diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 60116d13cb80..e85941bec857 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -23,6 +23,7 @@ struct queue_sysfs_entry { struct attribute attr; ssize_t (*show)(struct gendisk *disk, char *page); + int (*load_module)(struct gendisk *disk, const char *page, size_t count); ssize_t (*store)(struct gendisk *disk, const char *page, size_t count); }; @@ -413,6 +414,14 @@ static struct queue_sysfs_entry _prefix##_entry = { \ .store = _prefix##_store, \ }; +#define QUEUE_RW_LOAD_MODULE_ENTRY(_prefix, _name) \ +static struct queue_sysfs_entry _prefix##_entry = { \ + .attr = { .name = _name, .mode = 0644 }, \ + .show = _prefix##_show, \ + .load_module = _prefix##_load_module, \ + .store = _prefix##_store, \ +} + QUEUE_RW_ENTRY(queue_requests, "nr_requests"); QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb"); QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb"); @@ -420,7 +429,7 @@ QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb"); QUEUE_RO_ENTRY(queue_max_segments, "max_segments"); QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments"); QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size"); -QUEUE_RW_ENTRY(elv_iosched, "scheduler"); +QUEUE_RW_LOAD_MODULE_ENTRY(elv_iosched, "scheduler"); QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size"); QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size"); @@ -670,6 +679,17 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr, if (!entry->store) return -EIO; + /* + * If the attribute needs to load a module, do it before freezing the + * queue to ensure that the module file can be read when the request + * queue is the one for the device storing the module file. + */ + if (entry->load_module) { + res = entry->load_module(disk, page, length); + if (res) + return res; + } + blk_mq_freeze_queue(q); mutex_lock(&q->sysfs_lock); res = entry->store(disk, page, length); diff --git a/block/elevator.c b/block/elevator.c index f13d552a32c8..c355b55d0107 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -698,17 +698,26 @@ static int elevator_change(struct request_queue *q, const char *elevator_name) return 0; e = elevator_find_get(q, elevator_name); - if (!e) { - request_module("%s-iosched", elevator_name); - e = elevator_find_get(q, elevator_name); - if (!e) - return -EINVAL; - } + if (!e) + return -EINVAL; ret = elevator_switch(q, e); elevator_put(e); return ret; } +int elv_iosched_load_module(struct gendisk *disk, const char *buf, + size_t count) +{ + char elevator_name[ELV_NAME_MAX]; + + if (!elv_support_iosched(disk->queue)) + return -EOPNOTSUPP; + + strscpy(elevator_name, buf, sizeof(elevator_name)); + + return request_module("%s-iosched", strstrip(elevator_name)); +} + ssize_t elv_iosched_store(struct gendisk *disk, const char *buf, size_t count) { diff --git a/block/elevator.h b/block/elevator.h index 3fe18e1a8692..2a78544bf201 100644 --- a/block/elevator.h +++ b/block/elevator.h @@ -148,6 +148,8 @@ extern void elv_unregister(struct elevator_type *); * io scheduler sysfs switching */ ssize_t elv_iosched_show(struct gendisk *disk, char *page); +int elv_iosched_load_module(struct gendisk *disk, const char *page, + size_t count); ssize_t elv_iosched_store(struct gendisk *disk, const char *page, size_t count); extern bool elv_bio_merge_ok(struct request *, struct bio *);