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-rw-r--r--block/Makefile3
-rw-r--r--block/blk-core.c719
-rw-r--r--block/blk-sysfs.c298
-rw-r--r--block/blk-tag.c396
-rw-r--r--block/blk.h29
5 files changed, 735 insertions, 710 deletions
diff --git a/block/Makefile b/block/Makefile
index 75597c1263e..fcaae4ae670 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -2,7 +2,8 @@
# Makefile for the kernel block layer
#
-obj-$(CONFIG_BLOCK) := elevator.o blk-core.o ioctl.o genhd.o scsi_ioctl.o
+obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o ioctl.o \
+ genhd.o scsi_ioctl.o
obj-$(CONFIG_BLK_DEV_BSG) += bsg.o
obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o
diff --git a/block/blk-core.c b/block/blk-core.c
index 1932a56f5e4..937f9d0b9bd 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -32,6 +32,8 @@
#include <linux/fault-inject.h>
#include <linux/scatterlist.h>
+#include "blk.h"
+
/*
* for max sense size
*/
@@ -50,12 +52,12 @@ static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
/*
* For the allocated request tables
*/
-static struct kmem_cache *request_cachep;
+struct kmem_cache *request_cachep;
/*
* For queue allocation
*/
-static struct kmem_cache *requestq_cachep;
+struct kmem_cache *blk_requestq_cachep = NULL;
/*
* For io context allocations
@@ -80,25 +82,7 @@ static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
/* Number of requests a "batching" process may submit */
#define BLK_BATCH_REQ 32
-/*
- * Return the threshold (number of used requests) at which the queue is
- * considered to be congested. It include a little hysteresis to keep the
- * context switch rate down.
- */
-static inline int queue_congestion_on_threshold(struct request_queue *q)
-{
- return q->nr_congestion_on;
-}
-
-/*
- * The threshold at which a queue is considered to be uncongested
- */
-static inline int queue_congestion_off_threshold(struct request_queue *q)
-{
- return q->nr_congestion_off;
-}
-
-static void blk_queue_congestion_threshold(struct request_queue *q)
+void blk_queue_congestion_threshold(struct request_queue *q)
{
int nr;
@@ -817,397 +801,6 @@ void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
EXPORT_SYMBOL(blk_queue_update_dma_alignment);
-/**
- * blk_queue_find_tag - find a request by its tag and queue
- * @q: The request queue for the device
- * @tag: The tag of the request
- *
- * Notes:
- * Should be used when a device returns a tag and you want to match
- * it with a request.
- *
- * no locks need be held.
- **/
-struct request *blk_queue_find_tag(struct request_queue *q, int tag)
-{
- return blk_map_queue_find_tag(q->queue_tags, tag);
-}
-
-EXPORT_SYMBOL(blk_queue_find_tag);
-
-/**
- * __blk_free_tags - release a given set of tag maintenance info
- * @bqt: the tag map to free
- *
- * Tries to free the specified @bqt@. Returns true if it was
- * actually freed and false if there are still references using it
- */
-static int __blk_free_tags(struct blk_queue_tag *bqt)
-{
- int retval;
-
- retval = atomic_dec_and_test(&bqt->refcnt);
- if (retval) {
- BUG_ON(bqt->busy);
-
- kfree(bqt->tag_index);
- bqt->tag_index = NULL;
-
- kfree(bqt->tag_map);
- bqt->tag_map = NULL;
-
- kfree(bqt);
-
- }
-
- return retval;
-}
-
-/**
- * __blk_queue_free_tags - release tag maintenance info
- * @q: the request queue for the device
- *
- * Notes:
- * blk_cleanup_queue() will take care of calling this function, if tagging
- * has been used. So there's no need to call this directly.
- **/
-static void __blk_queue_free_tags(struct request_queue *q)
-{
- struct blk_queue_tag *bqt = q->queue_tags;
-
- if (!bqt)
- return;
-
- __blk_free_tags(bqt);
-
- q->queue_tags = NULL;
- q->queue_flags &= ~(1 << QUEUE_FLAG_QUEUED);
-}
-
-
-/**
- * blk_free_tags - release a given set of tag maintenance info
- * @bqt: the tag map to free
- *
- * For externally managed @bqt@ frees the map. Callers of this
- * function must guarantee to have released all the queues that
- * might have been using this tag map.
- */
-void blk_free_tags(struct blk_queue_tag *bqt)
-{
- if (unlikely(!__blk_free_tags(bqt)))
- BUG();
-}
-EXPORT_SYMBOL(blk_free_tags);
-
-/**
- * blk_queue_free_tags - release tag maintenance info
- * @q: the request queue for the device
- *
- * Notes:
- * This is used to disabled tagged queuing to a device, yet leave
- * queue in function.
