On 01/03/2013 02:43 PM, Alex Elder wrote:
Now that a big hunk in the middle of rbd_rq_fn() has been moved
into its own routine we can simplify it a little more.
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
Reviewed-by: Josh Durgin <josh.durgin@xxxxxxxxxxx>
drivers/block/rbd.c | 50
+++++++++++++++++++++++---------------------------
1 file changed, 23 insertions(+), 27 deletions(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 88b9b2e..0a35c34 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1647,53 +1647,49 @@ static int rbd_dev_do_request(struct request *rq,
static void rbd_rq_fn(struct request_queue *q)
{
struct rbd_device *rbd_dev = q->queuedata;
+ bool read_only = rbd_dev->mapping.read_only;
struct request *rq;
while ((rq = blk_fetch_request(q))) {
- struct bio *bio;
- bool do_write;
- unsigned int size;
- u64 ofs;
- struct ceph_snap_context *snapc;
+ struct ceph_snap_context *snapc = NULL;
int result;
dout("fetched request\n");
- /* filter out block requests we don't understand */
+ /* Filter out block requests we don't understand */
+
if ((rq->cmd_type != REQ_TYPE_FS)) {
__blk_end_request_all(rq, 0);
continue;
}
+ spin_unlock_irq(q->queue_lock);
- /* deduce our operation (read, write) */
- do_write = (rq_data_dir(rq) == WRITE);
- if (do_write && rbd_dev->mapping.read_only) {
- __blk_end_request_all(rq, -EROFS);
- continue;
- }
+ /* Stop writes to a read-only device */
- spin_unlock_irq(q->queue_lock);
+ result = -EROFS;
+ if (read_only && rq_data_dir(rq) == WRITE)
+ goto out_end_request;
+
+ /* Grab a reference to the snapshot context */
down_read(&rbd_dev->header_rwsem);
+ if (rbd_dev->exists) {
+ snapc = ceph_get_snap_context(rbd_dev->header.snapc);
+ rbd_assert(snapc != NULL);
+ }
+ up_read(&rbd_dev->header_rwsem);
- if (!rbd_dev->exists) {
+ if (!snapc) {
rbd_assert(rbd_dev->spec->snap_id != CEPH_NOSNAP);
- up_read(&rbd_dev->header_rwsem);
dout("request for non-existent snapshot");
- spin_lock_irq(q->queue_lock);
- __blk_end_request_all(rq, -ENXIO);
- continue;
+ result = -ENXIO;
+ goto out_end_request;
}
- snapc = ceph_get_snap_context(rbd_dev->header.snapc);
-
- up_read(&rbd_dev->header_rwsem);
-
- size = blk_rq_bytes(rq);
- ofs = blk_rq_pos(rq) * SECTOR_SIZE;
- bio = rq->bio;
-
- result = rbd_dev_do_request(rq, rbd_dev, snapc, ofs, size, bio);
+ result = rbd_dev_do_request(rq, rbd_dev, snapc,
+ blk_rq_pos(rq) * SECTOR_SIZE,
+ blk_rq_bytes(rq), rq->bio);
+out_end_request:
ceph_put_snap_context(snapc);
spin_lock_irq(q->queue_lock);
if (result < 0)
--
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