*
* Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
*
- * 30042000 Jens Axboe <axboe@suse.de> :
+ * 30042000 Jens Axboe <axboe@kernel.dk> :
*
* Split the elevator a bit so that it is possible to choose a different
* one or even write a new "plug in". There are three pieces:
#include <linux/blkdev.h>
#include <linux/elevator.h>
#include <linux/bio.h>
-#include <linux/config.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/delay.h>
+#include <linux/blktrace_api.h>
+#include <linux/hash.h>
#include <asm/uaccess.h>
static DEFINE_SPINLOCK(elv_list_lock);
static LIST_HEAD(elv_list);
+/*
+ * Merge hash stuff.
+ */
+static const int elv_hash_shift = 6;
+#define ELV_HASH_BLOCK(sec) ((sec) >> 3)
+#define ELV_HASH_FN(sec) (hash_long(ELV_HASH_BLOCK((sec)), elv_hash_shift))
+#define ELV_HASH_ENTRIES (1 << elv_hash_shift)
+#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors)
+#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
+
+/*
+ * Query io scheduler to see if the current process issuing bio may be
+ * merged with rq.
+ */
+static int elv_iosched_allow_merge(struct request *rq, struct bio *bio)
+{
+ request_queue_t *q = rq->q;
+ elevator_t *e = q->elevator;
+
+ if (e->ops->elevator_allow_merge_fn)
+ return e->ops->elevator_allow_merge_fn(q, rq, bio);
+
+ return 1;
+}
+
/*
* can we safely merge with this request?
*/
return 0;
/*
- * same device and no special stuff set, merge is ok
+ * must be same device and not a special request
*/
- if (rq->rq_disk == bio->bi_bdev->bd_disk &&
- !rq->waiting && !rq->special)
- return 1;
+ if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special)
+ return 0;
- return 0;
+ if (!elv_iosched_allow_merge(rq, bio))
+ return 0;
+
+ return 1;
}
EXPORT_SYMBOL(elv_rq_merge_ok);
static struct elevator_type *elevator_find(const char *name)
{
- struct elevator_type *e = NULL;
+ struct elevator_type *e;
struct list_head *entry;
list_for_each(entry, &elv_list) {
- struct elevator_type *__e;
- __e = list_entry(entry, struct elevator_type, list);
+ e = list_entry(entry, struct elevator_type, list);
- if (!strcmp(__e->elevator_name, name)) {
- e = __e;
- break;
- }
+ if (!strcmp(e->elevator_name, name))
+ return e;
}
- return e;
+ return NULL;
}
static void elevator_put(struct elevator_type *e)
return e;
}
-static int elevator_attach(request_queue_t *q, struct elevator_type *e,
- struct elevator_queue *eq)
+static void *elevator_init_queue(request_queue_t *q, struct elevator_queue *eq)
{
- int ret = 0;
-
- memset(eq, 0, sizeof(*eq));
- eq->ops = &e->ops;
- eq->elevator_type = e;
+ return eq->ops->elevator_init_fn(q);
+}
+static void elevator_attach(request_queue_t *q, struct elevator_queue *eq,
+ void *data)
+{
q->elevator = eq;
-
- if (eq->ops->elevator_init_fn)
- ret = eq->ops->elevator_init_fn(q, eq);
-
- return ret;
+ eq->elevator_data = data;
}
static char chosen_elevator[16];
strcpy(chosen_elevator, "anticipatory");
else
strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1);
- return 0;
+ return 1;
}
