92ce558SJens Axboe * We don't have an immediate reader, but we'll read the stuff 94200522fb4SJens Axboe * out of the pipe right after the splice_to_pipe(). So set 943b92ce558SJens Axboe * PIPE_READERS appropriately. 944b92ce558SJens Axboe */ 945b92ce558SJens Axboe pipe->readers = 1; 946b92ce558SJens Axboe 947b92ce558SJens Axboe current->splice_pipe = pipe; 948b92ce558SJens Axboe } 949b92ce558SJens Axboe 950b92ce558SJens Axboe /* 95173d62d83SIngo Molnar * Do the splice. 952b92ce558SJens Axboe */ 953b92ce558SJens Axboe ret = 0; 954b92ce558SJens Axboe bytes = 0; 955c66ab6faSJens Axboe len = sd->total_len; 956c66ab6faSJens Axboe flags = sd->flags; 957c66ab6faSJens Axboe 958c66ab6faSJens Axboe /* 959c66ab6faSJens Axboe * Don't block on output, we have to drain the direct pipe. 960c66ab6faSJens Axboe */ 961c66ab6faSJens Axboe sd->flags &= ~SPLICE_F_NONBLOCK; 9620ff28d9fSChristophe Leroy more = sd->flags & SPLICE_F_MORE; 963b92ce558SJens Axboe 964b92ce558SJens Axboe while (len) { 96551a92c0fSJens Axboe size_t read_len; 966a82c53a0STom Zanussi loff_t pos = sd->pos, prev_pos = pos; 967b92ce558SJens Axboe 968bcd4f3acSJens Axboe ret = do_splice_to(in, &pos, pipe, len, flags); 96951a92c0fSJens Axboe if (unlikely(ret <= 0)) 970b92ce558SJens Axboe goto out_release; 971b92ce558SJens Axboe 972b92ce558SJens Axboe read_len = ret; 973c66ab6faSJens Axboe sd->total_len = read_len; 974b92ce558SJens Axboe 975b92ce558SJens Axboe /* 9760ff28d9fSChristophe Leroy * If more data is pending, set SPLICE_F_MORE 9770ff28d9fSChristophe Leroy * If this is the last data and SPLICE_F_MORE was not set 9780ff28d9fSChristophe Leroy * initially, clears it. 9790ff28d9fSChristophe Leroy */ 9800ff28d9fSChristophe Leroy if (read_len < len) 9810ff28d9fSChristophe Leroy sd->flags |= SPLICE_F_MORE; 9820ff28d9fSChristophe Leroy else if (!more) 9830ff28d9fSChristophe Leroy sd->flags &= ~SPLICE_F_MORE; 9840ff28d9fSChristophe Leroy /* 985b92ce558SJens Axboe * NOTE: nonblocking mode only applies to the input. We 986b92ce558SJens Axboe * must not do the output in nonblocking mode as then we 987b92ce558SJens Axboe * could get stuck data in the internal pipe: 988b92ce558SJens Axboe */ 989c66ab6faSJens Axboe ret = actor(pipe, sd); 990a82c53a0STom Zanussi if (unlikely(ret <= 0)) { 991a82c53a0STom Zanussi sd->pos = prev_pos; 992b92ce558SJens Axboe goto out_release; 993a82c53a0STom Zanussi } 994b92ce558SJens Axboe 995b92ce558SJens Axboe bytes += ret; 996b92ce558SJens Axboe len -= ret; 997bcd4f3acSJens Axboe sd->pos = pos; 998b92ce558SJens Axboe 999a82c53a0STom Zanussi if (ret < read_len) { 1000a82c53a0STom Zanussi sd->pos = prev_pos + ret; 100151a92c0fSJens Axboe goto out_release; 1002b92ce558SJens Axboe } 1003a82c53a0STom Zanussi } 1004b92ce558SJens Axboe 10059e97198dSJens Axboe done: 1006b92ce558SJens Axboe pipe->nrbufs = pipe->curbuf = 0; 10079e97198dSJens Axboe file_accessed(in); 1008b92ce558SJens Axboe return bytes; 1009b92ce558SJens Axboe 1010b92ce558SJens Axboe out_release: 1011b92ce558SJens Axboe /* 1012b92ce558SJens Axboe * If we did an incomplete transfer we must release 1013b92ce558SJens Axboe * the pipe buffers in question: 1014b92ce558SJens Axboe */ 101535f3d14dSJens Axboe for (i = 0; i < pipe->buffers; i++) { 1016b92ce558SJens Axboe struct pipe_buffer *buf = pipe->bufs + i; 1017b92ce558SJens Axboe 1018a779638cSMiklos Szeredi if (buf->ops) 1019a779638cSMiklos Szeredi pipe_buf_release(pipe, buf); 1020b92ce558SJens Axboe } 1021b92ce558SJens Axboe 10229e97198dSJens Axboe if (!bytes) 10239e97198dSJens Axboe bytes = ret; 1024b92ce558SJens Axboe 10259e97198dSJens Axboe goto done; 1026c66ab6faSJens Axboe } 1027c66ab6faSJens Axboe EXPORT_SYMBOL(splice_direct_to_actor); 1028c66ab6faSJens Axboe 1029c66ab6faSJens Axboe static int direct_splice_actor(struct pipe_inode_info *pipe, 1030c66ab6faSJens Axboe struct splice_desc *sd) 1031c66ab6faSJens Axboe { 10326a14b90bSJens Axboe struct file *file = sd->u.file; 1033c66ab6faSJens Axboe 10347995bd28SAl Viro return do_splice_from(pipe, file, sd->opos, sd->total_len, 10352cb4b05eSChangli Gao sd->flags); 1036c66ab6faSJens Axboe } 1037c66ab6faSJens Axboe 1038932cc6d4SJens Axboe /** 1039932cc6d4SJens Axboe * do_splice_direct - splices data directly between two files 1040932cc6d4SJens Axboe * @in: file to splice from 1041932cc6d4SJens Axboe * @ppos: input file offset 1042932cc6d4SJens Axboe * @out: file to splice to 1043acdb37c3SRandy Dunlap * @opos: output file offset 1044932cc6d4SJens Axboe * @len: number of bytes to splice 1045932cc6d4SJens Axboe * @flags: splice modifier flags 1046932cc6d4SJens Axboe * 1047932cc6d4SJens Axboe * Description: 1048932cc6d4SJens Axboe * For use by do_sendfile(). splice can easily emulate sendfile, but 1049932cc6d4SJens Axboe * doing it in the application would incur an extra system call 1050932cc6d4SJens Axboe * (splice in + splice out, as compared to just sendfile()). So this helper 1051932cc6d4SJens Axboe * can splice directly through a process-private pipe. 1052932cc6d4SJens Axboe * 1053932cc6d4SJens Axboe */ 1054c66ab6faSJens Axboe long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 10557995bd28SAl Viro loff_t *opos, size_t len, unsigned int flags) 1056c66ab6faSJens Axboe { 1057c66ab6faSJens Axboe struct splice_desc sd = { 1058c66ab6faSJens Axboe .len = len, 1059c66ab6faSJens Axboe .total_len = len, 1060c66ab6faSJens Axboe .flags = flags, 1061c66ab6faSJens Axboe .pos = *ppos, 10626a14b90bSJens Axboe .u.file = out, 10637995bd28SAl Viro .opos = opos, 1064c66ab6faSJens Axboe }; 106551a92c0fSJens Axboe long ret; 1066c66ab6faSJens Axboe 106718c67cb9SAl Viro if (unlikely(!(out->f_mode & FMODE_WRITE))) 106818c67cb9SAl Viro return -EBADF; 106918c67cb9SAl Viro 107018c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 107118c67cb9SAl Viro return -EINVAL; 107218c67cb9SAl Viro 107318c67cb9SAl Viro ret = rw_verify_area(WRITE, out, opos, len); 107418c67cb9SAl Viro if (unlikely(ret < 0)) 107518c67cb9SAl Viro return ret; 107618c67cb9SAl Viro 1077c66ab6faSJens Axboe ret = splice_direct_to_actor(in, &sd, direct_splice_actor); 107851a92c0fSJens Axboe if (ret > 0) 1079a82c53a0STom Zanussi *ppos = sd.pos; 108051a92c0fSJens Axboe 1081c66ab6faSJens Axboe return ret; 1082b92ce558SJens Axboe } 10831c118596SMiklos Szeredi EXPORT_SYMBOL(do_splice_direct); 1084b92ce558SJens Axboe 10858924feffSAl Viro static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) 10868924feffSAl Viro { 108752bce911SLinus Torvalds for (;;) { 108852bce911SLinus Torvalds if (unlikely(!pipe->readers)) { 108952bce911SLinus Torvalds send_sig(SIGPIPE, current, 0); 109052bce911SLinus Torvalds return -EPIPE; 109152bce911SLinus Torvalds } 109252bce911SLinus Torvalds if (pipe->nrbufs != pipe->buffers) 109352bce911SLinus Torvalds return 0; 10948924feffSAl Viro if (flags & SPLICE_F_NONBLOCK) 10958924feffSAl Viro return -EAGAIN; 10968924feffSAl Viro if (signal_pending(current)) 10978924feffSAl Viro return -ERESTARTSYS; 10988924feffSAl Viro pipe->waiting_writers++; 10998924feffSAl Viro pipe_wait(pipe); 11008924feffSAl Viro pipe->waiting_writers--; 11018924feffSAl Viro } 11028924feffSAl Viro } 11038924feffSAl Viro 11047c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 11057c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 11067c77f0b3SMiklos Szeredi size_t len, unsigned int flags); 1107ddac0d39SJens Axboe 1108ddac0d39SJens Axboe /* 110983f9135bSJens Axboe * Determine where to splice to/from. 111083f9135bSJens Axboe */ 1111529565dcSIngo Molnar static long do_splice(struct file *in, loff_t __user *off_in, 1112529565dcSIngo Molnar struct file *out, loff_t __user *off_out, 1113529565dcSIngo Molnar size_t len, unsigned int flags) 11145274f052SJens Axboe { 11157c77f0b3SMiklos Szeredi struct pipe_inode_info *ipipe; 11167c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe; 11177995bd28SAl Viro loff_t offset; 1118a4514ebdSJens Axboe long ret; 11195274f052SJens Axboe 112071993e62SLinus Torvalds ipipe = get_pipe_info(in); 112171993e62SLinus Torvalds opipe = get_pipe_info(out); 11227c77f0b3SMiklos Szeredi 11237c77f0b3SMiklos Szeredi if (ipipe && opipe) { 11247c77f0b3SMiklos Szeredi if (off_in || off_out) 11257c77f0b3SMiklos Szeredi return -ESPIPE; 11267c77f0b3SMiklos Szeredi 11277c77f0b3SMiklos Szeredi if (!(in->f_mode & FMODE_READ)) 11287c77f0b3SMiklos Szeredi return -EBADF; 11297c77f0b3SMiklos Szeredi 11307c77f0b3SMiklos Szeredi if (!(out->f_mode & FMODE_WRITE)) 11317c77f0b3SMiklos Szeredi return -EBADF; 11327c77f0b3SMiklos Szeredi 11337c77f0b3SMiklos Szeredi /* Splicing to self would be fun, but... */ 11347c77f0b3SMiklos Szeredi if (ipipe == opipe) 11357c77f0b3SMiklos Szeredi return -EINVAL; 11367c77f0b3SMiklos Szeredi 11377c77f0b3SMiklos Szeredi return splice_pipe_to_pipe(ipipe, opipe, len, flags); 11387c77f0b3SMiklos Szeredi } 11397c77f0b3SMiklos Szeredi 11407c77f0b3SMiklos Szeredi if (ipipe) { 1141529565dcSIngo Molnar if (off_in) 1142529565dcSIngo Molnar return -ESPIPE; 1143b92ce558SJens Axboe if (off_out) { 114419c9a49bSChangli Gao if (!