Commit 85a8ce62c2ea ("block: add bio_truncate to fix guard_bio_eod") adds
bio_truncate() which changes to zero the truncated pages for any bio which
direction is READ. This way may change the behavior of guard_bio_eod(), so
change back to orginal behavior of just zeroing bio of REQ_OP_READ.
Meantime add kerneldoc for bio_truncate() as suggested by Christoph.
Fixes: 85a8ce62c2ea ("block: add bio_truncate to fix guard_bio_eod")
Reported-by: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/bio.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/block/bio.c b/block/bio.c
index 006bcc52a77e..94d697217887 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -538,6 +538,16 @@ void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start)
}
EXPORT_SYMBOL(zero_fill_bio_iter);
+/**
+ * bio_truncate - truncate the bio to small size of @new_size
+ * @bio: the bio to be truncated
+ * @new_size: new size for truncating the bio
+ *
+ * Description:
+ * Truncate the bio to new size of @new_size. If bio_op(bio) is
+ * REQ_OP_READ, zero the truncated part. This function should only
+ * be used for handling corner cases, such as bio eod.
+ */
void bio_truncate(struct bio *bio, unsigned new_size)
{
struct bio_vec bv;
@@ -548,7 +558,7 @@ void bio_truncate(struct bio *bio, unsigned new_size)
if (new_size >= bio->bi_iter.bi_size)
return;
- if (bio_data_dir(bio) != READ)
+ if (bio_op(bio) != REQ_OP_READ)
goto exit;
bio_for_each_segment(bv, bio, iter) {
--
2.20.1
