From 57d74df90783f6a6b3e79dfdd2a567ce5db3b790 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 14 Nov 2018 17:02:07 +0100 Subject: [PATCH] block: use atomic bitops for ->queue_flags ->queue_flags is generally not set or cleared in the fast path, and also generally set or cleared one flag at a time. Make use of the normal atomic bitops for it so that we don't need to take the queue_lock, which is otherwise mostly unused in the core block layer now. Reviewed-by: Hannes Reinecke Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/blk-core.c | 54 +++++++----------------------------------------- block/blk-mq.c | 2 +- block/blk-settings.c | 10 ++++----- block/blk-sysfs.c | 28 +++++++++++-------------- block/blk.h | 56 -------------------------------------------------- include/linux/blkdev.h | 1 - 6 files changed, 24 insertions(+), 127 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 1c9b697..5c8e66a 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -74,11 +74,7 @@ static struct workqueue_struct *kblockd_workqueue; */ void blk_queue_flag_set(unsigned int flag, struct request_queue *q) { - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - queue_flag_set(flag, q); - spin_unlock_irqrestore(q->queue_lock, flags); + set_bit(flag, &q->queue_flags); } EXPORT_SYMBOL(blk_queue_flag_set); @@ -89,11 +85,7 @@ EXPORT_SYMBOL(blk_queue_flag_set); */ void blk_queue_flag_clear(unsigned int flag, struct request_queue *q) { - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - queue_flag_clear(flag, q); - spin_unlock_irqrestore(q->queue_lock, flags); + clear_bit(flag, &q->queue_flags); } EXPORT_SYMBOL(blk_queue_flag_clear); @@ -107,38 +99,10 @@ EXPORT_SYMBOL(blk_queue_flag_clear); */ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q) { - unsigned long flags; - bool res; - - spin_lock_irqsave(q->queue_lock, flags); - res = queue_flag_test_and_set(flag, q); - spin_unlock_irqrestore(q->queue_lock, flags); - - return res; + return test_and_set_bit(flag, &q->queue_flags); } EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set); -/** - * blk_queue_flag_test_and_clear - atomically test and clear a queue flag - * @flag: flag to be cleared - * @q: request queue - * - * Returns the previous value of @flag - 0 if the flag was not set and 1 if - * the flag was set. - */ -bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q) -{ - unsigned long flags; - bool res; - - spin_lock_irqsave(q->queue_lock, flags); - res = queue_flag_test_and_clear(flag, q); - spin_unlock_irqrestore(q->queue_lock, flags); - - return res; -} -EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_clear); - void blk_rq_init(struct request_queue *q, struct request *rq) { memset(rq, 0, sizeof(*rq)); @@ -368,12 +332,10 @@ void blk_cleanup_queue(struct request_queue *q) /* mark @q DYING, no new request or merges will be allowed afterwards */ mutex_lock(&q->sysfs_lock); blk_set_queue_dying(q); - spin_lock_irq(lock); - queue_flag_set(QUEUE_FLAG_NOMERGES, q); - queue_flag_set(QUEUE_FLAG_NOXMERGES, q); - queue_flag_set(QUEUE_FLAG_DYING, q); - spin_unlock_irq(lock); + blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q); + blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q); + blk_queue_flag_set(QUEUE_FLAG_DYING, q); mutex_unlock(&q->sysfs_lock); /* @@ -384,9 +346,7 @@ void blk_cleanup_queue(struct request_queue *q) rq_qos_exit(q); - spin_lock_irq(lock); - queue_flag_set(QUEUE_FLAG_DEAD, q); - spin_unlock_irq(lock); + blk_queue_flag_set(QUEUE_FLAG_DEAD, q); /* * make sure all in-progress dispatch are completed because diff --git a/block/blk-mq.c b/block/blk-mq.c index 4c82b4b..e2717e8 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2756,7 +2756,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; if (!(set->flags & BLK_MQ_F_SG_MERGE)) - queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q); + blk_queue_flag_set(QUEUE_FLAG_NO_SG_MERGE, q); q->sg_reserved_size = INT_MAX; diff --git a/block/blk-settings.c b/block/blk-settings.c index cca8359..3abe831 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -834,16 +834,14 @@ EXPORT_SYMBOL(blk_set_queue_depth); */ void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua) { - spin_lock_irq(q->queue_lock); if (wc) - queue_flag_set(QUEUE_FLAG_WC, q); + blk_queue_flag_set(QUEUE_FLAG_WC, q); else - queue_flag_clear(QUEUE_FLAG_WC, q); + blk_queue_flag_clear(QUEUE_FLAG_WC, q); if (fua) - queue_flag_set(QUEUE_FLAG_FUA, q); + blk_queue_flag_set(QUEUE_FLAG_FUA, q); else - queue_flag_clear(QUEUE_FLAG_FUA, q); - spin_unlock_irq(q->queue_lock); + blk_queue_flag_clear(QUEUE_FLAG_FUA, q); wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags)); } diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index