block: continue ll_rw_blk.c splitup

Adds files for barrier handling, rq execution, io context handling,
mapping data to requests, and queue settings.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 8 insertions, 1247 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 937f9d0b9bd5..2c73ed1a8131 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -20,7 +20,6 @@
 #include <linux/kernel_stat.h>
 #include <linux/string.h>
 #include <linux/init.h>
-#include <linux/bootmem.h>      /* for max_pfn/max_low_pfn */
 #include <linux/completion.h>
 #include <linux/slab.h>
 #include <linux/swap.h>
@@ -34,20 +33,9 @@
 
 #include "blk.h"
 
-/*
- * for max sense size
- */
-#include <scsi/scsi_cmnd.h>
-
-static void blk_unplug_work(struct work_struct *work);
-static void blk_unplug_timeout(unsigned long data);
 static void drive_stat_acct(struct request *rq, int new_io);
-static void init_request_from_bio(struct request *req, struct bio *bio);
 static int __make_request(struct request_queue *q, struct bio *bio);
-static struct io_context *current_io_context(gfp_t gfp_flags, int node);
 static void blk_recalc_rq_segments(struct request *rq);
-static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
-                            struct bio *bio);
 
 /*
  * For the allocated request tables
@@ -60,28 +48,12 @@ struct kmem_cache *request_cachep;
 struct kmem_cache *blk_requestq_cachep = NULL;
 
 /*
- * For io context allocations
- */
-static struct kmem_cache *iocontext_cachep;
-
-/*
  * Controlling structure to kblockd
  */
 static struct workqueue_struct *kblockd_workqueue;
 
-unsigned long blk_max_low_pfn, blk_max_pfn;
-
-EXPORT_SYMBOL(blk_max_low_pfn);
-EXPORT_SYMBOL(blk_max_pfn);
-
 static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
 
-/* Amount of time in which a process may batch requests */
-#define BLK_BATCH_TIME  (HZ/50UL)
-
-/* Number of requests a "batching" process may submit */
-#define BLK_BATCH_REQ   32
-
 void blk_queue_congestion_threshold(struct request_queue *q)
 {
         int nr;
@@ -117,113 +89,7 @@ struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
 }
 EXPORT_SYMBOL(blk_get_backing_dev_info);
 
-/**
- * blk_queue_prep_rq - set a prepare_request function for queue
- * @q:          queue
- * @pfn:        prepare_request function
- *
- * It's possible for a queue to register a prepare_request callback which
- * is invoked before the request is handed to the request_fn. The goal of
- * the function is to prepare a request for I/O, it can be used to build a
- * cdb from the request data for instance.
- *
- */
-void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn)
-{
-        q->prep_rq_fn = pfn;
-}
-
-EXPORT_SYMBOL(blk_queue_prep_rq);
-
-/**
- * blk_queue_merge_bvec - set a merge_bvec function for queue
- * @q:          queue
- * @mbfn:       merge_bvec_fn
- *
- * Usually queues have static limitations on the max sectors or segments that
- * we can put in a request. Stacking drivers may have some settings that
- * are dynamic, and thus we have to query the queue whether it is ok to
- * add a new bio_vec to a bio at a given offset or not. If the block device
- * has such limitations, it needs to register a merge_bvec_fn to control
- * the size of bio's sent to it. Note that a block device *must* allow a
- * single page to be added to an empty bio. The block device driver may want
- * to use the bio_split() function to deal with these bio's. By default
- * no merge_bvec_fn is defined for a queue, and only the fixed limits are
- * honored.
- */
-void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn)
-{
-        q->merge_bvec_fn = mbfn;
-}
-
-EXPORT_SYMBOL(blk_queue_merge_bvec);
-
-void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
-{
-        q->softirq_done_fn = fn;
-}
-
-EXPORT_SYMBOL(blk_queue_softirq_done);
-
-/**
- * blk_queue_make_request - define an alternate make_request function for a device
- * @q:  the request queue for the device to be affected
- * @mfn: the alternate make_request function
- *
- * Description:
- *    The normal way for &struct bios to be passed to a device
- *    driver is for them to be collected into requests on a request
- *    queue, and then to allow the device driver to select requests
- *    off that queue when it is ready.  This works well for many block
- *    devices. However some block devices (typically virtual devices
- *    such as md or lvm) do not benefit from the processing on the
- *    request queue, and are served best by having the requests passed
- *    directly to them.  This can be achieved by providing a function
- *    to blk_queue_make_request().
- *
- * Caveat:
- *    The driver that does this *must* be able to deal appropriately
- *    with buffers in "highmemory". This can be accomplished by either calling
- *    __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
- *    blk_queue_bounce() to create a buffer in normal memory.
- **/
-void blk_queue_make_request(struct request_queue * q, make_request_fn * mfn)
-{
-        /*
-         * set defaults
-         */
-        q->nr_requests = BLKDEV_MAX_RQ;
-        blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
-        blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
-        q->make_request_fn = mfn;
-        q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
-        q->backing_dev_info.state = 0;
-        q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
-        blk_queue_max_sectors(q, SAFE_MAX_SECTORS);
-        blk_queue_hardsect_size(q, 512);
-        blk_queue_dma_alignment(q, 511);
-        blk_queue_congestion_threshold(q);
-        q->nr_batching = BLK_BATCH_REQ;
-
-        q->unplug_thresh = 4;           /* hmm */
-        q->unplug_delay = (3 * HZ) / 1000;      /* 3 milliseconds */
-        if (q->unplug_delay == 0)
-                q->unplug_delay = 1;
-
-        INIT_WORK(&q->unplug_work, blk_unplug_work);
-
-        q->unplug_timer.function = blk_unplug_timeout;
-        q->unplug_timer.data = (unsigned long)q;
-
-        /*
-         * by default assume old behaviour and bounce for any highmem page
-         */
-        blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
-}
-
-EXPORT_SYMBOL(blk_queue_make_request);
-
-static void rq_init(struct request_queue *q, struct request *rq)
+void rq_init(struct request_queue *q, struct request *rq)
 {
         INIT_LIST_HEAD(&rq->queuelist);
         INIT_LIST_HEAD(&rq->donelist);
@@ -247,255 +113,6 @@ static void rq_init(struct request_queue *q, struct request *rq)
         rq->next_rq = NULL;
 }
 
