aa1c09cb65
When the zoned mode is enabled in null_blk, Serializing read, write and zone management operations for each zone is necessary to protect device level information for managing zone resources (zone open and closed counters) as well as each zone condition and write pointer position. Commit35bc10b2ea("null_blk: synchronization fix for zoned device") introduced a spinlock to implement this serialization. However, when memory backing is also enabled, GFP_NOIO memory allocations are executed under the spinlock, resulting in might_sleep() warnings. Furthermore, the zone_lock spinlock is locked/unlocked using spin_lock_irq/spin_unlock_irq, similarly to the memory backing code with the nullb->lock spinlock. This nested use of irq locks wrecks the irq enabled/disabled state. Fix all this by introducing a bitmap for per-zone lock, with locking implemented using wait_on_bit_lock_io() and clear_and_wake_up_bit(). This locking mechanism allows keeping a zone locked while executing null_process_cmd(), serializing all operations to the zone while allowing to sleep during memory backing allocation with GFP_NOIO. Device level zone resource management information is protected using a spinlock which is not held while executing null_process_cmd(); Fixes:35bc10b2ea("null_blk: synchronization fix for zoned device") Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
137 lines
4.2 KiB
C
137 lines
4.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __BLK_NULL_BLK_H
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#define __BLK_NULL_BLK_H
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#undef pr_fmt
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/blkdev.h>
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#include <linux/slab.h>
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#include <linux/blk-mq.h>
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#include <linux/hrtimer.h>
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#include <linux/configfs.h>
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#include <linux/badblocks.h>
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#include <linux/fault-inject.h>
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struct nullb_cmd {
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struct request *rq;
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struct bio *bio;
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unsigned int tag;
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blk_status_t error;
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struct nullb_queue *nq;
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struct hrtimer timer;
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};
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struct nullb_queue {
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unsigned long *tag_map;
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wait_queue_head_t wait;
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unsigned int queue_depth;
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struct nullb_device *dev;
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unsigned int requeue_selection;
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struct nullb_cmd *cmds;
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};
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struct nullb_device {
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struct nullb *nullb;
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struct config_item item;
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struct radix_tree_root data; /* data stored in the disk */
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struct radix_tree_root cache; /* disk cache data */
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unsigned long flags; /* device flags */
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unsigned int curr_cache;
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struct badblocks badblocks;
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unsigned int nr_zones;
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unsigned int nr_zones_imp_open;
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unsigned int nr_zones_exp_open;
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unsigned int nr_zones_closed;
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struct blk_zone *zones;
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sector_t zone_size_sects;
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spinlock_t zone_dev_lock;
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unsigned long *zone_locks;
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unsigned long size; /* device size in MB */
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unsigned long completion_nsec; /* time in ns to complete a request */
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unsigned long cache_size; /* disk cache size in MB */
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unsigned long zone_size; /* zone size in MB if device is zoned */
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unsigned long zone_capacity; /* zone capacity in MB if device is zoned */
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unsigned int zone_nr_conv; /* number of conventional zones */
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unsigned int zone_max_open; /* max number of open zones */
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unsigned int zone_max_active; /* max number of active zones */
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unsigned int submit_queues; /* number of submission queues */
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unsigned int home_node; /* home node for the device */
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unsigned int queue_mode; /* block interface */
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unsigned int blocksize; /* block size */
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unsigned int irqmode; /* IRQ completion handler */
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unsigned int hw_queue_depth; /* queue depth */
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unsigned int index; /* index of the disk, only valid with a disk */
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unsigned int mbps; /* Bandwidth throttle cap (in MB/s) */
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bool blocking; /* blocking blk-mq device */
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bool use_per_node_hctx; /* use per-node allocation for hardware context */
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bool power; /* power on/off the device */
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bool memory_backed; /* if data is stored in memory */
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bool discard; /* if support discard */
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bool zoned; /* if device is zoned */
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};
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struct nullb {
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struct nullb_device *dev;
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struct list_head list;
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unsigned int index;
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struct request_queue *q;
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struct gendisk *disk;
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struct blk_mq_tag_set *tag_set;
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struct blk_mq_tag_set __tag_set;
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unsigned int queue_depth;
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atomic_long_t cur_bytes;
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struct hrtimer bw_timer;
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unsigned long cache_flush_pos;
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spinlock_t lock;
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struct nullb_queue *queues;
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unsigned int nr_queues;
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char disk_name[DISK_NAME_LEN];
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};
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blk_status_t null_process_cmd(struct nullb_cmd *cmd,
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enum req_opf op, sector_t sector,
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unsigned int nr_sectors);
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#ifdef CONFIG_BLK_DEV_ZONED
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int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q);
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int null_register_zoned_dev(struct nullb *nullb);
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void null_free_zoned_dev(struct nullb_device *dev);
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int null_report_zones(struct gendisk *disk, sector_t sector,
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unsigned int nr_zones, report_zones_cb cb, void *data);
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blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd,
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enum req_opf op, sector_t sector,
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sector_t nr_sectors);
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size_t null_zone_valid_read_len(struct nullb *nullb,
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sector_t sector, unsigned int len);
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#else
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static inline int null_init_zoned_dev(struct nullb_device *dev,
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struct request_queue *q)
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{
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pr_err("CONFIG_BLK_DEV_ZONED not enabled\n");
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return -EINVAL;
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}
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static inline int null_register_zoned_dev(struct nullb *nullb)
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{
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return -ENODEV;
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}
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static inline void null_free_zoned_dev(struct nullb_device *dev) {}
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static inline blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd,
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enum req_opf op, sector_t sector, sector_t nr_sectors)
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{
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return BLK_STS_NOTSUPP;
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}
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static inline size_t null_zone_valid_read_len(struct nullb *nullb,
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sector_t sector,
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unsigned int len)
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{
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return len;
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}
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#define null_report_zones NULL
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#endif /* CONFIG_BLK_DEV_ZONED */
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#endif /* __NULL_BLK_H */
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