1 files changed, 612 insertions, 0 deletions

diff --git a/kernel/block/blk-sysfs.c b/kernel/block/blk-sysfs.c
new file mode 100644
index 000000000..2b8fd302f
--- /dev/null
+++ b/kernel/block/blk-sysfs.c
@@ -0,0 +1,612 @@
+/*
+ * Functions related to sysfs handling
+ */
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/blktrace_api.h>
+#include <linux/blk-mq.h>
+
+#include "blk.h"
+#include "blk-cgroup.h"
+#include "blk-mq.h"
+
+struct queue_sysfs_entry {
+	struct attribute attr;
+	ssize_t (*show)(struct request_queue *, char *);
+	ssize_t (*store)(struct request_queue *, const char *, size_t);
+};
+
+static ssize_t
+queue_var_show(unsigned long var, char *page)
+{
+	return sprintf(page, "%lu\n", var);
+}
+
+static ssize_t
+queue_var_store(unsigned long *var, const char *page, size_t count)
+{
+	int err;
+	unsigned long v;
+
+	err = kstrtoul(page, 10, &v);
+	if (err || v > UINT_MAX)
+		return -EINVAL;
+
+	*var = v;
+
+	return count;
+}
+
+static ssize_t queue_requests_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(q->nr_requests, (page));
+}
+
+static ssize_t
+queue_requests_store(struct request_queue *q, const char *page, size_t count)
+{
+	unsigned long nr;
+	int ret, err;
+
+	if (!q->request_fn && !q->mq_ops)
+		return -EINVAL;
+
+	ret = queue_var_store(&nr, page, count);
+	if (ret < 0)
+		return ret;
+
+	if (nr < BLKDEV_MIN_RQ)
+		nr = BLKDEV_MIN_RQ;
+
+	if (q->request_fn)
+		err = blk_update_nr_requests(q, nr);
+	else
+		err = blk_mq_update_nr_requests(q, nr);
+
+	if (err)
+		return err;
+
+	return ret;
+}
+
+static ssize_t queue_ra_show(struct request_queue *q, char *page)
+{
+	unsigned long ra_kb = q->backing_dev_info.ra_pages <<
+					(PAGE_CACHE_SHIFT - 10);
+
+	return queue_var_show(ra_kb, (page));
+}
+
+static ssize_t
+queue_ra_store(struct request_queue *q, const char *page, size_t count)
+{
+	unsigned long ra_kb;
+	ssize_t ret = queue_var_store(&ra_kb, page, count);
+
+	if (ret < 0)
+		return ret;
+
+	q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
+
+	return ret;
+}
+
+static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
+{
+	int max_sectors_kb = queue_max_sectors(q) >> 1;
+
+	return queue_var_show(max_sectors_kb, (page));
+}
+
+static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(queue_max_segments(q), (page));
+}
+
+static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(q->limits.max_integrity_segments, (page));
+}
+
+static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
+{
+	if (blk_queue_cluster(q))
+		return queue_var_show(queue_max_segment_size(q), (page));
+
+	return queue_var_show(PAGE_CACHE_SIZE, (page));
+}
+
+static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(queue_logical_block_size(q), page);
+}
+
+static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(queue_physical_block_size(q), page);
+}
+
+static ssize_t queue_io_min_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(queue_io_min(q), page);
+}
+
+static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(queue_io_opt(q), page);
+}
+
+static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(q->limits.discard_granularity, page);
+}
+
+static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
+{
+	return sprintf(page, "%llu\n",
+		       (unsigned long long)q->limits.max_discard_sectors << 9);
+}
+
+static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(queue_discard_zeroes_data(q), page);
+}
+
+static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
+{
+	return sprintf(page, "%llu\n",
+		(unsigned long long)q->limits.max_write_same_sectors << 9);
+}
+
+
+static ssize_t
+queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
+{
+	unsigned long max_sectors_kb,
+		max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
+			page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
+	ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
+
+	if (ret < 0)
+		return ret;
+
+	if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
+		return -EINVAL;
+
+	spin_lock_irq(q->queue_lock);
+	q->limits.max_sectors = max_sectors_kb << 1;
+	spin_unlock_irq(q->queue_lock);
+
+	return ret;
+}
+
+static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
+{
+	int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
+
+	return queue_var_show(max_hw_sectors_kb, (page));
+}
+
+#define QUEUE_SYSFS_BIT_FNS(name, flag, neg)				\
+static ssize_t								\
