Initial import

1 files changed, 1673 insertions, 0 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
new file mode 100644
index 000000000..5d93a6645
--- /dev/null
+++ b/include/linux/blkdev.h
@@ -0,0 +1,1673 @@
+#ifndef _LINUX_BLKDEV_H
+#define _LINUX_BLKDEV_H
+
+#include <linux/sched.h>
+
+#ifdef CONFIG_BLOCK
+
+#include <linux/major.h>
+#include <linux/genhd.h>
+#include <linux/list.h>
+#include <linux/llist.h>
+#include <linux/timer.h>
+#include <linux/workqueue.h>
+#include <linux/pagemap.h>
+#include <linux/backing-dev.h>
+#include <linux/wait.h>
+#include <linux/mempool.h>
+#include <linux/bio.h>
+#include <linux/stringify.h>
+#include <linux/gfp.h>
+#include <linux/bsg.h>
+#include <linux/smp.h>
+#include <linux/rcupdate.h>
+#include <linux/percpu-refcount.h>
+
+#include <asm/scatterlist.h>
+
+struct module;
+struct scsi_ioctl_command;
+
+struct request_queue;
+struct elevator_queue;
+struct request_pm_state;
+struct blk_trace;
+struct request;
+struct sg_io_hdr;
+struct bsg_job;
+struct blkcg_gq;
+struct blk_flush_queue;
+
+#define BLKDEV_MIN_RQ	4
+#define BLKDEV_MAX_RQ	128	/* Default maximum */
+
+/*
+ * Maximum number of blkcg policies allowed to be registered concurrently.
+ * Defined here to simplify include dependency.
+ */
+#define BLKCG_MAX_POLS		2
+
+struct request;
+typedef void (rq_end_io_fn)(struct request *, int);
+
+#define BLK_RL_SYNCFULL		(1U << 0)
+#define BLK_RL_ASYNCFULL	(1U << 1)
+
+struct request_list {
+	struct request_queue	*q;	/* the queue this rl belongs to */
+#ifdef CONFIG_BLK_CGROUP
+	struct blkcg_gq		*blkg;	/* blkg this request pool belongs to */
+#endif
+	/*
+	 * count[], starved[], and wait[] are indexed by
+	 * BLK_RW_SYNC/BLK_RW_ASYNC
+	 */
+	int			count[2];
+	int			starved[2];
+	mempool_t		*rq_pool;
+	wait_queue_head_t	wait[2];
+	unsigned int		flags;
+};
+
+/*
+ * request command types
+ */
+enum rq_cmd_type_bits {
+	REQ_TYPE_FS		= 1,	/* fs request */
+	REQ_TYPE_BLOCK_PC,		/* scsi command */
+	REQ_TYPE_SENSE,			/* sense request */
+	REQ_TYPE_PM_SUSPEND,		/* suspend request */
+	REQ_TYPE_PM_RESUME,		/* resume request */
+	REQ_TYPE_PM_SHUTDOWN,		/* shutdown request */
+	REQ_TYPE_SPECIAL,		/* driver defined type */
+	/*
+	 * for ATA/ATAPI devices. this really doesn't belong here, ide should
+	 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
+	 * private REQ_LB opcodes to differentiate what type of request this is
+	 */
+	REQ_TYPE_ATA_TASKFILE,
+	REQ_TYPE_ATA_PC,
+};
+
+#define BLK_MAX_CDB	16
+
+/*
+ * Try to put the fields that are referenced together in the same cacheline.
+ *
+ * If you modify this structure, make sure to update blk_rq_init() and
+ * especially blk_mq_rq_ctx_init() to take care of the added fields.
+ */
+struct request {
+	struct list_head queuelist;
+	union {
+		struct call_single_data csd;
+		unsigned long fifo_time;
+	};
+
+	struct request_queue *q;
+	struct blk_mq_ctx *mq_ctx;
+
+	u64 cmd_flags;
+	enum rq_cmd_type_bits cmd_type;
+	unsigned long atomic_flags;
+
+	int cpu;
+
+	/* the following two fields are internal, NEVER access directly */
+	unsigned int __data_len;	/* total data len */
+	sector_t __sector;		/* sector cursor */
+
+	struct bio *bio;
+	struct bio *biotail;
+
+	/*
+	 * The hash is used inside the scheduler, and killed once the
+	 * request reaches the dispatch list. The ipi_list is only used
+	 * to queue the request for softirq completion, which is long
+	 * after the request has been unhashed (and even removed from
+	 * the dispatch list).
+	 */
+	union {
+		struct hlist_node hash;	/* merge hash */
+		struct list_head ipi_list;
+	};
+
+	/*
+	 * The rb_node is only used inside the io scheduler, requests
+	 * are pruned when moved to the dispatch queue. So let the
+	 * completion_data share space with the rb_node.
+	 */
+	union {
+		struct rb_node rb_node;	/* sort/lookup */
+		void *completion_data;
+	};
+
+	/*
+	 * Three pointers are available for the IO schedulers, if they need
+	 * more they have to dynamically allocate it.  Flush requests are
+	 * never put on the IO scheduler. So let the flush fields share
+	 * space with the elevator data.
+	 */
+	union {
+		struct {
+			struct io_cq		*icq;
+			void			*priv[2];
+		} elv;
+
+		struct {
+			unsigned int		seq;
+			struct list_head	list;
+			rq_end_io_fn		*saved_end_io;
+		} flush;
+	};
+
+	struct gendisk *rq_disk;
+	struct hd_struct *part;
+	unsigned long start_time;
+#ifdef CONFIG_BLK_CGROUP
+	struct request_list *rl;		/* rl this rq is alloced from */
+	unsigned long long start_time_ns;
+	unsigned long long io_start_time_ns;    /* when passed to hardware */
+#endif
+	/* Number of scatter-gather DMA addr+len pairs after
+	 * physical address coalescing is performed.
+	 */
+	unsigned short nr_phys_segments;
+#if defined(CONFIG_BLK_DEV_INTEGRITY)
+	unsigned short nr_integrity_segments;
+#endif
+
+	unsigned short ioprio;
+
+	void *special;		/* opaque pointer available for LLD use */
+
+	int tag;
+	int errors;
+
+	/*
+	 * when request is used as a packet command carrier
+	 */
+	unsigned char __cmd[BLK_MAX_CDB];
+	unsigned char *cmd;
+	unsigned short cmd_len;
+
+	unsigned int extra_len;	/* length of alignment and padding */
+	unsigned int sense_len;
+	unsigned int resid_len;	/* residual count */
+	void *sense;
+
+	unsigned long deadline;
+	struct list_head timeout_list;
+	unsigned int timeout;
+	int retries;
+
+	/*
+	 * completion callback.
