[PATCH v2 02/16] dmaengine: bcm-sba-raid: Reduce locking context in sba_alloc_request()

From: Anup Patel
Date: Tue Aug 01 2017 - 06:38:39 EST


We don't require to hold "sba->reqs_lock" for long-time
in sba_alloc_request() because lock protection is not
required when initializing members of "struct sba_request".

Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxxxx>
---
drivers/dma/bcm-sba-raid.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/dma/bcm-sba-raid.c b/drivers/dma/bcm-sba-raid.c
index 76999b7..f81d5ac 100644
--- a/drivers/dma/bcm-sba-raid.c
+++ b/drivers/dma/bcm-sba-raid.c
@@ -207,24 +207,24 @@ static struct sba_request *sba_alloc_request(struct sba_device *sba)
struct sba_request *req = NULL;

spin_lock_irqsave(&sba->reqs_lock, flags);
-
req = list_first_entry_or_null(&sba->reqs_free_list,
struct sba_request, node);
if (req) {
list_move_tail(&req->node, &sba->reqs_alloc_list);
- req->state = SBA_REQUEST_STATE_ALLOCED;
- req->fence = false;
- req->first = req;
- INIT_LIST_HEAD(&req->next);
- req->next_count = 1;
- atomic_set(&req->next_pending_count, 1);
-
sba->reqs_free_count--;
-
- dma_async_tx_descriptor_init(&req->tx, &sba->dma_chan);
}
-
spin_unlock_irqrestore(&sba->reqs_lock, flags);
+ if (!req)
+ return NULL;
+
+ req->state = SBA_REQUEST_STATE_ALLOCED;
+ req->fence = false;
+ req->first = req;
+ INIT_LIST_HEAD(&req->next);
+ req->next_count = 1;
+ atomic_set(&req->next_pending_count, 1);
+
+ dma_async_tx_descriptor_init(&req->tx, &sba->dma_chan);

return req;
}
--
2.7.4