- **/
-void blk_queue_free_tags(struct request_queue *q)
-{
- clear_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
-}
-
-EXPORT_SYMBOL(blk_queue_free_tags);
-
-static int
-init_tag_map(struct request_queue *q, struct blk_queue_tag *tags, int depth)
-{
- struct request **tag_index;
- unsigned long *tag_map;
- int nr_ulongs;
-
- if (q && depth > q->nr_requests * 2) {
- depth = q->nr_requests * 2;
- printk(KERN_ERR "%s: adjusted depth to %d\n",
- __FUNCTION__, depth);
- }
-
- tag_index = kzalloc(depth * sizeof(struct request *), GFP_ATOMIC);
- if (!tag_index)
- goto fail;
-
- nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG;
- tag_map = kzalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC);
- if (!tag_map)
- goto fail;
-
- tags->real_max_depth = depth;
- tags->max_depth = depth;
- tags->tag_index = tag_index;
- tags->tag_map = tag_map;
-
- return 0;
-fail:
- kfree(tag_index);
- return -ENOMEM;
-}
-
-static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q,
- int depth)
-{
- struct blk_queue_tag *tags;
-
- tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC);
- if (!tags)
- goto fail;
-
- if (init_tag_map(q, tags, depth))
- goto fail;
-
- tags->busy = 0;
- atomic_set(&tags->refcnt, 1);
- return tags;
-fail:
- kfree(tags);
- return NULL;
-}
-
-/**
- * blk_init_tags - initialize the tag info for an external tag map
- * @depth: the maximum queue depth supported
- * @tags: the tag to use
- **/
-struct blk_queue_tag *blk_init_tags(int depth)
-{
- return __blk_queue_init_tags(NULL, depth);
-}
-EXPORT_SYMBOL(blk_init_tags);
-
-/**
- * blk_queue_init_tags - initialize the queue tag info
- * @q: the request queue for the device
- * @depth: the maximum queue depth supported
- * @tags: the tag to use
- **/
-int blk_queue_init_tags(struct request_queue *q, int depth,
- struct blk_queue_tag *tags)
-{
- int rc;
-
- BUG_ON(tags && q->queue_tags && tags != q->queue_tags);
-
- if (!tags && !q->queue_tags) {
- tags = __blk_queue_init_tags(q, depth);
-
- if (!tags)
- goto fail;
- } else if (q->queue_tags) {
- if ((rc = blk_queue_resize_tags(q, depth)))
- return rc;
- set_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
- return 0;
- } else
- atomic_inc(&tags->refcnt);
-
- /*
- * assign it, all done
- */
- q->queue_tags = tags;
- q->queue_flags |= (1 << QUEUE_FLAG_QUEUED);
- INIT_LIST_HEAD(&q->tag_busy_list);
- return 0;
-fail:
- kfree(tags);
- return -ENOMEM;
-}
-
-EXPORT_SYMBOL(blk_queue_init_tags);
-
-/**
- * blk_queue_resize_tags - change the queueing depth
- * @q: the request queue for the device
- * @new_depth: the new max command queueing depth
- *
- * Notes:
- * Must be called with the queue lock held.
- **/
-int blk_queue_resize_tags(struct request_queue *q, int new_depth)
-{
- struct blk_queue_tag *bqt = q->queue_tags;
- struct request **tag_index;
- unsigned long *tag_map;
- int max_depth, nr_ulongs;
-
- if (!bqt)
- return -ENXIO;
-
- /*
- * if we already have large enough real_max_depth. just
- * adjust max_depth. *NOTE* as requests with tag value
- * between new_depth and real_max_depth can be in-flight, tag
- * map can not be shrunk blindly here.
- */
- if (new_depth <= bqt->real_max_depth) {
- bqt->max_depth = new_depth;
- return 0;
- }
-
- /*
- * Currently cannot replace a shared tag map with a new
- * one, so error out if this is the case
- */
- if (atomic_read(&bqt->refcnt) != 1)
- return -EBUSY;
-
- /*
- * save the old state info, so we can copy it back
- */
- tag_index = bqt->tag_index;
- tag_map = bqt->tag_map;
- max_depth = bqt->real_max_depth;
-
- if (init_tag_map(q, bqt, new_depth))
- return -ENOMEM;
-
- memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *));
- nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG;
- memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long));
-
- kfree(tag_index);
- kfree(tag_map);
- return 0;
-}
-
-EXPORT_SYMBOL(blk_queue_resize_tags);
-
-/**
- * blk_queue_end_tag - end tag operations for a request
- * @q: the request queue for the device
- * @rq: the request that has completed
- *
- * Description:
- * Typically called when end_that_request_first() returns 0, meaning
- * all transfers have been done for a request. It's important to call
- * this function before end_that_request_last(), as that will put the
- * request back on the free list thus corrupting the internal tag list.
- *
- * Notes:
- * queue lock must be held.
- **/
-void blk_queue_end_tag(struct request_queue *q, struct request *rq)
-{
- struct blk_queue_tag *bqt = q->queue_tags;
- int tag = rq->tag;
-
- BUG_ON(tag == -1);
-
- if (unlikely(tag >= bqt->real_max_depth))
- /*
- * This can happen after tag depth has been reduced.
- * FIXME: how about a warning or info message here?
- */
- return;
-
- list_del_init(&rq->queuelist);
- rq->cmd_flags &= ~REQ_QUEUED;
- rq->tag = -1;
-
- if (unlikely(bqt->tag_index[tag] == NULL))
- printk(KERN_ERR "%s: tag %d is missing\n",
- __FUNCTION__, tag);
-
- bqt->tag_index[tag] = NULL;
-
- if (unlikely(!test_bit(tag, bqt->tag_map))) {
- printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
- __FUNCTION__, tag);
- return;
- }
- /*
- * The tag_map bit acts as a lock for tag_index[bit], so we need
- * unlock memory barrier semantics.
- */
- clear_bit_unlock(tag, bqt->tag_map);
- bqt->busy--;
-}
-
-EXPORT_SYMBOL(blk_queue_end_tag);
-
-/**
- * blk_queue_start_tag - find a free tag and assign it
- * @q: the request queue for the device
- * @rq: the block request that needs tagging
- *
- * Description:
- * This can either be used as a stand-alone helper, or possibly be
- * assigned as the queue &prep_rq_fn (in which case &struct request
- * automagically gets a tag assigned). Note that this function
- * assumes that any type of request can be queued! if this is not
- * true for your device, you must check the request type before
- * calling this function. The request will also be removed from
- * the request queue, so it's the drivers responsibility to readd
- * it if it should need to be restarted for some reason.