+	 */
+	rq_end_io_fn *end_io;
+	void *end_io_data;
+
+	/* for bidi */
+	struct request *next_rq;
+};
+
+static inline unsigned short req_get_ioprio(struct request *req)
+{
+	return req->ioprio;
+}
+
+/*
+ * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
+ * requests. Some step values could eventually be made generic.
+ */
+struct request_pm_state
+{
+	/* PM state machine step value, currently driver specific */
+	int	pm_step;
+	/* requested PM state value (S1, S2, S3, S4, ...) */
+	u32	pm_state;
+	void*	data;		/* for driver use */
+};
+
+#include <linux/elevator.h>
+
+struct blk_queue_ctx;
+
+typedef void (request_fn_proc) (struct request_queue *q);
+typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
+typedef int (prep_rq_fn) (struct request_queue *, struct request *);
+typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
+
+struct bio_vec;
+struct bvec_merge_data {
+	struct block_device *bi_bdev;
+	sector_t bi_sector;
+	unsigned bi_size;
+	unsigned long bi_rw;
+};
+typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
+			     struct bio_vec *);
+typedef void (softirq_done_fn)(struct request *);
+typedef int (dma_drain_needed_fn)(struct request *);
+typedef int (lld_busy_fn) (struct request_queue *q);
+typedef int (bsg_job_fn) (struct bsg_job *);
+
+enum blk_eh_timer_return {
+	BLK_EH_NOT_HANDLED,
+	BLK_EH_HANDLED,
+	BLK_EH_RESET_TIMER,
+};
+
+typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
+
+enum blk_queue_state {
+	Queue_down,
+	Queue_up,
+};
+
+struct blk_queue_tag {
+	struct request **tag_index;	/* map of busy tags */
+	unsigned long *tag_map;		/* bit map of free/busy tags */
+	int busy;			/* current depth */
+	int max_depth;			/* what we will send to device */
+	int real_max_depth;		/* what the array can hold */
+	atomic_t refcnt;		/* map can be shared */
+	int alloc_policy;		/* tag allocation policy */
+	int next_tag;			/* next tag */
+};
+#define BLK_TAG_ALLOC_FIFO 0 /* allocate starting from 0 */
+#define BLK_TAG_ALLOC_RR 1 /* allocate starting from last allocated tag */
+
+#define BLK_SCSI_MAX_CMDS	(256)
+#define BLK_SCSI_CMD_PER_LONG	(BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
+
+struct queue_limits {
+	unsigned long		bounce_pfn;
+	unsigned long		seg_boundary_mask;
+
+	unsigned int		max_hw_sectors;
+	unsigned int		chunk_sectors;
+	unsigned int		max_sectors;
+	unsigned int		max_segment_size;
+	unsigned int		physical_block_size;
+	unsigned int		alignment_offset;
+	unsigned int		io_min;
+	unsigned int		io_opt;
+	unsigned int		max_discard_sectors;
+	unsigned int		max_write_same_sectors;
+	unsigned int		discard_granularity;
+	unsigned int		discard_alignment;
+
+	unsigned short		logical_block_size;
+	unsigned short		max_segments;
+	unsigned short		max_integrity_segments;
+
+	unsigned char		misaligned;
+	unsigned char		discard_misaligned;
+	unsigned char		cluster;
+	unsigned char		discard_zeroes_data;
+	unsigned char		raid_partial_stripes_expensive;
+};
+
+struct request_queue {
+	/*
+	 * Together with queue_head for cacheline sharing
+	 */
+	struct list_head	queue_head;
+	struct request		*last_merge;
+	struct elevator_queue	*elevator;
+	int			nr_rqs[2];	/* # allocated [a]sync rqs */
+	int			nr_rqs_elvpriv;	/* # allocated rqs w/ elvpriv */
+
+	/*
+	 * If blkcg is not used, @q->root_rl serves all requests.  If blkcg
+	 * is used, root blkg allocates from @q->root_rl and all other
+	 * blkgs from their own blkg->rl.  Which one to use should be
+	 * determined using bio_request_list().
+	 */
+	struct request_list	root_rl;
+
+	request_fn_proc		*request_fn;
+	make_request_fn		*make_request_fn;
+	prep_rq_fn		*prep_rq_fn;
+	unprep_rq_fn		*unprep_rq_fn;
+	merge_bvec_fn		*merge_bvec_fn;
+	softirq_done_fn		*softirq_done_fn;
+	rq_timed_out_fn		*rq_timed_out_fn;
+	dma_drain_needed_fn	*dma_drain_needed;
+	lld_busy_fn		*lld_busy_fn;
+
+	struct blk_mq_ops	*mq_ops;
+
+	unsigned int		*mq_map;
+
+	/* sw queues */
+	struct blk_mq_ctx __percpu	*queue_ctx;
+	unsigned int		nr_queues;
+
+	/* hw dispatch queues */
+	struct blk_mq_hw_ctx	**queue_hw_ctx;
+	unsigned int		nr_hw_queues;
+
+	/*
+	 * Dispatch queue sorting
+	 */
+	sector_t		end_sector;
+	struct request		*boundary_rq;
+
+	/*
+	 * Delayed queue handling
+	 */
+	struct delayed_work	delay_work;
+
+	struct backing_dev_info	backing_dev_info;
+
+	/*
+	 * The queue owner gets to use this for whatever they like.
+	 * ll_rw_blk doesn't touch it.
+	 */
+	void			*queuedata;
+
+	/*
+	 * various queue flags, see QUEUE_* below
+	 */
+	unsigned long		queue_flags;
+
+	/*
+	 * ida allocated id for this queue.  Used to index queues from
+	 * ioctx.
+	 */
+	int			id;
+
+	/*
+	 * queue needs bounce pages for pages above this limit
+	 */
+	gfp_t			bounce_gfp;
+
+	/*
+	 * protects queue structures from reentrancy. ->__queue_lock should
+	 * _never_ be used directly, it is queue private. always use
+	 * ->queue_lock.