-/**
- * blk_queue_ordered - does this queue support ordered writes
- * @q:        the request queue
- * @ordered:  one of QUEUE_ORDERED_*
- * @prepare_flush_fn: rq setup helper for cache flush ordered writes
- *
- * Description:
- *   For journalled file systems, doing ordered writes on a commit
- *   block instead of explicitly doing wait_on_buffer (which is bad
- *   for performance) can be a big win. Block drivers supporting this
- *   feature should call this function and indicate so.
- *
- **/
-int blk_queue_ordered(struct request_queue *q, unsigned ordered,
-                      prepare_flush_fn *prepare_flush_fn)
-{
-        if (ordered & (QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH) &&
-            prepare_flush_fn == NULL) {
-                printk(KERN_ERR "blk_queue_ordered: prepare_flush_fn required\n");
-                return -EINVAL;
-        }
-
-        if (ordered != QUEUE_ORDERED_NONE &&
-            ordered != QUEUE_ORDERED_DRAIN &&
-            ordered != QUEUE_ORDERED_DRAIN_FLUSH &&
-            ordered != QUEUE_ORDERED_DRAIN_FUA &&
-            ordered != QUEUE_ORDERED_TAG &&
-            ordered != QUEUE_ORDERED_TAG_FLUSH &&
-            ordered != QUEUE_ORDERED_TAG_FUA) {
-                printk(KERN_ERR "blk_queue_ordered: bad value %d\n", ordered);
-                return -EINVAL;
-        }
-
-        q->ordered = ordered;
-        q->next_ordered = ordered;
-        q->prepare_flush_fn = prepare_flush_fn;
-
-        return 0;
-}
-
-EXPORT_SYMBOL(blk_queue_ordered);
-
-/*
- * Cache flushing for ordered writes handling
- */
-inline unsigned blk_ordered_cur_seq(struct request_queue *q)
-{
-        if (!q->ordseq)
-                return 0;
-        return 1 << ffz(q->ordseq);
-}
-
-unsigned blk_ordered_req_seq(struct request *rq)
-{
-        struct request_queue *q = rq->q;
-
-        BUG_ON(q->ordseq == 0);
-
-        if (rq == &q->pre_flush_rq)
-                return QUEUE_ORDSEQ_PREFLUSH;
-        if (rq == &q->bar_rq)
-                return QUEUE_ORDSEQ_BAR;
-        if (rq == &q->post_flush_rq)
-                return QUEUE_ORDSEQ_POSTFLUSH;
-
-        /*
-         * !fs requests don't need to follow barrier ordering.  Always
-         * put them at the front.  This fixes the following deadlock.
-         *
-         * http://thread.gmane.org/gmane.linux.kernel/537473
-         */
-        if (!blk_fs_request(rq))
-                return QUEUE_ORDSEQ_DRAIN;
-
-        if ((rq->cmd_flags & REQ_ORDERED_COLOR) ==
-            (q->orig_bar_rq->cmd_flags & REQ_ORDERED_COLOR))
-                return QUEUE_ORDSEQ_DRAIN;
-        else
-                return QUEUE_ORDSEQ_DONE;
-}
-
-void blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
-{
-        struct request *rq;
-
-        if (error && !q->orderr)
-                q->orderr = error;
-
-        BUG_ON(q->ordseq & seq);
-        q->ordseq |= seq;
-
-        if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE)
-                return;
-
-        /*
-         * Okay, sequence complete.
-         */
-        q->ordseq = 0;
-        rq = q->orig_bar_rq;
-
-        if (__blk_end_request(rq, q->orderr, blk_rq_bytes(rq)))
-                BUG();
-}
-
-static void pre_flush_end_io(struct request *rq, int error)
-{
-        elv_completed_request(rq->q, rq);
-        blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_PREFLUSH, error);
-}
-
-static void bar_end_io(struct request *rq, int error)
-{
-        elv_completed_request(rq->q, rq);
-        blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_BAR, error);
-}
-
-static void post_flush_end_io(struct request *rq, int error)
-{
-        elv_completed_request(rq->q, rq);
-        blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_POSTFLUSH, error);
-}
-
-static void queue_flush(struct request_queue *q, unsigned which)
-{
-        struct request *rq;
-        rq_end_io_fn *end_io;
-
-        if (which == QUEUE_ORDERED_PREFLUSH) {
-                rq = &q->pre_flush_rq;
-                end_io = pre_flush_end_io;
-        } else {
-                rq = &q->post_flush_rq;
-                end_io = post_flush_end_io;
-        }
-
-        rq->cmd_flags = REQ_HARDBARRIER;
-        rq_init(q, rq);
-        rq->elevator_private = NULL;
-        rq->elevator_private2 = NULL;
-        rq->rq_disk = q->bar_rq.rq_disk;
-        rq->end_io = end_io;
-        q->prepare_flush_fn(q, rq);
-
-        elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
-}
-
-static inline struct request *start_ordered(struct request_queue *q,
-                                            struct request *rq)
-{
-        q->orderr = 0;
-        q->ordered = q->next_ordered;
-        q->ordseq |= QUEUE_ORDSEQ_STARTED;
-
-        /*
-         * Prep proxy barrier request.
-         */
-        blkdev_dequeue_request(rq);
-        q->orig_bar_rq = rq;
-        rq = &q->bar_rq;
-        rq->cmd_flags = 0;
-        rq_init(q, rq);
-        if (bio_data_dir(q->orig_bar_rq->bio) == WRITE)
-                rq->cmd_flags |= REQ_RW;
-        if (q->ordered & QUEUE_ORDERED_FUA)
-                rq->cmd_flags |= REQ_FUA;
-        rq->elevator_private = NULL;
-        rq->elevator_private2 = NULL;
-        init_request_from_bio(rq, q->orig_bar_rq->bio);
-        rq->end_io = bar_end_io;
-
-        /*
-         * Queue ordered sequence.  As we stack them at the head, we
-         * need to queue in reverse order.  Note that we rely on that
-         * no fs request uses ELEVATOR_INSERT_FRONT and thus no fs
-         * request gets inbetween ordered sequence. If this request is
-         * an empty barrier, we don't need to do a postflush ever since
-         * there will be no data written between the pre and post flush.
-         * Hence a single flush will suffice.
-         */
-        if ((q->ordered & QUEUE_ORDERED_POSTFLUSH) && !blk_empty_barrier(rq))
-                queue_flush(q, QUEUE_ORDERED_POSTFLUSH);
-        else
-                q->ordseq |= QUEUE_ORDSEQ_POSTFLUSH;
-
-        elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
-
-        if (q->ordered & QUEUE_ORDERED_PREFLUSH) {
-                queue_flush(q, QUEUE_ORDERED_PREFLUSH);
-                rq = &q->pre_flush_rq;
-        } else
-                q->ordseq |= QUEUE_ORDSEQ_PREFLUSH;
-
-        if ((q->ordered & QUEUE_ORDERED_TAG) || q->in_flight == 0)
-                q->ordseq |= QUEUE_ORDSEQ_DRAIN;
-        else
-                rq = NULL;
-
-        return rq;
-}
-
-int blk_do_ordered(struct request_queue *q, struct request **rqp)
-{
-        struct request *rq = *rqp;
-        const int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);
-
-        if (!q->ordseq) {
-                if (!is_barrier)
-                        return 1;
-
-                if (q->next_ordered != QUEUE_ORDERED_NONE) {
-                        *rqp = start_ordered(q, rq);
-                        return 1;
-                } else {
-                        /*
-                         * This can happen when the queue switches to
-                         * ORDERED_NONE while this request is on it.
-                         */
-                        blkdev_dequeue_request(rq);
-                        if (__blk_end_request(rq, -EOPNOTSUPP,
-                                              blk_rq_bytes(rq)))
-                                BUG();
-                        *rqp = NULL;
-                        return 0;
-                }
-        }
-
-        /*
-         * Ordered sequence in progress
-         */
-
-        /* Special requests are not subject to ordering rules. */
-        if (!blk_fs_request(rq) &&
-            rq != &q->pre_flush_rq && rq != &q->post_flush_rq)
-                return 1;
-
-        if (q->ordered & QUEUE_ORDERED_TAG) {
-                /* Ordered by tag.  Blocking the next barrier is enough. */
-                if (is_barrier && rq != &q->bar_rq)
-                        *rqp = NULL;
-        } else {
-                /* Ordered by draining.  Wait for turn. */
-                WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q));
-                if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q))
-                        *rqp = NULL;
-        }
-
-        return 1;
-}
-
 static void req_bio_endio(struct request *rq, struct bio *bio,
                           unsigned int nbytes, int error)
 {
@@ -528,279 +145,6 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
         }
 }
 
