we only use iov_iter_get_pages_alloc() and iov_iter_advance() -
pages are filled by kernel_readv() via a kvec array (as we used
to do all along), so iov_iter here is used only as a way of
arranging for those pages to be in pipe.
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/splice.c | 111 ++++++++++++++++++++++--------------------------------------
1 file changed, 40 insertions(+), 71 deletions(-)
diff --git a/fs/splice.c b/fs/splice.c
index 58c322a..0df907b 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -361,7 +361,7 @@ const struct pipe_buf_operations nosteal_pipe_buf_ops = {
};
EXPORT_SYMBOL(nosteal_pipe_buf_ops);
-static ssize_t kernel_readv(struct file *file, const struct iovec *vec,
+static ssize_t kernel_readv(struct file *file, const struct kvec *vec,
unsigned long vlen, loff_t offset)
{
mm_segment_t old_fs;
@@ -397,96 +397,65 @@ static ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
+ struct kvec *vec, __vec[PIPE_DEF_BUFFERS];
+ struct iov_iter to;
+ struct page **pages;
unsigned int nr_pages;
- unsigned int nr_freed;
- size_t offset;
- struct page *pages[PIPE_DEF_BUFFERS];
- struct partial_page partial[PIPE_DEF_BUFFERS];
- struct iovec *vec, __vec[PIPE_DEF_BUFFERS];
+ size_t offset, dummy, copied = 0;
ssize_t res;
- size_t this_len;
- int error;
int i;
- struct splice_pipe_desc spd = {
- .pages = pages,
- .partial = partial,
- .nr_pages_max = PIPE_DEF_BUFFERS,
- .flags = flags,
- .ops = &default_pipe_buf_ops,
- .spd_release = spd_release_page,
- };
- if (splice_grow_spd(pipe, &spd))
+ if (pipe->nrbufs == pipe->buffers)
+ return -EAGAIN;
+
+ /*
+ * Try to keep page boundaries matching to source pagecache ones -
+ * it probably won't be much help, but...
+ */
+ offset = *ppos & ~PAGE_MASK;
+
+ iov_iter_pipe(&to, ITER_PIPE | READ, pipe, len + offset);
+
+ res = iov_iter_get_pages_alloc(&to, &pages, len + offset, &dummy);
+ if (res <= 0)
return -ENOMEM;
- res = -ENOMEM;
+ nr_pages = res / PAGE_SIZE;
+
vec = __vec;
- if (spd.nr_pages_max > PIPE_DEF_BUFFERS) {
- vec = kmalloc(spd.nr_pages_max * sizeof(struct iovec), GFP_KERNEL);
- if (!vec)
- goto shrink_ret;
+ if (nr_pages > PIPE_DEF_BUFFERS) {
+ vec = kmalloc(nr_pages * sizeof(struct kvec), GFP_KERNEL);
+ if (unlikely(!vec)) {
+ res = -ENOMEM;
+ goto out;
+ }
}
- offset = *ppos & ~PAGE_MASK;
- nr_pages = (len + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
-
- for (i = 0; i < nr_pages && i < spd.nr_pages_max && len; i++) {
- struct page *page;
-
- page = alloc_page(GFP_USER);
- error = -ENOMEM;
- if (!page)
- goto err;
+ pipe->bufs[to.idx].offset = offset;
+ pipe->bufs[to.idx].len -= offset;
- this_len = min_t(size_t, len, PAGE_SIZE - offset);
- vec[i].iov_base = (void __user *) page_address(page);
+ for (i = 0; i < nr_pages; i++) {
+ size_t this_len = min_t(size_t, len, PAGE_SIZE - offset);
+ vec[i].iov_base = page_address(pages[i]) + offset;
vec[i].iov_len = this_len;
- spd.pages[i] = page;
- spd.nr_pages++;
len -= this_len;
offset = 0;
}
- res = kernel_readv(in, vec, spd.nr_pages, *ppos);
- if (res < 0) {
- error = res;
- goto err;
- }
-
- error = 0;
- if (!res)
- goto err;
-
- nr_freed = 0;
- for (i = 0; i < spd.nr_pages; i++) {
- this_len = min_t(size_t, vec[i].iov_len, res);
- spd.partial[i].offset = 0;
- spd.partial[i].len = this_len;
- if (!this_len) {
- __free_page(spd.pages[i]);
- spd.pages[i] = NULL;
- nr_freed++;
- }
- res -= this_len;
- }
- spd.nr_pages -= nr_freed;
-
- res = splice_to_pipe(pipe, &spd);
- if (res > 0)
+ res = kernel_readv(in, vec, nr_pages, *ppos);
+ if (res > 0) {
+ copied = res;
*ppos += res;
+ }
-shrink_ret:
if (vec != __vec)
kfree(vec);
- splice_shrink_spd(&spd);
+out:
+ for (i = 0; i < nr_pages; i++)
+ put_page(pages[i]);
+ kvfree(pages);
+ iov_iter_advance(&to, copied); /* truncates and discards */
return res;
-
-err:
- for (i = 0; i < spd.nr_pages; i++)
- __free_page(spd.pages[i]);
-
- res = error;
- goto shrink_ret;
}
/*
--
2.9.3
--
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