From e4025e46f093d4549d3043c2c54d444cec480d2b Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 10 Dec 2018 22:34:39 +0100 Subject: [PATCH] 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 Signed-off-by: Jens Axboe --- drivers/block/mtip32xx/mtip32xx.c | 6 +++--- drivers/block/mtip32xx/mtip32xx.h | 4 ++-- 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];