diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/block/null_blk/main.c | 2041 |
1 files changed, 2041 insertions, 0 deletions
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c new file mode 100644 index 000000000..35b390a78 --- /dev/null +++ b/drivers/block/null_blk/main.c @@ -0,0 +1,2041 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Add configfs and memory store: Kyungchan Koh <kkc6196@fb.com> and + * Shaohua Li <shli@fb.com> + */ +#include <linux/module.h> + +#include <linux/moduleparam.h> +#include <linux/sched.h> +#include <linux/fs.h> +#include <linux/init.h> +#include "null_blk.h" + +#define PAGE_SECTORS_SHIFT (PAGE_SHIFT - SECTOR_SHIFT) +#define PAGE_SECTORS (1 << PAGE_SECTORS_SHIFT) +#define SECTOR_MASK (PAGE_SECTORS - 1) + +#define FREE_BATCH 16 + +#define TICKS_PER_SEC 50ULL +#define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC) + +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION +static DECLARE_FAULT_ATTR(null_timeout_attr); +static DECLARE_FAULT_ATTR(null_requeue_attr); +static DECLARE_FAULT_ATTR(null_init_hctx_attr); +#endif + +static inline u64 mb_per_tick(int mbps) +{ + return (1 << 20) / TICKS_PER_SEC * ((u64) mbps); +} + +/* + * Status flags for nullb_device. + * + * CONFIGURED: Device has been configured and turned on. Cannot reconfigure. + * UP: Device is currently on and visible in userspace. + * THROTTLED: Device is being throttled. + * CACHE: Device is using a write-back cache. + */ +enum nullb_device_flags { + NULLB_DEV_FL_CONFIGURED = 0, + NULLB_DEV_FL_UP = 1, + NULLB_DEV_FL_THROTTLED = 2, + NULLB_DEV_FL_CACHE = 3, +}; + +#define MAP_SZ ((PAGE_SIZE >> SECTOR_SHIFT) + 2) +/* + * nullb_page is a page in memory for nullb devices. + * + * @page: The page holding the data. + * @bitmap: The bitmap represents which sector in the page has data. + * Each bit represents one block size. For example, sector 8 + * will use the 7th bit + * The highest 2 bits of bitmap are for special purpose. LOCK means the cache + * page is being flushing to storage. FREE means the cache page is freed and + * should be skipped from flushing to storage. Please see + * null_make_cache_space + */ +struct nullb_page { + struct page *page; + DECLARE_BITMAP(bitmap, MAP_SZ); +}; +#define NULLB_PAGE_LOCK (MAP_SZ - 1) +#define NULLB_PAGE_FREE (MAP_SZ - 2) + +static LIST_HEAD(nullb_list); +static struct mutex lock; +static int null_major; +static DEFINE_IDA(nullb_indexes); +static struct blk_mq_tag_set tag_set; + +enum { + NULL_IRQ_NONE = 0, + NULL_IRQ_SOFTIRQ = 1, + NULL_IRQ_TIMER = 2, +}; + +enum { + NULL_Q_BIO = 0, + NULL_Q_RQ = 1, + NULL_Q_MQ = 2, +}; + +static int g_no_sched; +module_param_named(no_sched, g_no_sched, int, 0444); +MODULE_PARM_DESC(no_sched, "No io scheduler"); + +static int g_submit_queues = 1; +module_param_named(submit_queues, g_submit_queues, int, 0444); +MODULE_PARM_DESC(submit_queues, "Number of submission queues"); + +static int g_home_node = NUMA_NO_NODE; +module_param_named(home_node, g_home_node, int, 0444); +MODULE_PARM_DESC(home_node, "Home node for the device"); + +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION +/* + * For more details about fault injection, please refer to + * Documentation/fault-injection/fault-injection.rst. + */ +static char g_timeout_str[80]; +module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444); +MODULE_PARM_DESC(timeout, "Fault injection. timeout=<interval>,<probability>,<space>,<times>"); + +static char g_requeue_str[80]; +module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444); +MODULE_PARM_DESC(requeue, "Fault injection. requeue=<interval>,<probability>,<space>,<times>"); + +static char g_init_hctx_str[80]; +module_param_string(init_hctx, g_init_hctx_str, sizeof(g_init_hctx_str), 0444); +MODULE_PARM_DESC(init_hctx, "Fault injection to fail hctx init. init_hctx=<interval>,<probability>,<space>,<times>"); +#endif + +static int g_queue_mode = NULL_Q_MQ; + +static int null_param_store_val(const char *str, int *val, int min, int max) +{ + int ret, new_val; + + ret = kstrtoint(str, 10, &new_val); + if (ret) + return -EINVAL; + + if (new_val < min || new_val > max) + return -EINVAL; + + *val = new_val; + return 0; +} + +static int null_set_queue_mode(const char *str, const struct kernel_param *kp) +{ + return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ); +} + +static const struct kernel_param_ops null_queue_mode_param_ops = { + .set = null_set_queue_mode, + .get = param_get_int, +}; + +device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444); +MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)"); + +static int g_gb = 250; +module_param_named(gb, g_gb, int, 0444); +MODULE_PARM_DESC(gb, "Size in GB"); + +static int g_bs = 512; +module_param_named(bs, g_bs, int, 0444); +MODULE_PARM_DESC(bs, "Block size (in bytes)"); + +static unsigned int nr_devices = 1; +module_param(nr_devices, uint, 0444); +MODULE_PARM_DESC(nr_devices, "Number of devices to register"); + +static bool g_blocking; +module_param_named(blocking, g_blocking, bool, 0444); +MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device"); + +static bool shared_tags; +module_param(shared_tags, bool, 0444); +MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq"); + +static bool g_shared_tag_bitmap; +module_param_named(shared_tag_bitmap, g_shared_tag_bitmap, bool, 0444); +MODULE_PARM_DESC(shared_tag_bitmap, "Use shared tag bitmap for all submission queues for blk-mq"); + +static int g_irqmode = NULL_IRQ_SOFTIRQ; + +static int null_set_irqmode(const char *str, const struct kernel_param *kp) +{ + return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE, + NULL_IRQ_TIMER); +} + +static const struct kernel_param_ops null_irqmode_param_ops = { + .set = null_set_irqmode, + .get = param_get_int, +}; + +device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444); +MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer"); + +static unsigned long g_completion_nsec = 10000; +module_param_named(completion_nsec, g_completion_nsec, ulong, 0444); +MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns"); + +static int g_hw_queue_depth = 64; +module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444); +MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64"); + +static bool g_use_per_node_hctx; +module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444); +MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false"); + +static