- *
- * Notes:
- * queue lock must be held.
- **/
-int blk_queue_start_tag(struct request_queue *q, struct request *rq)
-{
- struct blk_queue_tag *bqt = q->queue_tags;
- int tag;
-
- if (unlikely((rq->cmd_flags & REQ_QUEUED))) {
- printk(KERN_ERR
- "%s: request %p for device [%s] already tagged %d",
- __FUNCTION__, rq,
- rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag);
- BUG();
- }
-
- /*
- * Protect against shared tag maps, as we may not have exclusive
- * access to the tag map.
- */
- do {
- tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth);
- if (tag >= bqt->max_depth)
- return 1;
-
- } while (test_and_set_bit_lock(tag, bqt->tag_map));
- /*
- * We need lock ordering semantics given by test_and_set_bit_lock.
- * See blk_queue_end_tag for details.
- */
-
- rq->cmd_flags |= REQ_QUEUED;
- rq->tag = tag;
- bqt->tag_index[tag] = rq;
- blkdev_dequeue_request(rq);
- list_add(&rq->queuelist, &q->tag_busy_list);
- bqt->busy++;
- return 0;
-}
-
-EXPORT_SYMBOL(blk_queue_start_tag);
-
-/**
- * blk_queue_invalidate_tags - invalidate all pending tags
- * @q: the request queue for the device
- *
- * Description:
- * Hardware conditions may dictate a need to stop all pending requests.
- * In this case, we will safely clear the block side of the tag queue and
- * readd all requests to the request queue in the right order.
- *
- * Notes:
- * queue lock must be held.
- **/
-void blk_queue_invalidate_tags(struct request_queue *q)
-{
- struct list_head *tmp, *n;
-
- list_for_each_safe(tmp, n, &q->tag_busy_list)
- blk_requeue_request(q, list_entry_rq(tmp));
-}
-
-EXPORT_SYMBOL(blk_queue_invalidate_tags);
-
void blk_dump_rq_flags(struct request *rq, char *msg)
{
int bit;
@@ -1828,41 +1421,6 @@ void blk_run_queue(struct request_queue *q)
}
EXPORT_SYMBOL(blk_run_queue);
-/**
- * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
- * @kobj: the kobj belonging of the request queue to be released
- *
- * Description:
- * blk_cleanup_queue is the pair to blk_init_queue() or
- * blk_queue_make_request(). It should be called when a request queue is
- * being released; typically when a block device is being de-registered.
- * Currently, its primary task it to free all the &struct request
- * structures that were allocated to the queue and the queue itself.
- *
- * Caveat:
- * Hopefully the low level driver will have finished any
- * outstanding requests first...
- **/
-static void blk_release_queue(struct kobject *kobj)
-{
- struct request_queue *q =
- container_of(kobj, struct request_queue, kobj);
- struct request_list *rl = &q->rq;
-
- blk_sync_queue(q);
-
- if (rl->rq_pool)
- mempool_destroy(rl->rq_pool);
-
- if (q->queue_tags)
- __blk_queue_free_tags(q);
-
- blk_trace_shutdown(q);
-
- bdi_destroy(&q->backing_dev_info);
- kmem_cache_free(requestq_cachep, q);
-}
-
void blk_put_queue(struct request_queue *q)
{
kobject_put(&q->kobj);
@@ -1908,14 +1466,12 @@ struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
}
EXPORT_SYMBOL(blk_alloc_queue);
-static struct kobj_type queue_ktype;
-
struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
{
struct request_queue *q;
int err;
- q = kmem_cache_alloc_node(requestq_cachep,
+ q = kmem_cache_alloc_node(blk_requestq_cachep,
gfp_mask | __GFP_ZERO, node_id);
if (!q)
return NULL;
@@ -1924,13 +1480,13 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
q->backing_dev_info.unplug_io_data = q;
err = bdi_init(&q->backing_dev_info);
if (err) {
- kmem_cache_free(requestq_cachep, q);
+ kmem_cache_free(blk_requestq_cachep, q);
return NULL;
}
init_timer(&q->unplug_timer);
- kobject_init(&q->kobj, &queue_ktype);
+ kobject_init(&q->kobj, &blk_queue_ktype);
mutex_init(&q->sysfs_lock);
@@ -1987,7 +1543,7 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
q->node = node_id;
if (blk_init_free_list(q)) {
- kmem_cache_free(requestq_cachep, q);
+ kmem_cache_free(blk_requestq_cachep, q);
return NULL;
}
@@ -4012,7 +3568,7 @@ int __init blk_dev_init(void)
request_cachep = kmem_cache_create("blkdev_requests",
sizeof(struct request), 0, SLAB_PANIC, NULL);
- requestq_cachep = kmem_cache_create("blkdev_queue",
+ blk_requestq_cachep = kmem_cache_create("blkdev_queue",
sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
iocontext_cachep = kmem_cache_create("blkdev_ioc",
@@ -4200,258 +3756,3 @@ void swap_io_context(struct io_context **ioc1, struct io_context **ioc2)
}
EXPORT_SYMBOL(swap_io_context);
-/*
- * sysfs parts below
- */
-struct queue_sysfs_entry {
- struct attribute attr;
- ssize_t (*show)(struct request_queue *, char *);
- ssize_t (*store)(struct request_queue *, const char *, size_t);
-};
-
-static ssize_t
-queue_var_show(unsigned int var, char *page)
-{
- return sprintf(page, "%d\n", var);
-}
-
-static ssize_t
-queue_var_store(unsigned long *var, const char *page, size_t count)
-{
- char *p = (char *) page;
-
- *var = simple_strtoul(p, &p, 10);
- return count;
-}
-
-static ssize_t queue_requests_show(struct request_queue *q, char *page)
-{
