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@@ -27,15 +27,22 @@
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#include <linux/buffer_head.h>
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#include <linux/module.h>
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#include <linux/syscalls.h>
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+#include <linux/uio.h>
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+
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+struct partial_page {
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+ unsigned int offset;
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+ unsigned int len;
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+};
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/*
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- * Passed to the actors
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+ * Passed to splice_to_pipe
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*/
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-struct splice_desc {
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- unsigned int len, total_len; /* current and remaining length */
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+struct splice_pipe_desc {
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+ struct page **pages; /* page map */
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+ struct partial_page *partial; /* pages[] may not be contig */
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+ int nr_pages; /* number of pages in map */
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unsigned int flags; /* splice flags */
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- struct file *file; /* file to read/write */
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- loff_t pos; /* file position */
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+ struct pipe_buf_operations *ops;/* ops associated with output pipe */
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};
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/*
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@@ -128,6 +135,19 @@ static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info,
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kunmap(buf->page);
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}
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+static void *user_page_pipe_buf_map(struct file *file,
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+ struct pipe_inode_info *pipe,
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+ struct pipe_buffer *buf)
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+{
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+ return kmap(buf->page);
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+}
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+
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+static void user_page_pipe_buf_unmap(struct pipe_inode_info *pipe,
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+ struct pipe_buffer *buf)
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+{
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+ kunmap(buf->page);
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+}
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+
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static void page_cache_pipe_buf_get(struct pipe_inode_info *info,
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struct pipe_buffer *buf)
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{
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@@ -143,19 +163,33 @@ static struct pipe_buf_operations page_cache_pipe_buf_ops = {
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.get = page_cache_pipe_buf_get,
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};
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+static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
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+ struct pipe_buffer *buf)
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+{
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+ return 1;
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+}
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+
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+static struct pipe_buf_operations user_page_pipe_buf_ops = {
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+ .can_merge = 0,
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+ .map = user_page_pipe_buf_map,
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+ .unmap = user_page_pipe_buf_unmap,
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+ .release = page_cache_pipe_buf_release,
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+ .steal = user_page_pipe_buf_steal,
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+ .get = page_cache_pipe_buf_get,
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+};
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+
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/*
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* Pipe output worker. This sets up our pipe format with the page cache
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* pipe buffer operations. Otherwise very similar to the regular pipe_writev().
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*/
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-static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages,
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- int nr_pages, unsigned long len,
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- unsigned int offset, unsigned int flags)
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+static ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
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+ struct splice_pipe_desc *spd)
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{
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- int ret, do_wakeup, i;
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+ int ret, do_wakeup, page_nr;
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ret = 0;
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do_wakeup = 0;
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- i = 0;
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+ page_nr = 0;
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if (pipe->inode)
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mutex_lock(&pipe->inode->i_mutex);
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@@ -171,27 +205,19 @@ static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages,
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if (pipe->nrbufs < PIPE_BUFFERS) {
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int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1);
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struct pipe_buffer *buf = pipe->bufs + newbuf;
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- struct page *page = pages[i++];
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- unsigned long this_len;
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- this_len = PAGE_CACHE_SIZE - offset;
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- if (this_len > len)
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- this_len = len;
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-
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- buf->page = page;
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- buf->offset = offset;
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- buf->len = this_len;
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- buf->ops = &page_cache_pipe_buf_ops;
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+ buf->page = spd->pages[page_nr];
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+ buf->offset = spd->partial[page_nr].offset;
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+ buf->len = spd->partial[page_nr].len;
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+ buf->ops = spd->ops;
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pipe->nrbufs++;
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+ page_nr++;
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+ ret += buf->len;
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+
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if (pipe->inode)
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do_wakeup = 1;
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- ret += this_len;
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- len -= this_len;
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- offset = 0;
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- if (!--nr_pages)
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- break;
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- if (!len)
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+ if (!--spd->nr_pages)
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break;
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if (pipe->nrbufs < PIPE_BUFFERS)