+	 */
+	spinlock_t		__queue_lock;
+	spinlock_t		*queue_lock;
+
+	/*
+	 * queue kobject
+	 */
+	struct kobject kobj;
+
+	/*
+	 * mq queue kobject
+	 */
+	struct kobject mq_kobj;
+
+#ifdef CONFIG_PM
+	struct device		*dev;
+	int			rpm_status;
+	unsigned int		nr_pending;
+#endif
+
+	/*
+	 * queue settings
+	 */
+	unsigned long		nr_requests;	/* Max # of requests */
+	unsigned int		nr_congestion_on;
+	unsigned int		nr_congestion_off;
+	unsigned int		nr_batching;
+
+	unsigned int		dma_drain_size;
+	void			*dma_drain_buffer;
+	unsigned int		dma_pad_mask;
+	unsigned int		dma_alignment;
+
+	struct blk_queue_tag	*queue_tags;
+	struct list_head	tag_busy_list;
+
+	unsigned int		nr_sorted;
+	unsigned int		in_flight[2];
+	/*
+	 * Number of active block driver functions for which blk_drain_queue()
+	 * must wait. Must be incremented around functions that unlock the
+	 * queue_lock internally, e.g. scsi_request_fn().
+	 */
+	unsigned int		request_fn_active;
+
+	unsigned int		rq_timeout;
+	struct timer_list	timeout;
+	struct list_head	timeout_list;
+
+	struct list_head	icq_list;
+#ifdef CONFIG_BLK_CGROUP
+	DECLARE_BITMAP		(blkcg_pols, BLKCG_MAX_POLS);
+	struct blkcg_gq		*root_blkg;
+	struct list_head	blkg_list;
+#endif
+
+	struct queue_limits	limits;
+
+	/*
+	 * sg stuff
+	 */
+	unsigned int		sg_timeout;
+	unsigned int		sg_reserved_size;
+	int			node;
+#ifdef CONFIG_BLK_DEV_IO_TRACE
+	struct blk_trace	*blk_trace;
+#endif
+	/*
+	 * for flush operations
+	 */
+	unsigned int		flush_flags;
+	unsigned int		flush_not_queueable:1;
+	struct blk_flush_queue	*fq;
+
+	struct list_head	requeue_list;
+	spinlock_t		requeue_lock;
+	struct work_struct	requeue_work;
+
+	struct mutex		sysfs_lock;
+
+	int			bypass_depth;
+	int			mq_freeze_depth;
+
+#if defined(CONFIG_BLK_DEV_BSG)
+	bsg_job_fn		*bsg_job_fn;
+	int			bsg_job_size;
+	struct bsg_class_device bsg_dev;
+#endif
+
+#ifdef CONFIG_BLK_DEV_THROTTLING
+	/* Throttle data */
+	struct throtl_data *td;
+#endif
+	struct rcu_head		rcu_head;
+	wait_queue_head_t	mq_freeze_wq;
+	struct percpu_ref	mq_usage_counter;
+	struct list_head	all_q_node;
+
+	struct blk_mq_tag_set	*tag_set;
+	struct list_head	tag_set_list;
+};
+
+#define QUEUE_FLAG_QUEUED	1	/* uses generic tag queueing */
+#define QUEUE_FLAG_STOPPED	2	/* queue is stopped */
+#define	QUEUE_FLAG_SYNCFULL	3	/* read queue has been filled */
+#define QUEUE_FLAG_ASYNCFULL	4	/* write queue has been filled */
+#define QUEUE_FLAG_DYING	5	/* queue being torn down */
+#define QUEUE_FLAG_BYPASS	6	/* act as dumb FIFO queue */
+#define QUEUE_FLAG_BIDI		7	/* queue supports bidi requests */
+#define QUEUE_FLAG_NOMERGES     8	/* disable merge attempts */
+#define QUEUE_FLAG_SAME_COMP	9	/* complete on same CPU-group */
+#define QUEUE_FLAG_FAIL_IO     10	/* fake timeout */
+#define QUEUE_FLAG_STACKABLE   11	/* supports request stacking */
+#define QUEUE_FLAG_NONROT      12	/* non-rotational device (SSD) */
+#define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
+#define QUEUE_FLAG_IO_STAT     13	/* do IO stats */
+#define QUEUE_FLAG_DISCARD     14	/* supports DISCARD */
+#define QUEUE_FLAG_NOXMERGES   15	/* No extended merges */
+#define QUEUE_FLAG_ADD_RANDOM  16	/* Contributes to random pool */
+#define QUEUE_FLAG_SECDISCARD  17	/* supports SECDISCARD */
+#define QUEUE_FLAG_SAME_FORCE  18	/* force complete on same CPU */
+#define QUEUE_FLAG_DEAD        19	/* queue tear-down finished */
+#define QUEUE_FLAG_INIT_DONE   20	/* queue is initialized */
+#define QUEUE_FLAG_NO_SG_MERGE 21	/* don't attempt to merge SG segments*/
+#define QUEUE_FLAG_SG_GAPS     22	/* queue doesn't support SG gaps */
+
+#define QUEUE_FLAG_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
+				 (1 << QUEUE_FLAG_STACKABLE)	|	\
+				 (1 << QUEUE_FLAG_SAME_COMP)	|	\
+				 (1 << QUEUE_FLAG_ADD_RANDOM))
+
+#define QUEUE_FLAG_MQ_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
+				 (1 << QUEUE_FLAG_STACKABLE)	|	\
+				 (1 << QUEUE_FLAG_SAME_COMP))
+
+static inline void queue_lockdep_assert_held(struct request_queue *q)
+{
+	if (q->queue_lock)
+		lockdep_assert_held(q->queue_lock);
+}
+
+static inline void queue_flag_set_unlocked(unsigned int flag,
+					   struct request_queue *q)
+{
+	__set_bit(flag, &q->queue_flags);
+}
+
+static inline int queue_flag_test_and_clear(unsigned int flag,
+					    struct request_queue *q)
+{
+	queue_lockdep_assert_held(q);
+
+	if (test_bit(flag, &q->queue_flags)) {
+		__clear_bit(flag, &q->queue_flags);
+		return 1;
+	}
+
+	return 0;
+}
+
+static inline int queue_flag_test_and_set(unsigned int flag,
+					  struct request_queue *q)
+{
+	queue_lockdep_assert_held(q);
+
+	if (!test_bit(flag, &q->queue_flags)) {
+		__set_bit(flag, &q->queue_flags);
+		return 0;
+	}
+
+	return 1;
+}
+
+static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
+{
+	queue_lockdep_assert_held(q);
+	__set_bit(flag, &q->queue_flags);
+}
+
+static inline void queue_flag_clear_unlocked(unsigned int flag,
+					     struct request_queue *q)
+{
+	__clear_bit(flag, &q->queue_flags);
+}
+
+static inline int queue_in_flight(struct request_queue *q)
+{
+	return q->in_flight[0] + q->in_flight[1];
+}
+
+static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
+{
+	queue_lockdep_assert_held(q);
+	__clear_bit(flag, &q->queue_flags);
+}
+
+#define blk_queue_tagged(q)	test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
+#define blk_queue_stopped(q)	test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
+#define blk_queue_dying(q)	test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
+#define blk_queue_dead(q)	test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
+#define blk_queue_bypass(q)	test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
+#define blk_queue_init_done(q)	test_bit(QUEUE_FLAG_INIT_DONE, &(q)->queue_flags)
+#define blk_queue_nomerges(q)	test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
+#define blk_queue_noxmerges(q)	\
+	test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
+#define blk_queue_nonrot(q)	test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
+#define blk_queue_io_stat(q)	test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
+#define blk_queue_add_random(q)	test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
+#define blk_queue_stackable(q)	\
+	test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
+#define blk_queue_discard(q)	test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
+#define blk_queue_secdiscard(q)	(blk_queue_discard(q) && \
+	test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
+
+#define blk_noretry_request(rq) \
+	((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
+			     REQ_FAILFAST_DRIVER))
+
+#define blk_account_rq(rq) \
+	(((rq)->cmd_flags & REQ_STARTED) && \
+	 ((rq)->cmd_type == REQ_TYPE_FS))
+
+#define blk_pm_request(rq)	\
+	((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
+	 (rq)->cmd_type == REQ_TYPE_PM_RESUME)
+
+#define blk_rq_cpu_valid(rq)	((rq)->cpu != -1)
+#define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
+/* rq->queuelist of dequeued request must be list_empty() */
+#define blk_queued_rq(rq)	(!list_empty(&(rq)->queuelist))
+
+#define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)
+
+#define rq_data_dir(rq)		(((rq)->cmd_flags & 1) != 0)
+
+/*
+ * Driver can handle struct request, if it either has an old style
+ * request_fn defined, or is blk-mq based.