-/**
- * blk_queue_bounce_limit - set bounce buffer limit for queue
- * @q:  the request queue for the device
- * @dma_addr:   bus address limit
- *
- * Description:
- *    Different hardware can have different requirements as to what pages
- *    it can do I/O directly to. A low level driver can call
- *    blk_queue_bounce_limit to have lower memory pages allocated as bounce
- *    buffers for doing I/O to pages residing above @page.
- **/
-void blk_queue_bounce_limit(struct request_queue *q, u64 dma_addr)
-{
-        unsigned long bounce_pfn = dma_addr >> PAGE_SHIFT;
-        int dma = 0;
-
-        q->bounce_gfp = GFP_NOIO;
-#if BITS_PER_LONG == 64
-        /* Assume anything <= 4GB can be handled by IOMMU.
-           Actually some IOMMUs can handle everything, but I don't
-           know of a way to test this here. */
-        if (bounce_pfn < (min_t(u64,0xffffffff,BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
-                dma = 1;
-        q->bounce_pfn = max_low_pfn;
-#else
-        if (bounce_pfn < blk_max_low_pfn)
-                dma = 1;
-        q->bounce_pfn = bounce_pfn;
-#endif
-        if (dma) {
-                init_emergency_isa_pool();
-                q->bounce_gfp = GFP_NOIO | GFP_DMA;
-                q->bounce_pfn = bounce_pfn;
-        }
-}
-
-EXPORT_SYMBOL(blk_queue_bounce_limit);
-
-/**
- * blk_queue_max_sectors - set max sectors for a request for this queue
- * @q:  the request queue for the device
- * @max_sectors:  max sectors in the usual 512b unit
- *
- * Description:
- *    Enables a low level driver to set an upper limit on the size of
- *    received requests.
- **/
-void blk_queue_max_sectors(struct request_queue *q, unsigned int max_sectors)
-{
-        if ((max_sectors << 9) < PAGE_CACHE_SIZE) {
-                max_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
-                printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors);
-        }
-
-        if (BLK_DEF_MAX_SECTORS > max_sectors)
-                q->max_hw_sectors = q->max_sectors = max_sectors;
-        else {
-                q->max_sectors = BLK_DEF_MAX_SECTORS;
-                q->max_hw_sectors = max_sectors;
-        }
-}
-
-EXPORT_SYMBOL(blk_queue_max_sectors);
-
-/**
- * blk_queue_max_phys_segments - set max phys segments for a request for this queue
- * @q:  the request queue for the device
- * @max_segments:  max number of segments
- *
- * Description:
- *    Enables a low level driver to set an upper limit on the number of
- *    physical data segments in a request.  This would be the largest sized
- *    scatter list the driver could handle.
- **/
-void blk_queue_max_phys_segments(struct request_queue *q,
-                                 unsigned short max_segments)
-{
-        if (!max_segments) {
-                max_segments = 1;
-                printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
-        }
-
-        q->max_phys_segments = max_segments;
-}
-
-EXPORT_SYMBOL(blk_queue_max_phys_segments);
-
-/**
- * blk_queue_max_hw_segments - set max hw segments for a request for this queue
- * @q:  the request queue for the device
- * @max_segments:  max number of segments
- *
- * Description:
- *    Enables a low level driver to set an upper limit on the number of
- *    hw data segments in a request.  This would be the largest number of
- *    address/length pairs the host adapter can actually give as once
- *    to the device.
- **/
-void blk_queue_max_hw_segments(struct request_queue *q,
-                               unsigned short max_segments)
-{
-        if (!max_segments) {
-                max_segments = 1;
-                printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
-        }
-
-        q->max_hw_segments = max_segments;
-}
-
-EXPORT_SYMBOL(blk_queue_max_hw_segments);
-
-/**
- * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
- * @q:  the request queue for the device
- * @max_size:  max size of segment in bytes
- *
- * Description:
- *    Enables a low level driver to set an upper limit on the size of a
- *    coalesced segment
- **/
-void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
-{
-        if (max_size < PAGE_CACHE_SIZE) {
-                max_size = PAGE_CACHE_SIZE;
-                printk("%s: set to minimum %d\n", __FUNCTION__, max_size);
-        }
-
-        q->max_segment_size = max_size;
-}
-
-EXPORT_SYMBOL(blk_queue_max_segment_size);
-
-/**
- * blk_queue_hardsect_size - set hardware sector size for the queue
- * @q:  the request queue for the device
- * @size:  the hardware sector size, in bytes
- *
- * Description:
- *   This should typically be set to the lowest possible sector size
- *   that the hardware can operate on (possible without reverting to