__setup("elevator=", elevator_setup);
+static struct kobj_type elv_ktype;
+
+static elevator_t *elevator_alloc(request_queue_t *q, struct elevator_type *e)
+{
+ elevator_t *eq;
+ int i;
+
+ eq = kmalloc_node(sizeof(elevator_t), GFP_KERNEL, q->node);
+ if (unlikely(!eq))
+ goto err;
+
+ memset(eq, 0, sizeof(*eq));
+ eq->ops = &e->ops;
+ eq->elevator_type = e;
+ kobject_init(&eq->kobj);
+ snprintf(eq->kobj.name, KOBJ_NAME_LEN, "%s", "iosched");
+ eq->kobj.ktype = &elv_ktype;
+ mutex_init(&eq->sysfs_lock);
+
+ eq->hash = kmalloc_node(sizeof(struct hlist_head) * ELV_HASH_ENTRIES,
+ GFP_KERNEL, q->node);
+ if (!eq->hash)
+ goto err;
+
+ for (i = 0; i < ELV_HASH_ENTRIES; i++)
+ INIT_HLIST_HEAD(&eq->hash[i]);
+
+ return eq;
+err:
+ kfree(eq);
+ elevator_put(e);
+ return NULL;
+}
+
+static void elevator_release(struct kobject *kobj)
+{
+ elevator_t *e = container_of(kobj, elevator_t, kobj);
+
+ elevator_put(e->elevator_type);
+ kfree(e->hash);
+ kfree(e);
+}
+
int elevator_init(request_queue_t *q, char *name)
{
struct elevator_type *e = NULL;
struct elevator_queue *eq;
int ret = 0;
+ void *data;
INIT_LIST_HEAD(&q->queue_head);
q->last_merge = NULL;
e = elevator_get("noop");
}
- eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL);
- if (!eq) {
- elevator_put(e);
+ eq = elevator_alloc(q, e);
+ if (!eq)
return -ENOMEM;
- }
- ret = elevator_attach(q, e, eq);
- if (ret) {
- kfree(eq);
- elevator_put(e);
+ data = elevator_init_queue(q, eq);
+ if (!data) {
+ kobject_put(&eq->kobj);
+ return -ENOMEM;
}
+ elevator_attach(q, eq, data);
return ret;
}
+EXPORT_SYMBOL(elevator_init);
+
void elevator_exit(elevator_t *e)
{
+ mutex_lock(&e->sysfs_lock);
if (e->ops->elevator_exit_fn)
e->ops->elevator_exit_fn(e);
+ e->ops = NULL;
+ mutex_unlock(&e->sysfs_lock);
- elevator_put(e->elevator_type);
- e->elevator_type = NULL;
- kfree(e);
+ kobject_put(&e->kobj);
+}
+
+EXPORT_SYMBOL(elevator_exit);
+
+static inline void __elv_rqhash_del(struct request *rq)
+{
+ hlist_del_init(&rq->hash);
+}
+
+static void elv_rqhash_del(request_queue_t *q, struct request *rq)
+{
+ if (ELV_ON_HASH(rq))
+ __elv_rqhash_del(rq);
+}
+
+static void elv_rqhash_add(request_queue_t *q, struct request *rq)
+{
+ elevator_t *e = q->elevator;
+
+ BUG_ON(ELV_ON_HASH(rq));
+ hlist_add_head(&rq->hash, &e->hash[ELV_HASH_FN(rq_hash_key(rq))]);
+}
+
+static void elv_rqhash_reposition(request_queue_t *q, struct request *rq)
+{
+ __elv_rqhash_del(rq);
+ elv_rqhash_add(q, rq);
+}
+
+static struct request *elv_rqhash_find(request_queue_t *q, sector_t offset)
+{
+ elevator_t *e = q->elevator;
+ struct hlist_head *hash_list = &e->hash[ELV_HASH_FN(offset)];
+ struct hlist_node *entry, *next;
+ struct request *rq;
+
+ hlist_for_each_entry_safe(rq, entry, next, hash_list, hash) {
+ BUG_ON(!ELV_ON_HASH(rq));
+
+ if (unlikely(!rq_mergeable(rq))) {
+ __elv_rqhash_del(rq);
+ continue;
+ }
+
+ if (rq_hash_key(rq) == offset)
+ return rq;
+ }
+
+ return NULL;
+}
+
+/*
+ * RB-tree support functions for inserting/lookup/removal of requests
+ * in a sorted RB tree.