- return queue_var_show(q->nr_requests, (page));
-}
-
-static ssize_t
-queue_requests_store(struct request_queue *q, const char *page, size_t count)
-{
- struct request_list *rl = &q->rq;
- unsigned long nr;
- int ret = queue_var_store(&nr, page, count);
- if (nr < BLKDEV_MIN_RQ)
- nr = BLKDEV_MIN_RQ;
-
- spin_lock_irq(q->queue_lock);
- q->nr_requests = nr;
- blk_queue_congestion_threshold(q);
-
- if (rl->count[READ] >= queue_congestion_on_threshold(q))
- blk_set_queue_congested(q, READ);
- else if (rl->count[READ] < queue_congestion_off_threshold(q))
- blk_clear_queue_congested(q, READ);
-
- if (rl->count[WRITE] >= queue_congestion_on_threshold(q))
- blk_set_queue_congested(q, WRITE);
- else if (rl->count[WRITE] < queue_congestion_off_threshold(q))
- blk_clear_queue_congested(q, WRITE);
-
- if (rl->count[READ] >= q->nr_requests) {
- blk_set_queue_full(q, READ);
- } else if (rl->count[READ]+1 <= q->nr_requests) {
- blk_clear_queue_full(q, READ);
- wake_up(&rl->wait[READ]);
- }
-
- if (rl->count[WRITE] >= q->nr_requests) {
- blk_set_queue_full(q, WRITE);
- } else if (rl->count[WRITE]+1 <= q->nr_requests) {
- blk_clear_queue_full(q, WRITE);
- wake_up(&rl->wait[WRITE]);
- }
- spin_unlock_irq(q->queue_lock);
- return ret;
-}
-
-static ssize_t queue_ra_show(struct request_queue *q, char *page)
-{
- int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
-
- return queue_var_show(ra_kb, (page));
-}
-
-static ssize_t
-queue_ra_store(struct request_queue *q, const char *page, size_t count)
-{
- unsigned long ra_kb;
- ssize_t ret = queue_var_store(&ra_kb, page, count);
-
- spin_lock_irq(q->queue_lock);
- q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
- spin_unlock_irq(q->queue_lock);
-
- return ret;
-}
-
-static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
-{
- int max_sectors_kb = q->max_sectors >> 1;
-
- return queue_var_show(max_sectors_kb, (page));
-}
-
-static ssize_t
-queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
-{
- unsigned long max_sectors_kb,
- max_hw_sectors_kb = q->max_hw_sectors >> 1,
- page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
- ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
-
- if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
- return -EINVAL;
- /*
- * Take the queue lock to update the readahead and max_sectors
- * values synchronously:
- */
- spin_lock_irq(q->queue_lock);
- q->max_sectors = max_sectors_kb << 1;
- spin_unlock_irq(q->queue_lock);
-
- return ret;
-}
-
-static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
-{
- int max_hw_sectors_kb = q->max_hw_sectors >> 1;
-
- return queue_var_show(max_hw_sectors_kb, (page));
-}
-
-
-static struct queue_sysfs_entry queue_requests_entry = {
- .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
- .show = queue_requests_show,
- .store = queue_requests_store,
-};
-
-static struct queue_sysfs_entry queue_ra_entry = {
- .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
- .show = queue_ra_show,
- .store = queue_ra_store,
-};
-
-static struct queue_sysfs_entry queue_max_sectors_entry = {
- .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
- .show = queue_max_sectors_show,
- .store = queue_max_sectors_store,
-};
-
-static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
- .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
- .show = queue_max_hw_sectors_show,
-};
-
-static struct queue_sysfs_entry queue_iosched_entry = {
- .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
- .show = elv_iosched_show,
- .store = elv_iosched_store,
-};
-
-static struct attribute *default_attrs[] = {
- &queue_requests_entry.attr,
- &queue_ra_entry.attr,
- &queue_max_hw_sectors_entry.attr,
- &queue_max_sectors_entry.attr,
- &queue_iosched_entry.attr,
- NULL,
-};
-
-#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
-
-static ssize_t
-queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
-{
- struct queue_sysfs_entry *entry = to_queue(attr);
- struct request_queue *q =
- container_of(kobj, struct request_queue, kobj);
- ssize_t res;
-
- if (!entry->show)
- return -EIO;
- mutex_lock(&q->sysfs_lock);
- if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
- mutex_unlock(&q->sysfs_lock);
- return -ENOENT;
- }
- res = entry->show(q, page);
- mutex_unlock(&q->sysfs_lock);
- return res;
-}
-
-static ssize_t
-queue_attr_store(struct kobject *kobj, struct attribute *attr,
- const char *page, size_t length)
-{
- struct queue_sysfs_entry *entry = to_queue(attr);
- struct request_queue *q = container_of(kobj, struct request_queue, kobj);
-
- ssize_t res;
-
- if (!entry->store)
- return -EIO;
- mutex_lock(&q->sysfs_lock);
- if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
- mutex_unlock(&q->sysfs_lock);
- return -ENOENT;
- }
- res = entry->store(q, page, length);
- mutex_unlock(&q->sysfs_lock);
- return res;
-}
-
-static struct sysfs_ops queue_sysfs_ops = {
- .show = queue_attr_show,
- .store = queue_attr_store,
-};
-
-static struct kobj_type queue_ktype = {
