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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/block/null_blk/main.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/block/null_blk/main.c')
-rw-r--r--drivers/block/null_blk/main.c2361
1 files changed, 2361 insertions, 0 deletions
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
new file mode 100644
index 0000000000..9544746de1
--- /dev/null
+++ b/drivers/block/null_blk/main.c
@@ -0,0 +1,2361 @@
+// 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"
+
+#undef pr_fmt
+#define pr_fmt(fmt) "null_blk: " fmt
+
+#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,
+};
+
+static bool g_virt_boundary = false;
+module_param_named(virt_boundary, g_virt_boundary, bool, 0444);
+MODULE_PARM_DESC(virt_boundary, "Require a virtual boundary for the device. Default: False");
+
+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_poll_queues = 1;
+module_param_named(poll_queues, g_poll_queues, int, 0444);
+MODULE_PARM_DESC(poll_queues, "Number of IOPOLL 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 int g_max_sectors;
+module_param_named(max_sectors, g_max_sectors, int, 0444);
+MODULE_PARM_DESC(max_sectors, "Maximum size of a command (in 512B sectors)");
+
+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_memory_backed;
+module_param_named(memory_backed, g_memory_backed, bool, 0444);
+MODULE_PARM_DESC(memory_backed, "Create a memory-backed block device. Default: false");
+
+static bool g_discard;
+module_param_named(discard, g_discard, bool, 0444);
+MODULE_PARM_DESC(discard, "Support discard operations (requires memory-backed null_blk device). Default: false");
+
+static unsigned long g_cache_size;
+module_param_named(cache_size, g_cache_size, ulong, 0444);
+MODULE_PARM_DESC(mbps, "Cache size in MiB for memory-backed device. Default: 0 (none)");
+
+static unsigned int g_mbps;
+module_param_named(mbps, g_mbps, uint, 0444);
+MODULE_PARM_DESC(mbps, "Limit maximum bandwidth (in MiB/s). Default: 0 (no limit)");
+
+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 struct nullb *null_find_dev_by_name(const char *name);
+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(to_config_group(item), struct nullb_device, group) : 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_update_nr_hw_queues(struct nullb_device *dev,
+ unsigned int submit_queues,
+ unsigned int poll_queues)
+
+{
+ struct blk_mq_tag_set *set;
+ int ret, nr_hw_queues;
+
+ if (!dev->nullb)
+ return 0;
+
+ /*
+ * Make sure at least one submit queue exists.
+ */
+ if (!submit_queues)
+ return -EINVAL;
+
+ /*
+ * Make sure that null_init_hctx() does not access nullb->queues[] past
+ * the end of that array.
+ */
+ if (submit_queues > nr_cpu_ids || poll_queues > g_poll_queues)
+ return -EINVAL;
+
+ /*
+ * Keep previous and new queue numbers in nullb_device for reference in
+ * the call back function null_map_queues().
+ */
+ dev->prev_submit_queues = dev->submit_queues;
+ dev->prev_poll_queues = dev->poll_queues;
+ dev->submit_queues = submit_queues;
+ dev->poll_queues = poll_queues;
+
+ set = dev->nullb->tag_set;
+ nr_hw_queues = submit_queues + poll_queues;
+ blk_mq_update_nr_hw_queues(set, nr_hw_queues);
+ ret = set->nr_hw_queues == nr_hw_queues ? 0 : -ENOMEM;
+
+ if (ret) {
+ /* on error, revert the queue numbers */
+ dev->submit_queues = dev->prev_submit_queues;
+ dev->poll_queues = dev->prev_poll_queues;
+ }
+
+ return ret;
+}
+
+static int nullb_apply_submit_queues(struct nullb_device *dev,
+ unsigned int submit_queues)
+{
+ return nullb_update_nr_hw_queues(dev, submit_queues, dev->poll_queues);
+}
+
+static int nullb_apply_poll_queues(struct nullb_device *dev,
+ unsigned int poll_queues)
+{
+ return nullb_update_nr_hw_queues(dev, dev->submit_queues, poll_queues);
+}
+
+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(poll_queues, uint, nullb_apply_poll_queues);
+NULLB_DEVICE_ATTR(home_node, uint, NULL);
+NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
+NULLB_DEVICE_ATTR(blocksize, uint, NULL);
+NULLB_DEVICE_ATTR(max_sectors, 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);
+NULLB_DEVICE_ATTR(virt_boundary, bool, NULL);
+NULLB_DEVICE_ATTR(no_sched, bool, NULL);