+ */
+struct request *elv_rb_add(struct rb_root *root, struct request *rq)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent = NULL;
+ struct request *__rq;
+
+ while (*p) {
+ parent = *p;
+ __rq = rb_entry(parent, struct request, rb_node);
+
+ if (rq->sector < __rq->sector)
+ p = &(*p)->rb_left;
+ else if (rq->sector > __rq->sector)
+ p = &(*p)->rb_right;
+ else
+ return __rq;
+ }
+
+ rb_link_node(&rq->rb_node, parent, p);
+ rb_insert_color(&rq->rb_node, root);
+ return NULL;
+}
+
+EXPORT_SYMBOL(elv_rb_add);
+
+void elv_rb_del(struct rb_root *root, struct request *rq)
+{
+ BUG_ON(RB_EMPTY_NODE(&rq->rb_node));
+ rb_erase(&rq->rb_node, root);
+ RB_CLEAR_NODE(&rq->rb_node);
+}
+
+EXPORT_SYMBOL(elv_rb_del);
+
+struct request *elv_rb_find(struct rb_root *root, sector_t sector)
+{
+ struct rb_node *n = root->rb_node;
+ struct request *rq;
+
+ while (n) {
+ rq = rb_entry(n, struct request, rb_node);
+
+ if (sector < rq->sector)
+ n = n->rb_left;
+ else if (sector > rq->sector)
+ n = n->rb_right;
+ else
+ return rq;
+ }
+
+ return NULL;
}
+EXPORT_SYMBOL(elv_rb_find);
+
/*
* Insert rq into dispatch queue of q. Queue lock must be held on
- * entry. If sort != 0, rq is sort-inserted; otherwise, rq will be
- * appended to the dispatch queue. To be used by specific elevators.
+ * entry. rq is sort insted into the dispatch queue. To be used by
+ * specific elevators.
*/
void elv_dispatch_sort(request_queue_t *q, struct request *rq)
{
if (q->last_merge == rq)
q->last_merge = NULL;
+
+ elv_rqhash_del(q, rq);
+
q->nr_sorted--;
boundary = q->end_sector;
list_for_each_prev(entry, &q->queue_head) {
struct request *pos = list_entry_rq(entry);
- if (pos->flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED))
+ if (pos->cmd_flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED))
break;
if (rq->sector >= boundary) {
if (pos->sector < boundary)
list_add(&rq->queuelist, entry);
}
+EXPORT_SYMBOL(elv_dispatch_sort);
+
+/*
+ * Insert rq into dispatch queue of q. Queue lock must be held on
+ * entry. rq is added to the back of the dispatch queue. To be used by
+ * specific elevators.
+ */
+void elv_dispatch_add_tail(struct request_queue *q, struct request *rq)
+{
+ if (q->last_merge == rq)
+ q->last_merge = NULL;
+
+ elv_rqhash_del(q, rq);
+
+ q->nr_sorted--;
+
+ q->end_sector = rq_end_sector(rq);
+ q->boundary_rq = rq;
+ list_add_tail(&rq->queuelist, &q->queue_head);
+}
+
+EXPORT_SYMBOL(elv_dispatch_add_tail);
+
int elv_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
elevator_t *e = q->elevator;
+ struct request *__rq;
int ret;
+ /*
+ * First try one-hit cache.
+ */
if (q->last_merge) {
ret = elv_try_merge(q->last_merge, bio);
if (ret != ELEVATOR_NO_MERGE) {
}
}
+ /*
+ * See if our hash lookup can find a potential backmerge.