(out->f_mode & FMODE_PWRITE)) 1145b92ce558SJens Axboe return -EINVAL; 1146cbb7e577SJens Axboe if (copy_from_user(&offset, off_out, sizeof(loff_t))) 1147b92ce558SJens Axboe return -EFAULT; 11487995bd28SAl Viro } else { 11497995bd28SAl Viro offset = out->f_pos; 11507995bd28SAl Viro } 1151529565dcSIngo Molnar 115218c67cb9SAl Viro if (unlikely(!(out->f_mode & FMODE_WRITE))) 115318c67cb9SAl Viro return -EBADF; 115418c67cb9SAl Viro 115518c67cb9SAl Viro if (unlikely(out->f_flags & O_APPEND)) 115618c67cb9SAl Viro return -EINVAL; 115718c67cb9SAl Viro 115818c67cb9SAl Viro ret = rw_verify_area(WRITE, out, &offset, len); 115918c67cb9SAl Viro if (unlikely(ret < 0)) 116018c67cb9SAl Viro return ret; 116118c67cb9SAl Viro 1162500368f7SAl Viro file_start_write(out); 11637995bd28SAl Viro ret = do_splice_from(ipipe, out, &offset, len, flags); 1164500368f7SAl Viro file_end_write(out); 1165a4514ebdSJens Axboe 11667995bd28SAl Viro if (!off_out) 11677995bd28SAl Viro out->f_pos = offset; 11687995bd28SAl Viro else if (copy_to_user(off_out, &offset, sizeof(loff_t))) 1169a4514ebdSJens Axboe ret = -EFAULT; 1170a4514ebdSJens Axboe 1171a4514ebdSJens Axboe return ret; 1172529565dcSIngo Molnar } 11735274f052SJens Axboe 11747c77f0b3SMiklos Szeredi if (opipe) { 1175529565dcSIngo Molnar if (off_out) 1176529565dcSIngo Molnar return -ESPIPE; 1177b92ce558SJens Axboe if (off_in) { 117819c9a49bSChangli Gao if (!(in->f_mode & FMODE_PREAD)) 1179b92ce558SJens Axboe return -EINVAL; 1180cbb7e577SJens Axboe if (copy_from_user(&offset, off_in, sizeof(loff_t))) 1181b92ce558SJens Axboe return -EFAULT; 11827995bd28SAl Viro } else { 11837995bd28SAl Viro offset = in->f_pos; 11847995bd28SAl Viro } 1185529565dcSIngo Molnar 11868924feffSAl Viro pipe_lock(opipe); 11878924feffSAl Viro ret = wait_for_space(opipe, flags); 11888924feffSAl Viro if (!ret) 11897995bd28SAl Viro ret = do_splice_to(in, &offset, opipe, len, flags); 11908924feffSAl Viro pipe_unlock(opipe); 11918924feffSAl Viro if (ret > 0) 11928924feffSAl Viro wakeup_pipe_readers(opipe); 11937995bd28SAl Viro if (!off_in) 11947995bd28SAl Viro in->f_pos = offset; 11957995bd28SAl Viro else if (copy_to_user(off_in, &offset, sizeof(loff_t))) 1196a4514ebdSJens Axboe ret = -EFAULT; 1197a4514ebdSJens Axboe 1198a4514ebdSJens Axboe return ret; 1199529565dcSIngo Molnar } 12005274f052SJens Axboe 12015274f052SJens Axboe return -EINVAL; 12025274f052SJens Axboe } 12035274f052SJens Axboe 120479fddc4eSAl Viro static int iter_to_pipe(struct iov_iter *from, 120579fddc4eSAl Viro struct pipe_inode_info *pipe, 120679fddc4eSAl Viro unsigned flags) 1207912d35f8SJens Axboe { 120879fddc4eSAl Viro struct pipe_buffer buf = { 120979fddc4eSAl Viro .ops = &user_page_pipe_buf_ops, 121079fddc4eSAl Viro .flags = flags 121179fddc4eSAl Viro }; 121279fddc4eSAl Viro size_t total = 0; 121379fddc4eSAl Viro int ret = 0; 121479fddc4eSAl Viro bool failed = false; 121579fddc4eSAl Viro 121679fddc4eSAl Viro while (iov_iter_count(from) && !failed) { 121779fddc4eSAl Viro struct page *pages[16]; 1218db85a9ebSAl Viro ssize_t copied; 1219db85a9ebSAl Viro size_t start; 122079fddc4eSAl Viro int n; 1221912d35f8SJens Axboe 122279fddc4eSAl Viro copied = iov_iter_get_pages(from, pages, ~0UL, 16, &start); 122379fddc4eSAl Viro if (copied <= 0) { 122479fddc4eSAl Viro ret = copied; 122579fddc4eSAl Viro break; 122679fddc4eSAl Viro } 1227912d35f8SJens Axboe 122879fddc4eSAl Viro for (n = 0; copied; n++, start = 0) { 1229db85a9ebSAl Viro int size = min_t(int, copied, PAGE_SIZE - start); 123079fddc4eSAl Viro if (!failed) { 123179fddc4eSAl Viro buf.page = pages[n]; 123279fddc4eSAl Viro buf.offset = start; 123379fddc4eSAl Viro buf.len = size; 123479fddc4eSAl Viro ret = add_to_pipe(pipe, &buf); 123579fddc4eSAl Viro if (unlikely(ret < 0)) { 123679fddc4eSAl Viro failed = true; 123779fddc4eSAl Viro } else { 123879fddc4eSAl Viro iov_iter_advance(from, ret); 123979fddc4eSAl Viro total += ret; 124079fddc4eSAl Viro } 124179fddc4eSAl Viro } else { 124279fddc4eSAl Viro put_page(pages[n]); 124379fddc4eSAl Viro } 1244db85a9ebSAl Viro copied -= size; 1245912d35f8SJens Axboe } 1246912d35f8SJens Axboe } 124779fddc4eSAl Viro return total ? total : ret; 1248912d35f8SJens Axboe } 1249912d35f8SJens Axboe 12506a14b90bSJens Axboe static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 12516a14b90bSJens Axboe struct splice_desc *sd) 12526a14b90bSJens Axboe { 12536130f531SAl Viro int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data); 12546130f531SAl Viro return n == sd->len ? n : -EFAULT; 12556a14b90bSJens Axboe } 12566a14b90bSJens Axboe 12576a14b90bSJens Axboe /* 12586a14b90bSJens Axboe * For