Commit cda9205d authored by Chen, Kenneth W's avatar Chen, Kenneth W Committed by Linus Torvalds

[PATCH] fix blk_direct_IO bio preparation

For large size DIO that needs multiple bio, one full page worth of data was
lost at the boundary of bio's maximum sector or segment limits.  After a
bio is full and got submitted.  The outer while (nbytes) { ...  } loop will
allocate a new bio and just march on to index into next page.  It just
forgets about the page that bio_add_page() rejected when previous bio is
full.  Fix it by put the rejected page back to pvec so we pick it up again
for the next bio.
Signed-off-by: default avatarKen Chen <kenneth.w.chen@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 15c945c3
...@@ -190,6 +190,12 @@ static struct page *blk_get_page(unsigned long addr, size_t count, int rw, ...@@ -190,6 +190,12 @@ static struct page *blk_get_page(unsigned long addr, size_t count, int rw,
return pvec->page[pvec->idx++]; return pvec->page[pvec->idx++];
} }
/* return a page back to pvec array */
static void blk_unget_page(struct page *page, struct pvec *pvec)
{
pvec->page[--pvec->idx] = page;
}
static ssize_t static ssize_t
blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
loff_t pos, unsigned long nr_segs) loff_t pos, unsigned long nr_segs)
...@@ -278,6 +284,8 @@ same_bio: ...@@ -278,6 +284,8 @@ same_bio:
count = min(count, nbytes); count = min(count, nbytes);
goto same_bio; goto same_bio;
} }
} else {
blk_unget_page(page, &pvec);
} }
/* bio is ready, submit it */ /* bio is ready, submit it */
......
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