+ */
+ __rq = elv_rqhash_find(q, bio->bi_sector);
+ if (__rq && elv_rq_merge_ok(__rq, bio)) {
+ *req = __rq;
+ return ELEVATOR_BACK_MERGE;
+ }
+
if (e->ops->elevator_merge_fn)
return e->ops->elevator_merge_fn(q, req, bio);
return ELEVATOR_NO_MERGE;
}
-void elv_merged_request(request_queue_t *q, struct request *rq)
+void elv_merged_request(request_queue_t *q, struct request *rq, int type)
{
elevator_t *e = q->elevator;
if (e->ops->elevator_merged_fn)
- e->ops->elevator_merged_fn(q, rq);
+ e->ops->elevator_merged_fn(q, rq, type);
+
+ if (type == ELEVATOR_BACK_MERGE)
+ elv_rqhash_reposition(q, rq);
q->last_merge = rq;
}
if (e->ops->elevator_merge_req_fn)
e->ops->elevator_merge_req_fn(q, rq, next);
- q->nr_sorted--;
+ elv_rqhash_reposition(q, rq);
+ elv_rqhash_del(q, next);
+
+ q->nr_sorted--;
q->last_merge = rq;
}
e->ops->elevator_deactivate_req_fn(q, rq);
}
- rq->flags &= ~REQ_STARTED;
+ rq->cmd_flags &= ~REQ_STARTED;
elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE);
}
unsigned ordseq;
int unplug_it = 1;
+ blk_add_trace_rq(q, rq, BLK_TA_INSERT);
+
rq->q = q;
switch (where) {
case ELEVATOR_INSERT_FRONT:
- rq->flags |= REQ_SOFTBARRIER;
+ rq->cmd_flags |= REQ_SOFTBARRIER;
list_add(&rq->queuelist, &q->queue_head);
break;
case ELEVATOR_INSERT_BACK:
- rq->flags |= REQ_SOFTBARRIER;
+ rq->cmd_flags |= REQ_SOFTBARRIER;
elv_drain_elevator(q);
list_add_tail(&rq->queuelist, &q->queue_head);
/*
case ELEVATOR_INSERT_SORT:
BUG_ON(!blk_fs_request(rq));
- rq->flags |= REQ_SORTED;
+ rq->cmd_flags |= REQ_SORTED;
q->nr_sorted++;
- if (q->last_merge == NULL && rq_mergeable(rq))
- q->last_merge = rq;
+ if (rq_mergeable(rq)) {
+ elv_rqhash_add(q, rq);
+ if (!q->last_merge)
+ q->last_merge = rq;
+ }
+
/*
* Some ioscheds (cfq) run q->request_fn directly, so
* rq cannot be accessed after calling
* insertion; otherwise, requests should be requeued
* in ordseq order.
*/
- rq->flags |= REQ_SOFTBARRIER;
+ rq->cmd_flags |= REQ_SOFTBARRIER;
+
+ /*
+ * Most requeues happen because of a busy condition,
+ * don't force unplug of the queue for that case.
+ */
+ unplug_it = 0;
if (q->ordseq == 0) {
list_add(&rq->queuelist, &q->queue_head);
}
list_add_tail(&rq->queuelist, pos);
- /*
- * most requeues happen because of a busy condition, don't
- * force unplug of the queue for that case.
- */
- unplug_it = 0;
break;
default:
int plug)
{
if (q->ordcolor)
- rq->flags |= REQ_ORDERED_COLOR;
+ rq->cmd_flags |= REQ_ORDERED_COLOR;
- if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
+ if (rq->cmd_flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
/*
* toggle ordered color
*/
q->end_sector = rq_end_sector(rq);
q->boundary_rq = rq;
}
- } else if (!(rq->flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT)
+ } else if (!(rq->cmd_flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT)
where = ELEVATOR_INSERT_BACK;
if (plug)
elv_insert(q, rq, where);
}
+EXPORT_SYMBOL(__elv_add_request);
+
void elv_add_request(request_queue_t *q, struct request *rq, int where,
int plug)
{
spin_unlock_irqrestore(q->queue_lock, flags);
}
+EXPORT_SYMBOL(elv_add_request);
+
static inline struct request *__elv_next_request(request_queue_t *q)
{
struct request *rq;
int ret;