+NULLB_DEVICE_ATTR(shared_tag_bitmap, bool, 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;
+ ret = null_add_dev(dev);
+ if (ret) {
+ clear_bit(NULLB_DEV_FL_UP, &dev->flags);
+ return ret;
+ }
+
+ 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 ssize_t nullb_device_zone_readonly_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct nullb_device *dev = to_nullb_device(item);
+
+ return zone_cond_store(dev, page, count, BLK_ZONE_COND_READONLY);
+}
+CONFIGFS_ATTR_WO(nullb_device_, zone_readonly);
+
+static ssize_t nullb_device_zone_offline_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct nullb_device *dev = to_nullb_device(item);
+
+ return zone_cond_store(dev, page, count, BLK_ZONE_COND_OFFLINE);
+}
+CONFIGFS_ATTR_WO(nullb_device_, zone_offline);
+
+static struct configfs_attribute *nullb_device_attrs[] = {
+ &nullb_device_attr_size,
+ &nullb_device_attr_completion_nsec,
+ &nullb_device_attr_submit_queues,
+ &nullb_device_attr_poll_queues,
+ &nullb_device_attr_home_node,
+ &nullb_device_attr_queue_mode,
+ &nullb_device_attr_blocksize,
+ &nullb_device_attr_max_sectors,
+ &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,
+ &nullb_device_attr_zone_readonly,
+ &nullb_device_attr_zone_offline,
+ &nullb_device_attr_virt_boundary,
+ &nullb_device_attr_no_sched,
+ &nullb_device_attr_shared_tag_bitmap,
+ 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,
+};
+
+#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
+
+static void nullb_add_fault_config(struct nullb_device *dev)
+{
+ fault_config_init(&dev->timeout_config, "timeout_inject");
+ fault_config_init(&dev->requeue_config, "requeue_inject");
+ fault_config_init(&dev->init_hctx_fault_config, "init_hctx_fault_inject");
+
+ configfs_add_default_group(&dev->timeout_config.group, &dev->group);
+ configfs_add_default_group(&dev->requeue_config.group, &dev->group);
+ configfs_add_default_group(&dev->init_hctx_fault_config.group, &dev->group);
+}
+
+#else
+
+static void nullb_add_fault_config(struct nullb_device *dev)
+{
+}
+
+#endif
+
+static struct
+config_group *nullb_group_make_group(struct config_group *group, const char *name)
+{
+ struct nullb_device *dev;
+
+ if (null_find_dev_by_name(name))
+ return ERR_PTR(-EEXIST);
+
+ dev = null_alloc_dev();
+ if (!dev)
+ return ERR_PTR(-ENOMEM);
+
+ config_group_init_type_name(&dev->group, name, &nullb_device_type);
+ nullb_add_fault_config(dev);
+
+ return &dev->group;
+}
+
+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,
+ "badblocks,blocking,blocksize,cache_size,"
+ "completion_nsec,discard,home_node,hw_queue_depth,"
+ "irqmode,max_sectors,mbps,memory_backed,no_sched,"
+ "poll_queues,power,queue_mode,shared_tag_bitmap,size,"
+ "submit_queues,use_per_node_hctx,virt_boundary,zoned,"
+ "zone_capacity,zone_max_active,zone_max_open,"
+ "zone_nr_conv,zone_offline,zone_readonly,zone_size\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_group = nullb_group_make_group,
+ .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;
+
+#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
+ dev->timeout_config.attr = null_timeout_attr;
+ dev->requeue_config.attr = null_requeue_attr;
+ dev->init_hctx_fault_config.attr = null_init_hctx_attr;
+#endif
+
+ 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->prev_submit_queues = g_submit_queues;
+ dev->poll_queues = g_poll_queues;
+ dev->prev_poll_queues = g_poll_queues;
+ dev->home_node = g_home_node;
+ dev->queue_mode = g_queue_mode;
+ dev->blocksize = g_bs;
+ dev->max_sectors = g_max_sectors;
+ dev->irqmode = g_irqmode;
+ dev->hw_queue_depth = g_hw_queue_depth;
+ dev->blocking = g_blocking;
+ dev->memory_backed = g_memory_backed;
+ dev->discard = g_discard;
+ dev->cache_size = g_cache_size;
+ dev->mbps = g_mbps;
+ 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;
+ dev->virt_boundary = g_virt_boundary;
+ dev->no_sched = g_no_sched;
+ dev->shared_tag_bitmap = g_shared_tag_bitmap;
+ 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, struct bio *bio)
+{
+ struct nullb_cmd *cmd;
+ DEFINE_WAIT(wait);
+
+ do {
+ /*
+ * This avoids multiple return statements, multiple calls to
+ * __alloc_cmd() and a fast path call to prepare_to_wait().