lack of a better implementation, implement vmsplice() to userspace 12596a14b90bSJens Axboe * as a simple copy of the pipes pages to the user iov. 12606a14b90bSJens Axboe */ 12616130f531SAl Viro static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov, 12626a14b90bSJens Axboe unsigned long nr_segs, unsigned int flags) 12636a14b90bSJens Axboe { 12646a14b90bSJens Axboe struct pipe_inode_info *pipe; 12656a14b90bSJens Axboe struct splice_desc sd; 12666a14b90bSJens Axboe long ret; 12676130f531SAl Viro struct iovec iovstack[UIO_FASTIOV]; 12686130f531SAl Viro struct iovec *iov = iovstack; 12696130f531SAl Viro struct iov_iter iter; 12706a14b90bSJens Axboe 127171993e62SLinus Torvalds pipe = get_pipe_info(file); 12726a14b90bSJens Axboe if (!pipe) 12736a14b90bSJens Axboe return -EBADF; 12746a14b90bSJens Axboe 1275345995faSAl Viro ret = import_iovec(READ, uiov, nr_segs, 1276345995faSAl Viro ARRAY_SIZE(iovstack), &iov, &iter); 1277345995faSAl Viro if (ret < 0) 1278345995faSAl Viro return ret; 12796a14b90bSJens Axboe 1280345995faSAl Viro sd.total_len = iov_iter_count(&iter); 12816a14b90bSJens Axboe sd.len = 0; 12826a14b90bSJens Axboe sd.flags = flags; 12836130f531SAl Viro sd.u.data = &iter; 12846a14b90bSJens Axboe sd.pos = 0; 12856a14b90bSJens Axboe 1286345995faSAl Viro if (sd.total_len) { 12876130f531SAl Viro pipe_lock(pipe); 12886130f531SAl Viro ret = __splice_from_pipe(pipe, &sd, pipe_to_user); 128961e0d47cSMiklos Szeredi pipe_unlock(pipe); 1290345995faSAl Viro } 12916a14b90bSJens Axboe 12926130f531SAl Viro kfree(iov); 12936a14b90bSJens Axboe return ret; 12946a14b90bSJens Axboe } 12956a14b90bSJens Axboe 1296912d35f8SJens Axboe /* 1297912d35f8SJens Axboe * vmsplice splices a user address range into a pipe. It can be thought of 1298912d35f8SJens Axboe * as splice-from-memory, where the regular splice is splice-from-file (or 1299912d35f8SJens Axboe * to file). In both cases the output is a pipe, naturally. 1300912d35f8SJens Axboe */ 1301db85a9ebSAl Viro static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov, 1302912d35f8SJens Axboe unsigned long nr_segs, unsigned int flags) 1303912d35f8SJens Axboe { 1304ddac0d39SJens Axboe struct pipe_inode_info *pipe; 1305db85a9ebSAl Viro struct iovec iovstack[UIO_FASTIOV]; 1306db85a9ebSAl Viro struct iovec *iov = iovstack; 1307db85a9ebSAl Viro struct iov_iter from; 130835f3d14dSJens Axboe long ret; 130979fddc4eSAl Viro unsigned buf_flag = 0; 131079fddc4eSAl Viro 131179fddc4eSAl Viro if (flags & SPLICE_F_GIFT) 131279fddc4eSAl Viro buf_flag = PIPE_BUF_FLAG_GIFT; 1313912d35f8SJens Axboe 131471993e62SLinus Torvalds pipe = get_pipe_info(file); 1315ddac0d39SJens Axboe if (!pipe) 1316912d35f8SJens Axboe return -EBADF; 1317912d35f8SJens Axboe 1318db85a9ebSAl Viro ret = import_iovec(WRITE, uiov, nr_segs, 1319db85a9ebSAl Viro ARRAY_SIZE(iovstack), &iov, &from); 1320db85a9ebSAl Viro if (ret < 0) 1321db85a9ebSAl Viro return ret; 1322912d35f8SJens Axboe 13238924feffSAl Viro pipe_lock(pipe); 13248924feffSAl Viro ret = wait_for_space(pipe, flags); 132579fddc4eSAl Viro if (!ret) 132679fddc4eSAl Viro ret = iter_to_pipe(&from, pipe, buf_flag); 13278924feffSAl Viro pipe_unlock(pipe); 13288924feffSAl Viro if (ret > 0) 13298924feffSAl Viro wakeup_pipe_readers(pipe); 1330db85a9ebSAl Viro kfree(iov); 133135f3d14dSJens Axboe return ret; 1332912d35f8SJens Axboe } 1333912d35f8SJens Axboe 13346a14b90bSJens Axboe /* 13356a14b90bSJens Axboe * Note that vmsplice only really supports true splicing _from_ user memory 13366a14b90bSJens Axboe * to a pipe, not the other way around. Splicing from user memory is a simple 13376a14b90bSJens Axboe * operation that can be supported without any funky alignment restrictions 13386a14b90bSJens Axboe * or nasty vm tricks. We simply map in the user memory and fill them into 13396a14b90bSJens Axboe * a pipe. The reverse isn't quite as easy, though. There are two possible 13406a14b90bSJens Axboe * solutions for that: 13416a14b90bSJens Axboe * 13426a14b90bSJens Axboe * - memcpy() the data internally, at which point we might as well just 13436a14b90bSJens Axboe * do a regular read() on the buffer anyway. 13446a14b90bSJens Axboe * - Lots of nasty vm tricks, that are neither fast nor flexible (it 13456a14b90bSJens Axboe * has restriction limitations on both ends of the pipe). 13466a14b90bSJens Axboe * 13476a14b90bSJens Axboe * Currently we punt and implement it as a normal copy, see pipe_to_user(). 