while ((rq = __elv_next_request(q)) != NULL) {
- if (!(rq->flags & REQ_STARTED)) {
+ if (!(rq->cmd_flags & REQ_STARTED)) {
elevator_t *e = q->elevator;
/*
* it, a request that has been delayed should
* not be passed by new incoming requests
*/
- rq->flags |= REQ_STARTED;
+ rq->cmd_flags |= REQ_STARTED;
+ blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
}
if (!q->boundary_rq || q->boundary_rq == rq) {
q->boundary_rq = NULL;
}
- if ((rq->flags & REQ_DONTPREP) || !q->prep_rq_fn)
+ if ((rq->cmd_flags & REQ_DONTPREP) || !q->prep_rq_fn)
break;
ret = q->prep_rq_fn(q, rq);
nr_bytes = rq->data_len;
blkdev_dequeue_request(rq);
- rq->flags |= REQ_QUIET;
+ rq->cmd_flags |= REQ_QUIET;
end_that_request_chunk(rq, 0, nr_bytes);
end_that_request_last(rq, 0);
} else {
return rq;
}
+EXPORT_SYMBOL(elv_next_request);
+
void elv_dequeue_request(request_queue_t *q, struct request *rq)
{
BUG_ON(list_empty(&rq->queuelist));
+ BUG_ON(ELV_ON_HASH(rq));
list_del_init(&rq->queuelist);
q->in_flight++;
}
+EXPORT_SYMBOL(elv_dequeue_request);
+
int elv_queue_empty(request_queue_t *q)
{
elevator_t *e = q->elevator;
return 1;
}
+EXPORT_SYMBOL(elv_queue_empty);
+
struct request *elv_latter_request(request_queue_t *q, struct request *rq)
{
elevator_t *e = q->elevator;
return NULL;
}
-int elv_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
- gfp_t gfp_mask)
+int elv_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
{
elevator_t *e = q->elevator;
if (e->ops->elevator_set_req_fn)
- return e->ops->elevator_set_req_fn(q, rq, bio, gfp_mask);
+ return e->ops->elevator_set_req_fn(q, rq, gfp_mask);
rq->elevator_private = NULL;
return 0;
elevator_t *e = q->elevator;
if (e->ops->elevator_put_req_fn)
- e->ops->elevator_put_req_fn(q, rq);
+ e->ops->elevator_put_req_fn(rq);
}
-int elv_may_queue(request_queue_t *q, int rw, struct bio *bio)
+int elv_may_queue(request_queue_t *q, int rw)
{
elevator_t *e = q->elevator;
if (e->ops->elevator_may_queue_fn)
- return e->ops->elevator_may_queue_fn(q, rw, bio);
+ return e->ops->elevator_may_queue_fn(q, rw);
return ELV_MQUEUE_MAY;
}
}
}
-int elv_register_queue(struct request_queue *q)
+#define to_elv(atr) container_of((atr), struct elv_fs_entry, attr)
+
+static ssize_t
+elv_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = container_of(kobj, elevator_t, kobj);
+ struct elv_fs_entry *entry = to_elv(attr);
+ ssize_t error;
- e->kobj.parent = kobject_get(&q->kobj);
- if (!e->kobj.parent)
- return -EBUSY;
+ if (!entry->show)
+ return -EIO;
- snprintf(e->kobj.name, KOBJ_NAME_LEN, "%s", "iosched");
- e->kobj.ktype = e->elevator_type->elevator_ktype;
+ mutex_lock(&e->sysfs_lock);
+ error = e->ops ? entry->show(e, page) : -ENOENT;
+ mutex_unlock(&e->sysfs_lock);
+ return error;
+}
+
+static ssize_t
+elv_attr_store(struct kobject *kobj, struct attribute *attr,
+ const char *page, size_t length)
+{
+ elevator_t *e = container_of(kobj, elevator_t, kobj);
+ struct elv_fs_entry *entry = to_elv(attr);
+ ssize_t error;
+
+ if (!entry->store)
+ return -EIO;
- return kobject_register(&e->kobj);
+ mutex_lock(&e->sysfs_lock);
+ error = e->ops ? entry->store(e, page, length) : -ENOENT;
+ mutex_unlock(&e->sysfs_lock);
+ return error;
}
