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authorChen, Kenneth W <kenneth.w.chen@intel.com>2007-01-22 20:40:43 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-01-23 07:52:06 -0800
commitcda9205da24aeaa8fb086b0fb85cdf39571ecc3f (patch)
treec302c3d0b0558d3fc5ac0b5750e4f8150517ece5
parent15c945c3d0913d73a7d57d7a0a3c4e2902598cc6 (diff)
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[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: Ken Chen <kenneth.w.chen@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/block_dev.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index da020be25dd..d9bdf2b3ade 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -190,6 +190,12 @@ static struct page *blk_get_page(unsigned long addr, size_t count, int rw,
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
blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
loff_t pos, unsigned long nr_segs)
@@ -278,6 +284,8 @@ same_bio:
count = min(count, nbytes);
goto same_bio;
}
+ } else {
+ blk_unget_page(page, &pvec);
}
/* bio is ready, submit it */