bool g_zoned; +module_param_named(zoned, g_zoned, bool, S_IRUGO); +MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false"); + +static unsigned long g_zone_size = 256; +module_param_named(zone_size, g_zone_size, ulong, S_IRUGO); +MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256"); + +static unsigned long g_zone_capacity; +module_param_named(zone_capacity, g_zone_capacity, ulong, 0444); +MODULE_PARM_DESC(zone_capacity, "Zone capacity in MB when block device is zoned. Can be less than or equal to zone size. Default: Zone size"); + +static unsigned int g_zone_nr_conv; +module_param_named(zone_nr_conv, g_zone_nr_conv, uint, 0444); +MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones when block device is zoned. Default: 0"); + +static unsigned int g_zone_max_open; +module_param_named(zone_max_open, g_zone_max_open, uint, 0444); +MODULE_PARM_DESC(zone_max_open, "Maximum number of open zones when block device is zoned. Default: 0 (no limit)"); + +static unsigned int g_zone_max_active; +module_param_named(zone_max_active, g_zone_max_active, uint, 0444); +MODULE_PARM_DESC(zone_max_active, "Maximum number of active zones when block device is zoned. Default: 0 (no limit)"); + +static struct nullb_device *null_alloc_dev(void); +static void null_free_dev(struct nullb_device *dev); +static void null_del_dev(struct nullb *nullb); +static int null_add_dev(struct nullb_device *dev); +static void null_free_device_storage(struct nullb_device *dev, bool is_cache); + +static inline struct nullb_device *to_nullb_device(struct config_item *item) +{ + return item ? container_of(item, struct nullb_device, item) : NULL; +} + +static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page) +{ + return snprintf(page, PAGE_SIZE, "%u\n", val); +} + +static inline ssize_t nullb_device_ulong_attr_show(unsigned long val, + char *page) +{ + return snprintf(page, PAGE_SIZE, "%lu\n", val); +} + +static inline ssize_t nullb_device_bool_attr_show(bool val, char *page) +{ + return snprintf(page, PAGE_SIZE, "%u\n", val); +} + +static ssize_t nullb_device_uint_attr_store(unsigned int *val, + const char *page, size_t count) +{ + unsigned int tmp; + int result; + + result = kstrtouint(page, 0, &tmp); + if (result < 0) + return result; + + *val = tmp; + return count; +} + +static ssize_t nullb_device_ulong_attr_store(unsigned long *val, + const char *page, size_t count) +{ + int result; + unsigned long tmp; + + result = kstrtoul(page, 0, &tmp); + if (result < 0) + return result; + + *val = tmp; + return count; +} + +static ssize_t nullb_device_bool_attr_store(bool *val, const char *page, + size_t count) +{ + bool tmp; + int result; + + result = kstrtobool(page, &tmp); + if (result < 0) + return result; + + *val = tmp; + return count; +} + +/* The following macro should only be used with TYPE = {uint, ulong, bool}. */ +#define NULLB_DEVICE_ATTR(NAME, TYPE, APPLY) \ +static ssize_t \ +nullb_device_##NAME##_show(struct config_item *item, char *page) \ +{ \ + return nullb_device_##TYPE##_attr_show( \ + to_nullb_device(item)->NAME, page); \ +} \ +static ssize_t \ +nullb_device_##NAME##_store(struct config_item *item, const char *page, \ + size_t count) \ +{ \ + int (*apply_fn)(struct nullb_device *dev, TYPE new_value) = APPLY;\ + struct nullb_device *dev = to_nullb_device(item); \ + TYPE new_value = 0; \ + int ret; \ + \ + ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);\ + if (ret < 0) \ + return ret; \ + if (apply_fn) \ + ret = apply_fn(dev, new_value); \ + else if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags)) \ + ret = -EBUSY; \ + if (ret < 0) \ + return ret; \ + dev->NAME = new_value; \ + return count; \ +} \ +CONFIGFS_ATTR(nullb_device_, NAME); + +static int nullb_apply_submit_queues(struct nullb_device *dev, + unsigned int submit_queues) +{ + struct nullb *nullb = dev->nullb; + struct blk_mq_tag_set *set; + + if (!nullb) + return 0; + + /* + * Make sure that null_init_hctx() does not access nullb->queues[] past + * the end of that array. + */ + if (submit_queues > nr_cpu_ids) + return -EINVAL; + set = nullb->tag_set; + blk_mq_update_nr_hw_queues(set, submit_queues); + return set->nr_hw_queues == submit_queues ? 0 : -ENOMEM; +} + +NULLB_DEVICE_ATTR(size, ulong, NULL); +NULLB_DEVICE_ATTR(completion_nsec, ulong, NULL); +NULLB_DEVICE_ATTR(submit_queues, uint, nullb_apply_submit_queues); +NULLB_DEVICE_ATTR(home_node, uint, NULL); +NULLB_DEVICE_ATTR(queue_mode, uint, NULL); +NULLB_DEVICE_ATTR(blocksize, uint, NULL); +NULLB_DEVICE_ATTR(irqmode, uint, NULL); +NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL); +NULLB_DEVICE_ATTR(index, uint, NULL); +NULLB_DEVICE_ATTR(blocking, bool, NULL); +NULLB_DEVICE_ATTR(use_per_node_hctx, bool, NULL); +NULLB_DEVICE_ATTR(memory_backed, bool, NULL); +NULLB_DEVICE_ATTR(discard, bool, NULL); +NULLB_DEVICE_ATTR(mbps, uint, NULL); +NULLB_DEVICE_ATTR(cache_size, ulong, NULL); +NULLB_DEVICE_ATTR(zoned, bool, NULL); +NULLB_DEVICE_ATTR(zone_size, ulong, NULL); +NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL); +NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL); +NULLB_DEVICE_ATTR(zone_max_open, uint, NULL); +NULLB_DEVICE_ATTR(zone_max_active, uint, NULL); + +static ssize_t nullb_device_power_show(struct config_item *item, char *page) +{ + return nullb_device_bool_attr_show(to_nullb_device(item)->power, page); +} + +static ssize_t nullb_device_power_store(struct config_item *item, + const char *page, size_t count) +{ + struct nullb_device *dev = to_nullb_device(item); + bool newp = false; + ssize_t ret; + + ret = nullb_device_bool_attr_store(&newp, page, count); + if (ret < 0) + return ret; + + if (!dev->power && newp) { + if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags)) + return count; + if (null_add_dev(dev)) { + clear_bit(NULLB_DEV_FL_UP, &dev->flags); + return -ENOMEM; + } + + set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags); + dev->power = newp; + } else if (dev->power && !newp) { + if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) { + mutex_lock(&lock); + dev->power = newp; + null_del_dev(dev->nullb); + mutex_unlock(&lock); + } + clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags); + } + + return count; +} + +CONFIGFS_ATTR(nullb_device_, power); + +static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page) +{ + struct nullb_device *t_dev = to_nullb_device(item); + + return badblocks_show(&t_dev->badblocks, page, 0); +} + +static