+ */
+static inline bool queue_is_rq_based(struct request_queue *q)
+{
+	return q->request_fn || q->mq_ops;
+}
+
+static inline unsigned int blk_queue_cluster(struct request_queue *q)
+{
+	return q->limits.cluster;
+}
+
+/*
+ * We regard a request as sync, if either a read or a sync write
+ */
+static inline bool rw_is_sync(unsigned int rw_flags)
+{
+	return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
+}
+
+static inline bool rq_is_sync(struct request *rq)
+{
+	return rw_is_sync(rq->cmd_flags);
+}
+
+static inline bool blk_rl_full(struct request_list *rl, bool sync)
+{
+	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
+
+	return rl->flags & flag;
+}
+
+static inline void blk_set_rl_full(struct request_list *rl, bool sync)
+{
+	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
+
+	rl->flags |= flag;
+}
+
+static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
+{
+	unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
+
+	rl->flags &= ~flag;
+}
+
+static inline bool rq_mergeable(struct request *rq)
+{
+	if (rq->cmd_type != REQ_TYPE_FS)
+		return false;
+
+	if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
+		return false;
+
+	return true;
+}
+
+static inline bool blk_check_merge_flags(unsigned int flags1,
+					 unsigned int flags2)
+{
+	if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD))
+		return false;
+
+	if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE))
+		return false;
+
+	if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME))
+		return false;
+
+	return true;
+}
+
+static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
+{
+	if (bio_data(a) == bio_data(b))
+		return true;
+
+	return false;
+}
+
+/*
+ * q->prep_rq_fn return values
+ */
+#define BLKPREP_OK		0	/* serve it */
+#define BLKPREP_KILL		1	/* fatal error, kill */
+#define BLKPREP_DEFER		2	/* leave on queue */
+
+extern unsigned long blk_max_low_pfn, blk_max_pfn;
+
+/*
+ * standard bounce addresses:
+ *
+ * BLK_BOUNCE_HIGH	: bounce all highmem pages
+ * BLK_BOUNCE_ANY	: don't bounce anything
+ * BLK_BOUNCE_ISA	: bounce pages above ISA DMA boundary
+ */
+
+#if BITS_PER_LONG == 32
+#define BLK_BOUNCE_HIGH		((u64)blk_max_low_pfn << PAGE_SHIFT)
+#else
+#define BLK_BOUNCE_HIGH		-1ULL
+#endif
+#define BLK_BOUNCE_ANY		(-1ULL)
+#define BLK_BOUNCE_ISA		(DMA_BIT_MASK(24))
+
+/*
+ * default timeout for SG_IO if none specified
+ */
+#define BLK_DEFAULT_SG_TIMEOUT	(60 * HZ)
+#define BLK_MIN_SG_TIMEOUT	(7 * HZ)
+
+#ifdef CONFIG_BOUNCE
+extern int init_emergency_isa_pool(void);
+extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
+#else
+static inline int init_emergency_isa_pool(void)
+{
+	return 0;
+}
+static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
+{
+}
+#endif /* CONFIG_MMU */
+
+struct rq_map_data {
+	struct page **pages;
+	int page_order;
+	int nr_entries;
+	unsigned long offset;
+	int null_mapped;
+	int from_user;
+};
+
+struct req_iterator {
+	struct bvec_iter iter;
+	struct bio *bio;
+};
+
+/* This should not be used directly - use rq_for_each_segment */
+#define for_each_bio(_bio)		\
+	for (; _bio; _bio = _bio->bi_next)
+#define __rq_for_each_bio(_bio, rq)	\
+	if ((rq->bio))			\
+		for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
+
+#define rq_for_each_segment(bvl, _rq, _iter)			\
+	__rq_for_each_bio(_iter.bio, _rq)			\
+		bio_for_each_segment(bvl, _iter.bio, _iter.iter)
+
+#define rq_iter_last(bvec, _iter)				\
+		(_iter.bio->bi_next == NULL &&			\
+		 bio_iter_last(bvec, _iter.iter))
+
+#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+# error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
+#endif
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+extern void rq_flush_dcache_pages(struct request *rq);
+#else
+static inline void rq_flush_dcache_pages(struct request *rq)
+{
+}
+#endif
+
+extern int blk_register_queue(struct gendisk *disk);
+extern void blk_unregister_queue(struct gendisk *disk);
+extern void generic_make_request(struct bio *bio);
+extern void blk_rq_init(struct request_queue *q, struct request *rq);
+extern void blk_put_request(struct request *);
+extern void __blk_put_request(struct request_queue *, struct request *);
+extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
+extern struct request *blk_make_request(struct request_queue *, struct bio *,
+					gfp_t);
+extern void blk_rq_set_block_pc(struct request *);
+extern void blk_requeue_request(struct request_queue *, struct request *);
+extern void blk_add_request_payload(struct request *rq, struct page *page,
+		unsigned int len);
+extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
+extern int blk_lld_busy(struct request_queue *q);
+extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
+			     struct bio_set *bs, gfp_t gfp_mask,
+			     int (*bio_ctr)(struct bio *, struct bio *, void *),
+			     void *data);
+extern void blk_rq_unprep_clone(struct request *rq);
+extern int blk_insert_cloned_request(struct request_queue *q,
+				     struct request *rq);
+extern void blk_delay_queue(struct request_queue *, unsigned long);
+extern void blk_recount_segments(struct request_queue *, struct bio *);
+extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
+extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
+			      unsigned int, void __user *);
+extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
+			  unsigned int, void __user *);
+extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
+			 struct scsi_ioctl_command __user *);
+
+/*
+ * A queue has just exitted congestion.  Note this in the global counter of
+ * congested queues, and wake up anyone who was waiting for requests to be
+ * put back.
