On 01/17/2013 01:04 PM, Alex Elder wrote:
In rbd_rq_fn(), requests are fetched from the block layer and each
request is processed, looping through the request's list of bio's
until they've all been consumed.
Separate the handling for a single request into its own function to
make it a bit easier to see what's going on.
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
v2: Changed to handle 0-length requests the same as before.
Reviewed-by: Josh Durgin <josh.durgin@xxxxxxxxxxx>
drivers/block/rbd.c | 119
+++++++++++++++++++++++++++------------------------
1 file changed, 63 insertions(+), 56 deletions(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 8d93b6a..738d1e4 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1583,6 +1583,64 @@ static struct rbd_req_coll *rbd_alloc_coll(int
num_reqs)
return coll;
}
+static int rbd_dev_do_request(struct request *rq,
+ struct rbd_device *rbd_dev,
+ struct ceph_snap_context *snapc,
+ u64 ofs, unsigned int size,
+ struct bio *bio_chain)
+{
+ int num_segs;
+ struct rbd_req_coll *coll;
+ unsigned int bio_offset;
+ int cur_seg = 0;
+
+ dout("%s 0x%x bytes at 0x%llx\n",
+ rq_data_dir(rq) == WRITE ? "write" : "read",
+ size, (unsigned long long) blk_rq_pos(rq) * SECTOR_SIZE);
+
+ num_segs = rbd_get_num_segments(&rbd_dev->header, ofs, size);
+ if (num_segs <= 0)
+ return num_segs;
+
+ coll = rbd_alloc_coll(num_segs);
+ if (!coll)
+ return -ENOMEM;
+
+ bio_offset = 0;
+ do {
+ u64 limit = rbd_segment_length(rbd_dev, ofs, size);
+ unsigned int clone_size;
+ struct bio *bio_clone;
+
+ BUG_ON(limit > (u64)UINT_MAX);
+ clone_size = (unsigned int)limit;
+ dout("bio_chain->bi_vcnt=%hu\n", bio_chain->bi_vcnt);
+
+ kref_get(&coll->kref);
+
+ /* Pass a cloned bio chain via an osd request */
+
+ bio_clone = bio_chain_clone_range(&bio_chain,
+ &bio_offset, clone_size,
+ GFP_ATOMIC);
+ if (bio_clone)
+ (void)rbd_do_op(rq, rbd_dev, snapc,
+ ofs, clone_size,
+ bio_clone, coll, cur_seg);
+ else
+ rbd_coll_end_req_index(rq, coll, cur_seg,
+ (s32)-ENOMEM,
+ clone_size);
+ size -= clone_size;
+ ofs += clone_size;
+
+ cur_seg++;
+ } while (size > 0);
+ kref_put(&coll->kref, rbd_coll_release);
+
+ return 0;
+}
+
/*
* block device queue callback
*/
@@ -1596,10 +1654,8 @@ static void rbd_rq_fn(struct request_queue *q)
bool do_write;
unsigned int size;
u64 ofs;
- int num_segs, cur_seg = 0;
- struct rbd_req_coll *coll;
struct ceph_snap_context *snapc;
- unsigned int bio_offset;
+ int result;
dout("fetched request\n");
@@ -1637,60 +1693,11 @@ static void rbd_rq_fn(struct request_queue *q)
ofs = blk_rq_pos(rq) * SECTOR_SIZE;
bio = rq->bio;
- dout("%s 0x%x bytes at 0x%llx\n",
- do_write ? "write" : "read",
- size, (unsigned long long) blk_rq_pos(rq) * SECTOR_SIZE);
-
- num_segs = rbd_get_num_segments(&rbd_dev->header, ofs, size);
- if (num_segs <= 0) {
- spin_lock_irq(q->queue_lock);
- __blk_end_request_all(rq, num_segs);
- ceph_put_snap_context(snapc);
- continue;
- }
- coll = rbd_alloc_coll(num_segs);
- if (!coll) {
- spin_lock_irq(q->queue_lock);
- __blk_end_request_all(rq, -ENOMEM);
- ceph_put_snap_context(snapc);
- continue;
- }
-
- bio_offset = 0;
- do {
- u64 limit = rbd_segment_length(rbd_dev, ofs, size);
- unsigned int chain_size;
- struct bio *bio_chain;
-
- BUG_ON(limit > (u64) UINT_MAX);
- chain_size = (unsigned int) limit;
- dout("rq->bio->bi_vcnt=%hu\n", rq->bio->bi_vcnt);
-
- kref_get(&coll->kref);
-
- /* Pass a cloned bio chain via an osd request */
-
- bio_chain = bio_chain_clone_range(&bio,
- &bio_offset, chain_size,
- GFP_ATOMIC);
- if (bio_chain)
- (void) rbd_do_op(rq, rbd_dev, snapc,
- ofs, chain_size,
- bio_chain, coll, cur_seg);
- else
- rbd_coll_end_req_index(rq, coll, cur_seg,
- (s32)-ENOMEM,
- chain_size);
- size -= chain_size;
- ofs += chain_size;
-
- cur_seg++;
- } while (size > 0);
- kref_put(&coll->kref, rbd_coll_release);
-
- spin_lock_irq(q->queue_lock);
-
+ result = rbd_dev_do_request(rq, rbd_dev, snapc, ofs, size, bio);
ceph_put_snap_context(snapc);
+ spin_lock_irq(q->queue_lock);
+ if (!size || result < 0)
+ __blk_end_request_all(rq, result);
}
}
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