+queue_show_##name(struct request_queue *q, char *page)			\
+{									\
+	int bit;							\
+	bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);		\
+	return queue_var_show(neg ? !bit : bit, page);			\
+}									\
+static ssize_t								\
+queue_store_##name(struct request_queue *q, const char *page, size_t count) \
+{									\
+	unsigned long val;						\
+	ssize_t ret;							\
+	ret = queue_var_store(&val, page, count);			\
+	if (ret < 0)							\
+		 return ret;						\
+	if (neg)							\
+		val = !val;						\
+									\
+	spin_lock_irq(q->queue_lock);					\
+	if (val)							\
+		queue_flag_set(QUEUE_FLAG_##flag, q);			\
+	else								\
+		queue_flag_clear(QUEUE_FLAG_##flag, q);			\
+	spin_unlock_irq(q->queue_lock);					\
+	return ret;							\
+}
+
+QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
+QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
+QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
+#undef QUEUE_SYSFS_BIT_FNS
+
+static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
+{
+	return queue_var_show((blk_queue_nomerges(q) << 1) |
+			       blk_queue_noxmerges(q), page);
+}
+
+static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
+				    size_t count)
+{
+	unsigned long nm;
+	ssize_t ret = queue_var_store(&nm, page, count);
+
+	if (ret < 0)
+		return ret;
+
+	spin_lock_irq(q->queue_lock);
+	queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
+	queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
+	if (nm == 2)
+		queue_flag_set(QUEUE_FLAG_NOMERGES, q);
+	else if (nm)
+		queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
+	spin_unlock_irq(q->queue_lock);
+
+	return ret;
+}
+
+static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
+{
+	bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
+	bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
+
+	return queue_var_show(set << force, page);
+}
+
+static ssize_t
+queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
+{
+	ssize_t ret = -EINVAL;
+#ifdef CONFIG_SMP
+	unsigned long val;
+
+	ret = queue_var_store(&val, page, count);
+	if (ret < 0)
+		return ret;
+
+	spin_lock_irq(q->queue_lock);
+	if (val == 2) {
+		queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
+		queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
+	} else if (val == 1) {
+		queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
+		queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
+	} else if (val == 0) {
+		queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
+		queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
+	}
+	spin_unlock_irq(q->queue_lock);
+#endif
+	return ret;
+}
+
+static struct queue_sysfs_entry queue_requests_entry = {
+	.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_requests_show,
+	.store = queue_requests_store,
+};
+
+static struct queue_sysfs_entry queue_ra_entry = {
+	.attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_ra_show,
+	.store = queue_ra_store,
+};
+
+static struct queue_sysfs_entry queue_max_sectors_entry = {
+	.attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_max_sectors_show,
+	.store = queue_max_sectors_store,
+};
+
+static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
+	.attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
+	.show = queue_max_hw_sectors_show,
+};
+
+static struct queue_sysfs_entry queue_max_segments_entry = {
+	.attr = {.name = "max_segments", .mode = S_IRUGO },
+	.show = queue_max_segments_show,
+};
+
+static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
+	.attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
+	.show = queue_max_integrity_segments_show,
+};
+
+static struct queue_sysfs_entry queue_max_segment_size_entry = {
+	.attr = {.name = "max_segment_size", .mode = S_IRUGO },
+	.show = queue_max_segment_size_show,
+};
+
+static struct queue_sysfs_entry queue_iosched_entry = {
+	.attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
+	.show = elv_iosched_show,
+	.store = elv_iosched_store,
+};
+
+static struct queue_sysfs_entry queue_hw_sector_size_entry = {
+	.attr = {.name = "hw_sector_size", .mode = S_IRUGO },
+	.show = queue_logical_block_size_show,
+};
+
+static struct queue_sysfs_entry queue_logical_block_size_entry = {
+	.attr = {.name = "logical_block_size", .mode = S_IRUGO },
+	.show = queue_logical_block_size_show,
+};
+
+static struct queue_sysfs_entry queue_physical_block_size_entry = {