+ */
+static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
+{
+	clear_bdi_congested(&q->backing_dev_info, sync);
+}
+
+/*
+ * A queue has just entered congestion.  Flag that in the queue's VM-visible
+ * state flags and increment the global gounter of congested queues.
+ */
+static inline void blk_set_queue_congested(struct request_queue *q, int sync)
+{
+	set_bdi_congested(&q->backing_dev_info, sync);
+}
+
+extern void blk_start_queue(struct request_queue *q);
+extern void blk_stop_queue(struct request_queue *q);
+extern void blk_sync_queue(struct request_queue *q);
+extern void __blk_stop_queue(struct request_queue *q);
+extern void __blk_run_queue(struct request_queue *q);
+extern void blk_run_queue(struct request_queue *);
+extern void blk_run_queue_async(struct request_queue *q);
+extern int blk_rq_map_user(struct request_queue *, struct request *,
+			   struct rq_map_data *, void __user *, unsigned long,
+			   gfp_t);
+extern int blk_rq_unmap_user(struct bio *);
+extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
+extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
+			       struct rq_map_data *, const struct iov_iter *,
+			       gfp_t);
+extern int blk_execute_rq(struct request_queue *, struct gendisk *,
+			  struct request *, int);
+extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
+				  struct request *, int, rq_end_io_fn *);
+
+static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
+{
+	return bdev->bd_disk->queue;	/* this is never NULL */
+}
+
+/*
+ * blk_rq_pos()			: the current sector
+ * blk_rq_bytes()		: bytes left in the entire request
+ * blk_rq_cur_bytes()		: bytes left in the current segment
+ * blk_rq_err_bytes()		: bytes left till the next error boundary
+ * blk_rq_sectors()		: sectors left in the entire request
+ * blk_rq_cur_sectors()		: sectors left in the current segment
+ */
+static inline sector_t blk_rq_pos(const struct request *rq)
+{
+	return rq->__sector;
+}
+
+static inline unsigned int blk_rq_bytes(const struct request *rq)
+{
+	return rq->__data_len;
+}
+
+static inline int blk_rq_cur_bytes(const struct request *rq)
+{
+	return rq->bio ? bio_cur_bytes(rq->bio) : 0;
+}
+
+extern unsigned int blk_rq_err_bytes(const struct request *rq);
+
+static inline unsigned int blk_rq_sectors(const struct request *rq)
+{
+	return blk_rq_bytes(rq) >> 9;
+}
+
+static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
+{
+	return blk_rq_cur_bytes(rq) >> 9;
+}
+
+static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
+						     unsigned int cmd_flags)
+{
+	if (unlikely(cmd_flags & REQ_DISCARD))
+		return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
+
+	if (unlikely(cmd_flags & REQ_WRITE_SAME))
+		return q->limits.max_write_same_sectors;
+
+	return q->limits.max_sectors;
+}
+
+/*
+ * Return maximum size of a request at given offset. Only valid for
+ * file system requests.
+ */
+static inline unsigned int blk_max_size_offset(struct request_queue *q,
+					       sector_t offset)
+{
+	if (!q->limits.chunk_sectors)
+		return q->limits.max_sectors;
+
+	return q->limits.chunk_sectors -
+			(offset & (q->limits.chunk_sectors - 1));
+}
+
+static inline unsigned int blk_rq_get_max_sectors(struct request *rq)
+{
+	struct request_queue *q = rq->q;
+
+	if (unlikely(rq->cmd_type == REQ_TYPE_BLOCK_PC))
+		return q->limits.max_hw_sectors;
+
+	if (!q->limits.chunk_sectors)
+		return blk_queue_get_max_sectors(q, rq->cmd_flags);
+
+	return min(blk_max_size_offset(q, blk_rq_pos(rq)),
+			blk_queue_get_max_sectors(q, rq->cmd_flags));
+}
+
+static inline unsigned int blk_rq_count_bios(struct request *rq)
+{
+	unsigned int nr_bios = 0;
+	struct bio *bio;
+
+	__rq_for_each_bio(bio, rq)
+		nr_bios++;
+
+	return nr_bios;
+}
+
+/*
+ * Request issue related functions.
+ */
+extern struct request *blk_peek_request(struct request_queue *q);
+extern void blk_start_request(struct request *rq);
+extern struct request *blk_fetch_request(struct request_queue *q);
+
+/*
+ * Request completion related functions.
+ *
+ * blk_update_request() completes given number of bytes and updates
+ * the request without completing it.
+ *
+ * blk_end_request() and friends.  __blk_end_request() must be called
+ * with the request queue spinlock acquired.
+ *
+ * Several drivers define their own end_request and call
+ * blk_end_request() for parts of the original function.
+ * This prevents code duplication in drivers.