ssize_t nullb_device_badblocks_store(struct config_item *item, + const char *page, size_t count) +{ + struct nullb_device *t_dev = to_nullb_device(item); + char *orig, *buf, *tmp; + u64 start, end; + int ret; + + orig = kstrndup(page, count, GFP_KERNEL); + if (!orig) + return -ENOMEM; + + buf = strstrip(orig); + + ret = -EINVAL; + if (buf[0] != '+' && buf[0] != '-') + goto out; + tmp = strchr(&buf[1], '-'); + if (!tmp) + goto out; + *tmp = '\0'; + ret = kstrtoull(buf + 1, 0, &start); + if (ret) + goto out; + ret = kstrtoull(tmp + 1, 0, &end); + if (ret) + goto out; + ret = -EINVAL; + if (start > end) + goto out; + /* enable badblocks */ + cmpxchg(&t_dev->badblocks.shift, -1, 0); + if (buf[0] == '+') + ret = badblocks_set(&t_dev->badblocks, start, + end - start + 1, 1); + else + ret = badblocks_clear(&t_dev->badblocks, start, + end - start + 1); + if (ret == 0) + ret = count; +out: + kfree(orig); + return ret; +} +CONFIGFS_ATTR(nullb_device_, badblocks); + +static struct configfs_attribute *nullb_device_attrs[] = { + &nullb_device_attr_size, + &nullb_device_attr_completion_nsec, + &nullb_device_attr_submit_queues, + &nullb_device_attr_home_node, + &nullb_device_attr_queue_mode, + &nullb_device_attr_blocksize, + &nullb_device_attr_irqmode, + &nullb_device_attr_hw_queue_depth, + &nullb_device_attr_index, + &nullb_device_attr_blocking, + &nullb_device_attr_use_per_node_hctx, + &nullb_device_attr_power, + &nullb_device_attr_memory_backed, + &nullb_device_attr_discard, + &nullb_device_attr_mbps, + &nullb_device_attr_cache_size, + &nullb_device_attr_badblocks, + &nullb_device_attr_zoned, + &nullb_device_attr_zone_size, + &nullb_device_attr_zone_capacity, + &nullb_device_attr_zone_nr_conv, + &nullb_device_attr_zone_max_open, + &nullb_device_attr_zone_max_active, + NULL, +}; + +static void nullb_device_release(struct config_item *item) +{ + struct nullb_device *dev = to_nullb_device(item); + + null_free_device_storage(dev, false); + null_free_dev(dev); +} + +static struct configfs_item_operations nullb_device_ops = { + .release = nullb_device_release, +}; + +static const struct config_item_type nullb_device_type = { + .ct_item_ops = &nullb_device_ops, + .ct_attrs = nullb_device_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct +config_item *nullb_group_make_item(struct config_group *group, const char *name) +{ + struct nullb_device *dev; + + dev = null_alloc_dev(); + if (!dev) + return ERR_PTR(-ENOMEM); + + config_item_init_type_name(&dev->item, name, &nullb_device_type); + + return &dev->item; +} + +static void +nullb_group_drop_item(struct config_group *group, struct config_item *item) +{ + struct nullb_device *dev = to_nullb_device(item); + + if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) { + mutex_lock(&lock); + dev->power = false; + null_del_dev(dev->nullb); + mutex_unlock(&lock); + } + + config_item_put(item); +} + +static ssize_t memb_group_features_show(struct config_item *item, char *page) +{ + return snprintf(page, PAGE_SIZE, + "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_capacity,zone_nr_conv,zone_max_open,zone_max_active\n"); +} + +CONFIGFS_ATTR_RO(memb_group_, features); + +static struct configfs_attribute *nullb_group_attrs[] = { + &memb_group_attr_features, + NULL, +}; + +static struct configfs_group_operations nullb_group_ops = { + .make_item = nullb_group_make_item, + .drop_item = nullb_group_drop_item, +}; + +static const struct config_item_type nullb_group_type = { + .ct_group_ops = &nullb_group_ops, + .ct_attrs = nullb_group_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct configfs_subsystem nullb_subsys = { + .su_group = { + .cg_item = { + .ci_namebuf = "nullb", + .ci_type = &nullb_group_type, + }, + }, +}; + +static inline int null_cache_active(struct nullb *nullb) +{ + return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags); +} + +static struct nullb_device *null_alloc_dev(void) +{ + struct nullb_device *dev; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) + return NULL; + INIT_RADIX_TREE(&dev->data, GFP_ATOMIC); + INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC); + if (badblocks_init(&dev->badblocks, 0)) { + kfree(dev); + return NULL; + } + + dev->size = g_gb * 1024; + dev->completion_nsec = g_completion_nsec; + dev->submit_queues = g_submit_queues; + dev->home_node = g_home_node; + dev->queue_mode = g_queue_mode; + dev->blocksize = g_bs; + dev->irqmode = g_irqmode; + dev->hw_queue_depth = g_hw_queue_depth; + dev->blocking = g_blocking; + dev->use_per_node_hctx = g_use_per_node_hctx; + dev->zoned = g_zoned; + dev->zone_size = g_zone_size; + dev->zone_capacity = g_zone_capacity; + dev->zone_nr_conv = g_zone_nr_conv; + dev->zone_max_open = g_zone_max_open; + dev->zone_max_active = g_zone_max_active; + return dev; +} + +static void null_free_dev(struct nullb_device *dev) +{ + if (!dev) + return; + + null_free_zoned_dev(dev); + badblocks_exit(&dev->badblocks); + kfree(dev); +} + +static void put_tag(struct nullb_queue *nq, unsigned int tag) +{ + clear_bit_unlock(tag, nq->tag_map); + + if (waitqueue_active(&nq->wait)) + wake_up(&nq->wait); +} + +static unsigned int get_tag(struct nullb_queue *nq) +{ + unsigned int tag; + + do { + tag = find_first_zero_bit(nq->tag_map, nq->queue_depth); + if (tag >= nq->queue_depth) + return -1U; + } while (test_and_set_bit_lock(tag, nq->tag_map)); + + return tag; +} + +static void free_cmd(struct nullb_cmd *cmd) +{ + put_tag(cmd->nq, cmd->tag); +} + +static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer); + +static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq) +{ + struct nullb_cmd *cmd; + unsigned int tag; + + tag = get_tag(nq); + if (tag != -1U) { + cmd = &nq->cmds[tag]; + cmd->tag = tag; + cmd->error = BLK_STS_OK; + cmd->nq = nq; + if (nq->dev->irqmode == NULL_IRQ_TIMER) { + hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); + cmd->timer.function = null_cmd_timer_expired; + } + return cmd; + } + + return NULL; +} + +static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait) +{ + struct nullb_cmd *cmd; + DEFINE_WAIT(wait); + + cmd = __alloc_cmd(nq); + if (cmd || !can_wait) + return cmd; + + do { + prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE); + cmd = __alloc_cmd(nq); + if (cmd) + break; + + io_schedule(); + } while (1); + + finish_wait(&nq->wait, &wait); + return cmd; +} + +static void end_cmd(struct nullb_cmd *cmd) +{ + int queue_mode = cmd->nq->dev->queue_mode; + + switch (queue_mode) { + case NULL_Q_MQ: + blk_mq_end_request(cmd->rq, cmd->error); + return; + case NULL_Q_BIO: + cmd->bio->bi_status = cmd->error; + bio_endio(cmd->bio); + break; + } + + free_cmd(cmd); +} + +static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer) +{ + end_cmd(container_of(timer, struct nullb_cmd, timer)); + + return HRTIMER_NORESTART; +} + +static void null_cmd_end_timer(struct nullb_cmd *cmd) +{ + ktime_t kt = cmd->nq->dev->completion_nsec; + + hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL); +} + +static void null_complete_rq(struct request *rq) +{ + end_cmd(blk_mq_rq_to_pdu(rq)); +} + +static struct nullb_page *null_alloc_page(gfp_t gfp_flags) +{ + struct nullb_page *t_page; + + t_page = kmalloc(sizeof(struct nullb_page), gfp_flags); + if (!t_page) + goto out; + + t_page->page = alloc_pages(gfp_flags, 0); + if (!t_page->page) + goto out_freepage; + + memset(t_page->bitmap, 0, sizeof(t_page->bitmap)); + return t_page; +out_freepage: + kfree(t_page); +out: + return NULL; +} + +static void null_free_page(struct nullb_page *t_page) +{ + __set_bit(NULLB_PAGE_FREE, t_page->bitmap); + if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap)) + return; + __free_page(t_page->page); + kfree(t_page); +} + +static bool null_page_empty(struct nullb_page *page) +{ + int size = MAP_SZ - 2; + + return find_first_bit(page->bitmap, size) == size; +} + +static void null_free_sector(struct nullb *nullb, sector_t sector, + bool is_cache) +{ + unsigned int sector_bit; + u64 idx; + struct nullb_page *t_page, *ret; + struct radix_tree_root *root; + + root = is_cache ? &nullb->dev->cache : &nullb->dev->data; + idx = sector >> PAGE_SECTORS_SHIFT; + sector_bit = (sector & SECTOR_MASK); + + t_page = radix_tree_lookup(root, idx); + if (t_page) { + __clear_bit(sector_bit, t_page->bitmap); + + if (null_page_empty(t_page)) { + ret = radix_tree_delete_item(root, idx, t_page); + WARN_ON(ret != t_page); + null_free_page(ret); + if (is_cache) + nullb->dev->curr_cache -= PAGE_SIZE; + } + } +} + +static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx, + struct nullb_page *t_page, bool is_cache) +{ + struct radix_tree_root *root; + + root = is_cache ? &nullb->dev->cache : &nullb->dev->data; + + if (radix_tree_insert(root, idx, t_page)) { + null_free_page(t_page); + t_page = radix_tree_lookup(root, idx); + WARN_ON(!t_page || t_page->page->index != idx); + } else if (is_cache) + nullb->dev->curr_cache += PAGE_SIZE; + + return t_page; +} + +static void null_free_device_storage(struct nullb_device *dev, bool is_cache) +{ + unsigned long pos = 0; + int nr_pages; + struct nullb_page *ret, *t_pages[FREE_BATCH]; + struct radix_tree_root *root; + + root = is_cache ? &dev->cache : &dev->data; + + do { + int i; + + nr_pages = radix_tree_gang_lookup(root, + (void **)t_pages, pos, FREE_BATCH); + + for (i = 0; i < nr_pages; i++) { + pos = t_pages[i]->page->index; + ret = radix_tree_delete_item(root, pos, t_pages[i]); + WARN_ON(ret != t_pages[i]); + null_free_page(ret); + } + + pos++; + } while (nr_pages == FREE_BATCH); + + if (is_cache) + dev->curr_cache = 0; +} + +static struct nullb_page *__null_lookup_page(struct nullb *nullb, + sector_t sector, bool for_write, bool is_cache) +{ + unsigned int sector_bit; + u64 idx; + struct nullb_page *t_page; + struct radix_tree_root *root; + + idx = sector >> PAGE_SECTORS_SHIFT; + sector_bit = (sector & SECTOR_MASK); + + root = is_cache ? &nullb->dev->cache : &nullb->dev->data; + t_page = radix_tree_lookup(root, idx); + WARN_ON(t_page && t_page->page->index != idx); + + if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap))) + return t_page; + + return NULL; +} + +static struct nullb_page *null_lookup_page(struct nullb *nullb, + sector_t sector, bool for_write, bool ignore_cache) +{ + struct nullb_page *page = NULL; + + if (!ignore_cache) + page = __null_lookup_page(nullb, sector, for_write, true); + if (page) + return page; + return __null_lookup_page(nullb, sector, for_write, false); +} + +static struct nullb_page *null_insert_page(struct nullb *nullb, + sector_t sector, bool ignore_cache) + __releases(&nullb->lock) + __acquires(&nullb->lock) +{ + u64 idx; + struct nullb_page *t_page; + + t_page = null_lookup_page(nullb, sector, true, ignore_cache); + if (t_page) + return t_page; + + spin_unlock_irq(&nullb->lock); + + t_page = null_alloc_page(GFP_NOIO); + if (!t_page) + goto out_lock; + + if (radix_tree_preload(GFP_NOIO)) + goto out_freepage; + + spin_lock_irq(&nullb->lock); + idx = sector >> PAGE_SECTORS_SHIFT; + t_page->page->index = idx; + t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache); + radix_tree_preload_end(); + + return t_page; +out_freepage: + null_free_page(t_page); +out_lock: + spin_lock_irq(&nullb->lock); + return null_lookup_page(nullb, sector, true, ignore_cache); +} + +static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page) +{ + int i; + unsigned int offset; + u64 idx; + struct nullb_page *t_page, *ret; + void *dst, *src; + + idx = c_page->page->index; + + t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true); + + __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap); + if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) { + null_free_page(c_page); + if (t_page && null_page_empty(t_page)) { + ret = radix_tree_delete_item(&nullb->dev->data, + idx, t_page); + null_free_page(t_page); + } + return 0; + } + + if (!t_page) + return -ENOMEM; + + src = kmap_atomic(c_page->page); + dst = kmap_atomic(t_page->page); + + for (i = 0; i < PAGE_SECTORS; + i += (nullb->dev->blocksize >> SECTOR_SHIFT)) { + if (test_bit(i, c_page->bitmap)) { + offset = (i << SECTOR_SHIFT); + memcpy(dst + offset, src + offset, + nullb->dev->blocksize); + __set_bit(i, t_page->bitmap); + } + } + + kunmap_atomic(dst); + kunmap_atomic(src); + + ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page); + null_free_page(ret); + nullb->dev->curr_cache -= PAGE_SIZE; + + return 0; +} + +static int null_make_cache_space(struct nullb *nullb, unsigned long n) +{ + int i, err, nr_pages; + struct nullb_page *c_pages[FREE_BATCH]; + unsigned long flushed = 0, one_round; + +again: + if ((nullb->dev->cache_size * 1024 * 1024) > + nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0) + return 0; + + nr_pages = radix_tree_gang_lookup(&nullb->dev->cache, + (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH); + /* + * nullb_flush_cache_page could unlock before using the