From: Mike Christie <michaelc@xxxxxxxxxxx>
bio_map_user_iov grabs a extra reference to the bio incase
a function that does not exist (bio_map_user_iov comments
reference __bio_map_user) bounced the bio.
This patch has blk_rq_map_user_iov grab a extra reference instead
of the bio function (blk_rq_map_user_iov was actually already
grabbing an extra reference), and it adds a blk_queue_bounce to bounce
the bio.
It also removes the bio_endio call in the failure path. This should
be needed because the bio layer did not bounce the bio.
There was also an extra bio_put in bio_unmap_user to handle the
extra get in bio_map_user_iov. This patch also removes that since
it is not needed.
Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx>
---
block/ll_rw_blk.c | 9 +++++++--
fs/bio.c | 43 +++++++++++--------------------------------
2 files changed, 18 insertions(+), 34 deletions(-)
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index fad17de..2e00bd2 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -2692,13 +2692,18 @@ int blk_rq_map_user_iov(struct bio_set *bs, struct request *rq,
return PTR_ERR(bio);
if (bio->bi_size != len) {
- bio_endio(bio, 0);
bio_unmap_user(bio);
return -EINVAL;
}
- bio_get(bio);
blk_rq_bio_prep(rq->q, rq, bio);
+ blk_queue_bounce(rq->q, &rq->bio);
+ /*
+ * If the bio was bounced then the bounced bio would be freed
+ * when its endio is called, so we must grab an extra reference
+ * for the unamp code.
+ */
+ bio_get(rq->bio);
rq->buffer = rq->data = NULL;
return 0;
}
diff --git a/fs/bio.c b/fs/bio.c
index df90896..05ffe68 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -727,25 +727,19 @@ struct bio *bio_map_user_iov(struct request_queue *q, struct bio_set *bs,
struct sg_iovec *iov, int iov_count,
int write_to_vm, gfp_t gfp_mask)
{
- struct bio *bio;
-
- bio = __bio_map_user_iov(q, bs, iov, iov_count, write_to_vm, gfp_mask);
-
- if (IS_ERR(bio))
- return bio;
-
- /*
- * subtle -- if __bio_map_user() ended up bouncing a bio,
- * it would normally disappear when its bi_end_io is run.
- * however, we need it for the unmap, so grab an extra
- * reference to it
- */
- bio_get(bio);
-
- return bio;
+ return __bio_map_user_iov(q, bs, iov, iov_count, write_to_vm, gfp_mask);
}
-static void __bio_unmap_user(struct bio *bio)
+/**
+ * bio_unmap_user - unmap a bio
+ * @bio: the bio being unmapped
+ *
+ * Unmap a bio previously mapped by bio_map_user(). Must be called with
+ * a process context.
+ *
+ * bio_unmap_user() may sleep.
+ */
+void bio_unmap_user(struct bio *bio)
{
struct bio_vec *bvec;
int i;
@@ -763,21 +757,6 @@ static void __bio_unmap_user(struct bio *bio)
bio_put(bio);
}
-/**
- * bio_unmap_user - unmap a bio
- * @bio: the bio being unmapped
- *
- * Unmap a bio previously mapped by bio_map_user(). Must be called with
- * a process context.
- *
- * bio_unmap_user() may sleep.
- */
-void bio_unmap_user(struct bio *bio)
-{
- __bio_unmap_user(bio);
- bio_put(bio);
-}
-
static void bio_map_kern_endio(struct bio *bio, int err)
{
bio_put(bio);
--
1.5.1.2
--
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