13486a14b90bSJens Axboe * 13496a14b90bSJens Axboe */ 1350836f92adSHeiko Carstens SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, iov, 1351836f92adSHeiko Carstens unsigned long, nr_segs, unsigned int, flags) 1352912d35f8SJens Axboe { 13532903ff01SAl Viro struct fd f; 1354912d35f8SJens Axboe long error; 1355912d35f8SJens Axboe 13563d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 13573d6ea290SAl Viro return -EINVAL; 13586a14b90bSJens Axboe if (unlikely(nr_segs > UIO_MAXIOV)) 13596a14b90bSJens Axboe return -EINVAL; 13606a14b90bSJens Axboe else if (unlikely(!nr_segs)) 13616a14b90bSJens Axboe return 0; 13626a14b90bSJens Axboe 1363912d35f8SJens Axboe error = -EBADF; 13642903ff01SAl Viro f = fdget(fd); 13652903ff01SAl Viro if (f.file) { 13662903ff01SAl Viro if (f.file->f_mode & FMODE_WRITE) 13672903ff01SAl Viro error = vmsplice_to_pipe(f.file, iov, nr_segs, flags); 13682903ff01SAl Viro else if (f.file->f_mode & FMODE_READ) 13692903ff01SAl Viro error = vmsplice_to_user(f.file, iov, nr_segs, flags); 1370912d35f8SJens Axboe 13712903ff01SAl Viro fdput(f); 1372912d35f8SJens Axboe } 1373912d35f8SJens Axboe 1374912d35f8SJens Axboe return error; 1375912d35f8SJens Axboe } 1376912d35f8SJens Axboe 137776b021d0SAl Viro #ifdef CONFIG_COMPAT 137876b021d0SAl Viro COMPAT_SYSCALL_DEFINE4(vmsplice, int, fd, const struct compat_iovec __user *, iov32, 137976b021d0SAl Viro unsigned int, nr_segs, unsigned int, flags) 138076b021d0SAl Viro { 138176b021d0SAl Viro unsigned i; 138276b021d0SAl Viro struct iovec __user *iov; 138376b021d0SAl Viro if (nr_segs > UIO_MAXIOV) 138476b021d0SAl Viro return -EINVAL; 138576b021d0SAl Viro iov = compat_alloc_user_space(nr_segs * sizeof(struct iovec)); 138676b021d0SAl Viro for (i = 0; i < nr_segs; i++) { 138776b021d0SAl Viro struct compat_iovec v; 138876b021d0SAl Viro if (get_user(v.iov_base, &iov32[i].iov_base) || 138976b021d0SAl Viro get_user(v.iov_len, &iov32[i].iov_len) || 139076b021d0SAl Viro put_user(compat_ptr(v.iov_base), &iov[i].iov_base) || 139176b021d0SAl Viro put_user(v.iov_len, &iov[i].iov_len)) 139276b021d0SAl Viro return -EFAULT; 139376b021d0SAl Viro } 139476b021d0SAl Viro return sys_vmsplice(fd, iov, nr_segs, flags); 139576b021d0SAl Viro } 139676b021d0SAl Viro #endif 139776b021d0SAl Viro 1398836f92adSHeiko Carstens SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, 1399836f92adSHeiko Carstens int, fd_out, loff_t __user *, off_out, 1400836f92adSHeiko Carstens size_t, len, unsigned int, flags) 14015274f052SJens Axboe { 14022903ff01SAl Viro struct fd in, out; 14035274f052SJens Axboe long error; 14045274f052SJens Axboe 14055274f052SJens Axboe if (unlikely(!len)) 14065274f052SJens Axboe return 0; 14075274f052SJens Axboe 14083d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 14093d6ea290SAl Viro return -EINVAL; 14103d6ea290SAl Viro 14115274f052SJens Axboe error = -EBADF; 14122903ff01SAl Viro in = fdget(fd_in); 14132903ff01SAl Viro if (in.file) { 14142903ff01SAl Viro if (in.file->f_mode & FMODE_READ) { 14152903ff01SAl Viro out = fdget(fd_out); 14162903ff01SAl Viro if (out.file) { 14172903ff01SAl Viro if (out.file->f_mode & FMODE_WRITE) 14182903ff01SAl Viro error = do_splice(in.file, off_in, 14192903ff01SAl Viro out.file, off_out, 1420529565dcSIngo Molnar len, flags); 14212903ff01SAl Viro fdput(out); 14225274f052SJens Axboe } 14235274f052SJens Axboe } 14242903ff01SAl Viro fdput(in); 14255274f052SJens Axboe } 14265274f052SJens Axboe return error; 14275274f052SJens Axboe } 142870524490SJens Axboe 142970524490SJens Axboe /* 1430aadd06e5SJens Axboe * Make sure there's data to read. Wait for input if we can, otherwise 1431aadd06e5SJens Axboe * return an appropriate error. 1432aadd06e5SJens Axboe */ 14337c77f0b3SMiklos Szeredi static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1434aadd06e5SJens Axboe { 1435aadd06e5SJens Axboe int ret; 1436aadd06e5SJens Axboe 1437aadd06e5SJens Axboe /* 1438aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1439aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1440aadd06e5SJens Axboe */ 1441aadd06e5SJens Axboe if (pipe->nrbufs) 1442aadd06e5SJens Axboe return 0; 1443aadd06e5SJens Axboe 1444aadd06e5SJens Axboe ret = 0; 144561e0d47cSMiklos Szeredi pipe_lock(pipe); 1446aadd06e5SJens Axboe 1447aadd06e5SJens Axboe while (!pipe->nrbufs) { 1448aadd06e5SJens Axboe if (signal_pending(current)) { 1449aadd06e5SJens Axboe ret = -ERESTARTSYS; 1450aadd06e5SJens Axboe break; 1451aadd06e5SJens Axboe } 1452aadd06e5SJens Axboe if (!pipe->writers) 1453aadd06e5SJens Axboe break; 1454aadd06e5SJens Axboe if (!pipe->waiting_writers) { 1455aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1456aadd06e5SJens Axboe ret = -EAGAIN; 1457aadd06e5SJens Axboe break; 1458aadd06e5SJens Axboe } 1459aadd06e5SJens Axboe } 1460aadd06e5SJens Axboe pipe_wait(pipe); 1461aadd06e5SJens Axboe } 1462aadd06e5SJens Axboe 146361e0d47cSMiklos Szeredi pipe_unlock(pipe); 1464aadd06e5SJens Axboe return ret; 1465aadd06e5SJens Axboe } 1466aadd06e5SJens Axboe 1467aadd06e5SJens Axboe /* 1468aadd06e5SJens Axboe * Make sure there's writeable room. Wait for room if we can, otherwise 1469aadd06e5SJens Axboe * return an appropriate error. 