diff options
Diffstat (limited to 'fs/splice.c')
| -rw-r--r-- | fs/splice.c | 201 |
1 files changed, 107 insertions, 94 deletions
diff --git a/fs/splice.c b/fs/splice.c index 9bc07d2b53c..f5cb9ba8451 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -32,6 +32,7 @@ #include <linux/gfp.h> #include <linux/socket.h> #include <linux/compat.h> +#include <linux/aio.h> #include "internal.h" /* @@ -717,63 +718,6 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe, sd->len, &pos, more); } -/* - * This is a little more tricky than the file -> pipe splicing. There are - * basically three cases: - * - * - Destination page already exists in the address space and there - * are users of it. For that case we have no other option that - * copying the data. Tough luck. - * - Destination page already exists in the address space, but there - * are no users of it. Make sure it's uptodate, then drop it. Fall - * through to last case. - * - Destination page does not exist, we can add the pipe page to - * the page cache and avoid the copy. - * - * If asked to move pages to the output file (SPLICE_F_MOVE is set in - * sd->flags), we attempt to migrate pages from the pipe to the output - * file address space page cache. This is possible if no one else has - * the pipe page referenced outside of the pipe and page cache. If - * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create - * a new page in the output file page cache and fill/dirty that. - */ -int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf, - struct splice_desc *sd) -{ - struct file *file = sd->u.file; - struct address_space *mapping = file->f_mapping; - unsigned int offset, this_len; - struct page *page; - void *fsdata; - int ret; - - offset = sd->pos & ~PAGE_CACHE_MASK; - - this_len = sd->len; - if (this_len + offset > PAGE_CACHE_SIZE) - this_len = PAGE_CACHE_SIZE - offset; - - ret = pagecache_write_begin(file, mapping, sd->pos, this_len, - AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); - if (unlikely(ret)) - goto out; - - if (buf->page != page) { - char *src = kmap_atomic(buf->page); - char *dst = kmap_atomic(page); - - memcpy(dst + offset, src + buf->offset, this_len); - flush_dcache_page(page); - kunmap_atomic(dst); - kunmap_atomic(src); - } - ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, - page, fsdata); -out: - return ret; -} -EXPORT_SYMBOL(pipe_to_file); - static void wakeup_pipe_writers(struct pipe_inode_info *pipe) { smp_mb(); @@ -802,7 +746,7 @@ static void wakeup_pipe_writers(struct pipe_inode_info *pipe) * locking is required around copying the pipe buffers to the * destination. */ -int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, +static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, splice_actor *actor) { int ret; @@ -849,7 +793,6 @@ int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, return 1; } -EXPORT_SYMBOL(splice_from_pipe_feed); /** * splice_from_pipe_next - wait for some data to splice from @@ -861,7 +804,7 @@ EXPORT_SYMBOL(splice_from_pipe_feed); * value (one) if pipe buffers are available. It will return zero * or -errno if no more data needs to be spliced. */ -int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) +static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) { while (!pipe->nrbufs) { if (!pipe->writers) @@ -886,7 +829,6 @@ int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) return 1; } -EXPORT_SYMBOL(splice_from_pipe_next); /** * splice_from_pipe_begin - start splicing from pipe @@ -897,12 +839,11 @@ EXPORT_SYMBOL(splice_from_pipe_next); * splice_from_pipe_next() and splice_from_pipe_feed() to * initialize the necessary fields of @sd. */ -void splice_from_pipe_begin(struct splice_desc *sd) +static void splice_from_pipe_begin(struct splice_desc *sd) { sd->num_spliced = 0; sd->need_wakeup = false; } -EXPORT_SYMBOL(splice_from_pipe_begin); /** * splice_from_pipe_end - finish splicing from pipe @@ -914,12 +855,11 @@ EXPORT_SYMBOL(splice_from_pipe_begin); * be called after a loop containing splice_from_pipe_next() and * splice_from_pipe_feed(). */ -void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) +static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) { if (sd->need_wakeup) wakeup_pipe_writers(pipe); } -EXPORT_SYMBOL(splice_from_pipe_end); /** * __splice_from_pipe - splice data from a pipe to given actor @@ -985,7 +925,7 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, } /** - * generic_file_splice_write - splice data