c_pages. To + * avoid race, we don't allow page free + */ + for (i = 0; i < nr_pages; i++) { + nullb->cache_flush_pos = c_pages[i]->page->index; + /* + * We found the page which is being flushed to disk by other + * threads + */ + if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap)) + c_pages[i] = NULL; + else + __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap); + } + + one_round = 0; + for (i = 0; i < nr_pages; i++) { + if (c_pages[i] == NULL) + continue; + err = null_flush_cache_page(nullb, c_pages[i]); + if (err) + return err; + one_round++; + } + flushed += one_round << PAGE_SHIFT; + + if (n > flushed) { + if (nr_pages == 0) + nullb->cache_flush_pos = 0; + if (one_round == 0) { + /* give other threads a chance */ + spin_unlock_irq(&nullb->lock); + spin_lock_irq(&nullb->lock); + } + goto again; + } + return 0; +} + +static int copy_to_nullb(struct nullb *nullb, struct page *source, + unsigned int off, sector_t sector, size_t n, bool is_fua) +{ + size_t temp, count = 0; + unsigned int offset; + struct nullb_page *t_page; + void *dst, *src; + + while (count < n) { + temp = min_t(size_t, nullb->dev->blocksize, n - count); + + if (null_cache_active(nullb) && !is_fua) + null_make_cache_space(nullb, PAGE_SIZE); + + offset = (sector & SECTOR_MASK) << SECTOR_SHIFT; + t_page = null_insert_page(nullb, sector, + !null_cache_active(nullb) || is_fua); + if (!t_page) + return -ENOSPC; + + src = kmap_atomic(source); + dst = kmap_atomic(t_page->page); + memcpy(dst + offset, src + off + count, temp); + kunmap_atomic(dst); + kunmap_atomic(src); + + __set_bit(sector & SECTOR_MASK, t_page->bitmap); + + if (is_fua) + null_free_sector(nullb, sector, true); + + count += temp; + sector += temp >> SECTOR_SHIFT; + } + return 0; +} + +static int copy_from_nullb(struct nullb *nullb, struct page *dest, + unsigned int off, sector_t sector, size_t n) +{ + size_t temp, count = 0; + unsigned int offset; + struct nullb_page *t_page; + void *dst, *src; + + while (count < n) { + temp = min_t(size_t, nullb->dev->blocksize, n - count); + + offset = (sector & SECTOR_MASK) << SECTOR_SHIFT; + t_page = null_lookup_page(nullb, sector, false, + !null_cache_active(nullb)); + + dst = kmap_atomic(dest); + if (!t_page) { + memset(dst + off + count, 0, temp); + goto next; + } + src = kmap_atomic(t_page->page); + memcpy(dst + off + count, src + offset, temp); + kunmap_atomic(src); +next: + kunmap_atomic(dst); + + count += temp; + sector += temp >> SECTOR_SHIFT; + } + return 0; +} + +static void nullb_fill_pattern(struct nullb *nullb, struct page *page, + unsigned int len, unsigned int off) +{ + void *dst; + + dst = kmap_atomic(page); + memset(dst + off, 0xFF, len); + kunmap_atomic(dst); +} + +static void null_handle_discard(struct nullb *nullb, sector_t sector, size_t n) +{ + size_t temp; + + spin_lock_irq(&nullb->lock); + while (n > 0) { + temp = min_t(size_t, n, nullb->dev->blocksize); + null_free_sector(nullb, sector, false); + if (null_cache_active(nullb)) + null_free_sector(nullb, sector, true); + sector += temp >> SECTOR_SHIFT; + n -= temp; + } + spin_unlock_irq(&nullb->lock); +} + +static int null_handle_flush(struct nullb *nullb) +{ + int err; + + if (!null_cache_active(nullb)) + return 0; + + spin_lock_irq(&nullb->lock); + while (true) { + err = null_make_cache_space(nullb, + nullb->dev->cache_size * 1024 * 1024); + if (err || nullb->dev->curr_cache == 0) + break; + } + + WARN_ON(!radix_tree_empty(&nullb->dev->cache)); + spin_unlock_irq(&nullb->lock); + return err; +} + +static int null_transfer(struct nullb *nullb, struct page *page, + unsigned int len, unsigned int off, bool is_write, sector_t sector, + bool is_fua) +{ + struct nullb_device *dev = nullb->dev; + unsigned int valid_len = len; + int err = 0; + + if (!is_write) { + if (dev->zoned) + valid_len = null_zone_valid_read_len(nullb, + sector, len); + + if (valid_len) { + err = copy_from_nullb(nullb, page, off, + sector, valid_len); + off += valid_len; + len -= valid_len; + } + + if (len) + nullb_fill_pattern(nullb, page, len, off); + flush_dcache_page(page); + } else { + flush_dcache_page(page); + err = copy_to_nullb(nullb, page, off, sector, len, is_fua); + } + + return err; +} + +static int null_handle_rq(struct nullb_cmd *cmd) +{ + struct request *rq = cmd->rq; + struct nullb *nullb = cmd->nq->dev->nullb; + int err; + unsigned int len; + sector_t sector; + struct req_iterator iter; + struct bio_vec bvec; + + sector = blk_rq_pos(rq); + + if (req_op(rq) == REQ_OP_DISCARD) { + null_handle_discard(nullb, sector, blk_rq_bytes(rq)); + return 0; + } + + spin_lock_irq(&nullb->lock); + rq_for_each_segment(bvec, rq, iter) { + len = bvec.bv_len; + err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset, + op_is_write(req_op(rq)), sector, + rq->cmd_flags & REQ_FUA); + if (err) { + spin_unlock_irq(&nullb->lock); + return err; + } + sector += len >> SECTOR_SHIFT; + } + spin_unlock_irq(&nullb->lock); + + return 0; +} + +static int null_handle_bio(struct nullb_cmd *cmd) +{ + struct bio *bio = cmd->bio; + struct nullb *nullb = cmd->nq->dev->nullb; + int err; + unsigned int len; + sector_t sector; + struct bio_vec bvec; + struct bvec_iter iter; + + sector = bio->bi_iter.bi_sector; + + if (bio_op(bio) == REQ_OP_DISCARD) { + null_handle_discard(nullb, sector, + bio_sectors(bio) << SECTOR_SHIFT); + return 0; + } + + spin_lock_irq(&nullb->lock); + bio_for_each_segment(bvec, bio, iter) { + len = bvec.bv_len; + err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset, + op_is_write(bio_op(bio)), sector, + bio->bi_opf & REQ_FUA); + if (err) { + spin_unlock_irq(&nullb->lock); + return err; + } + sector += len >> SECTOR_SHIFT; + } + spin_unlock_irq(&nullb->lock); + return 0; +} + +static void null_stop_queue(struct nullb *nullb) +{ + struct request_queue *q = nullb->q; + + if (nullb->dev->queue_mode == NULL_Q_MQ) + blk_mq_stop_hw_queues(q); +} + +static void null_restart_queue_async(struct nullb *nullb) +{ + struct request_queue *q = nullb->q; + + if (nullb->dev->queue_mode == NULL_Q_MQ) + blk_mq_start_stopped_hw_queues(q, true); +} + +static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd) +{ + struct nullb_device *dev = cmd->nq->dev; + struct nullb *nullb = dev->nullb; + blk_status_t sts = BLK_STS_OK; + struct request *rq = cmd->rq; + + if (!hrtimer_active(&nullb->bw_timer)) + hrtimer_restart(&nullb->bw_timer); + + if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) { + null_stop_queue(nullb); + /* race