+ */
+extern bool blk_update_request(struct request *rq, int error,
+			       unsigned int nr_bytes);
+extern void blk_finish_request(struct request *rq, int error);
+extern bool blk_end_request(struct request *rq, int error,
+			    unsigned int nr_bytes);
+extern void blk_end_request_all(struct request *rq, int error);
+extern bool blk_end_request_cur(struct request *rq, int error);
+extern bool blk_end_request_err(struct request *rq, int error);
+extern bool __blk_end_request(struct request *rq, int error,
+			      unsigned int nr_bytes);
+extern void __blk_end_request_all(struct request *rq, int error);
+extern bool __blk_end_request_cur(struct request *rq, int error);
+extern bool __blk_end_request_err(struct request *rq, int error);
+
+extern void blk_complete_request(struct request *);
+extern void __blk_complete_request(struct request *);
+extern void blk_abort_request(struct request *);
+extern void blk_unprep_request(struct request *);
+
+/*
+ * Access functions for manipulating queue properties
+ */
+extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
+					spinlock_t *lock, int node_id);
+extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
+extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
+						      request_fn_proc *, spinlock_t *);
+extern void blk_cleanup_queue(struct request_queue *);
+extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
+extern void blk_queue_bounce_limit(struct request_queue *, u64);
+extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
+extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
+extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int);
+extern void blk_queue_max_segments(struct request_queue *, unsigned short);
+extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
+extern void blk_queue_max_discard_sectors(struct request_queue *q,
+		unsigned int max_discard_sectors);
+extern void blk_queue_max_write_same_sectors(struct request_queue *q,
+		unsigned int max_write_same_sectors);
+extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
+extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
+extern void blk_queue_alignment_offset(struct request_queue *q,
+				       unsigned int alignment);
+extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
+extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
+extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
+extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
+extern void blk_set_default_limits(struct queue_limits *lim);
+extern void blk_set_stacking_limits(struct queue_limits *lim);
+extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
+			    sector_t offset);
+extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
+			    sector_t offset);
+extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
+			      sector_t offset);
+extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
+extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
+extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
+extern int blk_queue_dma_drain(struct request_queue *q,
+			       dma_drain_needed_fn *dma_drain_needed,
+			       void *buf, unsigned int size);
+extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
+extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
+extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
+extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
+extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
+extern void blk_queue_dma_alignment(struct request_queue *, int);
+extern void blk_queue_update_dma_alignment(struct request_queue *, int);
+extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
+extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
+extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
+extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
+extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
+extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
+
+extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
+extern void blk_dump_rq_flags(struct request *, char *);
+extern long nr_blockdev_pages(void);
+
+bool __must_check blk_get_queue(struct request_queue *);
+struct request_queue *blk_alloc_queue(gfp_t);
+struct request_queue *blk_alloc_queue_node(gfp_t, int);
+extern void blk_put_queue(struct request_queue *);
+
+/*
+ * block layer runtime pm functions
+ */
+#ifdef CONFIG_PM
+extern void blk_pm_runtime_init(struct request_queue *q, struct device *dev);
+extern int blk_pre_runtime_suspend(struct request_queue *q);
+extern void blk_post_runtime_suspend(struct request_queue *q, int err);
+extern void blk_pre_runtime_resume(struct request_queue *q);
+extern void blk_post_runtime_resume(struct request_queue *q, int err);
+#else
+static inline void blk_pm_runtime_init(struct request_queue *q,
+	struct device *dev) {}
+static inline int blk_pre_runtime_suspend(struct request_queue *q)
+{
+	return -ENOSYS;
+}
+static inline void blk_post_runtime_suspend(struct request_queue *q, int err) {}
+static inline void blk_pre_runtime_resume(struct request_queue *q) {}
+static inline void blk_post_runtime_resume(struct request_queue *q, int err) {}
+#endif
+
+/*
+ * blk_plug permits building a queue of related requests by holding the I/O
+ * fragments for a short period. This allows merging of sequential requests
+ * into single larger request. As the requests are moved from a per-task list to
+ * the device's request_queue in a batch, this results in improved scalability
+ * as the lock contention for request_queue lock is reduced.
+ *
+ * It is ok not to disable preemption when adding the request to the plug list
+ * or when attempting a merge, because blk_schedule_flush_list() will only flush
+ * the plug list when the task sleeps by itself. For details, please see
+ * schedule() where blk_schedule_flush_plug() is called.
+ */
+struct blk_plug {
+	struct list_head list; /* requests */
+	struct list_head mq_list; /* blk-mq requests */
+	struct list_head cb_list; /* md requires an unplug callback */
+};
+#define BLK_MAX_REQUEST_COUNT 16
+
+struct blk_plug_cb;
+typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
+struct blk_plug_cb {
+	struct list_head list;
+	blk_plug_cb_fn callback;
+	void *data;
+};
+extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
+					     void *data, int size);
+extern void blk_start_plug(struct blk_plug *);
+extern void blk_finish_plug(struct blk_plug *);
+extern void blk_flush_plug_list(struct blk_plug *, bool);
+
+static inline void blk_flush_plug(struct task_struct *tsk)
+{
+	struct blk_plug *plug = tsk->plug;
+
+	if (plug)
+		blk_flush_plug_list(plug, false);
+}
+
+static inline void blk_schedule_flush_plug(struct task_struct *tsk)
+{
+	struct blk_plug *plug = tsk->plug;
+
+	if (plug)
+		blk_flush_plug_list(plug, true);
+}
+
+static inline bool blk_needs_flush_plug(struct task_struct *tsk)
+{
+	struct blk_plug *plug = tsk->plug;
+
+	return plug &&
+		(!list_empty(&plug->list) ||
+		 !list_empty(&plug->mq_list) ||
+		 !list_empty(&plug->cb_list));
+}
+
+/*
+ * tag stuff
+ */
+extern int blk_queue_start_tag(struct request_queue *, struct request *);
+extern struct request *blk_queue_find_tag(struct request_queue *, int);
