dm kcopyd: avoid useless atomic operations

The functions set_bit and clear_bit are atomic. We don't need
atomicity when making flags for dm-kcopyd. So, change them to direct
manipulation of the flags.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-kcopyd.c

@@ -341,7 +341,7 @@ static void client_free_pages(struct dm_kcopyd_client *kc)
 struct kcopyd_job {
 	struct dm_kcopyd_client *kc;
 	struct list_head list;
-	unsigned long flags;
+	unsigned flags;
 
 	/*
 	 * Error state of the job.
@@ -418,7 +418,7 @@ static struct kcopyd_job *pop_io_job(struct list_head *jobs,
 	 * constraint and sequential writes that are at the right position.
 	 */
 	list_for_each_entry(job, jobs, list) {
-		if (job->rw == READ || !test_bit(DM_KCOPYD_WRITE_SEQ, &job->flags)) {
+		if (job->rw == READ || !(job->flags & BIT(DM_KCOPYD_WRITE_SEQ))) {
 			list_del(&job->list);
 			return job;
 		}
@@ -525,7 +525,7 @@ static void complete_io(unsigned long error, void *context)
 		else
 			job->read_err = 1;
 
-		if (!test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) {
+		if (!(job->flags & BIT(DM_KCOPYD_IGNORE_ERROR))) {
 			push(&kc->complete_jobs, job);
 			wake(kc);
 			return;
@@ -565,7 +565,7 @@ static int run_io_job(struct kcopyd_job *job)
 	 * If we need to write sequentially and some reads or writes failed,
 	 * no point in continuing.
 	 */
-	if (test_bit(DM_KCOPYD_WRITE_SEQ, &job->flags) &&
+	if (job->flags & BIT(DM_KCOPYD_WRITE_SEQ) &&
 	    job->master_job->write_err) {
 		job->write_err = job->master_job->write_err;
 		return -EIO;
@@ -709,7 +709,7 @@ static void segment_complete(int read_err, unsigned long write_err,
 	 * Only dispatch more work if there hasn't been an error.
 	 */
 	if ((!job->read_err && !job->write_err) ||
-	    test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) {
+	    job->flags & BIT(DM_KCOPYD_IGNORE_ERROR)) {
 		/* get the next chunk of work */
 		progress = job->progress;
 		count = job->source.count - progress;
@@ -801,10 +801,10 @@ void dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
 	 * we need to write sequentially. If one of the destination is a
 	 * host-aware device, then leave it to the caller to choose what to do.
 	 */
-	if (!test_bit(DM_KCOPYD_WRITE_SEQ, &job->flags)) {
+	if (!(job->flags & BIT(DM_KCOPYD_WRITE_SEQ))) {
 		for (i = 0; i < job->num_dests; i++) {
 			if (bdev_zoned_model(dests[i].bdev) == BLK_ZONED_HM) {
-				set_bit(DM_KCOPYD_WRITE_SEQ, &job->flags);
+				job->flags |= BIT(DM_KCOPYD_WRITE_SEQ);
 				break;
 			}
 		}
@@ -813,9 +813,9 @@ void dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
 	/*
 	 * If we need to write sequentially, errors cannot be ignored.
 	 */
-	if (test_bit(DM_KCOPYD_WRITE_SEQ, &job->flags) &&
-	    test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags))
-		clear_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags);
+	if (job->flags & BIT(DM_KCOPYD_WRITE_SEQ) &&
+	    job->flags & BIT(DM_KCOPYD_IGNORE_ERROR))
+		job->flags &= ~BIT(DM_KCOPYD_IGNORE_ERROR);
 
 	if (from) {
 		job->source = *from;

drivers/md/dm-raid1.c

@@ -364,7 +364,7 @@ static void recover(struct mirror_set *ms, struct dm_region *reg)
 
 	/* hand to kcopyd */
 	if (!errors_handled(ms))
-		set_bit(DM_KCOPYD_IGNORE_ERROR, &flags);
+		flags |= BIT(DM_KCOPYD_IGNORE_ERROR);
 
 	dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to,
 		       flags, recovery_complete, reg);

drivers/md/dm-zoned-reclaim.c

@@ -134,7 +134,7 @@ static int dmz_reclaim_copy(struct dmz_reclaim *zrc,
 	dst_zone_block = dmz_start_block(zmd, dst_zone);
 
 	if (dmz_is_seq(dst_zone))
-		set_bit(DM_KCOPYD_WRITE_SEQ, &flags);
+		flags |= BIT(DM_KCOPYD_WRITE_SEQ);
 
 	while (block < end_block) {
 		if (src_zone->dev->flags & DMZ_BDEV_DYING)