+ */
+ cmd = __alloc_cmd(nq);
+ if (cmd) {
+ cmd->bio = bio;
+ return cmd;
+ }
+ prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
+ io_schedule();
+ finish_wait(&nq->wait, &wait);
+ } while (1);
+}
+
+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(void)
+{
+ struct nullb_page *t_page;
+
+ t_page = kmalloc(sizeof(struct nullb_page), GFP_NOIO);
+ if (!t_page)
+ return NULL;
+
+ t_page->page = alloc_pages(GFP_NOIO, 0);
+ if (!t_page->page) {
+ kfree(t_page);
+ return NULL;
+ }
+
+ memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
+ return t_page;
+}
+
+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();
+ 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_local_page(c_page->page);
+ dst = kmap_local_page(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_local(dst);
+ kunmap_local(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;
+
+ 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;
+
+ memcpy_page(t_page->page, offset, source, off + count, temp);
+
+ __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;
+
+ 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));
+
+ if (t_page)
+ memcpy_page(dest, off + count, t_page->page, offset,
+ temp);
+ else
+ zero_user(dest, off + count, temp);
+
+ 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)
+{
+ memset_page(page, off, 0xff, len);
+}
+
+blk_status_t null_handle_discard(struct nullb_device *dev,
+ sector_t sector, sector_t nr_sectors)
+{
+ struct nullb *nullb = dev->nullb;
+ size_t n = nr_sectors << SECTOR_SHIFT;
+ size_t temp;
+
+ spin_lock_irq(&nullb->lock);
+ while (n > 0) {
+ temp = min_t(size_t, n, 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);
+
+ return BLK_STS_OK;
+}
+
+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 = blk_rq_pos(rq);
+ struct req_iterator iter;
+ struct bio_vec bvec;
+
+ 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 = bio->bi_iter.bi_sector;
+ struct bio_vec bvec;
+ struct bvec_iter iter;
+
+ 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_op op,
+ sector_t sector,
+ sector_t nr_sectors)
+{
+ struct nullb_device *dev = cmd->nq->dev;
+ int err;
+
+ if (op == REQ_OP_DISCARD)
+ return null_handle_discard(dev, sector, nr_sectors);
+
+ 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_op 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, sector, nr_sectors);
+
+ return BLK_STS_OK;
+}
+
+static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
+ sector_t nr_sectors, enum req_op 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 void 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_bdev->bd_disk->private_data;
+ struct nullb_queue *nq = nullb_to_queue(nullb);
+
+ null_handle_cmd(alloc_cmd(nq, bio), sector, nr_sectors, bio_op(bio));
+}
+
+#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
+
+static bool should_timeout_request(struct request *rq)
+{
+ struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
+ struct nullb_device *dev = cmd->nq->dev;
+
+ return should_fail(&dev->timeout_config.attr, 1);
+}
+
+static bool should_requeue_request(struct request *rq)
+{
+ struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
+ struct nullb_device *dev = cmd->nq->dev;
+
+ return should_fail(&dev->requeue_config.attr, 1);
+}
+
+static bool should_init_hctx_fail(struct nullb_device *dev)
+{
+ return should_fail(&dev->init_hctx_fault_config.attr, 1);
+}
+
+#else
+
+static bool should_timeout_request(struct request *rq)
+{
+ return false;
+}
+
+static bool should_requeue_request(struct request *rq)
+{
+ return false;
+}
+
+static bool should_init_hctx_fail(struct nullb_device *dev)
+{
+ return false;
+}
+
+#endif
+
+static void null_map_queues(struct blk_mq_tag_set *set)
+{
+ struct nullb *nullb = set->driver_data;
+ int i, qoff;
+ unsigned int submit_queues = g_submit_queues;
+ unsigned int poll_queues = g_poll_queues;
+
+ if (nullb) {
+ struct nullb_device *dev = nullb->dev;
+
+ /*
+ * Refer nr_hw_queues of the tag set to check if the expected
+ * number of hardware queues are prepared. If block layer failed
+ * to prepare them, use previous numbers of submit queues and
+ * poll queues to map queues.