- .sysfs_ops = &queue_sysfs_ops,
- .default_attrs = default_attrs,
- .release = blk_release_queue,
-};
-
-int blk_register_queue(struct gendisk *disk)
-{
- int ret;
-
- struct request_queue *q = disk->queue;
-
- if (!q || !q->request_fn)
- return -ENXIO;
-
- ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
- "%s", "queue");
- if (ret < 0)
- return ret;
-
- kobject_uevent(&q->kobj, KOBJ_ADD);
-
- ret = elv_register_queue(q);
- if (ret) {
- kobject_uevent(&q->kobj, KOBJ_REMOVE);
- kobject_del(&q->kobj);
- return ret;
- }
-
- return 0;
-}
-
-void blk_unregister_queue(struct gendisk *disk)
-{
- struct request_queue *q = disk->queue;
-
- if (q && q->request_fn) {
- elv_unregister_queue(q);
-
- kobject_uevent(&q->kobj, KOBJ_REMOVE);
- kobject_del(&q->kobj);
- kobject_put(&disk->dev.kobj);
- }
-}
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
new file mode 100644
index 00000000000..d9b9afab345
--- /dev/null
+++ b/block/blk-sysfs.c
@@ -0,0 +1,298 @@
+/*
+ * Functions related to sysfs handling
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/blktrace_api.h>
+
+#include "blk.h"
+
+struct queue_sysfs_entry {
+ struct attribute attr;
+ ssize_t (*show)(struct request_queue *, char *);
+ ssize_t (*store)(struct request_queue *, const char *, size_t);
+};
+
+static ssize_t
+queue_var_show(unsigned int var, char *page)
+{
+ return sprintf(page, "%d\n", var);
+}
+
+static ssize_t
+queue_var_store(unsigned long *var, const char *page, size_t count)
+{
+ char *p = (char *) page;
+
+ *var = simple_strtoul(p, &p, 10);
+ return count;
+}
+
+static ssize_t queue_requests_show(struct request_queue *q, char *page)
+{
+ return queue_var_show(q->nr_requests, (page));
+}
+
+static ssize_t
+queue_requests_store(struct request_queue *q, const char *page, size_t count)
+{
+ struct request_list *rl = &q->rq;
+ unsigned long nr;
+ int ret = queue_var_store(&nr, page, count);
+ if (nr < BLKDEV_MIN_RQ)
+ nr = BLKDEV_MIN_RQ;
+
+ spin_lock_irq(q->queue_lock);
+ q->nr_requests = nr;
+ blk_queue_congestion_threshold(q);
+
+ if (rl->count[READ] >= queue_congestion_on_threshold(q))
+ blk_set_queue_congested(q, READ);
+ else if (rl->count[READ] < queue_congestion_off_threshold(q))
+ blk_clear_queue_congested(q, READ);
+
+ if (rl->count[WRITE] >= queue_congestion_on_threshold(q))
+ blk_set_queue_congested(q, WRITE);
+ else if (rl->count[WRITE] < queue_congestion_off_threshold(q))
+ blk_clear_queue_congested(q, WRITE);
+
+ if (rl->count[READ] >= q->nr_requests) {
+ blk_set_queue_full(q, READ);
+ } else if (rl->count[READ]+1 <= q->nr_requests) {
+ blk_clear_queue_full(q, READ);
+ wake_up(&rl->wait[READ]);
+ }
+
+ if (rl->count[WRITE] >= q->nr_requests) {
+ blk_set_queue_full(q, WRITE);
+ } else if (rl->count[WRITE]+1 <= q->nr_requests) {
+ blk_clear_queue_full(q, WRITE);
+ wake_up(&rl->wait[WRITE]);
+ }
+ spin_unlock_irq(q->queue_lock);
+ return ret;
+}
+
+static ssize_t queue_ra_show(struct request_queue *q, char *page)
+{
+ int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
+
+ return queue_var_show(ra_kb, (page));
+}
+
+static ssize_t
+queue_ra_store(struct request_queue *q, const char *page, size_t count)
+{
+ unsigned long ra_kb;
+ ssize_t ret = queue_var_store(&ra_kb, page, count);
+
+ spin_lock_irq(q->queue_lock);
+ q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
+ spin_unlock_irq(q->queue_lock);
+
+ return ret;
+}
+
+static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
+{
+ int max_sectors_kb = q->max_sectors >> 1;
+
+ return queue_var_show(max_sectors_kb, (page));
+}
+
+static ssize_t
+queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
+{
+ unsigned long max_sectors_kb,
+ max_hw_sectors_kb = q->max_hw_sectors >> 1,
+ page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
+ ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
+
+ if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
+ return -EINVAL;
+ /*
+ * Take the queue lock to update the readahead and max_sectors
+ * values synchronously:
+ */
+ spin_lock_irq(q->queue_lock);
+ q->max_sectors = max_sectors_kb << 1;
+ spin_unlock_irq(q->queue_lock);
+
+ return ret;
+}
+
+static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
+{
+ int max_hw_sectors_kb = q->max_hw_sectors >> 1;
+
+ return queue_var_show(max_hw_sectors_kb, (page));
+}
+
+
+static struct queue_sysfs_entry queue_requests_entry = {
+ .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
+ .show = queue_requests_show,
+ .store = queue_requests_store,
+};
+
+static struct queue_sysfs_entry queue_ra_entry = {
+ .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
+ .show = queue_ra_show,
+ .store = queue_ra_store,
+};
+
+static struct queue_sysfs_entry queue_max_sectors_entry = {
+ .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
+ .show = queue_max_sectors_show,
+ .store = queue_max_sectors_store,
+};
+
+static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
+ .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