with timer */ + if (atomic_long_read(&nullb->cur_bytes) > 0) + null_restart_queue_async(nullb); + /* requeue request */ + sts = BLK_STS_DEV_RESOURCE; + } + return sts; +} + +static inline blk_status_t null_handle_badblocks(struct nullb_cmd *cmd, + sector_t sector, + sector_t nr_sectors) +{ + struct badblocks *bb = &cmd->nq->dev->badblocks; + sector_t first_bad; + int bad_sectors; + + if (badblocks_check(bb, sector, nr_sectors, &first_bad, &bad_sectors)) + return BLK_STS_IOERR; + + return BLK_STS_OK; +} + +static inline blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd, + enum req_opf op) +{ + struct nullb_device *dev = cmd->nq->dev; + int err; + + if (dev->queue_mode == NULL_Q_BIO) + err = null_handle_bio(cmd); + else + err = null_handle_rq(cmd); + + return errno_to_blk_status(err); +} + +static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd) +{ + struct nullb_device *dev = cmd->nq->dev; + struct bio *bio; + + if (dev->memory_backed) + return; + + if (dev->queue_mode == NULL_Q_BIO && bio_op(cmd->bio) == REQ_OP_READ) { + zero_fill_bio(cmd->bio); + } else if (req_op(cmd->rq) == REQ_OP_READ) { + __rq_for_each_bio(bio, cmd->rq) + zero_fill_bio(bio); + } +} + +static inline void nullb_complete_cmd(struct nullb_cmd *cmd) +{ + /* + * Since root privileges are required to configure the null_blk + * driver, it is fine that this driver does not initialize the + * data buffers of read commands. Zero-initialize these buffers + * anyway if KMSAN is enabled to prevent that KMSAN complains + * about null_blk not initializing read data buffers. + */ + if (IS_ENABLED(CONFIG_KMSAN)) + nullb_zero_read_cmd_buffer(cmd); + + /* Complete IO by inline, softirq or timer */ + switch (cmd->nq->dev->irqmode) { + case NULL_IRQ_SOFTIRQ: + switch (cmd->nq->dev->queue_mode) { + case NULL_Q_MQ: + blk_mq_complete_request(cmd->rq); + break; + case NULL_Q_BIO: + /* + * XXX: no proper submitting cpu information available. + */ + end_cmd(cmd); + break; + } + break; + case NULL_IRQ_NONE: + end_cmd(cmd); + break; + case NULL_IRQ_TIMER: + null_cmd_end_timer(cmd); + break; + } +} + +blk_status_t null_process_cmd(struct nullb_cmd *cmd, + enum req_opf op, sector_t sector, + unsigned int nr_sectors) +{ + struct nullb_device *dev = cmd->nq->dev; + blk_status_t ret; + + if (dev->badblocks.shift != -1) { + ret = null_handle_badblocks(cmd, sector, nr_sectors); + if (ret != BLK_STS_OK) + return ret; + } + + if (dev->memory_backed) + return null_handle_memory_backed(cmd, op); + + return BLK_STS_OK; +} + +static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector, + sector_t nr_sectors, enum req_opf op) +{ + struct nullb_device *dev = cmd->nq->dev; + struct nullb *nullb = dev->nullb; + blk_status_t sts; + + if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) { + sts = null_handle_throttled(cmd); + if (sts != BLK_STS_OK) + return sts; + } + + if (op == REQ_OP_FLUSH) { + cmd->error = errno_to_blk_status(null_handle_flush(nullb)); + goto out; + } + + if (dev->zoned) + sts = null_process_zoned_cmd(cmd, op, sector, nr_sectors); + else + sts = null_process_cmd(cmd, op, sector, nr_sectors); + + /* Do not overwrite errors (e.g. timeout errors) */ + if (cmd->error == BLK_STS_OK) + cmd->error = sts; + +out: + nullb_complete_cmd(cmd); + return BLK_STS_OK; +} + +static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer) +{ + struct nullb *nullb = container_of(timer, struct nullb, bw_timer); + ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL); + unsigned int mbps = nullb->dev->mbps; + + if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps)) + return HRTIMER_NORESTART; + + atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps)); + null_restart_queue_async(nullb); + + hrtimer_forward_now(&nullb->bw_timer, timer_interval); + + return HRTIMER_RESTART; +} + +static void nullb_setup_bwtimer(struct nullb *nullb) +{ + ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL); + + hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + nullb->bw_timer.function = nullb_bwtimer_fn; + atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps)); + hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL); +} + +static struct nullb_queue *nullb_to_queue(struct nullb *nullb) +{ + int index = 0; + + if (nullb->nr_queues != 1) + index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues); + + return &nullb->queues[index]; +} + +static blk_qc_t null_submit_bio(struct bio *bio) +{ + sector_t sector = bio->bi_iter.bi_sector; + sector_t nr_sectors = bio_sectors(bio); + struct nullb *nullb = bio->bi_disk->private_data; + struct nullb_queue *nq = nullb_to_queue(nullb); + struct nullb_cmd *cmd; + + cmd = alloc_cmd(nq, 1); + cmd->bio = bio; + + null_handle_cmd(cmd, sector, nr_sectors, bio_op(bio)); + return BLK_QC_T_NONE; +} + +static bool should_timeout_request(struct request *rq) +{ +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION + if (g_timeout_str[0]) + return should_fail(&null_timeout_attr, 1); +#endif + return false; +} + +static bool should_requeue_request(struct request *rq) +{ +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION + if (g_requeue_str[0]) + return should_fail(&null_requeue_attr, 1); +#endif + return false; +} + +static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res) +{ + struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); + + pr_info("rq %p timed out\n", rq); + + /* + * If the device is marked as blocking (i.e. memory backed or zoned + * device), the submission path may be blocked waiting for resources + * and cause real timeouts. For these real timeouts, the submission + * path will complete the request using blk_mq_complete_request(). + * Only fake timeouts need to execute blk_mq_complete_request() here. + */ + cmd->error = BLK_STS_TIMEOUT; + if (cmd->fake_timeout) + blk_mq_complete_request(rq); + return BLK_EH_DONE; +} + +static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq); + struct nullb_queue *nq = hctx->driver_data; + sector_t nr_sectors = blk_rq_sectors(bd->rq); + sector_t sector = blk_rq_pos(bd->rq); + + might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); + + if (nq->dev->irqmode == NULL_IRQ_TIMER) { + hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + cmd->timer.function = null_cmd_timer_expired; + } + cmd->rq = bd->rq; + cmd->error = BLK_STS_OK; + cmd->nq = nq; + cmd->fake_timeout = should_timeout_request(bd->rq) || + blk_should_fake_timeout(bd->rq->q); + + blk_mq_start_request(bd->rq); + + if (should_requeue_request(bd->rq)) { + /* + * Alternate between hitting the core BUSY path, and the + * driver driven requeue path + */ + nq->requeue_selection++; + if (nq->requeue_selection & 1) + return BLK_STS_RESOURCE; + else { + blk_mq_requeue_request(bd->rq, true); + return BLK_STS_OK; + } + } + if (cmd->fake_timeout) + return BLK_STS_OK; + + return null_handle_cmd(cmd, sector, nr_sectors, req_op(bd->rq)); +} + +static void cleanup_queue(struct nullb_queue *nq) +{ + kfree(nq->tag_map); + kfree(nq->cmds); +} + +static void cleanup_queues(struct nullb *nullb) +{ + int i; + + for (i = 0; i < nullb->nr_queues; i++) + cleanup_queue(&nullb->queues[i]); + + kfree(nullb->queues); +} + +static void null_exit_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) +{ + struct nullb_queue *nq = hctx->driver_data; + struct nullb *nullb = nq->dev->nullb; + + nullb->nr_queues--; +} + +static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq) +{ + init_waitqueue_head(&nq->wait); + nq->queue_depth = nullb->queue_depth; + nq->dev = nullb->dev; +} + +static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data, + unsigned int hctx_idx) +{ + struct nullb *nullb = hctx->queue->queuedata; + struct nullb_queue *nq; + +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION + if (g_init_hctx_str[0] && should_fail(&null_init_hctx_attr, 1)) + return -EFAULT; +#endif + + nq = &nullb->queues[hctx_idx]; + hctx->driver_data = nq; + null_init_queue(nullb, nq); + nullb->nr_queues++; + + return 0; +} + +static const struct blk_mq_ops null_mq_ops = { + .queue_rq = null_queue_rq, + .complete = null_complete_rq, + .timeout = null_timeout_rq, + .init_hctx = null_init_hctx, + .exit_hctx = null_exit_hctx, +}; + +static void null_del_dev(struct nullb *nullb) +{ + struct nullb_device *dev; + + if (!nullb) + return; + + dev = nullb->dev; + + ida_simple_remove(&nullb_indexes, nullb->index); + + list_del_init(&nullb->list); + + del_gendisk(nullb->disk); + + if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) { + hrtimer_cancel(&nullb->bw_timer); + atomic_long_set(&nullb->cur_bytes, LONG_MAX); + null_restart_queue_async(nullb); + } + + blk_cleanup_queue(nullb->q); + if (dev->queue_mode == NULL_Q_MQ && + nullb->tag_set == &nullb->__tag_set) + blk_mq_free_tag_set(nullb->tag_set); + put_disk(nullb->disk); + cleanup_queues(nullb); + if (null_cache_active(nullb)) + null_free_device_storage(nullb->dev, true); + kfree(nullb); + dev->nullb = NULL; +} + +static void null_config_discard(struct nullb *nullb) +{ + if (nullb->dev->discard == false) + return; + + if (nullb->dev->zoned) { + nullb->dev->discard = false; + pr_info("discard option is ignored in zoned mode\n"); + return; + } + + nullb->q->limits.discard_granularity = nullb->dev->blocksize; + nullb->q->limits.discard_alignment = nullb->dev->blocksize; + blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9); + blk_queue_flag_set(QUEUE_FLAG_DISCARD, nullb->q); +} + +static const struct block_device_operations null_bio_ops = { + .owner = THIS_MODULE, + .submit_bio = null_submit_bio, + .report_zones = null_report_zones, +}; + +static const struct block_device_operations null_rq_ops = { + .owner = THIS_MODULE, + .report_zones = null_report_zones, +}; + +static int setup_commands(struct nullb_queue *nq) +{ + struct nullb_cmd *cmd; + int i, tag_size; + + nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL); + if (!nq->cmds) + return -ENOMEM; + + tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG; + nq->tag_map = kcalloc(tag_size, sizeof(unsigned long), GFP_KERNEL); + if (!nq->tag_map) { + kfree(nq->cmds); + return -ENOMEM; + } + + for (i = 0; i < nq->queue_depth; i++) { + cmd = &nq->cmds[i]; + cmd->tag = -1U; + } + + return 0; +} + +static int setup_queues(struct nullb *nullb) +{ + nullb->queues = kcalloc(nr_cpu_ids, sizeof(struct nullb_queue), + GFP_KERNEL); + if (!nullb->queues) + return -ENOMEM; + + nullb->queue_depth = nullb->dev->hw_queue_depth; + + return 0; +} + +static int init_driver_queues(struct nullb *nullb) +{ + struct nullb_queue *nq; + int i, ret = 0; + + for (i = 0; i < nullb->dev->submit_queues; i++) { + nq = &nullb->queues[i]; + + null_init_queue(nullb, nq); + + ret = setup_commands(nq); + if (ret) + return ret; + nullb->nr_queues++; + } + return 0; +} + +static int null_gendisk_register(struct nullb *nullb) +{ + sector_t size = ((sector_t)nullb->dev->size * SZ_1M) >> SECTOR_SHIFT; + struct gendisk *disk; + + disk = nullb->disk = alloc_disk_node(1, nullb->dev->home_node); + if (!disk) + return -ENOMEM; + set_capacity(disk, size); + + disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO; + disk->major = null_major; + disk->first_minor = nullb->index; + if (queue_is_mq(nullb->q)) + disk->fops = &null_rq_ops; + else + disk->fops = &null_bio_ops; + disk->private_data = nullb; + disk->queue = nullb->q; + strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN); + + if (nullb->dev->zoned) { + int ret = null_register_zoned_dev(nullb); + + if (ret) + return ret; + } + + add_disk(disk); + return 0; +} + +static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set) +{ + set->ops = &null_mq_ops; + set->nr_hw_queues = nullb ? nullb->dev->submit_queues : + g_submit_queues; + set->queue_depth = nullb ? nullb->dev->hw_queue_depth : + g_hw_queue_depth; + set->numa_node = nullb ? nullb->dev->home_node : g_home_node; + set->cmd_size = sizeof(struct nullb_cmd); + set->flags = BLK_MQ_F_SHOULD_MERGE; + if (g_no_sched) + set->flags |= BLK_MQ_F_NO_SCHED; + if (g_shared_tag_bitmap) + set->flags |= BLK_MQ_F_TAG_HCTX_SHARED; + set->driver_data = NULL; + + if ((nullb && nullb->dev->blocking) || g_blocking) + set->flags |= BLK_MQ_F_BLOCKING; + + return blk_mq_alloc_tag_set(set); +} + +static int null_validate_conf(struct nullb_device *dev) +{ + if (dev->queue_mode == NULL_Q_RQ) { + pr_err("legacy IO path is no longer available\n"); + return -EINVAL; + } + + dev->blocksize = round_down(dev->blocksize, 512); + dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096); + + if (dev->queue_mode == NULL_Q_MQ && dev->use_per_node_hctx) { + if (dev->submit_queues != nr_online_nodes) + dev->submit_queues = nr_online_nodes; + } else if (dev->submit_queues > nr_cpu_ids) + dev->submit_queues = nr_cpu_ids; + else if (dev->submit_queues == 0) + dev->submit_queues = 1; + + dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ); + dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER); + + /* Do memory allocation, so set blocking */ + if (dev->memory_backed) + dev->blocking = true; + else /* cache is meaningless */ + dev->cache_size = 0; + dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024, + dev->cache_size); + dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps); + /* can not stop a queue */ + if (dev->queue_mode == NULL_Q_BIO) + dev->mbps = 0; + + if (dev->zoned && + (!dev->zone_size || !is_power_of_2(dev->zone_size))) { + pr_err("zone_size must be power-of-two\n"); + return -EINVAL; + } + + return 0; +} + +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION +static bool __null_setup_fault(struct fault_attr *attr, char *str) +{ + if (!str[0]) + return true; + + if (!setup_fault_attr(attr, str)) + return false; + + attr->verbose = 0; + return true; +} +#endif + +static bool null_setup_fault(void) +{ +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION + if (!