+extern void blk_queue_end_tag(struct request_queue *, struct request *);
+extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int);
+extern void blk_queue_free_tags(struct request_queue *);
+extern int blk_queue_resize_tags(struct request_queue *, int);
+extern void blk_queue_invalidate_tags(struct request_queue *);
+extern struct blk_queue_tag *blk_init_tags(int, int);
+extern void blk_free_tags(struct blk_queue_tag *);
+
+static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
+						int tag)
+{
+	if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
+		return NULL;
+	return bqt->tag_index[tag];
+}
+
+#define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
+
+extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
+extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
+		sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
+extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
+		sector_t nr_sects, gfp_t gfp_mask, struct page *page);
+extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+		sector_t nr_sects, gfp_t gfp_mask, bool discard);
+static inline int sb_issue_discard(struct super_block *sb, sector_t block,
+		sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
+{
+	return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
+				    nr_blocks << (sb->s_blocksize_bits - 9),
+				    gfp_mask, flags);
+}
+static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
+		sector_t nr_blocks, gfp_t gfp_mask)
+{
+	return blkdev_issue_zeroout(sb->s_bdev,
+				    block << (sb->s_blocksize_bits - 9),
+				    nr_blocks << (sb->s_blocksize_bits - 9),
+				    gfp_mask, true);
+}
+
+extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
+
+enum blk_default_limits {
+	BLK_MAX_SEGMENTS	= 128,
+	BLK_SAFE_MAX_SECTORS	= 255,
+	BLK_MAX_SEGMENT_SIZE	= 65536,
+	BLK_SEG_BOUNDARY_MASK	= 0xFFFFFFFFUL,
+};
+
+#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
+
+static inline unsigned long queue_bounce_pfn(struct request_queue *q)
+{
+	return q->limits.bounce_pfn;
+}
+
+static inline unsigned long queue_segment_boundary(struct request_queue *q)
+{
+	return q->limits.seg_boundary_mask;
+}
+
+static inline unsigned int queue_max_sectors(struct request_queue *q)
+{
+	return q->limits.max_sectors;
+}
+
+static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
+{
+	return q->limits.max_hw_sectors;
+}
+
+static inline unsigned short queue_max_segments(struct request_queue *q)
+{
+	return q->limits.max_segments;
+}
+
+static inline unsigned int queue_max_segment_size(struct request_queue *q)
+{
+	return q->limits.max_segment_size;
+}
+
+static inline unsigned short queue_logical_block_size(struct request_queue *q)
+{
+	int retval = 512;
+
+	if (q && q->limits.logical_block_size)
+		retval = q->limits.logical_block_size;
+
+	return retval;
+}
+
+static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
+{
+	return queue_logical_block_size(bdev_get_queue(bdev));
+}
+
+static inline unsigned int queue_physical_block_size(struct request_queue *q)
+{
+	return q->limits.physical_block_size;
+}
+
+static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
+{
+	return queue_physical_block_size(bdev_get_queue(bdev));
+}
+
+static inline unsigned int queue_io_min(struct request_queue *q)
+{
+	return q->limits.io_min;
+}
+
+static inline int bdev_io_min(struct block_device *bdev)
+{
+	return queue_io_min(bdev_get_queue(bdev));
+}
+
+static inline unsigned int queue_io_opt(struct request_queue *q)
+{
+	return q->limits.io_opt;
+}
+
+static inline int bdev_io_opt(struct block_device *bdev)
+{
+	return queue_io_opt(bdev_get_queue(bdev));
+}
+
+static inline int queue_alignment_offset(struct request_queue *q)
+{
+	if (q->limits.misaligned)
+		return -1;
+
+	return q->limits.alignment_offset;
+}
+
+static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
+{
+	unsigned int granularity = max(lim->physical_block_size, lim->io_min);
+	unsigned int alignment = sector_div(sector, granularity >> 9) << 9;
+
+	return (granularity + lim->alignment_offset - alignment) % granularity;
+}
+
+static inline int bdev_alignment_offset(struct block_device *bdev)
+{
+	struct request_queue *q = bdev_get_queue(bdev);
+
+	if (q->limits.misaligned)
+		return -1;
+
+	if (bdev != bdev->bd_contains)
+		return bdev->bd_part->alignment_offset;
+
+	return q->limits.alignment_offset;
+}
+
+static inline int queue_discard_alignment(struct request_queue *q)
+{
+	if (q->limits.discard_misaligned)
+		return -1;
+
+	return q->limits.discard_alignment;
+}
+
+static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
+{
+	unsigned int alignment, granularity, offset;
+
+	if (!lim->max_discard_sectors)
+		return 0;
+
+	/* Why are these in bytes, not sectors? */
+	alignment = lim->discard_alignment >> 9;
+	granularity = lim->discard_granularity >> 9;
+	if (!granularity)
+		return 0;
+
+	/* Offset of the partition start in 'granularity' sectors */
+	offset = sector_div(sector, granularity);
+
+	/* And why do we do this modulus *again* in blkdev_issue_discard()? */
+	offset = (granularity + alignment - offset) % granularity;
+
+	/* Turn it back into bytes, gaah */
+	return offset << 9;
+}
+
+static inline int bdev_discard_alignment(struct block_device *bdev)
+{
+	struct request_queue *q = bdev_get_queue(bdev);
+
+	if (bdev != bdev->bd_contains)
+		return bdev->bd_part->discard_alignment;
+
+	return q->limits.discard_alignment;
+}
+
+static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
+{
+	if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
+		return 1;
+
+	return 0;
+}
+
+static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
+{
+	return queue_discard_zeroes_data(bdev_get_queue(bdev));
+}
+
+static inline unsigned int bdev_write_same(struct block_device *bdev)
+{
+	struct request_queue *q = bdev_get_queue(bdev);
+
+	if (q)
+		return q->limits.max_write_same_sectors;
+
+	return 0;
+}
+
+static inline int queue_dma_alignment(struct request_queue *q)
+{
+	return q ? q->dma_alignment : 511;
+}
+
+static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
+				 unsigned int len)
+{
+	unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
+	return !(addr & alignment) && !(len & alignment);
+}
+
+/* assumes size > 256 */
+static inline unsigned int blksize_bits(unsigned int size)
+{
+	unsigned int bits = 8;
+	do {
+		bits++;
+		size >>= 1;
+	} while (size > 256);
+	return bits;
+}
+
+static inline unsigned int block_size(struct block_device *bdev)
+{
+	return bdev->bd_block_size;
+}
+
+static inline bool queue_flush_queueable(struct request_queue *q)
+{
+	return !q->flush_not_queueable;
+}
+
+typedef struct {struct page *v;} Sector;
+
+unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
+
+static inline void put_dev_sector(Sector p)
+{
+	page_cache_release(p.v);
+}
+
+struct work_struct;
+int kblockd_schedule_work(struct work_struct *work);
+int kblockd_schedule_delayed_work(struct delayed_work *dwork, unsigned long delay);
+int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);
+
+#ifdef CONFIG_BLK_CGROUP
+/*
+ * This should not be using sched_clock(). A real patch is in progress
+ * to fix this up, until that is in place we need to disable preemption
+ * around sched_clock() in this function and set_io_start_time_ns().