+ .show = queue_max_hw_sectors_show,
+};
+
+static struct queue_sysfs_entry queue_iosched_entry = {
+ .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
+ .show = elv_iosched_show,
+ .store = elv_iosched_store,
+};
+
+static struct attribute *default_attrs[] = {
+ &queue_requests_entry.attr,
+ &queue_ra_entry.attr,
+ &queue_max_hw_sectors_entry.attr,
+ &queue_max_sectors_entry.attr,
+ &queue_iosched_entry.attr,
+ NULL,
+};
+
+#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
+
+static ssize_t
+queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
+{
+ struct queue_sysfs_entry *entry = to_queue(attr);
+ struct request_queue *q =
+ container_of(kobj, struct request_queue, kobj);
+ ssize_t res;
+
+ if (!entry->show)
+ return -EIO;
+ mutex_lock(&q->sysfs_lock);
+ if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
+ mutex_unlock(&q->sysfs_lock);
+ return -ENOENT;
+ }
+ res = entry->show(q, page);
+ mutex_unlock(&q->sysfs_lock);
+ return res;
+}
+
+static ssize_t
+queue_attr_store(struct kobject *kobj, struct attribute *attr,
+ const char *page, size_t length)
+{
+ struct queue_sysfs_entry *entry = to_queue(attr);
+ struct request_queue *q = container_of(kobj, struct request_queue, kobj);
+
+ ssize_t res;
+
+ if (!entry->store)
+ return -EIO;
+ mutex_lock(&q->sysfs_lock);
+ if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
+ mutex_unlock(&q->sysfs_lock);
+ return -ENOENT;
+ }
+ res = entry->store(q, page, length);
+ mutex_unlock(&q->sysfs_lock);
+ return res;
+}
+
+/**
+ * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
+ * @kobj: the kobj belonging of the request queue to be released
+ *
+ * Description:
+ * blk_cleanup_queue is the pair to blk_init_queue() or
+ * blk_queue_make_request(). It should be called when a request queue is
+ * being released; typically when a block device is being de-registered.
+ * Currently, its primary task it to free all the &struct request
+ * structures that were allocated to the queue and the queue itself.
+ *
+ * Caveat:
+ * Hopefully the low level driver will have finished any
+ * outstanding requests first...
+ **/
+static void blk_release_queue(struct kobject *kobj)
+{
+ struct request_queue *q =
+ container_of(kobj, struct request_queue, kobj);
+ struct request_list *rl = &q->rq;
+
+ blk_sync_queue(q);
+
+ if (rl->rq_pool)
+ mempool_destroy(rl->rq_pool);
+
+ if (q->queue_tags)
+ __blk_queue_free_tags(q);
+
+ blk_trace_shutdown(q);
+
+ bdi_destroy(&q->backing_dev_info);
+ kmem_cache_free(blk_requestq_cachep, q);
+}
+
+static struct sysfs_ops queue_sysfs_ops = {
+ .show = queue_attr_show,
+ .store = queue_attr_store,
+};
+
+struct kobj_type blk_queue_ktype = {
+ .sysfs_ops = &queue_sysfs_ops,
+ .default_attrs = default_attrs,
+ .release = blk_release_queue,
+};
+
+int blk_register_queue(struct gendisk *disk)
+{
+ int ret;
+
+ struct request_queue *q = disk->queue;
+
+ if (!q || !q->request_fn)
+ return -ENXIO;
+
+ ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
+ "%s", "queue");
+ if (ret < 0)
+ return ret;
+
+ kobject_uevent(&q->kobj, KOBJ_ADD);
+
+ ret = elv_register_queue(q);
+ if (ret) {
+ kobject_uevent(&q->kobj, KOBJ_REMOVE);
+ kobject_del(&q->kobj);
+ return ret;
+ }
+
+ return 0;
+}
+
+void blk_unregister_queue(struct gendisk *disk)
+{
+ struct request_queue *q = disk->queue;
+
+ if (q && q->request_fn) {
+ elv_unregister_queue(q);
+
+ kobject_uevent(&q->kobj, KOBJ_REMOVE);
+ kobject_del(&q->kobj);
+ kobject_put(&disk->dev.kobj);
+ }
+}
diff --git a/block/blk-tag.c b/block/blk-tag.c
new file mode 100644
index 00000000000..d1fd300e8ae
--- /dev/null
+++ b/block/blk-tag.c
@@ -0,0 +1,396 @@
+/*
+ * Functions related to tagged command queuing
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+
+/**
+ * blk_queue_find_tag - find a request by its tag and queue
+ * @q: The request queue for the device
+ * @tag: The tag of the request
+ *
+ * Notes:
+ * Should be used when a device returns a tag and you want to match
+ * it with a request.
+ *
+ * no locks need be held.
+ **/
+struct request *blk_queue_find_tag(struct request_queue *q, int tag)
+{
+ return blk_map_queue_find_tag(q->queue_tags, tag);
+}
+
+EXPORT_SYMBOL(blk_queue_find_tag);
+
+/**
+ * __blk_free_tags - release a given set of tag maintenance info
+ * @bqt: the tag map to free
+ *
+ * Tries to free the specified @bqt@. Returns true if it was
+ * actually freed and false if there are still references using it
+ */
+static int __blk_free_tags(struct blk_queue_tag *bqt)
+{
+ int retval;
+
+ retval = atomic_dec_and_test(&bqt->refcnt);
+ if (retval) {
+ BUG_ON(bqt->busy);
+
+ kfree(bqt->tag_index);
+ bqt->tag_index = NULL;
+
+ kfree(bqt->tag_map);
+ bqt->tag_map = NULL;
+
+ kfree(bqt);
+ }
+
+ return retval;
+}
+
+/**
+ * __blk_queue_free_tags - release tag maintenance info
+ * @q: the request queue for the device
+ *
+ * Notes:
+ * blk_cleanup_queue() will take care of calling this function, if tagging
+ * has been used. So there's no need to call this directly.
