block: remove BLK_MQ_F_NO_SCHED

The only queues that really can't support a scheduler are those that
do not have a gendisk associated with them, and thus can't be used for
non-passthrough commands.  In addition to those null_blk can optionally
set the flag, which is a bad odd.  Replace the null_blk usage with
BLK_MQ_F_NO_SCHED_BY_DEFAULT to keep the expected semantics and then
remove BLK_MQ_F_NO_SCHED as the non-disk queues never call into
elevator_init_mq or blk_register_queue which adds the sysfs attributes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250106083531.799976-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 4b6b20ccdb53999d172450d282ac4c659c253c5f..64b3c333aa476fb213a968c8d7d77235feb87700 100644 (file)
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -185,7 +185,6 @@ static const char *const hctx_flag_name[] = {
        HCTX_FLAG_NAME(STACKING),
        HCTX_FLAG_NAME(TAG_HCTX_SHARED),
        HCTX_FLAG_NAME(BLOCKING),
-       HCTX_FLAG_NAME(NO_SCHED),
        HCTX_FLAG_NAME(NO_SCHED_BY_DEFAULT),
 };
 #undef HCTX_FLAG_NAME

diff --git a/block/bsg-lib.c b/block/bsg-lib.c
index 32da4a4429ce550f6cbf25bfb84026f1ae5bae45..93523d8f81950960312e9a1a2698aa17682d7b71 100644 (file)
--- a/block/bsg-lib.c
+++ b/block/bsg-lib.c
@@ -381,7 +381,7 @@ struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
        set->queue_depth = 128;
        set->numa_node = NUMA_NO_NODE;
        set->cmd_size = sizeof(struct bsg_job) + dd_job_size;
-       set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING;
+       set->flags = BLK_MQ_F_BLOCKING;
        if (blk_mq_alloc_tag_set(set))
                goto out_tag_set;
 

diff --git a/block/elevator.c b/block/elevator.c
index be6e994256ac8a09971e3ebb95153af22adb6650..b81216c48b6bcb638058ccc206dc0b2a90460477 100644 (file)
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -547,14 +547,6 @@ void elv_unregister(struct elevator_type *e)
 }
 EXPORT_SYMBOL_GPL(elv_unregister);
 
-static inline bool elv_support_iosched(struct request_queue *q)
-{
-       if (!queue_is_mq(q) ||
-           (q->tag_set->flags & BLK_MQ_F_NO_SCHED))
-               return false;
-       return true;
-}
-
 /*
  * For single queue devices, default to using mq-deadline. If we have multiple
  * queues or mq-deadline is not available, default to "none".
@@ -580,9 +572,6 @@ void elevator_init_mq(struct request_queue *q)
        struct elevator_type *e;
        int err;
 
-       if (!elv_support_iosched(q))
-               return;
-
        WARN_ON_ONCE(blk_queue_registered(q));
 
        if (unlikely(q->elevator))
@@ -714,9 +703,6 @@ void elv_iosched_load_module(struct gendisk *disk, const char *buf,
        struct elevator_type *found;
        const char *name;
 
-       if (!elv_support_iosched(disk->queue))
-               return;
-
        strscpy(elevator_name, buf, sizeof(elevator_name));
        name = strstrip(elevator_name);
 
@@ -734,9 +720,6 @@ ssize_t elv_iosched_store(struct gendisk *disk, const char *buf,
        char elevator_name[ELV_NAME_MAX];
        int ret;
 
-       if (!elv_support_iosched(disk->queue))
-               return count;
-
        strscpy(elevator_name, buf, sizeof(elevator_name));
        ret = elevator_change(disk->queue, strstrip(elevator_name));
        if (!ret)
@@ -751,9 +734,6 @@ ssize_t elv_iosched_show(struct gendisk *disk, char *name)
        struct elevator_type *cur = NULL, *e;
        int len = 0;
 
-       if (!elv_support_iosched(q))
-               return sprintf(name, "none\n");
-
        if (!q->elevator) {
                len += sprintf(name+len, "[none] ");
        } else {