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continue;
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@@ -199,7 +225,7 @@ static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages,
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break;
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}
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- if (flags & SPLICE_F_NONBLOCK) {
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+ if (spd->flags & SPLICE_F_NONBLOCK) {
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if (!ret)
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ret = -EAGAIN;
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break;
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@@ -234,8 +260,8 @@ static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages,
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kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
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}
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- while (i < nr_pages)
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- page_cache_release(pages[i++]);
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+ while (page_nr < spd->nr_pages)
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+ page_cache_release(spd->pages[page_nr++]);
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return ret;
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}
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@@ -246,17 +272,24 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
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unsigned int flags)
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{
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struct address_space *mapping = in->f_mapping;
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- unsigned int loff, offset, nr_pages;
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+ unsigned int loff, nr_pages;
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struct page *pages[PIPE_BUFFERS];
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+ struct partial_page partial[PIPE_BUFFERS];
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struct page *page;
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pgoff_t index, end_index;
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loff_t isize;
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- size_t bytes;
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- int i, error;
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+ size_t total_len;
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+ int error;
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+ struct splice_pipe_desc spd = {
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+ .pages = pages,
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+ .partial = partial,
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+ .flags = flags,
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+ .ops = &page_cache_pipe_buf_ops,
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+ };
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index = *ppos >> PAGE_CACHE_SHIFT;
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- loff = offset = *ppos & ~PAGE_CACHE_MASK;
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- nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
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+ loff = *ppos & ~PAGE_CACHE_MASK;
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+ nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
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if (nr_pages > PIPE_BUFFERS)
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nr_pages = PIPE_BUFFERS;
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@@ -266,15 +299,15 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
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* read-ahead if this is a non-zero offset (we are likely doing small
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* chunk splice and the page is already there) for a single page.
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*/
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- if (!offset || nr_pages > 1)
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- do_page_cache_readahead(mapping, in, index, nr_pages);
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+ if (!loff || spd.nr_pages > 1)
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+ do_page_cache_readahead(mapping, in, index, spd.nr_pages);
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/*
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* Now fill in the holes:
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*/
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error = 0;
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- bytes = 0;
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- for (i = 0; i < nr_pages; i++, index++) {
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+ total_len = 0;
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+ for (spd.nr_pages = 0; spd.nr_pages < nr_pages; spd.nr_pages++, index++) {
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unsigned int this_len;
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if (!len)
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@@ -283,7 +316,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
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/*
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* this_len is the max we'll use from this page
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*/
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- this_len = min(len, PAGE_CACHE_SIZE - loff);
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+ this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
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find_page:
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/*
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* lookup the page for this index
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@@ -367,26 +400,29 @@ readpage:
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*/
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if (end_index == index) {
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loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK);
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- if (bytes + loff > isize) {
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+ if (total_len + loff > isize) {
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page_cache_release(page);
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break;
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}
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/*
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* force quit after adding this page
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*/
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- nr_pages = i;
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+ nr_pages = spd.nr_pages;
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this_len = min(this_len, loff);
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+ loff = 0;
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}
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}
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fill_it:
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- pages[i] = page;
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- bytes += this_len;
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+ pages[spd.nr_pages] = page;
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+ partial[spd.nr_pages].offset = loff;
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+ partial[spd.nr_pages].len = this_len;
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len -= this_len;
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+ total_len += this_len;
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loff = 0;
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}
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- if (i)
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- return move_to_pipe(pipe, pages, i, bytes, offset, flags);
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+ if (spd.nr_pages)
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+ return splice_to_pipe(pipe, &spd);
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return error;
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}
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@@ -439,14 +475,13 @@ EXPORT_SYMBOL(generic_file_splice_read);
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/*
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* Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'
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- * using sendpage().
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+ * using sendpage(). Return the number of bytes sent.