+ */
+static inline void set_start_time_ns(struct request *req)
+{
+	preempt_disable();
+	req->start_time_ns = sched_clock();
+	preempt_enable();
+}
+
+static inline void set_io_start_time_ns(struct request *req)
+{
+	preempt_disable();
+	req->io_start_time_ns = sched_clock();
+	preempt_enable();
+}
+
+static inline uint64_t rq_start_time_ns(struct request *req)
+{
+        return req->start_time_ns;
+}
+
+static inline uint64_t rq_io_start_time_ns(struct request *req)
+{
+        return req->io_start_time_ns;
+}
+#else
+static inline void set_start_time_ns(struct request *req) {}
+static inline void set_io_start_time_ns(struct request *req) {}
+static inline uint64_t rq_start_time_ns(struct request *req)
+{
+	return 0;
+}
+static inline uint64_t rq_io_start_time_ns(struct request *req)
+{
+	return 0;
+}
+#endif
+
+#define MODULE_ALIAS_BLOCKDEV(major,minor) \
+	MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
+#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
+	MODULE_ALIAS("block-major-" __stringify(major) "-*")
+
+#if defined(CONFIG_BLK_DEV_INTEGRITY)
+
+enum blk_integrity_flags {
+	BLK_INTEGRITY_VERIFY		= 1 << 0,
+	BLK_INTEGRITY_GENERATE		= 1 << 1,
+	BLK_INTEGRITY_DEVICE_CAPABLE	= 1 << 2,
+	BLK_INTEGRITY_IP_CHECKSUM	= 1 << 3,
+};
+
+struct blk_integrity_iter {
+	void			*prot_buf;
+	void			*data_buf;
+	sector_t		seed;
+	unsigned int		data_size;
+	unsigned short		interval;
+	const char		*disk_name;
+};
+
+typedef int (integrity_processing_fn) (struct blk_integrity_iter *);
+
+struct blk_integrity {
+	integrity_processing_fn	*generate_fn;
+	integrity_processing_fn	*verify_fn;
+
+	unsigned short		flags;
+	unsigned short		tuple_size;
+	unsigned short		interval;
+	unsigned short		tag_size;
+
+	const char		*name;
+
+	struct kobject		kobj;
+};
+
+extern bool blk_integrity_is_initialized(struct gendisk *);
+extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
+extern void blk_integrity_unregister(struct gendisk *);
+extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
+extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
+				   struct scatterlist *);
+extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
+extern bool blk_integrity_merge_rq(struct request_queue *, struct request *,
+				   struct request *);
+extern bool blk_integrity_merge_bio(struct request_queue *, struct request *,
+				    struct bio *);
+
+static inline
+struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
+{
+	return bdev->bd_disk->integrity;
+}
+
+static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
+{
+	return disk->integrity;
+}
+
+static inline bool blk_integrity_rq(struct request *rq)
+{
+	return rq->cmd_flags & REQ_INTEGRITY;
+}
+
+static inline void blk_queue_max_integrity_segments(struct request_queue *q,
+						    unsigned int segs)
+{
+	q->limits.max_integrity_segments = segs;
+}
+
+static inline unsigned short
+queue_max_integrity_segments(struct request_queue *q)
+{
+	return q->limits.max_integrity_segments;
+}
+
+#else /* CONFIG_BLK_DEV_INTEGRITY */
+
+struct bio;
+struct block_device;
+struct gendisk;
+struct blk_integrity;
+
+static inline int blk_integrity_rq(struct request *rq)
+{
+	return 0;
+}
+static inline int blk_rq_count_integrity_sg(struct request_queue *q,
+					    struct bio *b)
+{
+	return 0;
+}
+static inline int blk_rq_map_integrity_sg(struct request_queue *q,
+					  struct bio *b,
+					  struct scatterlist *s)
+{
+	return 0;
+}
+static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
+{
+	return NULL;
+}
+static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
+{
+	return NULL;
+}
+static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
+{
+	return 0;
+}
+static inline int blk_integrity_register(struct gendisk *d,
+					 struct blk_integrity *b)
+{
+	return 0;
+}
+static inline void blk_integrity_unregister(struct gendisk *d)
+{
+}
+static inline void blk_queue_max_integrity_segments(struct request_queue *q,
+						    unsigned int segs)
+{
+}
+static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
+{
+	return 0;
+}
+static inline bool blk_integrity_merge_rq(struct request_queue *rq,
+					  struct request *r1,
+					  struct request *r2)
+{
+	return true;
+}
+static inline bool blk_integrity_merge_bio(struct request_queue *rq,
+					   struct request *r,
+					   struct bio *b)
+{
+	return true;
+}
+static inline bool blk_integrity_is_initialized(struct gendisk *g)
+{
+	return 0;
+}
+
+#endif /* CONFIG_BLK_DEV_INTEGRITY */
+
+struct block_device_operations {
+	int (*open) (struct block_device *, fmode_t);
+	void (*release) (struct gendisk *, fmode_t);
+	int (*rw_page)(struct block_device *, sector_t, struct page *, int rw);
+	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
+	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
+	long (*direct_access)(struct block_device *, sector_t,
+					void **, unsigned long *pfn, long size);
+	unsigned int (*check_events) (struct gendisk *disk,
+				      unsigned int clearing);
+	/* ->media_changed() is DEPRECATED, use ->check_events() instead */
+	int (*media_changed) (struct gendisk *);
+	void (*unlock_native_capacity) (struct gendisk *);
+	int (*revalidate_disk) (struct gendisk *);
+	int (*getgeo)(struct block_device *, struct hd_geometry *);
+	/* this callback is with swap_lock and sometimes page table lock held */
+	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
+	struct module *owner;
+};
+
+extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
+				 unsigned long);
+extern int bdev_read_page(struct block_device *, sector_t, struct page *);
+extern int bdev_write_page(struct block_device *, sector_t, struct page *,
+						struct writeback_control *);
+extern long bdev_direct_access(struct block_device *, sector_t, void **addr,
+						unsigned long *pfn, long size);
+#else /* CONFIG_BLOCK */
+
+struct block_device;
+
+/*
+ * stubs for when the block layer is configured out
+ */
+#define buffer_heads_over_limit 0
+
+static inline long nr_blockdev_pages(void)
+{
+	return 0;
+}
+
+struct blk_plug {
+};
+
+static inline void blk_start_plug(struct blk_plug *plug)
+{
+}
+
+static inline void blk_finish_plug(struct blk_plug *plug)
+{
+}
+
+static inline void blk_flush_plug(struct task_struct *task)
+{
+}
+
+static inline void blk_schedule_flush_plug(struct task_struct *task)
+{
+}
+
+
+static inline bool blk_needs_flush_plug(struct task_struct *tsk)
+{
+	return false;
+}
+
+static inline int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
+				     sector_t *error_sector)
+{
+	return 0;
+}
+
+#endif /* CONFIG_BLOCK */
+
+#endif