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 178e62cd9a9f288243c989a3386645fdcb874694..d94ef37480bd457042c6e1ebef64604bc221ae09 100644 (file)
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1792,7 +1792,7 @@ static int null_init_global_tag_set(void)
        tag_set.queue_depth = g_hw_queue_depth;
        tag_set.numa_node = g_home_node;
        if (g_no_sched)
-               tag_set.flags |= BLK_MQ_F_NO_SCHED;
+               tag_set.flags |= BLK_MQ_F_NO_SCHED_BY_DEFAULT;
        if (g_shared_tag_bitmap)
                tag_set.flags |= BLK_MQ_F_TAG_HCTX_SHARED;
        if (g_blocking)
@@ -1817,7 +1817,7 @@ static int null_setup_tagset(struct nullb *nullb)
        nullb->tag_set->queue_depth = nullb->dev->hw_queue_depth;
        nullb->tag_set->numa_node = nullb->dev->home_node;
        if (nullb->dev->no_sched)
-               nullb->tag_set->flags |= BLK_MQ_F_NO_SCHED;
+               nullb->tag_set->flags |= BLK_MQ_F_NO_SCHED_BY_DEFAULT;
        if (nullb->dev->shared_tag_bitmap)
                nullb->tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
        if (nullb->dev->blocking)

diff --git a/drivers/nvme/host/apple.c b/drivers/nvme/host/apple.c
index 83c60468542c88a7e41665233746bf90b3435a81..1de11b722f049abbc96a6bb62b072ac973b8c4aa 100644 (file)
--- a/drivers/nvme/host/apple.c
+++ b/drivers/nvme/host/apple.c
@@ -1251,7 +1251,6 @@ static int apple_nvme_alloc_tagsets(struct apple_nvme *anv)
        anv->admin_tagset.timeout = NVME_ADMIN_TIMEOUT;
        anv->admin_tagset.numa_node = NUMA_NO_NODE;
        anv->admin_tagset.cmd_size = sizeof(struct apple_nvme_iod);
-       anv->admin_tagset.flags = BLK_MQ_F_NO_SCHED;
        anv->admin_tagset.driver_data = &anv->adminq;
 
        ret = blk_mq_alloc_tag_set(&anv->admin_tagset);

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 42283d268500d6b6c8f09c093ce401baf262442a..c2250ddef5a299fdee3d4fcbd9ae0729d469f1f0 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4564,7 +4564,6 @@ int nvme_alloc_admin_tag_set(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set,
                /* Reserved for fabric connect and keep alive */
                set->reserved_tags = 2;
        set->numa_node = ctrl->numa_node;
-       set->flags = BLK_MQ_F_NO_SCHED;
        if (ctrl->ops->flags & NVME_F_BLOCKING)
                set->flags |= BLK_MQ_F_BLOCKING;
        set->cmd_size = cmd_size;

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 8a01e4393159d57d8d2c7a5078a1d55a26369dd3..fd53c9f402c342e9af04b4bd5352a2035aa598d3 100644 (file)
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -10412,7 +10412,6 @@ static int ufshcd_add_scsi_host(struct ufs_hba *hba)
                .nr_hw_queues   = 1,
                .queue_depth    = hba->nutmrs,
                .ops            = &ufshcd_tmf_ops,
-               .flags          = BLK_MQ_F_NO_SCHED,
        };
        err = blk_mq_alloc_tag_set(&hba->tmf_tag_set);
        if (err < 0)

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 6340293511c9997075b6c03ca42d389952488f77..f2ff0ffa05351da338c523f69f59cf5339e594ed 100644 (file)
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -676,8 +676,6 @@ enum {
        BLK_MQ_F_STACKING       = 1 << 2,
        BLK_MQ_F_TAG_HCTX_SHARED = 1 << 3,
        BLK_MQ_F_BLOCKING       = 1 << 4,
-       /* Do not allow an I/O scheduler to be configured. */
-       BLK_MQ_F_NO_SCHED       = 1 << 5,
 
        /*
         * Select 'none' during queue registration in case of a single hwq