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*/
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static int pipe_to_sendpage(struct pipe_inode_info *info,
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struct pipe_buffer *buf, struct splice_desc *sd)
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{
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struct file *file = sd->file;
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loff_t pos = sd->pos;
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- unsigned int offset;
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ssize_t ret;
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void *ptr;
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int more;
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@@ -461,16 +496,13 @@ static int pipe_to_sendpage(struct pipe_inode_info *info,
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if (IS_ERR(ptr))
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return PTR_ERR(ptr);
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- offset = pos & ~PAGE_CACHE_MASK;
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more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
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- ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos,more);
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+ ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len,
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+ &pos, more);
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buf->ops->unmap(info, buf);
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- if (ret == sd->len)
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- return 0;
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-
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- return -EIO;
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+ return ret;
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}
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/*
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@@ -499,7 +531,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
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struct file *file = sd->file;
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struct address_space *mapping = file->f_mapping;
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gfp_t gfp_mask = mapping_gfp_mask(mapping);
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- unsigned int offset;
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+ unsigned int offset, this_len;
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struct page *page;
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pgoff_t index;
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char *src;
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@@ -515,6 +547,10 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
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index = sd->pos >> PAGE_CACHE_SHIFT;
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offset = sd->pos & ~PAGE_CACHE_MASK;
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+ this_len = sd->len;
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+ if (this_len + offset > PAGE_CACHE_SIZE)
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+ this_len = PAGE_CACHE_SIZE - offset;
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+
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/*
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* Reuse buf page, if SPLICE_F_MOVE is set.
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*/
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@@ -558,7 +594,7 @@ find_page:
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* the full page.
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*/
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if (!PageUptodate(page)) {
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- if (sd->len < PAGE_CACHE_SIZE) {
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+ if (this_len < PAGE_CACHE_SIZE) {
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ret = mapping->a_ops->readpage(file, page);
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if (unlikely(ret))
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goto out;
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@@ -582,7 +618,7 @@ find_page:
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}
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}
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- ret = mapping->a_ops->prepare_write(file, page, 0, sd->len);
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+ ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);
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if (ret == AOP_TRUNCATED_PAGE) {
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page_cache_release(page);
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goto find_page;
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@@ -592,18 +628,22 @@ find_page:
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if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) {
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char *dst = kmap_atomic(page, KM_USER0);
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- memcpy(dst + offset, src + buf->offset, sd->len);
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+ memcpy(dst + offset, src + buf->offset, this_len);
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flush_dcache_page(page);
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kunmap_atomic(dst, KM_USER0);
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}
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- ret = mapping->a_ops->commit_write(file, page, 0, sd->len);
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+ ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
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if (ret == AOP_TRUNCATED_PAGE) {
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page_cache_release(page);
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goto find_page;
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} else if (ret)
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goto out;
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+ /*
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+ * Return the number of bytes written.
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+ */
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+ ret = this_len;
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mark_page_accessed(page);
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balance_dirty_pages_ratelimited(mapping);
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out:
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@@ -616,17 +656,14 @@ out_nomem:
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return ret;
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}
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-typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
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- struct splice_desc *);
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-
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/*
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* Pipe input worker. Most of this logic works like a regular pipe, the
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* key here is the 'actor' worker passed in that actually moves the data
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* to the wanted destination. See pipe_to_file/pipe_to_sendpage above.
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*/
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-static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
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- loff_t *ppos, size_t len, unsigned int flags,
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- splice_actor *actor)
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+ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
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+ loff_t *ppos, size_t len, unsigned int flags,
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+ splice_actor *actor)
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{
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int ret, do_wakeup, err;
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struct splice_desc sd;
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@@ -652,16 +689,22 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
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sd.len = sd.total_len;
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err = actor(pipe, buf, &sd);
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- if (err) {
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+ if (err <= 0) {
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if (!ret && err != -ENODATA)
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ret = err;
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break;
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}
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- ret += sd.len;
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- buf->offset += sd.len;
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- buf->len -= sd.len;
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+ ret += err;
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+ buf->offset += err;
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+ buf->len -= err;
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+
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+ sd.len -= err;
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+ sd.pos += err;
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+ sd.total_len -= err;
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+ if (sd.len)
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+ continue;
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if (!buf->len) {
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buf->ops = NULL;
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@@ -672,8 +715,6 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
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do_wakeup = 1;
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}
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- sd.pos += sd.len;
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- sd.total_len -= sd.len;
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if (!sd.total_len)
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break;
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}
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@@ -741,7 +782,7 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
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struct address_space *mapping = out->f_mapping;
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ssize_t ret;
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- ret = move_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
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+ ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
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if (ret > 0) {
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struct inode *inode = mapping->host;
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@@ -783,7 +824,7 @@ EXPORT_SYMBOL(generic_file_splice_write);
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ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out,
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loff_t *ppos, size_t len, unsigned int flags)
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{
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|
|
- return move_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage);
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|
|
+ return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage);
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|
|
}
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|
|
|
|
|
EXPORT_SYMBOL(generic_splice_sendpage);
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|
|
@@ -870,7 +911,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
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|
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/*
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* We don't have an immediate reader, but we'll read the stuff
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|
- * out of the pipe right after the move_to_pipe(). So set
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|
+ * out of the pipe right after the splice_to_pipe(). So set
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* PIPE_READERS appropriately.