1470aadd06e5SJens Axboe */ 14717c77f0b3SMiklos Szeredi static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) 1472aadd06e5SJens Axboe { 1473aadd06e5SJens Axboe int ret; 1474aadd06e5SJens Axboe 1475aadd06e5SJens Axboe /* 1476aadd06e5SJens Axboe * Check ->nrbufs without the inode lock first. This function 1477aadd06e5SJens Axboe * is speculative anyways, so missing one is ok. 1478aadd06e5SJens Axboe */ 147935f3d14dSJens Axboe if (pipe->nrbufs < pipe->buffers) 1480aadd06e5SJens Axboe return 0; 1481aadd06e5SJens Axboe 1482aadd06e5SJens Axboe ret = 0; 148361e0d47cSMiklos Szeredi pipe_lock(pipe); 1484aadd06e5SJens Axboe 148535f3d14dSJens Axboe while (pipe->nrbufs >= pipe->buffers) { 1486aadd06e5SJens Axboe if (!pipe->readers) { 1487aadd06e5SJens Axboe send_sig(SIGPIPE, current, 0); 1488aadd06e5SJens Axboe ret = -EPIPE; 1489aadd06e5SJens Axboe break; 1490aadd06e5SJens Axboe } 1491aadd06e5SJens Axboe if (flags & SPLICE_F_NONBLOCK) { 1492aadd06e5SJens Axboe ret = -EAGAIN; 1493aadd06e5SJens Axboe break; 1494aadd06e5SJens Axboe } 1495aadd06e5SJens Axboe if (signal_pending(current)) { 1496aadd06e5SJens Axboe ret = -ERESTARTSYS; 1497aadd06e5SJens Axboe break; 1498aadd06e5SJens Axboe } 1499aadd06e5SJens Axboe pipe->waiting_writers++; 1500aadd06e5SJens Axboe pipe_wait(pipe); 1501aadd06e5SJens Axboe pipe->waiting_writers--; 1502aadd06e5SJens Axboe } 1503aadd06e5SJens Axboe 150461e0d47cSMiklos Szeredi pipe_unlock(pipe); 1505aadd06e5SJens Axboe return ret; 1506aadd06e5SJens Axboe } 1507aadd06e5SJens Axboe 1508aadd06e5SJens Axboe /* 15097c77f0b3SMiklos Szeredi * Splice contents of ipipe to opipe. 15107c77f0b3SMiklos Szeredi */ 15117c77f0b3SMiklos Szeredi static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 15127c77f0b3SMiklos Szeredi struct pipe_inode_info *opipe, 15137c77f0b3SMiklos Szeredi size_t len, unsigned int flags) 15147c77f0b3SMiklos Szeredi { 15157c77f0b3SMiklos Szeredi struct pipe_buffer *ibuf, *obuf; 15167c77f0b3SMiklos Szeredi int ret = 0, nbuf; 15177c77f0b3SMiklos Szeredi bool input_wakeup = false; 15187c77f0b3SMiklos Szeredi 15197c77f0b3SMiklos Szeredi 15207c77f0b3SMiklos Szeredi retry: 15217c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 15227c77f0b3SMiklos Szeredi if (ret) 15237c77f0b3SMiklos Szeredi return ret; 15247c77f0b3SMiklos Szeredi 15257c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 15267c77f0b3SMiklos Szeredi if (ret) 15277c77f0b3SMiklos Szeredi return ret; 15287c77f0b3SMiklos Szeredi 15297c77f0b3SMiklos Szeredi /* 15307c77f0b3SMiklos Szeredi * Potential ABBA deadlock, work around it by ordering lock 15317c77f0b3SMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 15327c77f0b3SMiklos Szeredi * could deadlock (one doing tee from A -> B, the other from B -> A). 15337c77f0b3SMiklos Szeredi */ 15347c77f0b3SMiklos Szeredi pipe_double_lock(ipipe, opipe); 15357c77f0b3SMiklos Szeredi 15367c77f0b3SMiklos Szeredi do { 15377c77f0b3SMiklos Szeredi if (!opipe->readers) { 15387c77f0b3SMiklos Szeredi send_sig(SIGPIPE, current, 0); 15397c77f0b3SMiklos Szeredi if (!ret) 15407c77f0b3SMiklos Szeredi ret = -EPIPE; 15417c77f0b3SMiklos Szeredi break; 15427c77f0b3SMiklos Szeredi } 15437c77f0b3SMiklos Szeredi 15447c77f0b3SMiklos Szeredi if (!ipipe->nrbufs && !ipipe->writers) 15457c77f0b3SMiklos Szeredi break; 15467c77f0b3SMiklos Szeredi 15477c77f0b3SMiklos Szeredi /* 15487c77f0b3SMiklos Szeredi * Cannot make any progress, because either the input 15497c77f0b3SMiklos Szeredi * pipe is empty or the output pipe is full. 15507c77f0b3SMiklos Szeredi */ 155135f3d14dSJens Axboe if (!ipipe->nrbufs || opipe->nrbufs >= opipe->buffers) { 15527c77f0b3SMiklos Szeredi /* Already processed some buffers, break */ 15537c77f0b3SMiklos Szeredi if (ret) 15547c77f0b3SMiklos Szeredi break; 15557c77f0b3SMiklos Szeredi 15567c77f0b3SMiklos Szeredi if (flags & SPLICE_F_NONBLOCK) { 15577c77f0b3SMiklos Szeredi ret = -EAGAIN; 15587c77f0b3SMiklos Szeredi break; 15597c77f0b3SMiklos Szeredi } 15607c77f0b3SMiklos Szeredi 15617c77f0b3SMiklos Szeredi /* 15627c77f0b3SMiklos Szeredi * We raced with another reader/writer and haven't 15637c77f0b3SMiklos Szeredi * managed to process any buffers. A zero return 15647c77f0b3SMiklos Szeredi * value means EOF, so retry instead. 