+ **/
+void __blk_queue_free_tags(struct request_queue *q)
+{
+ struct blk_queue_tag *bqt = q->queue_tags;
+
+ if (!bqt)
+ return;
+
+ __blk_free_tags(bqt);
+
+ q->queue_tags = NULL;
+ q->queue_flags &= ~(1 << QUEUE_FLAG_QUEUED);
+}
+
+/**
+ * blk_free_tags - release a given set of tag maintenance info
+ * @bqt: the tag map to free
+ *
+ * For externally managed @bqt@ frees the map. Callers of this
+ * function must guarantee to have released all the queues that
+ * might have been using this tag map.
+ */
+void blk_free_tags(struct blk_queue_tag *bqt)
+{
+ if (unlikely(!__blk_free_tags(bqt)))
+ BUG();
+}
+EXPORT_SYMBOL(blk_free_tags);
+
+/**
+ * blk_queue_free_tags - release tag maintenance info
+ * @q: the request queue for the device
+ *
+ * Notes:
+ * This is used to disabled tagged queuing to a device, yet leave
+ * queue in function.
+ **/
+void blk_queue_free_tags(struct request_queue *q)
+{
+ clear_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
+}
+
+EXPORT_SYMBOL(blk_queue_free_tags);
+
+static int
+init_tag_map(struct request_queue *q, struct blk_queue_tag *tags, int depth)
+{
+ struct request **tag_index;
+ unsigned long *tag_map;
+ int nr_ulongs;
+
+ if (q && depth > q->nr_requests * 2) {
+ depth = q->nr_requests * 2;
+ printk(KERN_ERR "%s: adjusted depth to %d\n",
+ __FUNCTION__, depth);
+ }
+
+ tag_index = kzalloc(depth * sizeof(struct request *), GFP_ATOMIC);
+ if (!tag_index)
+ goto fail;
+
+ nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG;
+ tag_map = kzalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC);
+ if (!tag_map)
+ goto fail;
+
+ tags->real_max_depth = depth;
+ tags->max_depth = depth;
+ tags->tag_index = tag_index;
+ tags->tag_map = tag_map;
+
+ return 0;
+fail:
+ kfree(tag_index);
+ return -ENOMEM;
+}
+
+static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q,
+ int depth)
+{
+ struct blk_queue_tag *tags;
+
+ tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC);
+ if (!tags)
+ goto fail;
+
+ if (init_tag_map(q, tags, depth))
+ goto fail;
+
+ tags->busy = 0;
+ atomic_set(&tags->refcnt, 1);
+ return tags;
+fail:
+ kfree(tags);
+ return NULL;
+}
+
+/**
+ * blk_init_tags - initialize the tag info for an external tag map
+ * @depth: the maximum queue depth supported
+ * @tags: the tag to use
+ **/
+struct blk_queue_tag *blk_init_tags(int depth)
+{
+ return __blk_queue_init_tags(NULL, depth);
+}
+EXPORT_SYMBOL(blk_init_tags);
+
+/**
+ * blk_queue_init_tags - initialize the queue tag info
+ * @q: the request queue for the device
+ * @depth: the maximum queue depth supported
+ * @tags: the tag to use
+ **/
+int blk_queue_init_tags(struct request_queue *q, int depth,
+ struct blk_queue_tag *tags)
+{
+ int rc;
+
+ BUG_ON(tags && q->queue_tags && tags != q->queue_tags);
+
+ if (!tags && !q->queue_tags) {
+ tags = __blk_queue_init_tags(q, depth);
+
+ if (!tags)
+ goto fail;
+ } else if (q->queue_tags) {
+ if ((rc = blk_queue_resize_tags(q, depth)))
+ return rc;
+ set_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
+ return 0;
+ } else
+ atomic_inc(&tags->refcnt);
+
+ /*
+ * assign it, all done
+ */
+ q->queue_tags = tags;
+ q->queue_flags |= (1 << QUEUE_FLAG_QUEUED);
+ INIT_LIST_HEAD(&q->tag_busy_list);
+ return 0;
+fail:
+ kfree(tags);
+ return -ENOMEM;
+}
+
+EXPORT_SYMBOL(blk_queue_init_tags);
+
+/**
+ * blk_queue_resize_tags - change the queueing depth
+ * @q: the request queue for the device
+ * @new_depth: the new max command queueing depth
+ *
+ * Notes:
+ * Must be called with the queue lock held.
+ **/
+int blk_queue_resize_tags(struct request_queue *q, int new_depth)
+{
+ struct blk_queue_tag *bqt = q->queue_tags;
+ struct request **tag_index;
+ unsigned long *tag_map;
+ int max_depth, nr_ulongs;
+
+ if (!bqt)
+ return -ENXIO;
+
+ /*
+ * if we already have large enough real_max_depth. just
+ * adjust max_depth. *NOTE* as requests with tag value
+ * between new_depth and real_max_depth can be in-flight, tag
+ * map can not be shrunk blindly here.
