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authorArnd Bergmann <arnd@arndb.de>2018-12-10 22:34:39 +0100
committerJens Axboe <axboe@kernel.dk>2018-12-10 14:44:56 -0700
commite4025e46f093d4549d3043c2c54d444cec480d2b (patch)
treed96d7141ef0bdcc4147fb55530b2d9857f7a93a7
parent6f75723190d88e1319bea623bfe0292bf3917965 (diff)
mtip32xx: avoid using semaphores
The "cmd_slot_unal" semaphore is never used in a blocking way but only as an atomic counter. Change the code to using atomic_dec_if_positive() as a better API. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--drivers/block/mtip32xx/mtip32xx.c6
-rw-r--r--drivers/block/mtip32xx/mtip32xx.h4
2 files changed, 5 insertions, 5 deletions
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 2b0ac9d01e51..d7dc307d0cc8 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -2680,7 +2680,7 @@ static void mtip_softirq_done_fn(struct request *rq)
cmd->direction);
if (unlikely(cmd->unaligned))
- up(&dd->port->cmd_slot_unal);
+ atomic_inc(&dd->port->cmd_slot_unal);
blk_mq_end_request(rq, cmd->status);
}
@@ -2990,7 +2990,7 @@ static int mtip_hw_init(struct driver_data *dd)
else
dd->unal_qdepth = 0;
- sema_init(&dd->port->cmd_slot_unal, dd->unal_qdepth);
+ atomic_set(&dd->port->cmd_slot_unal, dd->unal_qdepth);
/* Spinlock to prevent concurrent issue */
for (i = 0; i < MTIP_MAX_SLOT_GROUPS; i++)
@@ -3533,7 +3533,7 @@ static bool mtip_check_unal_depth(struct blk_mq_hw_ctx *hctx,
cmd->unaligned = 1;
}
- if (cmd->unaligned && down_trylock(&dd->port->cmd_slot_unal))
+ if (cmd->unaligned && atomic_dec_if_positive(&dd->port->cmd_slot_unal) >= 0)
return true;
return false;
diff --git a/drivers/block/mtip32xx/mtip32xx.h b/drivers/block/mtip32xx/mtip32xx.h
index c33f8c3d9fb4..abce25f27f57 100644
--- a/drivers/block/mtip32xx/mtip32xx.h
+++ b/drivers/block/mtip32xx/mtip32xx.h
@@ -433,8 +433,8 @@ struct mtip_port {
*/
unsigned long ic_pause_timer;
- /* Semaphore to control queue depth of unaligned IOs */
- struct semaphore cmd_slot_unal;
+ /* Counter to control queue depth of unaligned IOs */
+ atomic_t cmd_slot_unal;
/* Spinlock for working around command-issue bug. */
spinlock_t cmd_issue_lock[MTIP_MAX_SLOT_GROUPS];