- *   even internal read-modify-write operations). Usually the default
- *   of 512 covers most hardware.
- **/
-void blk_queue_hardsect_size(struct request_queue *q, unsigned short size)
-{
-        q->hardsect_size = size;
-}
-
-EXPORT_SYMBOL(blk_queue_hardsect_size);
-
-/*
- * Returns the minimum that is _not_ zero, unless both are zero.
- */
-#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
-
-/**
- * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
- * @t:  the stacking driver (top)
- * @b:  the underlying device (bottom)
- **/
-void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
-{
-        /* zero is "infinity" */
-        t->max_sectors = min_not_zero(t->max_sectors,b->max_sectors);
-        t->max_hw_sectors = min_not_zero(t->max_hw_sectors,b->max_hw_sectors);
-
-        t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments);
-        t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments);
-        t->max_segment_size = min(t->max_segment_size,b->max_segment_size);
-        t->hardsect_size = max(t->hardsect_size,b->hardsect_size);
-        if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags))
-                clear_bit(QUEUE_FLAG_CLUSTER, &t->queue_flags);
-}
-
-EXPORT_SYMBOL(blk_queue_stack_limits);
-
-/**
- * blk_queue_dma_drain - Set up a drain buffer for excess dma.
- *
- * @q:  the request queue for the device
- * @buf:        physically contiguous buffer
- * @size:       size of the buffer in bytes
- *
- * Some devices have excess DMA problems and can't simply discard (or
- * zero fill) the unwanted piece of the transfer.  They have to have a
- * real area of memory to transfer it into.  The use case for this is
- * ATAPI devices in DMA mode.  If the packet command causes a transfer
- * bigger than the transfer size some HBAs will lock up if there
- * aren't DMA elements to contain the excess transfer.  What this API
- * does is adjust the queue so that the buf is always appended
- * silently to the scatterlist.
- *
- * Note: This routine adjusts max_hw_segments to make room for
- * appending the drain buffer.  If you call
- * blk_queue_max_hw_segments() or blk_queue_max_phys_segments() after
- * calling this routine, you must set the limit to one fewer than your
- * device can support otherwise there won't be room for the drain
- * buffer.
- */
-int blk_queue_dma_drain(struct request_queue *q, void *buf,
-                                unsigned int size)
-{
-        if (q->max_hw_segments < 2 || q->max_phys_segments < 2)
-                return -EINVAL;
-        /* make room for appending the drain */
-        --q->max_hw_segments;
-        --q->max_phys_segments;
-        q->dma_drain_buffer = buf;
-        q->dma_drain_size = size;
-
-        return 0;
-}
-
-EXPORT_SYMBOL_GPL(blk_queue_dma_drain);
-
-/**
- * blk_queue_segment_boundary - set boundary rules for segment merging
- * @q:  the request queue for the device
- * @mask:  the memory boundary mask
- **/
-void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
-{
-        if (mask < PAGE_CACHE_SIZE - 1) {
-                mask = PAGE_CACHE_SIZE - 1;
-                printk("%s: set to minimum %lx\n", __FUNCTION__, mask);
-        }
-
-        q->seg_boundary_mask = mask;
-}
-
-EXPORT_SYMBOL(blk_queue_segment_boundary);
-
-/**
- * blk_queue_dma_alignment - set dma length and memory alignment
- * @q:     the request queue for the device
- * @mask:  alignment mask
- *
- * description:
- *    set required memory and length aligment for direct dma transactions.
- *    this is used when buiding direct io requests for the queue.
- *
- **/
-void blk_queue_dma_alignment(struct request_queue *q, int mask)
-{
-        q->dma_alignment = mask;
-}
-
-EXPORT_SYMBOL(blk_queue_dma_alignment);
-
-/**
- * blk_queue_update_dma_alignment - update dma length and memory alignment
- * @q:     the request queue for the device
- * @mask:  alignment mask
- *
- * description:
- *    update required memory and length aligment for direct dma transactions.
- *    If the requested alignment is larger than the current alignment, then
- *    the current queue alignment is updated to the new value, otherwise it
- *    is left alone.  The design of this is to allow multiple objects
- *    (driver, device, transport etc) to set their respective
- *    alignments without having them interfere.
- *
- **/
-void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
-{
-        BUG_ON(mask > PAGE_SIZE);
-
-        if (mask > q->dma_alignment)
-                q->dma_alignment = mask;
-}
-
-EXPORT_SYMBOL(blk_queue_update_dma_alignment);
-
 void blk_dump_rq_flags(struct request *rq, char *msg)
 {
         int bit;
@@ -1074,8 +418,8 @@ static inline int ll_new_hw_segment(struct request_queue *q,
         return 1;
 }
 