+ */
+ if (set->nr_hw_queues ==
+ dev->submit_queues + dev->poll_queues) {
+ submit_queues = dev->submit_queues;
+ poll_queues = dev->poll_queues;
+ } else if (set->nr_hw_queues ==
+ dev->prev_submit_queues + dev->prev_poll_queues) {
+ submit_queues = dev->prev_submit_queues;
+ poll_queues = dev->prev_poll_queues;
+ } else {
+ pr_warn("tag set has unexpected nr_hw_queues: %d\n",
+ set->nr_hw_queues);
+ WARN_ON_ONCE(true);
+ submit_queues = 1;
+ poll_queues = 0;
+ }
+ }
+
+ for (i = 0, qoff = 0; i < set->nr_maps; i++) {
+ struct blk_mq_queue_map *map = &set->map[i];
+
+ switch (i) {
+ case HCTX_TYPE_DEFAULT:
+ map->nr_queues = submit_queues;
+ break;
+ case HCTX_TYPE_READ:
+ map->nr_queues = 0;
+ continue;
+ case HCTX_TYPE_POLL:
+ map->nr_queues = poll_queues;
+ break;
+ }
+ map->queue_offset = qoff;
+ qoff += map->nr_queues;
+ blk_mq_map_queues(map);
+ }
+}
+
+static int null_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
+{
+ struct nullb_queue *nq = hctx->driver_data;
+ LIST_HEAD(list);
+ int nr = 0;
+ struct request *rq;
+
+ spin_lock(&nq->poll_lock);
+ list_splice_init(&nq->poll_list, &list);
+ list_for_each_entry(rq, &list, queuelist)
+ blk_mq_set_request_complete(rq);
+ spin_unlock(&nq->poll_lock);
+
+ while (!list_empty(&list)) {
+ struct nullb_cmd *cmd;
+ struct request *req;
+
+ req = list_first_entry(&list, struct request, queuelist);
+ list_del_init(&req->queuelist);
+ cmd = blk_mq_rq_to_pdu(req);
+ cmd->error = null_process_cmd(cmd, req_op(req), blk_rq_pos(req),
+ blk_rq_sectors(req));
+ if (!blk_mq_add_to_batch(req, iob, (__force int) cmd->error,
+ blk_mq_end_request_batch))
+ end_cmd(cmd);
+ nr++;
+ }
+
+ return nr;
+}
+
+static enum blk_eh_timer_return null_timeout_rq(struct request *rq)
+{
+ struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
+ struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
+
+ if (hctx->type == HCTX_TYPE_POLL) {
+ struct nullb_queue *nq = hctx->driver_data;
+
+ spin_lock(&nq->poll_lock);
+ /* The request may have completed meanwhile. */
+ if (blk_mq_request_completed(rq)) {
+ spin_unlock(&nq->poll_lock);
+ return BLK_EH_DONE;
+ }
+ list_del_init(&rq->queuelist);
+ spin_unlock(&nq->poll_lock);
+ }
+
+ 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 || hctx->type == HCTX_TYPE_POLL)
+ 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 request *rq = bd->rq;
+ struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
+ struct nullb_queue *nq = hctx->driver_data;
+ sector_t nr_sectors = blk_rq_sectors(rq);
+ sector_t sector = blk_rq_pos(rq);
+ const bool is_poll = hctx->type == HCTX_TYPE_POLL;
+
+ might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
+
+ if (!is_poll && nq->dev->irqmode == NULL_IRQ_TIMER) {
+ hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ cmd->timer.function = null_cmd_timer_expired;
+ }
+ cmd->rq = rq;
+ cmd->error = BLK_STS_OK;
+ cmd->nq = nq;
+ cmd->fake_timeout = should_timeout_request(rq) ||
+ blk_should_fake_timeout(rq->q);
+
+ blk_mq_start_request(rq);
+
+ if (should_requeue_request(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;
+ blk_mq_requeue_request(rq, true);