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|
*/
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|
pipe->readers = 1;
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|
@@ -1010,6 +1051,174 @@ static long do_splice(struct file *in, loff_t __user *off_in,
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|
return -EINVAL;
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|
}
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|
|
|
|
|
+/*
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|
|
+ * Map an iov into an array of pages and offset/length tupples. With the
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|
|
+ * partial_page structure, we can map several non-contiguous ranges into
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|
+ * our ones pages[] map instead of splitting that operation into pieces.
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|
+ * Could easily be exported as a generic helper for other users, in which
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|
+ * case one would probably want to add a 'max_nr_pages' parameter as well.
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|
|
+ */
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|
|
+static int get_iovec_page_array(const struct iovec __user *iov,
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|
|
+ unsigned int nr_vecs, struct page **pages,
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|
|
+ struct partial_page *partial)
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|
|
+{
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|
|
+ int buffers = 0, error = 0;
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|
+
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|
|
+ /*
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|
|
+ * It's ok to take the mmap_sem for reading, even
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|
+ * across a "get_user()".
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|
|
+ */
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|
|
+ down_read(¤t->mm->mmap_sem);
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|
+
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|
|
+ while (nr_vecs) {
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|
|
+ unsigned long off, npages;
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|
|
+ void __user *base;
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|
|
+ size_t len;
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|
|
+ int i;
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|
|
+
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|
|
+ /*
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|
|
+ * Get user address base and length for this iovec.
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|
|
+ */
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|
|
+ error = get_user(base, &iov->iov_base);
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|
|
+ if (unlikely(error))
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|
|
+ break;
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|
|
+ error = get_user(len, &iov->iov_len);
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|
|
+ if (unlikely(error))
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|
|
+ break;
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|
|
+
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|
|
+ /*
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|
|
+ * Sanity check this iovec. 0 read succeeds.
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|
|
+ */
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|
|
+ if (unlikely(!len))
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|
|
+ break;
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|
|
+ error = -EFAULT;
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|
|
+ if (unlikely(!base))
|
|
|
+ break;
|
|
|
+
|
|
|
+ /*
|
|
|
+ * Get this base offset and number of pages, then map
|
|
|
+ * in the user pages.
|
|
|
+ */
|
|
|
+ off = (unsigned long) base & ~PAGE_MASK;
|
|
|
+ npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
|
+ if (npages > PIPE_BUFFERS - buffers)
|
|
|
+ npages = PIPE_BUFFERS - buffers;
|
|
|
+
|
|
|
+ error = get_user_pages(current, current->mm,
|
|
|
+ (unsigned long) base, npages, 0, 0,
|
|
|
+ &pages[buffers], NULL);
|
|
|
+
|
|
|
+ if (unlikely(error <= 0))
|
|
|
+ break;
|
|
|
+
|
|
|
+ /*
|
|
|
+ * Fill this contiguous range into the partial page map.
|
|
|
+ */
|
|
|
+ for (i = 0; i < error; i++) {
|
|
|
+ const int plen = min_t(size_t, len, PAGE_SIZE) - off;
|
|
|
+
|
|
|
+ partial[buffers].offset = off;
|
|
|
+ partial[buffers].len = plen;
|
|
|
+
|
|
|
+ off = 0;
|
|
|
+ len -= plen;
|
|
|
+ buffers++;
|
|
|
+ }
|
|
|
+
|
|
|
+ /*
|
|
|
+ * We didn't complete this iov, stop here since it probably
|
|
|
+ * means we have to move some of this into a pipe to
|
|
|
+ * be able to continue.