+	.attr = {.name = "physical_block_size", .mode = S_IRUGO },
+	.show = queue_physical_block_size_show,
+};
+
+static struct queue_sysfs_entry queue_io_min_entry = {
+	.attr = {.name = "minimum_io_size", .mode = S_IRUGO },
+	.show = queue_io_min_show,
+};
+
+static struct queue_sysfs_entry queue_io_opt_entry = {
+	.attr = {.name = "optimal_io_size", .mode = S_IRUGO },
+	.show = queue_io_opt_show,
+};
+
+static struct queue_sysfs_entry queue_discard_granularity_entry = {
+	.attr = {.name = "discard_granularity", .mode = S_IRUGO },
+	.show = queue_discard_granularity_show,
+};
+
+static struct queue_sysfs_entry queue_discard_max_entry = {
+	.attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
+	.show = queue_discard_max_show,
+};
+
+static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
+	.attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
+	.show = queue_discard_zeroes_data_show,
+};
+
+static struct queue_sysfs_entry queue_write_same_max_entry = {
+	.attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
+	.show = queue_write_same_max_show,
+};
+
+static struct queue_sysfs_entry queue_nonrot_entry = {
+	.attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_show_nonrot,
+	.store = queue_store_nonrot,
+};
+
+static struct queue_sysfs_entry queue_nomerges_entry = {
+	.attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_nomerges_show,
+	.store = queue_nomerges_store,
+};
+
+static struct queue_sysfs_entry queue_rq_affinity_entry = {
+	.attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_rq_affinity_show,
+	.store = queue_rq_affinity_store,
+};
+
+static struct queue_sysfs_entry queue_iostats_entry = {
+	.attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_show_iostats,
+	.store = queue_store_iostats,
+};
+
+static struct queue_sysfs_entry queue_random_entry = {
+	.attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_show_random,
+	.store = queue_store_random,
+};
+
+static struct attribute *default_attrs[] = {
+	&queue_requests_entry.attr,
+	&queue_ra_entry.attr,
+	&queue_max_hw_sectors_entry.attr,
+	&queue_max_sectors_entry.attr,
+	&queue_max_segments_entry.attr,
+	&queue_max_integrity_segments_entry.attr,
+	&queue_max_segment_size_entry.attr,
+	&queue_iosched_entry.attr,
+	&queue_hw_sector_size_entry.attr,
+	&queue_logical_block_size_entry.attr,
+	&queue_physical_block_size_entry.attr,
+	&queue_io_min_entry.attr,
+	&queue_io_opt_entry.attr,
+	&queue_discard_granularity_entry.attr,
+	&queue_discard_max_entry.attr,
+	&queue_discard_zeroes_data_entry.attr,
+	&queue_write_same_max_entry.attr,
+	&queue_nonrot_entry.attr,
+	&queue_nomerges_entry.attr,
+	&queue_rq_affinity_entry.attr,
+	&queue_iostats_entry.attr,
+	&queue_random_entry.attr,
+	NULL,
+};
+
+#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
+
+static ssize_t
+queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
+{
+	struct queue_sysfs_entry *entry = to_queue(attr);
+	struct request_queue *q =
+		container_of(kobj, struct request_queue, kobj);
+	ssize_t res;
+
+	if (!entry->show)
+		return -EIO;
+	mutex_lock(&q->sysfs_lock);
+	if (blk_queue_dying(q)) {
+		mutex_unlock(&q->sysfs_lock);
+		return -ENOENT;
+	}
+	res = entry->show(q, page);
+	mutex_unlock(&q->sysfs_lock);
+	return res;
+}
+
+static ssize_t
+queue_attr_store(struct kobject *kobj, struct attribute *attr,
+		    const char *page, size_t length)
+{
+	struct queue_sysfs_entry *entry = to_queue(attr);
+	struct request_queue *q;
+	ssize_t res;
+
+	if (!entry->store)
+		return -EIO;
+
+	q = container_of(kobj, struct request_queue, kobj);
+	mutex_lock(&q->sysfs_lock);
+	if (blk_queue_dying(q)) {
+		mutex_unlock(&q->sysfs_lock);
+		return -ENOENT;
+	}
+	res = entry->store(q, page, length);
+	mutex_unlock(&q->sysfs_lock);
+	return res;
+}
+
+static void blk_free_queue_rcu(struct rcu_head *rcu_head)
+{
+	struct request_queue *q = container_of(rcu_head, struct request_queue,
+					       rcu_head);
+	kmem_cache_free(blk_requestq_cachep, q);
+}
+
+/**
+ * blk_release_queue: - release a &struct request_queue when it is no longer needed
+ * @kobj:    the kobj belonging to the request queue to be released
+ *
+ * Description:
+ *     blk_release_queue is the pair to blk_init_queue() or
+ *     blk_queue_make_request().  It should be called when a request queue is
+ *     being released; typically when a block device is being de-registered.