+ return BLK_STS_OK;
+ }
+
+ if (is_poll) {
+ spin_lock(&nq->poll_lock);
+ list_add_tail(&rq->queuelist, &nq->poll_list);
+ spin_unlock(&nq->poll_lock);
+ return BLK_STS_OK;
+ }
+ if (cmd->fake_timeout)
+ return BLK_STS_OK;
+
+ return null_handle_cmd(cmd, sector, nr_sectors, req_op(rq));
+}
+
+static void cleanup_queue(struct nullb_queue *nq)
+{
+ bitmap_free(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;
+ INIT_LIST_HEAD(&nq->poll_list);
+ spin_lock_init(&nq->poll_lock);
+}
+
+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;
+
+ if (should_init_hctx_fail(nullb->dev))
+ return -EFAULT;
+
+ 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,
+ .poll = null_poll,
+ .map_queues = null_map_queues,
+ .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);
+ }
+
+ put_disk(nullb->disk);
+ if (dev->queue_mode == NULL_Q_MQ &&
+ nullb->tag_set == &nullb->__tag_set)
+ blk_mq_free_tag_set(nullb->tag_set);
+ 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->memory_backed) {
+ nullb->dev->discard = false;
+ pr_info("discard option is ignored without memory backing\n");
+ 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;
+ blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
+}
+
+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;
+
+ nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL);
+ if (!nq->cmds)
+ return -ENOMEM;
+
+ nq->tag_map = bitmap_zalloc(nq->queue_depth, 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)
+{
+ int nqueues = nr_cpu_ids;
+
+ if (g_poll_queues)
+ nqueues += g_poll_queues;
+
+ nullb->queues = kcalloc(nqueues, 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 = nullb->disk;
+
+ set_capacity(disk, size);
+
+ disk->major = null_major;
+ disk->first_minor = nullb->index;
+ disk->minors = 1;
+ if (queue_is_mq(nullb->q))
+ disk->fops = &null_rq_ops;
+ else
+ disk->fops = &null_bio_ops;
+ disk->private_data = nullb;
+ 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;
+ }
+
+ return add_disk(disk);
+}
+
+static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
+{
+ unsigned int flags = BLK_MQ_F_SHOULD_MERGE;
+ int hw_queues, numa_node;
+ unsigned int queue_depth;
+ int poll_queues;
+
+ if (nullb) {
+ hw_queues = nullb->dev->submit_queues;
+ poll_queues = nullb->dev->poll_queues;
+ queue_depth = nullb->dev->hw_queue_depth;
+ numa_node = nullb->dev->home_node;
+ if (nullb->dev->no_sched)
+ flags |= BLK_MQ_F_NO_SCHED;
+ if (nullb->dev->shared_tag_bitmap)
+ flags |= BLK_MQ_F_TAG_HCTX_SHARED;
+ if (nullb->dev->blocking)
+ flags |= BLK_MQ_F_BLOCKING;
+ } else {
+ hw_queues = g_submit_queues;
+ poll_queues = g_poll_queues;
+ queue_depth = g_hw_queue_depth;
+ numa_node = g_home_node;
+ if (g_no_sched)
+ flags |= BLK_MQ_F_NO_SCHED;
+ if (g_shared_tag_bitmap)
+ flags |= BLK_MQ_F_TAG_HCTX_SHARED;
+ if (g_blocking)
+ flags |= BLK_MQ_F_BLOCKING;
+ }
+
+ set->ops = &null_mq_ops;
+ set->cmd_size = sizeof(struct nullb_cmd);
+ set->flags = flags;
+ set->driver_data = nullb;
+ set->nr_hw_queues = hw_queues;
+ set->queue_depth = queue_depth;
+ set->numa_node = numa_node;
+ if (poll_queues) {
+ set->nr_hw_queues += poll_queues;