15657c77f0b3SMiklos Szeredi */ 15667c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 15677c77f0b3SMiklos Szeredi pipe_unlock(opipe); 15687c77f0b3SMiklos Szeredi goto retry; 15697c77f0b3SMiklos Szeredi } 15707c77f0b3SMiklos Szeredi 15717c77f0b3SMiklos Szeredi ibuf = ipipe->bufs + ipipe->curbuf; 157235f3d14dSJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (opipe->buffers - 1); 15737c77f0b3SMiklos Szeredi obuf = opipe->bufs + nbuf; 15747c77f0b3SMiklos Szeredi 15757c77f0b3SMiklos Szeredi if (len >= ibuf->len) { 15767c77f0b3SMiklos Szeredi /* 15777c77f0b3SMiklos Szeredi * Simply move the whole buffer from ipipe to opipe 15787c77f0b3SMiklos Szeredi */ 15797c77f0b3SMiklos Szeredi *obuf = *ibuf; 15807c77f0b3SMiklos Szeredi ibuf->ops = NULL; 15817c77f0b3SMiklos Szeredi opipe->nrbufs++; 158235f3d14dSJens Axboe ipipe->curbuf = (ipipe->curbuf + 1) & (ipipe->buffers - 1); 15837c77f0b3SMiklos Szeredi ipipe->nrbufs--; 15847c77f0b3SMiklos Szeredi input_wakeup = true; 15857c77f0b3SMiklos Szeredi } else { 15867c77f0b3SMiklos Szeredi /* 15877c77f0b3SMiklos Szeredi * Get a reference to this pipe buffer, 15887c77f0b3SMiklos Szeredi * so we can copy the contents over. 15897c77f0b3SMiklos Szeredi */ 15907bf2d1dfSMiklos Szeredi pipe_buf_get(ipipe, ibuf); 15917c77f0b3SMiklos Szeredi *obuf = *ibuf; 15927c77f0b3SMiklos Szeredi 15937c77f0b3SMiklos Szeredi /* 15947c77f0b3SMiklos Szeredi * Don't inherit the gift flag, we need to 15957c77f0b3SMiklos Szeredi * prevent multiple steals of this page. 15967c77f0b3SMiklos Szeredi */ 15977c77f0b3SMiklos Szeredi obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 15987c77f0b3SMiklos Szeredi 15997c77f0b3SMiklos Szeredi obuf->len = len; 16007c77f0b3SMiklos Szeredi opipe->nrbufs++; 16017c77f0b3SMiklos Szeredi ibuf->offset += obuf->len; 16027c77f0b3SMiklos Szeredi ibuf->len -= obuf->len; 16037c77f0b3SMiklos Szeredi } 16047c77f0b3SMiklos Szeredi ret += obuf->len; 16057c77f0b3SMiklos Szeredi len -= obuf->len; 16067c77f0b3SMiklos Szeredi } while (len); 16077c77f0b3SMiklos Szeredi 16087c77f0b3SMiklos Szeredi pipe_unlock(ipipe); 16097c77f0b3SMiklos Szeredi pipe_unlock(opipe); 16107c77f0b3SMiklos Szeredi 16117c77f0b3SMiklos Szeredi /* 16127c77f0b3SMiklos Szeredi * If we put data in the output pipe, wakeup any potential readers. 16137c77f0b3SMiklos Szeredi */ 1614825cdcb1SNamhyung Kim if (ret > 0) 1615825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 1616825cdcb1SNamhyung Kim 16177c77f0b3SMiklos Szeredi if (input_wakeup) 16187c77f0b3SMiklos Szeredi wakeup_pipe_writers(ipipe); 16197c77f0b3SMiklos Szeredi 16207c77f0b3SMiklos Szeredi return ret; 16217c77f0b3SMiklos Szeredi } 16227c77f0b3SMiklos Szeredi 16237c77f0b3SMiklos Szeredi /* 162470524490SJens Axboe * Link contents of ipipe to opipe. 162570524490SJens Axboe */ 162670524490SJens Axboe static int link_pipe(struct pipe_inode_info *ipipe, 162770524490SJens Axboe struct pipe_inode_info *opipe, 162870524490SJens Axboe size_t len, unsigned int flags) 162970524490SJens Axboe { 163070524490SJens Axboe struct pipe_buffer *ibuf, *obuf; 1631aadd06e5SJens Axboe int ret = 0, i = 0, nbuf; 163270524490SJens Axboe 163370524490SJens Axboe /* 163470524490SJens Axboe * Potential ABBA deadlock, work around it by ordering lock 163561e0d47cSMiklos Szeredi * grabbing by pipe info address. Otherwise two different processes 163670524490SJens Axboe * could deadlock (one doing tee from A -> B, the other from B -> A). 163770524490SJens Axboe */ 163861e0d47cSMiklos Szeredi pipe_double_lock(ipipe, opipe); 163970524490SJens Axboe 1640aadd06e5SJens Axboe do { 164170524490SJens Axboe if (!opipe->readers) { 164270524490SJens Axboe send_sig(SIGPIPE, current, 0); 164370524490SJens Axboe if (!ret) 164470524490SJens Axboe ret = -EPIPE; 164570524490SJens Axboe break; 164670524490SJens Axboe } 164770524490SJens Axboe 164870524490SJens Axboe /* 1649aadd06e5SJens Axboe * If we have iterated all input buffers or ran out of 1650aadd06e5SJens Axboe * output room, break. 