__null_setup_fault(&null_timeout_attr, g_timeout_str)) + return false; + if (!__null_setup_fault(&null_requeue_attr, g_requeue_str)) + return false; + if (!__null_setup_fault(&null_init_hctx_attr, g_init_hctx_str)) + return false; +#endif + return true; +} + +static int null_add_dev(struct nullb_device *dev) +{ + struct nullb *nullb; + int rv; + + rv = null_validate_conf(dev); + if (rv) + return rv; + + nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node); + if (!nullb) { + rv = -ENOMEM; + goto out; + } + nullb->dev = dev; + dev->nullb = nullb; + + spin_lock_init(&nullb->lock); + + rv = setup_queues(nullb); + if (rv) + goto out_free_nullb; + + if (dev->queue_mode == NULL_Q_MQ) { + if (shared_tags) { + nullb->tag_set = &tag_set; + rv = 0; + } else { + nullb->tag_set = &nullb->__tag_set; + rv = null_init_tag_set(nullb, nullb->tag_set); + } + + if (rv) + goto out_cleanup_queues; + + if (!null_setup_fault()) + goto out_cleanup_queues; + + nullb->tag_set->timeout = 5 * HZ; + nullb->q = blk_mq_init_queue_data(nullb->tag_set, nullb); + if (IS_ERR(nullb->q)) { + rv = -ENOMEM; + goto out_cleanup_tags; + } + } else if (dev->queue_mode == NULL_Q_BIO) { + nullb->q = blk_alloc_queue(dev->home_node); + if (!nullb->q) { + rv = -ENOMEM; + goto out_cleanup_queues; + } + rv = init_driver_queues(nullb); + if (rv) + goto out_cleanup_blk_queue; + } + + if (dev->mbps) { + set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags); + nullb_setup_bwtimer(nullb); + } + + if (dev->cache_size > 0) { + set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags); + blk_queue_write_cache(nullb->q, true, true); + } + + if (dev->zoned) { + rv = null_init_zoned_dev(dev, nullb->q); + if (rv) + goto out_cleanup_blk_queue; + } + + nullb->q->queuedata = nullb; + blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q); + blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q); + + mutex_lock(&lock); + rv = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL); + if (rv < 0) { + mutex_unlock(&lock); + goto out_cleanup_zone; + } + nullb->index = rv; + dev->index = rv; + mutex_unlock(&lock); + + blk_queue_logical_block_size(nullb->q, dev->blocksize); + blk_queue_physical_block_size(nullb->q, dev->blocksize); + + null_config_discard(nullb); + + sprintf(nullb->disk_name, "nullb%d", nullb->index); + + rv = null_gendisk_register(nullb); + if (rv) + goto out_ida_free; + + mutex_lock(&lock); + list_add_tail(&nullb->list, &nullb_list); + mutex_unlock(&lock); + + return 0; + +out_ida_free: + ida_free(&nullb_indexes, nullb->index); +out_cleanup_zone: + null_free_zoned_dev(dev); +out_cleanup_blk_queue: + blk_cleanup_queue(nullb->q); +out_cleanup_tags: + if (dev->queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set) + blk_mq_free_tag_set(nullb->tag_set); +out_cleanup_queues: + cleanup_queues(nullb); +out_free_nullb: + kfree(nullb); + dev->nullb = NULL; +out: + return rv; +} + +static int __init null_init(void) +{ + int ret = 0; + unsigned int i; + struct nullb *nullb; + struct nullb_device *dev; + + if (g_bs > PAGE_SIZE) { + pr_warn("invalid block size\n"); + pr_warn("defaults block size to %lu\n", PAGE_SIZE); + g_bs = PAGE_SIZE; + } + + if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) { + pr_err("invalid home_node value\n"); + g_home_node = NUMA_NO_NODE; + } + + if (g_queue_mode == NULL_Q_RQ) { + pr_err("legacy IO path no longer available\n"); + return -EINVAL; + } + if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) { + if (g_submit_queues != nr_online_nodes) { + pr_warn("submit_queues param is set to %u.\n", + nr_online_nodes); + g_submit_queues = nr_online_nodes; + } + } else if (g_submit_queues > nr_cpu_ids) + g_submit_queues = nr_cpu_ids; + else if (g_submit_queues <= 0) + g_submit_queues = 1; + + if (g_queue_mode == NULL_Q_MQ && shared_tags) { + ret = null_init_tag_set(NULL, &tag_set); + if (ret) + return ret; + } + + config_group_init(&nullb_subsys.su_group); + mutex_init(&nullb_subsys.su_mutex); + + ret = configfs_register_subsystem(&nullb_subsys); + if (ret) + goto err_tagset; + + mutex_init(&lock); + + null_major = register_blkdev(0, "nullb"); + if (null_major < 0) { + ret = null_major; + goto err_conf; + } + + for (i = 0; i < nr_devices; i++) { + dev = null_alloc_dev(); + if (!dev) { + ret = -ENOMEM; + goto err_dev; + } + ret = null_add_dev(dev); + if (ret) { + null_free_dev(dev); + goto err_dev; + } + } + + pr_info("module loaded\n"); + return 0; + +err_dev: + while (!list_empty(&nullb_list)) { + nullb = list_entry(nullb_list.next, struct nullb, list); + dev = nullb->dev; + null_del_dev(nullb); + null_free_dev(dev); + } + unregister_blkdev(null_major, "nullb"); +err_conf: + configfs_unregister_subsystem(&nullb_subsys); +err_tagset: + if (g_queue_mode == NULL_Q_MQ && shared_tags) + blk_mq_free_tag_set(&tag_set); + return ret; +} + +static void __exit null_exit(void) +{ + struct nullb *nullb; + + configfs_unregister_subsystem(&nullb_subsys); + + unregister_blkdev(null_major, "nullb"); + + mutex_lock(&lock); + while (!list_empty(&nullb_list)) { + struct nullb_device *dev; + + nullb = list_entry(nullb_list.next, struct nullb, list); + dev = nullb->dev; + null_del_dev(nullb); + null_free_dev(dev); + } + mutex_unlock(&lock); + + if (g_queue_mode == NULL_Q_MQ && shared_tags) + blk_mq_free_tag_set(&tag_set); +} + +module_init(null_init); +module_exit(null_exit); + +MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>"); +MODULE_LICENSE("GPL"); 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