+ *     Currently, its primary task it to free all the &struct request
+ *     structures that were allocated to the queue and the queue itself.
+ *
+ * Note:
+ *     The low level driver must have finished any outstanding requests first
+ *     via blk_cleanup_queue().
+ **/
+static void blk_release_queue(struct kobject *kobj)
+{
+	struct request_queue *q =
+		container_of(kobj, struct request_queue, kobj);
+
+	blkcg_exit_queue(q);
+
+	if (q->elevator) {
+		spin_lock_irq(q->queue_lock);
+		ioc_clear_queue(q);
+		spin_unlock_irq(q->queue_lock);
+		elevator_exit(q->elevator);
+	}
+
+	blk_exit_rl(&q->root_rl);
+
+	if (q->queue_tags)
+		__blk_queue_free_tags(q);
+
+	if (!q->mq_ops)
+		blk_free_flush_queue(q->fq);
+	else
+		blk_mq_release(q);
+
+	blk_trace_shutdown(q);
+
+	ida_simple_remove(&blk_queue_ida, q->id);
+	call_rcu(&q->rcu_head, blk_free_queue_rcu);
+}
+
+static const struct sysfs_ops queue_sysfs_ops = {
+	.show	= queue_attr_show,
+	.store	= queue_attr_store,
+};
+
+struct kobj_type blk_queue_ktype = {
+	.sysfs_ops	= &queue_sysfs_ops,
+	.default_attrs	= default_attrs,
+	.release	= blk_release_queue,
+};
+
+int blk_register_queue(struct gendisk *disk)
+{
+	int ret;
+	struct device *dev = disk_to_dev(disk);
+	struct request_queue *q = disk->queue;
+
+	if (WARN_ON(!q))
+		return -ENXIO;
+
+	/*
+	 * SCSI probing may synchronously create and destroy a lot of
+	 * request_queues for non-existent devices.  Shutting down a fully
+	 * functional queue takes measureable wallclock time as RCU grace
+	 * periods are involved.  To avoid excessive latency in these
+	 * cases, a request_queue starts out in a degraded mode which is
+	 * faster to shut down and is made fully functional here as
+	 * request_queues for non-existent devices never get registered.
+	 */
+	if (!blk_queue_init_done(q)) {
+		queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
+		blk_queue_bypass_end(q);
+		if (q->mq_ops)
+			blk_mq_finish_init(q);
+	}
+
+	ret = blk_trace_init_sysfs(dev);
+	if (ret)
+		return ret;
+
+	ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
+	if (ret < 0) {
+		blk_trace_remove_sysfs(dev);
+		return ret;
+	}
+
+	kobject_uevent(&q->kobj, KOBJ_ADD);
+
+	if (q->mq_ops)
+		blk_mq_register_disk(disk);
+
+	if (!q->request_fn)
+		return 0;
+
+	ret = elv_register_queue(q);
+	if (ret) {
+		kobject_uevent(&q->kobj, KOBJ_REMOVE);
+		kobject_del(&q->kobj);
+		blk_trace_remove_sysfs(dev);
+		kobject_put(&dev->kobj);
+		return ret;
+	}
+
+	return 0;
+}
+
+void blk_unregister_queue(struct gendisk *disk)
+{
+	struct request_queue *q = disk->queue;
+
+	if (WARN_ON(!q))
+		return;
+
+	if (q->mq_ops)
+		blk_mq_unregister_disk(disk);
+
+	if (q->request_fn)
+		elv_unregister_queue(q);
+
+	kobject_uevent(&q->kobj, KOBJ_REMOVE);
+	kobject_del(&q->kobj);
+	blk_trace_remove_sysfs(disk_to_dev(disk));
+	kobject_put(&disk_to_dev(disk)->kobj);
+}