Proxmox-Port/linux-loongson
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson synced 2025-08-27 06:50:37 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

block: prevent adding/deleting disk during updating nr_hw_queues

Browse Source 
Both adding/deleting disk code are reader of `nr_hw_queues`, so we can't
allow them in-progress when updating nr_hw_queues, kernel panic and
kasan has been reported in [1].

Prevent adding/deleting disk during updating nr_hw_queues by adding
rw_semaphore to tagset, write lock is grabbed in blk_mq_update_nr_hw_queues(),
and read lock is acquired when adding/deleting disk.

Also mark GFP_NOIO allocation scope for adding/deleting disk because
blk_mq_update_nr_hw_queues() is part of some driver's error handler.

This way avoids lot of trouble.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Suggested-by: Nilay Shroff <nilay@linux.ibm.com>
Reported-by: Nilay Shroff <nilay@linux.ibm.com>
Closes: https://lore.kernel.org/linux-block/a5896cdb-a59a-4a37-9f99-20522f5d2987@linux.ibm.com/
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250505141805.2751237-9-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2025-05-05 22:17:46 +08:00 committed by Jens Axboe
parent 5fad1490ef
commit 98e68f6702
3 changed files with 86 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
block/blk-mq.c
View File

@ -4846,6 +4846,8 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
goto out_free_srcu;
}
init_rwsem(&set->update_nr_hwq_lock);
ret = -ENOMEM;
set->tags = kcalloc_node(set->nr_hw_queues,
sizeof(struct blk_mq_tags *), GFP_KERNEL,
@ -5141,9 +5143,11 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
{
down_write(&set->update_nr_hwq_lock);
mutex_lock(&set->tag_list_lock);
__blk_mq_update_nr_hw_queues(set, nr_hw_queues);
mutex_unlock(&set->tag_list_lock);
up_write(&set->update_nr_hwq_lock);
}
EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);

113
block/genhd.c
View File

@ -415,19 +415,9 @@ static void add_disk_final(struct gendisk *disk)
set_bit(GD_ADDED, &disk->state);
}
/**
* add_disk_fwnode - add disk information to kernel list with fwnode
* @parent: parent device for the disk
* @disk: per-device partitioning information
* @groups: Additional per-device sysfs groups
* @fwnode: attached disk fwnode
*
* This function registers the partitioning information in @disk
* with the kernel. Also attach a fwnode to the disk device.
*/
int __must_check add_disk_fwnode(struct device *parent, struct gendisk *disk,
const struct attribute_group **groups,
struct fwnode_handle *fwnode)
static int __add_disk(struct device *parent, struct gendisk *disk,
const struct attribute_group **groups,
struct fwnode_handle *fwnode)
{
struct device *ddev = disk_to_dev(disk);
@ -550,7 +540,6 @@ int __must_check add_disk_fwnode(struct device *parent, struct gendisk *disk,
*/
disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor);
}
add_disk_final(disk);
return 0;
out_unregister_bdi:
@ -580,6 +569,45 @@ int __must_check add_disk_fwnode(struct device *parent, struct gendisk *disk,
}
return ret;
}
/**
* add_disk_fwnode - add disk information to kernel list with fwnode
* @parent: parent device for the disk
* @disk: per-device partitioning information
* @groups: Additional per-device sysfs groups
* @fwnode: attached disk fwnode
*
* This function registers the partitioning information in @disk
* with the kernel. Also attach a fwnode to the disk device.
*/
int __must_check add_disk_fwnode(struct device *parent, struct gendisk *disk,
const struct attribute_group **groups,
struct fwnode_handle *fwnode)
{
struct blk_mq_tag_set *set;
unsigned int memflags;
int ret;
if (queue_is_mq(disk->queue)) {
set = disk->queue->tag_set;
memflags = memalloc_noio_save();
down_read(&set->update_nr_hwq_lock);
ret = __add_disk(parent, disk, groups, fwnode);
up_read(&set->update_nr_hwq_lock);
memalloc_noio_restore(memflags);
} else {
ret = __add_disk(parent, disk, groups, fwnode);
}
/*
* add_disk_final() needn't to read `nr_hw_queues`, so move it out
* of read lock `set->update_nr_hwq_lock` for avoiding unnecessary
* lock dependency on `disk->open_mutex` from scanning partition.
*/
if (!ret)
add_disk_final(disk);
return ret;
}
EXPORT_SYMBOL_GPL(add_disk_fwnode);
/**
@ -660,26 +688,7 @@ void blk_mark_disk_dead(struct gendisk *disk)
}
EXPORT_SYMBOL_GPL(blk_mark_disk_dead);
/**
* del_gendisk - remove the gendisk
* @disk: the struct gendisk to remove
*
* Removes the gendisk and all its associated resources. This deletes the
* partitions associated with the gendisk, and unregisters the associated
* request_queue.
*
* This is the counter to the respective __device_add_disk() call.
*
* The final removal of the struct gendisk happens when its refcount reaches 0
* with put_disk(), which should be called after del_gendisk(), if
* __device_add_disk() was used.
*
* Drivers exist which depend on the release of the gendisk to be synchronous,
* it should not be deferred.
*
* Context: can sleep
*/
void del_gendisk(struct gendisk *disk)
static void __del_gendisk(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
struct block_device *part;
@ -772,6 +781,42 @@ void del_gendisk(struct gendisk *disk)
if (start_drain)
blk_unfreeze_release_lock(q);
}
/**
* del_gendisk - remove the gendisk
* @disk: the struct gendisk to remove
*
* Removes the gendisk and all its associated resources. This deletes the
* partitions associated with the gendisk, and unregisters the associated
* request_queue.
*
* This is the counter to the respective __device_add_disk() call.
*
* The final removal of the struct gendisk happens when its refcount reaches 0
* with put_disk(), which should be called after del_gendisk(), if
* __device_add_disk() was used.
*
* Drivers exist which depend on the release of the gendisk to be synchronous,
* it should not be deferred.
*
* Context: can sleep
*/
void del_gendisk(struct gendisk *disk)
{
struct blk_mq_tag_set *set;
unsigned int memflags;
if (!queue_is_mq(disk->queue)) {
__del_gendisk(disk);
} else {
set = disk->queue->tag_set;
memflags = memalloc_noio_save();
down_read(&set->update_nr_hwq_lock);
__del_gendisk(disk);
up_read(&set->update_nr_hwq_lock);
memalloc_noio_restore(memflags);
}
}
EXPORT_SYMBOL(del_gendisk);
/**

3
include/linux/blk-mq.h
View File

@ -9,6 +9,7 @@
#include <linux/prefetch.h>
#include <linux/srcu.h>
#include <linux/rw_hint.h>
#include <linux/rwsem.h>
struct blk_mq_tags;
struct blk_flush_queue;
@ -527,6 +528,8 @@ struct blk_mq_tag_set {
struct mutex tag_list_lock;
struct list_head tag_list;
struct srcu_struct *srcu;
struct rw_semaphore update_nr_hwq_lock;
};
/**