|
|
|
+ */
|
|
|
+ if (len)
|
|
|
+ break;
|
|
|
+
|
|
|
+ /*
|
|
|
+ * Don't continue if we mapped fewer pages than we asked for,
|
|
|
+ * or if we mapped the max number of pages that we have
|
|
|
+ * room for.
|
|
|
+ */
|
|
|
+ if (error < npages || buffers == PIPE_BUFFERS)
|
|
|
+ break;
|
|
|
+
|
|
|
+ nr_vecs--;
|
|
|
+ iov++;
|
|
|
+ }
|
|
|
+
|
|
|
+ up_read(¤t->mm->mmap_sem);
|
|
|
+
|
|
|
+ if (buffers)
|
|
|
+ return buffers;
|
|
|
+
|
|
|
+ return error;
|
|
|
+}
|
|
|
+
|
|
|
+/*
|
|
|
+ * vmsplice splices a user address range into a pipe. It can be thought of
|
|
|
+ * as splice-from-memory, where the regular splice is splice-from-file (or
|
|
|
+ * to file). In both cases the output is a pipe, naturally.
|
|
|
+ *
|
|
|
+ * Note that vmsplice only supports splicing _from_ user memory to a pipe,
|
|
|
+ * not the other way around. Splicing from user memory is a simple operation
|
|
|
+ * that can be supported without any funky alignment restrictions or nasty
|
|
|
+ * vm tricks. We simply map in the user memory and fill them into a pipe.
|
|
|
+ * The reverse isn't quite as easy, though. There are two possible solutions
|
|
|
+ * for that:
|
|
|
+ *
|
|
|
+ * - memcpy() the data internally, at which point we might as well just
|
|
|
+ * do a regular read() on the buffer anyway.
|
|
|
+ * - Lots of nasty vm tricks, that are neither fast nor flexible (it
|
|
|
+ * has restriction limitations on both ends of the pipe).
|
|
|
+ *
|
|
|
+ * Alas, it isn't here.
|
|
|
+ *
|
|
|
+ */
|
|
|
+static long do_vmsplice(struct file *file, const struct iovec __user *iov,
|
|
|
+ unsigned long nr_segs, unsigned int flags)
|
|
|
+{
|
|
|
+ struct pipe_inode_info *pipe = file->f_dentry->d_inode->i_pipe;
|
|
|
+ struct page *pages[PIPE_BUFFERS];
|
|
|
+ struct partial_page partial[PIPE_BUFFERS];
|
|
|
+ struct splice_pipe_desc spd = {
|
|
|
+ .pages = pages,
|
|
|
+ .partial = partial,
|
|
|
+ .flags = flags,
|
|
|
+ .ops = &user_page_pipe_buf_ops,
|
|
|
+ };
|
|
|
+
|
|
|
+ if (unlikely(!pipe))
|
|
|
+ return -EBADF;
|
|
|
+ if (unlikely(nr_segs > UIO_MAXIOV))
|
|
|
+ return -EINVAL;
|
|
|
+ else if (unlikely(!nr_segs))
|
|
|
+ return 0;
|
|
|
+
|
|
|
+ spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial);
|
|
|
+ if (spd.nr_pages <= 0)
|
|
|
+ return spd.nr_pages;
|
|
|
+
|
|
|
+ return splice_to_pipe(pipe, &spd);
|
|
|
+}
|
|
|
+
|
|
|
+asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov,
|
|
|
+ unsigned long nr_segs, unsigned int flags)
|
|
|
+{
|
|
|
+ struct file *file;
|
|
|
+ long error;
|
|
|
+ int fput;
|
|
|
+
|
|
|
+ error = -EBADF;
|
|
|
+ file = fget_light(fd, &fput);
|
|
|
+ if (file) {
|
|
|
+ if (file->f_mode & FMODE_WRITE)
|
|
|
+ error = do_vmsplice(file, iov, nr_segs, flags);
|
|
|
+
|
|
|
+ fput_light(file, fput);
|
|
|
+ }
|
|
|
+
|
|
|
+ return error;
|
|
|
+}
|
|
|
+
|
|
|
asmlinkage long sys_splice(int fd_in, loff_t __user *off_in,
|
|
|
int fd_out, loff_t __user *off_out,
|
|
|
size_t len, unsigned int flags)
|
Jeff Garzik