From 077413082f9ade9ca4d9774dbdc81ee7256d8089 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Tue, 5 Feb 2013 23:41:50 -0600 Subject: rbd: add barriers near done flag operations Somehow, I missed this little item in Documentation/atomic_ops.txt: *** WARNING: atomic_read() and atomic_set() DO NOT IMPLY BARRIERS! *** Create and use some helper functions that include the proper memory barriers for manipulating the done field. Signed-off-by: Alex Elder Reviewed-by: Josh Durgin --- drivers/block/rbd.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) (limited to 'drivers/block/rbd.c') diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 91983a60487b..982963ec2607 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -1216,10 +1216,28 @@ static int rbd_obj_request_wait(struct rbd_obj_request *obj_request) return wait_for_completion_interruptible(&obj_request->completion); } +static void obj_request_done_init(struct rbd_obj_request *obj_request) +{ + atomic_set(&obj_request->done, 0); + smp_wmb(); +} + +static void obj_request_done_set(struct rbd_obj_request *obj_request) +{ + atomic_set(&obj_request->done, 1); + smp_wmb(); +} + +static bool obj_request_done_test(struct rbd_obj_request *obj_request) +{ + smp_rmb(); + return atomic_read(&obj_request->done) != 0; +} + static void rbd_osd_trivial_callback(struct rbd_obj_request *obj_request, struct ceph_osd_op *op) { - atomic_set(&obj_request->done, 1); + obj_request_done_set(obj_request); } static void rbd_obj_request_complete(struct rbd_obj_request *obj_request) @@ -1249,14 +1267,14 @@ static void rbd_osd_read_callback(struct rbd_obj_request *obj_request, xferred = obj_request->length; } obj_request->xferred = xferred; - atomic_set(&obj_request->done, 1); + obj_request_done_set(obj_request); } static void rbd_osd_write_callback(struct rbd_obj_request *obj_request, struct ceph_osd_op *op) { obj_request->xferred = le64_to_cpu(op->extent.length); - atomic_set(&obj_request->done, 1); + obj_request_done_set(obj_request); } static void rbd_osd_req_callback(struct ceph_osd_request *osd_req, @@ -1300,7 +1318,7 @@ static void rbd_osd_req_callback(struct ceph_osd_request *osd_req, break; } - if (atomic_read(&obj_request->done)) + if (obj_request_done_test(obj_request)) rbd_obj_request_complete(obj_request); } @@ -1407,7 +1425,7 @@ static struct rbd_obj_request *rbd_obj_request_create(const char *object_name, obj_request->which = BAD_WHICH; obj_request->type = type; INIT_LIST_HEAD(&obj_request->links); - atomic_set(&obj_request->done, 0); + obj_request_done_init(obj_request); init_completion(&obj_request->completion); kref_init(&obj_request->kref); @@ -1611,7 +1629,7 @@ static void rbd_img_obj_callback(struct rbd_obj_request *obj_request) rbd_assert(more); rbd_assert(which < img_request->obj_request_count); - if (!atomic_read(&obj_request->done)) + if (!obj_request_done_test(obj_request)) break; rbd_assert(obj_request->xferred <= (u64) UINT_MAX); -- cgit v1.2.3