d4b1b84..22fd086 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -316,14 +316,12 @@ static ssize_t queue_nomerges_store(struct request_queue *q, const char *page, if (ret < 0) return ret; - spin_lock_irq(q->queue_lock); - queue_flag_clear(QUEUE_FLAG_NOMERGES, q); - queue_flag_clear(QUEUE_FLAG_NOXMERGES, q); + blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q); + blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q); if (nm == 2) - queue_flag_set(QUEUE_FLAG_NOMERGES, q); + blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q); else if (nm) - queue_flag_set(QUEUE_FLAG_NOXMERGES, q); - spin_unlock_irq(q->queue_lock); + blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q); return ret; } @@ -347,18 +345,16 @@ queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count) if (ret < 0) return ret; - spin_lock_irq(q->queue_lock); if (val == 2) { - queue_flag_set(QUEUE_FLAG_SAME_COMP, q); - queue_flag_set(QUEUE_FLAG_SAME_FORCE, q); + blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q); + blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q); } else if (val == 1) { - queue_flag_set(QUEUE_FLAG_SAME_COMP, q); - queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q); + blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q); + blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q); } else if (val == 0) { - queue_flag_clear(QUEUE_FLAG_SAME_COMP, q); - queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q); + blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q); + blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q); } - spin_unlock_irq(q->queue_lock); #endif return ret; } @@ -889,7 +885,7 @@ int blk_register_queue(struct gendisk *disk) WARN_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags), "%s is registering an already registered queue\n", kobject_name(&dev->kobj)); - queue_flag_set_unlocked(QUEUE_FLAG_REGISTERED, q); + blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q); /* * SCSI probing may synchronously create and destroy a lot of @@ -901,7 +897,7 @@ int blk_register_queue(struct gendisk *disk) * request_queues for non-existent devices never get registered. */ if (!blk_queue_init_done(q)) { - queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q); + blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q); percpu_ref_switch_to_percpu(&q->q_usage_counter); } diff --git a/block/blk.h b/block/blk.h index 08a5845..f2ddc71 100644 --- a/block/blk.h +++ b/block/blk.h @@ -48,62 +48,6 @@ static inline void queue_lockdep_assert_held(struct request_queue *q) lockdep_assert_held(q->queue_lock); } -static inline void queue_flag_set_unlocked(unsigned int flag, - struct request_queue *q) -{ - if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) && - kref_read(&q->kobj.kref)) - lockdep_assert_held(q->queue_lock); - __set_bit(flag, &q->queue_flags); -} - -static inline void queue_flag_clear_unlocked(unsigned int flag, - struct request_queue *q) -{ - if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) && - kref_read(&q->kobj.kref)) - lockdep_assert_held(q->queue_lock); - __clear_bit(flag, &q->queue_flags); -} - -static inline int queue_flag_test_and_clear(unsigned int flag, - struct request_queue *q) -{ - queue_lockdep_assert_held(q); - - if (test_bit(flag, &q->queue_flags)) { - __clear_bit(flag, &q->queue_flags); - return 1; - } - - return 0; -} - -static inline int queue_flag_test_and_set(unsigned int flag, - struct request_queue *q) -{ - queue_lockdep_assert_held(q); - - if (!test_bit(flag, &q->queue_flags)) { - __set_bit(flag, &q->queue_flags); - return 0; - } - - return 1; -} - -static inline void queue_flag_set(unsigned int flag, struct request_queue *q) -{ - queue_lockdep_assert_held(q); - __set_bit(flag, &q->queue_flags); -} - -static inline void queue_flag_clear(unsigned int flag, struct request_queue *q) -{ - queue_lockdep_assert_held(q); - __clear_bit(flag, &q->queue_flags); -} - static inline struct blk_flush_queue * blk_get_flush_queue(struct request_queue *q, struct blk_mq_ctx *ctx) { diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 60507ab..30d8e0f 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -621,7 +621,6 @@ struct request_queue { void blk_queue_flag_set(unsigned int flag, struct request_queue *q); void blk_queue_flag_clear(unsigned int flag, struct request_queue *q); bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q); -bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q); #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags) #define blk_queue_dying(q) test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags) -- 2.7.4