+ set->nr_maps = 3;
+ } else {
+ set->nr_maps = 1;
+ }
+
+ 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->prev_submit_queues = dev->submit_queues;
+
+ if (dev->poll_queues > g_poll_queues)
+ dev->poll_queues = g_poll_queues;
+ dev->prev_poll_queues = dev->poll_queues;
+
+ 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;
+
+ nullb->tag_set->timeout = 5 * HZ;
+ nullb->disk = blk_mq_alloc_disk(nullb->tag_set, nullb);
+ if (IS_ERR(nullb->disk)) {
+ rv = PTR_ERR(nullb->disk);
+ goto out_cleanup_tags;
+ }
+ nullb->q = nullb->disk->queue;
+ } else if (dev->queue_mode == NULL_Q_BIO) {
+ rv = -ENOMEM;
+ nullb->disk = blk_alloc_disk(nullb->dev->home_node);
+ if (!nullb->disk)
+ goto out_cleanup_queues;
+
+ nullb->q = nullb->disk->queue;
+ rv = init_driver_queues(nullb);
+ if (rv)
+ goto out_cleanup_disk;
+ }
+
+ 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_disk;
+ }
+
+ nullb->q->queuedata = nullb;
+ blk_queue_flag_set(QUEUE_FLAG_NONROT, 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);
+ if (dev->max_sectors)
+ blk_queue_max_hw_sectors(nullb->q, dev->max_sectors);
+
+ if (dev->virt_boundary)
+ blk_queue_virt_boundary(nullb->q, PAGE_SIZE - 1);
+
+ null_config_discard(nullb);
+
+ if (config_item_name(&dev->group.cg_item)) {
+ /* Use configfs dir name as the device name */
+ snprintf(nullb->disk_name, sizeof(nullb->disk_name),
+ "%s", config_item_name(&dev->group.cg_item));
+ } else {
+ 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);
+
+ pr_info("disk %s created\n", nullb->disk_name);
+
+ return 0;
+
+out_ida_free:
+ ida_free(&nullb_indexes, nullb->index);
+out_cleanup_zone:
+ null_free_zoned_dev(dev);
+out_cleanup_disk:
+ put_disk(nullb->disk);
+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 struct nullb *null_find_dev_by_name(const char *name)
+{
+ struct nullb *nullb = NULL, *nb;
+
+ mutex_lock(&lock);
+ list_for_each_entry(nb, &nullb_list, list) {
+ if (strcmp(nb->disk_name, name) == 0) {
+ nullb = nb;
+ break;
+ }
+ }
+ mutex_unlock(&lock);
+
+ return nullb;
+}
+
+static int null_create_dev(void)
+{
+ struct nullb_device *dev;
+ int ret;
+
+ dev = null_alloc_dev();
+ if (!dev)
+ return -ENOMEM;
+
+ ret = null_add_dev(dev);
+ if (ret) {
+ null_free_dev(dev);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void null_destroy_dev(struct nullb *nullb)
+{
+ struct nullb_device *dev = nullb->dev;
+
+ null_del_dev(nullb);
+ null_free_device_storage(dev, false);
+ null_free_dev(dev);
+}
+
+static int __init null_init(void)
+{
+ int ret = 0;
+ unsigned int i;
+ struct nullb *nullb;
+
+ 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 (!null_setup_fault())
+ return -EINVAL;
+
+ if (g_queue_mode == NULL_Q_RQ) {
+ pr_err("legacy IO path is 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++) {
+ ret = null_create_dev();
+ if (ret)
+ 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);
+ null_destroy_dev(nullb);
+ }
+ 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)) {
+ nullb = list_entry(nullb_list.next, struct nullb, list);
+ null_destroy_dev(nullb);
+ }
+ 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");