-static int ll_back_merge_fn(struct request_queue *q, struct request *req,
-                            struct bio *bio)
+int ll_back_merge_fn(struct request_queue *q, struct request *req,
+                     struct bio *bio)
 {
         unsigned short max_sectors;
         int len;
@@ -1285,7 +629,7 @@ static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
         blk_unplug(q);
 }
 
-static void blk_unplug_work(struct work_struct *work)
+void blk_unplug_work(struct work_struct *work)
 {
         struct request_queue *q =
                 container_of(work, struct request_queue, unplug_work);
@@ -1296,7 +640,7 @@ static void blk_unplug_work(struct work_struct *work)
         q->unplug_fn(q);
 }
 
-static void blk_unplug_timeout(unsigned long data)
+void blk_unplug_timeout(unsigned long data)
 {
         struct request_queue *q = (struct request_queue *)data;
 
@@ -1961,393 +1305,6 @@ void blk_insert_request(struct request_queue *q, struct request *rq,
 
 EXPORT_SYMBOL(blk_insert_request);
 
-static int __blk_rq_unmap_user(struct bio *bio)
-{
-        int ret = 0;
-
-        if (bio) {
-                if (bio_flagged(bio, BIO_USER_MAPPED))
-                        bio_unmap_user(bio);
-                else
-                        ret = bio_uncopy_user(bio);
-        }
-
-        return ret;
-}
-
-int blk_rq_append_bio(struct request_queue *q, struct request *rq,
-                      struct bio *bio)
-{
-        if (!rq->bio)
-                blk_rq_bio_prep(q, rq, bio);
-        else if (!ll_back_merge_fn(q, rq, bio))
-                return -EINVAL;
-        else {
-                rq->biotail->bi_next = bio;
-                rq->biotail = bio;
-
-                rq->data_len += bio->bi_size;
-        }
-        return 0;
-}
-EXPORT_SYMBOL(blk_rq_append_bio);
-
-static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
-                             void __user *ubuf, unsigned int len)
-{
-        unsigned long uaddr;
-        struct bio *bio, *orig_bio;
-        int reading, ret;
-
-        reading = rq_data_dir(rq) == READ;
-
-        /*
-         * if alignment requirement is satisfied, map in user pages for
-         * direct dma. else, set up kernel bounce buffers
-         */
-        uaddr = (unsigned long) ubuf;
-        if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
-                bio = bio_map_user(q, NULL, uaddr, len, reading);
-        else
-                bio = bio_copy_user(q, uaddr, len, reading);
-
-        if (IS_ERR(bio))
-                return PTR_ERR(bio);
-
-        orig_bio = bio;
-        blk_queue_bounce(q, &bio);
-
-        /*
-         * We link the bounce buffer in and could have to traverse it
-         * later so we have to get a ref to prevent it from being freed
-         */
-        bio_get(bio);
-
-        ret = blk_rq_append_bio(q, rq, bio);
-        if (!ret)
-                return bio->bi_size;
-
-        /* if it was boucned we must call the end io function */
-        bio_endio(bio, 0);
-        __blk_rq_unmap_user(orig_bio);
-        bio_put(bio);
-        return ret;
-}
-
-/**
- * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
- * @q:          request queue where request should be inserted
- * @rq:         request structure to fill
- * @ubuf:       the user buffer
- * @len:        length of user data
- *
- * Description:
- *    Data will be mapped directly for zero copy io, if possible. Otherwise
- *    a kernel bounce buffer is used.
- *
- *    A matching blk_rq_unmap_user() must be issued at the end of io, while
- *    still in process context.
- *
- *    Note: The mapped bio may need to be bounced through blk_queue_bounce()
- *    before being submitted to the device, as pages mapped may be out of
- *    reach. It's the callers responsibility to make sure this happens. The
- *    original bio must be passed back in to blk_rq_unmap_user() for proper
- *    unmapping.
- */
-int blk_rq_map_user(struct request_queue *q, struct request *rq,
-                    void __user *ubuf, unsigned long len)
-{
-        unsigned long bytes_read = 0;
-        struct bio *bio = NULL;
-        int ret;
-
-        if (len > (q->max_hw_sectors << 9))
-                return -EINVAL;
-        if (!len || !ubuf)
-                return -EINVAL;
-
-        while (bytes_read != len) {
-                unsigned long map_len, end, start;
-
-                map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
-                end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
-                                                                >> PAGE_SHIFT;
-                start = (unsigned long)ubuf >> PAGE_SHIFT;
-
-                /*
-                 * A bad offset could cause us to require BIO_MAX_PAGES + 1
-                 * pages. If this happens we just lower the requested
-                 * mapping len by a page so that we can fit
-                 */
-                if (end - start > BIO_MAX_PAGES)
-                        map_len -= PAGE_SIZE;
-
-                ret = __blk_rq_map_user(q, rq, ubuf, map_len);
-                if (ret < 0)
-                        goto unmap_rq;
-                if (!bio)
-                        bio = rq->bio;
-                bytes_read += ret;
-                ubuf += ret;
-        }
-
-        rq->buffer = rq->data = NULL;
-        return 0;
-unmap_rq:
-        blk_rq_unmap_user(bio);
-        return ret;
-}
-
-EXPORT_SYMBOL(blk_rq_map_user);
-
-/**
- * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
- * @q:          request queue where request should be inserted
- * @rq:         request to map data to
- * @iov:        pointer to the iovec
- * @iov_count:  number of elements in the iovec
- * @len:        I/O byte count
- *
- * Description:
- *    Data will be mapped directly for zero copy io, if possible. Otherwise
- *    a kernel bounce buffer is used.
- *
- *    A matching blk_rq_unmap_user() must be issued at the end of io, while
- *    still in process context.
- *
- *    Note: The mapped bio may need to be bounced through blk_queue_bounce()
- *    before being submitted to the device, as pages mapped may be out of
- *    reach. It's the callers responsibility to make sure this happens. The
- *    original bio must be passed back in to blk_rq_unmap_user() for proper
- *    unmapping.
- */
-int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
-                        struct sg_iovec *iov, int iov_count, unsigned int len)
-{
-        struct bio *bio;
-
-        if (!iov || iov_count <= 0)
-                return -EINVAL;
-