+ */
+ if (new_depth <= bqt->real_max_depth) {
+ bqt->max_depth = new_depth;
+ return 0;
+ }
+
+ /*
+ * Currently cannot replace a shared tag map with a new
+ * one, so error out if this is the case
+ */
+ if (atomic_read(&bqt->refcnt) != 1)
+ return -EBUSY;
+
+ /*
+ * save the old state info, so we can copy it back
+ */
+ tag_index = bqt->tag_index;
+ tag_map = bqt->tag_map;
+ max_depth = bqt->real_max_depth;
+
+ if (init_tag_map(q, bqt, new_depth))
+ return -ENOMEM;
+
+ memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *));
+ nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG;
+ memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long));
+
+ kfree(tag_index);
+ kfree(tag_map);
+ return 0;
+}
+
+EXPORT_SYMBOL(blk_queue_resize_tags);
+
+/**
+ * blk_queue_end_tag - end tag operations for a request
+ * @q: the request queue for the device
+ * @rq: the request that has completed
+ *
+ * Description:
+ * Typically called when end_that_request_first() returns 0, meaning
+ * all transfers have been done for a request. It's important to call
+ * this function before end_that_request_last(), as that will put the
+ * request back on the free list thus corrupting the internal tag list.
+ *
+ * Notes:
+ * queue lock must be held.
+ **/
+void blk_queue_end_tag(struct request_queue *q, struct request *rq)
+{
+ struct blk_queue_tag *bqt = q->queue_tags;
+ int tag = rq->tag;
+
+ BUG_ON(tag == -1);
+
+ if (unlikely(tag >= bqt->real_max_depth))
+ /*
+ * This can happen after tag depth has been reduced.
+ * FIXME: how about a warning or info message here?
+ */
+ return;
+
+ list_del_init(&rq->queuelist);
+ rq->cmd_flags &= ~REQ_QUEUED;
+ rq->tag = -1;
+
+ if (unlikely(bqt->tag_index[tag] == NULL))
+ printk(KERN_ERR "%s: tag %d is missing\n",
+ __FUNCTION__, tag);
+
+ bqt->tag_index[tag] = NULL;
+
+ if (unlikely(!test_bit(tag, bqt->tag_map))) {
+ printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
+ __FUNCTION__, tag);
+ return;
+ }
+ /*
+ * The tag_map bit acts as a lock for tag_index[bit], so we need
+ * unlock memory barrier semantics.
+ */
+ clear_bit_unlock(tag, bqt->tag_map);
+ bqt->busy--;
+}
+
+EXPORT_SYMBOL(blk_queue_end_tag);
+
+/**
+ * blk_queue_start_tag - find a free tag and assign it
+ * @q: the request queue for the device
+ * @rq: the block request that needs tagging
+ *
+ * Description:
+ * This can either be used as a stand-alone helper, or possibly be
+ * assigned as the queue &prep_rq_fn (in which case &struct request
+ * automagically gets a tag assigned). Note that this function
+ * assumes that any type of request can be queued! if this is not
+ * true for your device, you must check the request type before
+ * calling this function. The request will also be removed from
+ * the request queue, so it's the drivers responsibility to readd
+ * it if it should need to be restarted for some reason.
+ *
+ * Notes:
+ * queue lock must be held.
+ **/
+int blk_queue_start_tag(struct request_queue *q, struct request *rq)
+{
+ struct blk_queue_tag *bqt = q->queue_tags;
+ int tag;
+
+ if (unlikely((rq->cmd_flags & REQ_QUEUED))) {
+ printk(KERN_ERR
+ "%s: request %p for device [%s] already tagged %d",
+ __FUNCTION__, rq,
+ rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag);
+ BUG();
+ }
+
+ /*
+ * Protect against shared tag maps, as we may not have exclusive
+ * access to the tag map.
+ */
+ do {
+ tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth);
+ if (tag >= bqt->max_depth)
+ return 1;
+
+ } while (test_and_set_bit_lock(tag, bqt->tag_map));
+ /*
+ * We need lock ordering semantics given by test_and_set_bit_lock.
+ * See blk_queue_end_tag for details.
+ */
+
+ rq->cmd_flags |= REQ_QUEUED;
+ rq->tag = tag;
+ bqt->tag_index[tag] = rq;
+ blkdev_dequeue_request(rq);
+ list_add(&rq->queuelist, &q->tag_busy_list);
+ bqt->busy++;
+ return 0;
+}
+
+EXPORT_SYMBOL(blk_queue_start_tag);
+
+/**
+ * blk_queue_invalidate_tags - invalidate all pending tags
+ * @q: the request queue for the device
+ *
+ * Description:
+ * Hardware conditions may dictate a need to stop all pending requests.
+ * In this case, we will safely clear the block side of the tag queue and
+ * readd all requests to the request queue in the right order.
+ *
+ * Notes:
+ * queue lock must be held.
+ **/
+void blk_queue_invalidate_tags(struct request_queue *q)
+{
+ struct list_head *tmp, *n;
+
+ list_for_each_safe(tmp, n, &q->tag_busy_list)
+ blk_requeue_request(q, list_entry_rq(tmp));
+}
+
+EXPORT_SYMBOL(blk_queue_invalidate_tags);
diff --git a/block/blk.h b/block/blk.h
new file mode 100644
index 00000000000..d88549df1b0
--- /dev/null
+++ b/block/blk.h
@@ -0,0 +1,29 @@
+#ifndef BLK_INTERNAL_H
+#define BLK_INTERNAL_H
+
+extern struct kmem_cache *blk_requestq_cachep;
+extern struct kobj_type blk_queue_ktype;
+
+void __blk_queue_free_tags(struct request_queue *q);
+
+void blk_queue_congestion_threshold(struct request_queue *q);
+
+/*
+ * Return the threshold (number of used requests) at which the queue is
+ * considered to be congested. It include a little hysteresis to keep the
+ * context switch rate down.
+ */
+static inline int queue_congestion_on_threshold(struct request_queue *q)
+{
+ return q->nr_congestion_on;
+}
+
+/*
+ * The threshold at which a queue is considered to be uncongested
+ */
+static inline int queue_congestion_off_threshold(struct request_queue *q)
+{
+ return q->nr_congestion_off;
+}
+
+#endif