165170524490SJens Axboe */ 165235f3d14dSJens Axboe if (i >= ipipe->nrbufs || opipe->nrbufs >= opipe->buffers) 1653aadd06e5SJens Axboe break; 1654aadd06e5SJens Axboe 165535f3d14dSJens Axboe ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (ipipe->buffers-1)); 165635f3d14dSJens Axboe nbuf = (opipe->curbuf + opipe->nrbufs) & (opipe->buffers - 1); 165770524490SJens Axboe 165870524490SJens Axboe /* 165970524490SJens Axboe * Get a reference to this pipe buffer, 166070524490SJens Axboe * so we can copy the contents over. 166170524490SJens Axboe */ 16627bf2d1dfSMiklos Szeredi pipe_buf_get(ipipe, ibuf); 166370524490SJens Axboe 166470524490SJens Axboe obuf = opipe->bufs + nbuf; 166570524490SJens Axboe *obuf = *ibuf; 166670524490SJens Axboe 16677afa6fd0SJens Axboe /* 16687afa6fd0SJens Axboe * Don't inherit the gift flag, we need to 16697afa6fd0SJens Axboe * prevent multiple steals of this page. 16707afa6fd0SJens Axboe */ 16717afa6fd0SJens Axboe obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 16727afa6fd0SJens Axboe 167370524490SJens Axboe if (obuf->len > len) 167470524490SJens Axboe obuf->len = len; 167570524490SJens Axboe 167670524490SJens Axboe opipe->nrbufs++; 167770524490SJens Axboe ret += obuf->len; 167870524490SJens Axboe len -= obuf->len; 1679aadd06e5SJens Axboe i++; 1680aadd06e5SJens Axboe } while (len); 168170524490SJens Axboe 168202cf01aeSJens Axboe /* 168302cf01aeSJens Axboe * return EAGAIN if we have the potential of some data in the 168402cf01aeSJens Axboe * future, otherwise just return 0 168502cf01aeSJens Axboe */ 168602cf01aeSJens Axboe if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK)) 168702cf01aeSJens Axboe ret = -EAGAIN; 168802cf01aeSJens Axboe 168961e0d47cSMiklos Szeredi pipe_unlock(ipipe); 169061e0d47cSMiklos Szeredi pipe_unlock(opipe); 169170524490SJens Axboe 1692aadd06e5SJens Axboe /* 1693aadd06e5SJens Axboe * If we put data in the output pipe, wakeup any potential readers. 1694aadd06e5SJens Axboe */ 1695825cdcb1SNamhyung Kim if (ret > 0) 1696825cdcb1SNamhyung Kim wakeup_pipe_readers(opipe); 169770524490SJens Axboe 169870524490SJens Axboe return ret; 169970524490SJens Axboe } 170070524490SJens Axboe 170170524490SJens Axboe /* 170270524490SJens Axboe * This is a tee(1) implementation that works on pipes. It doesn't copy 170370524490SJens Axboe * any data, it simply references the 'in' pages on the 'out' pipe. 170470524490SJens Axboe * The 'flags' used are the SPLICE_F_* variants, currently the only 170570524490SJens Axboe * applicable one is SPLICE_F_NONBLOCK. 170670524490SJens Axboe */ 170770524490SJens Axboe static long do_tee(struct file *in, struct file *out, size_t len, 170870524490SJens Axboe unsigned int flags) 170970524490SJens Axboe { 171071993e62SLinus Torvalds struct pipe_inode_info *ipipe = get_pipe_info(in); 171171993e62SLinus Torvalds struct pipe_inode_info *opipe = get_pipe_info(out); 1712aadd06e5SJens Axboe int ret = -EINVAL; 171370524490SJens Axboe 171470524490SJens Axboe /* 1715aadd06e5SJens Axboe * Duplicate the contents of ipipe to opipe without actually 1716aadd06e5SJens Axboe * copying the data. 171770524490SJens Axboe */ 1718aadd06e5SJens Axboe if (ipipe && opipe && ipipe != opipe) { 1719aadd06e5SJens Axboe /* 1720aadd06e5SJens Axboe * Keep going, unless we encounter an error. The ipipe/opipe 1721aadd06e5SJens Axboe * ordering doesn't really matter. 1722aadd06e5SJens Axboe */ 17237c77f0b3SMiklos Szeredi ret = ipipe_prep(ipipe, flags); 1724aadd06e5SJens Axboe if (!ret) { 17257c77f0b3SMiklos Szeredi ret = opipe_prep(opipe, flags); 172602cf01aeSJens Axboe if (!ret) 1727aadd06e5SJens Axboe ret = link_pipe(ipipe, opipe, len, flags); 1728aadd06e5SJens Axboe } 1729aadd06e5SJens Axboe } 173070524490SJens Axboe 1731aadd06e5SJens Axboe return ret; 173270524490SJens Axboe } 173370524490SJens Axboe 1734836f92adSHeiko Carstens SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) 173570524490SJens Axboe { 17362903ff01SAl Viro struct fd in; 17372903ff01SAl Viro int error; 173870524490SJens Axboe 17393d6ea290SAl Viro if (unlikely(flags & ~SPLICE_F_ALL)) 17403d6ea290SAl Viro return -EINVAL; 17413d6ea290SAl Viro 174270524490SJens Axboe if (unlikely(!len)) 174370524490SJens Axboe return 0; 174470524490SJens Axboe 174570524490SJens Axboe error = -EBADF; 17462903ff01SAl Viro in = fdget(fdin); 17472903ff01SAl Viro if (in.file) { 17482903ff01SAl Viro if (in.file->f_mode & FMODE_READ) { 17492903ff01SAl Viro struct fd out = fdget(fdout); 17502903ff01SAl Viro if (out.file) { 17512903ff01SAl Viro if (out.file->f_mode & FMODE_WRITE) 17522903ff01SAl Viro error = do_tee(in.file, out.file, 17532903ff01SAl Viro len, flags); 17542903ff01SAl Viro fdput(out); 175570524490SJens Axboe } 175670524490SJens Axboe } 17572903ff01SAl Viro fdput(in); 175870524490SJens Axboe } 175970524490SJens Axboe 176070524490SJens Axboe return error; 176170524490SJens Axboe } 1762