-        /* we don't allow misaligned data like bio_map_user() does.  If the
-         * user is using sg, they're expected to know the alignment constraints
-         * and respect them accordingly */
-        bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ);
-        if (IS_ERR(bio))
-                return PTR_ERR(bio);
-
-        if (bio->bi_size != len) {
-                bio_endio(bio, 0);
-                bio_unmap_user(bio);
-                return -EINVAL;
-        }
-
-        bio_get(bio);
-        blk_rq_bio_prep(q, rq, bio);
-        rq->buffer = rq->data = NULL;
-        return 0;
-}
-
-EXPORT_SYMBOL(blk_rq_map_user_iov);
-
-/**
- * blk_rq_unmap_user - unmap a request with user data
- * @bio:               start of bio list
- *
- * Description:
- *    Unmap a rq previously mapped by blk_rq_map_user(). The caller must
- *    supply the original rq->bio from the blk_rq_map_user() return, since
- *    the io completion may have changed rq->bio.
- */
-int blk_rq_unmap_user(struct bio *bio)
-{
-        struct bio *mapped_bio;
-        int ret = 0, ret2;
-
-        while (bio) {
-                mapped_bio = bio;
-                if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
-                        mapped_bio = bio->bi_private;
-
-                ret2 = __blk_rq_unmap_user(mapped_bio);
-                if (ret2 && !ret)
-                        ret = ret2;
-
-                mapped_bio = bio;
-                bio = bio->bi_next;
-                bio_put(mapped_bio);
-        }
-
-        return ret;
-}
-
-EXPORT_SYMBOL(blk_rq_unmap_user);
-
-/**
- * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
- * @q:          request queue where request should be inserted
- * @rq:         request to fill
- * @kbuf:       the kernel buffer
- * @len:        length of user data
- * @gfp_mask:   memory allocation flags
- */
-int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
-                    unsigned int len, gfp_t gfp_mask)
-{
-        struct bio *bio;
-
-        if (len > (q->max_hw_sectors << 9))
-                return -EINVAL;
-        if (!len || !kbuf)
-                return -EINVAL;
-
-        bio = bio_map_kern(q, kbuf, len, gfp_mask);
-        if (IS_ERR(bio))
-                return PTR_ERR(bio);
-
-        if (rq_data_dir(rq) == WRITE)
-                bio->bi_rw |= (1 << BIO_RW);
-
-        blk_rq_bio_prep(q, rq, bio);
-        blk_queue_bounce(q, &rq->bio);
-        rq->buffer = rq->data = NULL;
-        return 0;
-}
-
-EXPORT_SYMBOL(blk_rq_map_kern);
-
-/**
- * blk_execute_rq_nowait - insert a request into queue for execution
- * @q:          queue to insert the request in
- * @bd_disk:    matching gendisk
- * @rq:         request to insert
- * @at_head:    insert request at head or tail of queue
- * @done:       I/O completion handler
- *
- * Description:
- *    Insert a fully prepared request at the back of the io scheduler queue
- *    for execution.  Don't wait for completion.
- */
-void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
-                           struct request *rq, int at_head,
-                           rq_end_io_fn *done)
-{
-        int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
-
-        rq->rq_disk = bd_disk;
-        rq->cmd_flags |= REQ_NOMERGE;
-        rq->end_io = done;
-        WARN_ON(irqs_disabled());
-        spin_lock_irq(q->queue_lock);
-        __elv_add_request(q, rq, where, 1);
-        __generic_unplug_device(q);
-        spin_unlock_irq(q->queue_lock);
-}
-EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
-
-/**
- * blk_execute_rq - insert a request into queue for execution
- * @q:          queue to insert the request in
- * @bd_disk:    matching gendisk
- * @rq:         request to insert
- * @at_head:    insert request at head or tail of queue
- *
- * Description:
- *    Insert a fully prepared request at the back of the io scheduler queue
- *    for execution and wait for completion.
- */
-int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
-                   struct request *rq, int at_head)
-{
-        DECLARE_COMPLETION_ONSTACK(wait);
-        char sense[SCSI_SENSE_BUFFERSIZE];
-        int err = 0;
-
-        /*
-         * we need an extra reference to the request, so we can look at
-         * it after io completion
-         */
-        rq->ref_count++;
-
-        if (!rq->sense) {
-                memset(sense, 0, sizeof(sense));
-                rq->sense = sense;
-                rq->sense_len = 0;
-        }
-
-        rq->end_io_data = &wait;
-        blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
-        wait_for_completion(&wait);
-
-        if (rq->errors)
-                err = -EIO;
-
-        return err;
-}
-
-EXPORT_SYMBOL(blk_execute_rq);
-
-static void bio_end_empty_barrier(struct bio *bio, int err)
-{
-        if (err)
-                clear_bit(BIO_UPTODATE, &bio->bi_flags);
-
-        complete(bio->bi_private);
-}
-
-/**
- * blkdev_issue_flush - queue a flush
- * @bdev:       blockdev to issue flush for
- * @error_sector:       error sector
- *
- * Description:
- *    Issue a flush for the block device in question. Caller can supply
- *    room for storing the error offset in case of a flush error, if they
- *    wish to.  Caller must run wait_for_completion() on its own.
- */
-int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
-{
-        DECLARE_COMPLETION_ONSTACK(wait);
-        struct request_queue *q;
-        struct bio *bio;
-        int ret;
-
-        if (bdev->bd_disk == NULL)
-                return -ENXIO;
-
-        q = bdev_get_queue(bdev);
-        if (!q)
-                return -ENXIO;
-
-        bio = bio_alloc(GFP_KERNEL, 0);
-        if (!bio)
-                return -ENOMEM;
-
-        bio->bi_end_io = bio_end_empty_barrier;
-        bio->bi_private = &wait;
-        bio->bi_bdev = bdev;
-        submit_bio(1 << BIO_RW_BARRIER, bio);
-
-        wait_for_completion(&wait);
-
-        /*
-         * The driver must store the error location in ->bi_sector, if
-         * it supports it. For non-stacked drivers, this should be copied
-         * from rq->sector.
-         */
-        if (error_sector)
-                *error_sector = bio->bi_sector;
-
-        ret = 0;
-        if (!bio_flagged(bio, BIO_UPTODATE))
-                ret = -EIO;
-
-        bio_put(bio);
-        return ret;
-}
-
-EXPORT_SYMBOL(blkdev_issue_flush);
-
 static void drive_stat_acct(struct request *rq, int new_io)
 {
         int rw = rq_data_dir(rq);
@@ -2459,26 +1416,6 @@ void blk_put_request(struct request *req)
 