from a pipe to a file + * iter_file_splice_write - splice data from a pipe to a file * @pipe: pipe info * @out: file to write to * @ppos: position in @out @@ -995,40 +935,122 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, * Description: * Will either move or copy pages (determined by @flags options) from * the given pipe inode to the given file. + * This one is ->write_iter-based. * */ ssize_t -generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, +iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, loff_t *ppos, size_t len, unsigned int flags) { - struct address_space *mapping = out->f_mapping; - struct inode *inode = mapping->host; struct splice_desc sd = { .total_len = len, .flags = flags, .pos = *ppos, .u.file = out, }; + int nbufs = pipe->buffers; + struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec), + GFP_KERNEL); ssize_t ret; + if (unlikely(!array)) + return -ENOMEM; + pipe_lock(pipe); splice_from_pipe_begin(&sd); - do { + while (sd.total_len) { + struct iov_iter from; + struct kiocb kiocb; + size_t left; + int n, idx; + ret = splice_from_pipe_next(pipe, &sd); if (ret <= 0) break; - mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD); - ret = file_remove_suid(out); - if (!ret) { - ret = file_update_time(out); - if (!ret) - ret = splice_from_pipe_feed(pipe, &sd, - pipe_to_file); + if (unlikely(nbufs < pipe->buffers)) { + kfree(array); + nbufs = pipe->buffers; + array = kcalloc(nbufs, sizeof(struct bio_vec), + GFP_KERNEL); + if (!array) { + ret = -ENOMEM; + break; + } } - mutex_unlock(&inode->i_mutex); - } while (ret > 0); + + /* build the vector */ + left = sd.total_len; + for (n = 0, idx = pipe->curbuf; left && n < pipe->nrbufs; n++, idx++) { + struct pipe_buffer *buf = pipe->bufs + idx; + size_t this_len = buf->len; + + if (this_len > left) + this_len = left; + + if (idx == pipe->buffers - 1) + idx = -1; + + ret = buf->ops->confirm(pipe, buf); + if (unlikely(ret)) { + if (ret == -ENODATA) + ret = 0; + goto done; + } + + array[n].bv_page = buf->page; + array[n].bv_len = this_len; + array[n].bv_offset = buf->offset; + left -= this_len; + } + + /* ... iov_iter */ + from.type = ITER_BVEC | WRITE; + from.bvec = array; + from.nr_segs = n; + from.count = sd.total_len - left; + from.iov_offset = 0; + + /* ... and iocb */ + init_sync_kiocb(&kiocb, out); + kiocb.ki_pos = sd.pos; + kiocb.ki_nbytes = sd.total_len - left; + + /* now, send it */ + ret = out->f_op->write_iter(&kiocb, &from); + if (-EIOCBQUEUED == ret) + ret = wait_on_sync_kiocb(&kiocb); + + if (ret <= 0) + break; + + sd.num_spliced += ret; + sd.total_len -= ret; + *ppos = sd.pos = kiocb.ki_pos; + + /* dismiss the fully eaten buffers, adjust the partial one */ + while (ret) { + struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; + if (ret >= buf->len) { + const struct pipe_buf_operations *ops = buf->ops; + ret -= buf->len; + buf->len = 0; + buf->ops = NULL; + ops->release(pipe, buf); + pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); + pipe->nrbufs--; + if (pipe->files) + sd.need_wakeup = true; + } else { + buf->offset += ret; + buf->len -= ret; + ret = 0; + } + } + } +done: + kfree(array); splice_from_pipe_end(pipe, &sd); pipe_unlock(pipe); @@ -1036,21 +1058,10 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, if (sd.num_spliced) ret = sd.num_spliced; - if (ret > 0) { - int err; - - err = generic_write_sync(out, *ppos, ret); - if (err) - ret = err; - else - *ppos += ret; - balance_dirty_pages_ratelimited(mapping); - } - return ret; } -EXPORT_SYMBOL(generic_file_splice_write); +EXPORT_SYMBOL(iter_file_splice_write); static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf, struct splice_desc *sd) @@ -1537,7 +1548,7 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov, struct iovec iovstack[UIO_FASTIOV]; struct iovec *iov = iovstack; struct iov_iter iter; - ssize_t count = 0; + ssize_t count; pipe = get_pipe_info(file); if (!pipe) @@ -1546,9 +1557,10 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov, ret = rw_copy_check_uvector(READ, uiov, nr_segs, ARRAY_SIZE(iovstack), iovstack, &iov); if (ret <= 0) - return ret; + goto out; - iov_iter_init(&iter, iov, nr_segs, count, 0); + count = ret; + iov_iter_init(&iter, READ, iov, nr_segs, count); sd.len = 0; sd.total_len = count; @@ -1560,6 +1572,7 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov, ret = __splice_from_pipe(pipe, &sd, pipe_to_user); pipe_unlock(pipe); +out: if (iov != iovstack) kfree(iov); |