| Message ID | 3113838.1676468540@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | splice: Clean up direct_splice_read() a bit | expand |
I forgot to commit the cast change too. Try the attached instead.
David
---
splice: Clean up direct_splice_read() a bit
Do a couple of cleanups to direct_splice_read():
(1) Cast to struct page **, not void *.
(2) Simplify the calculation of the number of pages to keep/reclaim in
direct_splice_read().
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---
diff --git a/fs/splice.c b/fs/splice.c
index 9e798c901087..e97f9aa30717 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -295,7 +295,7 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos,
struct kiocb kiocb;
struct page **pages;
ssize_t ret;
- size_t used, npages, chunk, remain, reclaim;
+ size_t used, npages, chunk, remain, keep = 0;
int i;
/* Work out how much data we can actually add into the pipe */
@@ -309,7 +309,7 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos,
if (!bv)
return -ENOMEM;
- pages = (void *)(bv + npages);
+ pages = (struct page **)(bv + npages);
npages = alloc_pages_bulk_array(GFP_USER, npages, pages);
if (!npages) {
kfree(bv);
@@ -332,11 +332,8 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos,
kiocb.ki_pos = *ppos;
ret = call_read_iter(in, &kiocb, &to);
- reclaim = npages * PAGE_SIZE;
- remain = 0;
if (ret > 0) {
- reclaim -= ret;
- remain = ret;
+ keep = DIV_ROUND_UP(ret, PAGE_SIZE);
*ppos = kiocb.ki_pos;
file_accessed(in);
} else if (ret < 0) {
@@ -349,14 +346,12 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos,
}
/* Free any pages that didn't get touched at all. */
- reclaim /= PAGE_SIZE;
- if (reclaim) {
- npages -= reclaim;
- release_pages(pages + npages, reclaim);
- }
+ if (keep < npages)
+ release_pages(pages + keep, npages - keep);
/* Push the remaining pages into the pipe. */
- for (i = 0; i < npages; i++) {
+ remain = ret;
+ for (i = 0; i < keep; i++) {
struct pipe_buffer *buf = pipe_head_buf(pipe);
chunk = min_t(size_t, remain, PAGE_SIZE);
diff --git a/fs/splice.c b/fs/splice.c index 9e798c901087..572d3e2a669a 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -295,7 +295,7 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos, struct kiocb kiocb; struct page **pages; ssize_t ret; - size_t used, npages, chunk, remain, reclaim; + size_t used, npages, chunk, remain, keep = 0; int i; /* Work out how much data we can actually add into the pipe */ @@ -332,11 +332,8 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos, kiocb.ki_pos = *ppos; ret = call_read_iter(in, &kiocb, &to); - reclaim = npages * PAGE_SIZE; - remain = 0; if (ret > 0) { - reclaim -= ret; - remain = ret; + keep = DIV_ROUND_UP(ret, PAGE_SIZE); *ppos = kiocb.ki_pos; file_accessed(in); } else if (ret < 0) { @@ -349,14 +346,12 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos, } /* Free any pages that didn't get touched at all. */ - reclaim /= PAGE_SIZE; - if (reclaim) { - npages -= reclaim; - release_pages(pages + npages, reclaim); - } + if (keep < npages) + release_pages(pages + keep, npages - keep); /* Push the remaining pages into the pipe. */ - for (i = 0; i < npages; i++) { + remain = ret; + for (i = 0; i < keep; i++) { struct pipe_buffer *buf = pipe_head_buf(pipe); chunk = min_t(size_t, remain, PAGE_SIZE);
How about the attached? I won't fold it down for the moment, but it could be pushed along later. David --- splice: Clean up direct_splice_read() a bit Do a couple of cleanups to direct_splice_read(): (1) Cast to struct page **, not void *. (2) Simplify the calculation of the number of pages to keep/reclaim in direct_splice_read(). Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> cc: Christoph Hellwig <hch@lst.de> cc: Jens Axboe <axboe@kernel.dk> cc: Al Viro <viro@zeniv.linux.org.uk> cc: David Hildenbrand <david@redhat.com> cc: John Hubbard <jhubbard@nvidia.com> cc: linux-mm@kvack.org cc: linux-block@vger.kernel.org cc: linux-fsdevel@vger.kernel.org