On Mon, Jun 25, 2012 at 12:37 AM, Guangliang Zhao <gzhao@xxxxxxxx> wrote:
> Signed-off-by: Guangliang Zhao <gzhao@xxxxxxxx>
> ---
> drivers/block/rbd.c | 10 ++++------
> 1 files changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 65665c9..3d6dfc8 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -719,8 +719,6 @@ static struct bio *bio_chain_clone(struct bio **old, struct bio **next,
> goto err_out;
>
> if (total + old_chain->bi_size > len) {
> - struct bio_pair *bp;
> -
> /*
> * this split can only happen with a single paged bio,
> * split_bio will BUG_ON if this is not the case
> @@ -732,13 +730,13 @@ static struct bio *bio_chain_clone(struct bio **old, struct bio **next,
>
> /* split the bio. We'll release it either in the next
> call, or it will have to be released outside */
> - bp = bio_split(old_chain, (len - total) / SECTOR_SIZE);
> - if (!bp)
> + *bp = bio_split(old_chain, (len - total) / SECTOR_SIZE);
> + if (!*bp)
> goto err_out;
>
> - __bio_clone(tmp, &bp->bio1);
> + __bio_clone(tmp, &(*bp)->bio1);
>
> - *next = &bp->bio2;
> + *next = &(*bp)->bio2;
> } else {
> __bio_clone(tmp, old_chain);
> *next = old_chain->bi_next;
The above patch looks right, that is, fixes a leak. However, I'm not
too sure that we're not missing some bigger problem that was hidden
(due to the leak). Effectively we never called bio_pair_release() on
the bio_pair that we created in bio_chain_clone(). However, I think we
should only call that after we're done with sending the data. So we
should keep the bio_pair with the request and clear it up when we're
done with the request. Something along the lines of:
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 013c7a5..7bf3e36 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -131,6 +131,7 @@ struct rbd_req_coll {
*/
struct rbd_request {
struct request *rq; /* blk layer request */
+ struct bio_pair *bp;
struct bio *bio; /* cloned bio */
struct page **pages; /* list of used pages */
u64 len;
@@ -867,6 +868,7 @@ static int rbd_do_request(struct request *rq,
struct ceph_snap_context *snapc,
u64 snapid,
const char *obj, u64 ofs, u64 len,
+ struct bio_pair *bp,
struct bio *bio,
struct page **pages,
int num_pages,
@@ -918,6 +920,7 @@ static int rbd_do_request(struct request *rq,
req->r_callback = rbd_cb;
req_data->rq = rq;
+ req_data->bp = bp;
req_data->bio = bio;
req_data->pages = pages;
req_data->len = len;
@@ -968,6 +971,7 @@ static int rbd_do_request(struct request *rq,
done_err:
bio_chain_put(req_data->bio);
+ bio_pair_release(req_data->bp);
ceph_osdc_put_request(req);
done_pages:
rbd_coll_end_req(req_data, ret, len);
@@ -1010,6 +1014,9 @@ static void rbd_req_cb(struct ceph_osd_request
*req, struct ceph_msg *msg)
if (req_data->bio)
bio_chain_put(req_data->bio);
+ if (req_data->bp)
+ bio_pair_release(req_data->bp);
+
ceph_osdc_put_request(req);
kfree(req_data);
}
@@ -1060,7 +1067,7 @@ static int rbd_req_sync_op(struct rbd_device *dev,
}
ret = rbd_do_request(NULL, dev, snapc, snapid,
- obj, ofs, len, NULL,
+ obj, ofs, len, NULL, NULL,
pages, num_pages,
flags,
ops,
@@ -1091,6 +1098,7 @@ static int rbd_do_op(struct request *rq,
u64 snapid,
int opcode, int flags, int num_reply,
u64 ofs, u64 len,
+ struct bio_pair *bp,
struct bio *bio,
struct rbd_req_coll *coll,
int coll_index)
@@ -1124,6 +1132,7 @@ static int rbd_do_op(struct request *rq,
ret = rbd_do_request(rq, rbd_dev, snapc, snapid,
seg_name, seg_ofs, seg_len,
+ bp,
bio,
NULL, 0,
flags,
@@ -1145,6 +1154,7 @@ static int rbd_req_write(struct request *rq,
struct rbd_device *rbd_dev,
struct ceph_snap_context *snapc,
u64 ofs, u64 len,
+ struct bio_pair *bp,
struct bio *bio,
int coll_index)
@@ -1153,7 +1163,7 @@ static int rbd_req_write(struct request *rq,
CEPH_OSD_OP_WRITE,
CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
2,
- ofs, len, bio, coll, coll_index);
+ ofs, len, bp, bio, coll, coll_index);
}
/*
@@ -1163,6 +1173,7 @@ static int rbd_req_read(struct request *rq,
struct rbd_device *rbd_dev,
u64 snapid,
u64 ofs, u64 len,
+ struct bio_pair *bp,
struct bio *bio,
struct rbd_req_coll *coll,
int coll_index)
@@ -1172,7 +1183,7 @@ static int rbd_req_read(struct request *rq,
CEPH_OSD_OP_READ,
CEPH_OSD_FLAG_READ,
2,
- ofs, len, bio, coll, coll_index);
+ ofs, len, bp, bio, coll, coll_index);
}
/*
@@ -1215,7 +1226,7 @@ static int rbd_req_sync_notify_ack(struct rbd_device *dev,
ops[0].watch.flag = 0;
ret = rbd_do_request(NULL, dev, NULL, CEPH_NOSNAP,
- obj, 0, 0, NULL,
+ obj, 0, 0, NULL, NULL,
pages, 0,
CEPH_OSD_FLAG_READ,
ops,
@@ -1517,13 +1528,13 @@ static void rbd_rq_fn(struct request_queue *q)
rbd_req_write(rq, rbd_dev,
rbd_dev->header.snapc,
ofs,
- op_size, bio,
+ op_size, bp, bio,
coll, cur_seg);
else
rbd_req_read(rq, rbd_dev,
cur_snap_id(rbd_dev),
ofs,
- op_size, bio,
+ op_size, bp, bio,
coll, cur_seg);
next_seg:
@@ -1535,8 +1546,6 @@ next_seg:
} while (size > 0);
kref_put(&coll->kref, rbd_coll_release);
- if (bp)
- bio_pair_release(bp);
spin_lock_irq(q->queue_lock);
}
}
--
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