 EXPORT_SYMBOL(blk_put_request);
 
-/**
- * blk_end_sync_rq - executes a completion event on a request
- * @rq: request to complete
- * @error: end io status of the request
- */
-void blk_end_sync_rq(struct request *rq, int error)
-{
-        struct completion *waiting = rq->end_io_data;
-
-        rq->end_io_data = NULL;
-        __blk_put_request(rq->q, rq);
-
-        /*
-         * complete last, if this is a stack request the process (and thus
-         * the rq pointer) could be invalid right after this complete()
-         */
-        complete(waiting);
-}
-EXPORT_SYMBOL(blk_end_sync_rq);
-
 /*
  * Has to be called with the request spinlock acquired
  */
@@ -2557,7 +1494,7 @@ static inline int attempt_front_merge(struct request_queue *q,
         return 0;
 }
 
-static void init_request_from_bio(struct request *req, struct bio *bio)
+void init_request_from_bio(struct request *req, struct bio *bio)
 {
         req->cmd_type = REQ_TYPE_FS;
 
@@ -3524,8 +2461,8 @@ int blk_end_request_callback(struct request *rq, int error, int nr_bytes,
 }
 EXPORT_SYMBOL_GPL(blk_end_request_callback);
 
-static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
-                            struct bio *bio)
+void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
+                     struct bio *bio)
 {
         /* first two bits are identical in rq->cmd_flags and bio->bi_rw */
         rq->cmd_flags |= (bio->bi_rw & 3);
@@ -3571,188 +2508,12 @@ int __init blk_dev_init(void)
         blk_requestq_cachep = kmem_cache_create("blkdev_queue",
                         sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
 
-        iocontext_cachep = kmem_cache_create("blkdev_ioc",
-                        sizeof(struct io_context), 0, SLAB_PANIC, NULL);
-
         for_each_possible_cpu(i)
                 INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
 
         open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
         register_hotcpu_notifier(&blk_cpu_notifier);
 
-        blk_max_low_pfn = max_low_pfn - 1;
-        blk_max_pfn = max_pfn - 1;
-
-        return 0;
-}
-
-static void cfq_dtor(struct io_context *ioc)
-{
-        struct cfq_io_context *cic[1];
-        int r;
-
-        /*
-         * We don't have a specific key to lookup with, so use the gang
-         * lookup to just retrieve the first item stored. The cfq exit
-         * function will iterate the full tree, so any member will do.
-         */
-        r = radix_tree_gang_lookup(&ioc->radix_root, (void **) cic, 0, 1);
-        if (r > 0)
-                cic[0]->dtor(ioc);
-}
-
-/*
- * IO Context helper functions. put_io_context() returns 1 if there are no
- * more users of this io context, 0 otherwise.
- */
-int put_io_context(struct io_context *ioc)
-{
-        if (ioc == NULL)
-                return 1;
-
-        BUG_ON(atomic_read(&ioc->refcount) == 0);
-
-        if (atomic_dec_and_test(&ioc->refcount)) {
-                rcu_read_lock();
-                if (ioc->aic && ioc->aic->dtor)
-                        ioc->aic->dtor(ioc->aic);
-                rcu_read_unlock();
-                cfq_dtor(ioc);
-
-                kmem_cache_free(iocontext_cachep, ioc);
-                return 1;
-        }
         return 0;
 }
-EXPORT_SYMBOL(put_io_context);
-
-static void cfq_exit(struct io_context *ioc)
-{
-        struct cfq_io_context *cic[1];
-        int r;
-
-        rcu_read_lock();
-        /*
-         * See comment for cfq_dtor()
-         */
-        r = radix_tree_gang_lookup(&ioc->radix_root, (void **) cic, 0, 1);
-        rcu_read_unlock();
-
-        if (r > 0)
-                cic[0]->exit(ioc);
-}
-
-/* Called by the exitting task */
-void exit_io_context(void)
-{
-        struct io_context *ioc;
-
-        task_lock(current);
-        ioc = current->io_context;
-        current->io_context = NULL;
-        task_unlock(current);
-
-        if (atomic_dec_and_test(&ioc->nr_tasks)) {
-                if (ioc->aic && ioc->aic->exit)
-                        ioc->aic->exit(ioc->aic);
-                cfq_exit(ioc);
-
-                put_io_context(ioc);
-        }
-}
-
-struct io_context *alloc_io_context(gfp_t gfp_flags, int node)
-{
-        struct io_context *ret;
-
-        ret = kmem_cache_alloc_node(iocontext_cachep, gfp_flags, node);
-        if (ret) {
-                atomic_set(&ret->refcount, 1);
-                atomic_set(&ret->nr_tasks, 1);
-                spin_lock_init(&ret->lock);
-                ret->ioprio_changed = 0;
-                ret->ioprio = 0;
-                ret->last_waited = jiffies; /* doesn't matter... */
-                ret->nr_batch_requests = 0; /* because this is 0 */
-                ret->aic = NULL;
-                INIT_RADIX_TREE(&ret->radix_root, GFP_ATOMIC | __GFP_HIGH);
-                ret->ioc_data = NULL;
-        }
-
-        return ret;
-}
-
-/*
- * If the current task has no IO context then create one and initialise it.
- * Otherwise, return its existing IO context.
- *
- * This returned IO context doesn't have a specifically elevated refcount,
- * but since the current task itself holds a reference, the context can be
- * used in general code, so long as it stays within `current` context.
- */
-static struct io_context *current_io_context(gfp_t gfp_flags, int node)
-{
-        struct task_struct *tsk = current;
-        struct io_context *ret;
-
-        ret = tsk->io_context;
-        if (likely(ret))
-                return ret;
-
-        ret = alloc_io_context(gfp_flags, node);
-        if (ret) {
-                /* make sure set_task_ioprio() sees the settings above */
-                smp_wmb();
-                tsk->io_context = ret;
-        }
-
-        return ret;
-}
-
-/*
- * If the current task has no IO context then create one and initialise it.
- * If it does have a context, take a ref on it.
- *
- * This is always called in the context of the task which submitted the I/O.
- */
-struct io_context *get_io_context(gfp_t gfp_flags, int node)
-{
-        struct io_context *ret = NULL;
-
-        /*
-         * Check for unlikely race with exiting task. ioc ref count is
-         * zero when ioc is being detached.
-         */
-        do {
-                ret = current_io_context(gfp_flags, node);
-                if (unlikely(!ret))
-                        break;
-        } while (!atomic_inc_not_zero(&ret->refcount));
-
-        return ret;
-}
-EXPORT_SYMBOL(get_io_context);
-
-void copy_io_context(struct io_context **pdst, struct io_context **psrc)
-{
-        struct io_context *src = *psrc;
-        struct io_context *dst = *pdst;
-
-        if (src) {
-                BUG_ON(atomic_read(&src->refcount) == 0);
-                atomic_inc(&src->refcount);
-                put_io_context(dst);
-                *pdst = src;
-        }
-}
-EXPORT_SYMBOL(copy_io_context);
-
-void swap_io_context(struct io_context **ioc1, struct io_context **ioc2)
-{
-        struct io_context *temp;
-        temp = *ioc1;
-        *ioc1 = *ioc2;
-        *ioc2 = temp;
-}
-EXPORT_SYMBOL(swap_io_context);