-void elv_unregister_queue(struct request_queue *q)
+static struct sysfs_ops elv_sysfs_ops = {
+ .show = elv_attr_show,
+ .store = elv_attr_store,
+};
+
+static struct kobj_type elv_ktype = {
+ .sysfs_ops = &elv_sysfs_ops,
+ .release = elevator_release,
+};
+
+int elv_register_queue(struct request_queue *q)
{
- if (q) {
- elevator_t *e = q->elevator;
- kobject_unregister(&e->kobj);
- kobject_put(&q->kobj);
+ elevator_t *e = q->elevator;
+ int error;
+
+ e->kobj.parent = &q->kobj;
+
+ error = kobject_add(&e->kobj);
+ if (!error) {
+ struct elv_fs_entry *attr = e->elevator_type->elevator_attrs;
+ if (attr) {
+ while (attr->attr.name) {
+ if (sysfs_create_file(&e->kobj, &attr->attr))
+ break;
+ attr++;
+ }
+ }
+ kobject_uevent(&e->kobj, KOBJ_ADD);
}
+ return error;
+}
+
+static void __elv_unregister_queue(elevator_t *e)
+{
+ kobject_uevent(&e->kobj, KOBJ_REMOVE);
+ kobject_del(&e->kobj);
+}
+
+void elv_unregister_queue(struct request_queue *q)
+{
+ if (q)
+ __elv_unregister_queue(q->elevator);
}
int elv_register(struct elevator_type *e)
{
spin_lock_irq(&elv_list_lock);
- if (elevator_find(e->elevator_name))
- BUG();
+ BUG_ON(elevator_find(e->elevator_name));
list_add_tail(&e->list, &elv_list);
spin_unlock_irq(&elv_list_lock);
/*
* Iterate every thread in the process to remove the io contexts.
*/
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- struct io_context *ioc = p->io_context;
- if (ioc && ioc->cic) {
- ioc->cic->exit(ioc->cic);
- ioc->cic->dtor(ioc->cic);
- ioc->cic = NULL;
- }
- if (ioc && ioc->aic) {
- ioc->aic->exit(ioc->aic);
- ioc->aic->dtor(ioc->aic);
- ioc->aic = NULL;
- }
- } while_each_thread(g, p);
- read_unlock(&tasklist_lock);
+ if (e->ops.trim) {
+ read_lock(&tasklist_lock);
+ do_each_thread(g, p) {
+ task_lock(p);
+ if (p->io_context)
+ e->ops.trim(p->io_context);
+ task_unlock(p);
+ } while_each_thread(g, p);
+ read_unlock(&tasklist_lock);
+ }
spin_lock_irq(&elv_list_lock);
list_del_init(&e->list);
* need for the new one. this way we have a chance of going back to the old
* one, if the new one fails init for some reason.
*/
-static void elevator_switch(request_queue_t *q, struct elevator_type *new_e)
+static int elevator_switch(request_queue_t *q, struct elevator_type *new_e)
{
elevator_t *old_elevator, *e;
+ void *data;
/*
* Allocate new elevator
*/
- e = kmalloc(sizeof(elevator_t), GFP_KERNEL);
+ e = elevator_alloc(q, new_e);
if (!e)
- goto error;
+ return 0;
+
+ data = elevator_init_queue(q, e);
+ if (!data) {
+ kobject_put(&e->kobj);
+ return 0;
+ }
/*
* Turn on BYPASS and drain all requests w/ elevator private data
elv_drain_elevator(q);
}
- spin_unlock_irq(q->queue_lock);
-
/*
- * unregister old elevator data
+ * Remember old elevator.
*/
- elv_unregister_queue(q);
old_elevator = q->elevator;
/*
* attach and start new elevator
*/
- if (elevator_attach(q, new_e, e))
- goto fail;
+ elevator_attach(q, e, data);
+
+ spin_unlock_irq(q->queue_lock);
+
+ __elv_unregister_queue(old_elevator);
if (elv_register_queue(q))
goto fail_register;
*/
elevator_exit(old_elevator);
clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
- return;
+ return 1;
fail_register:
/*
* one again (along with re-adding the sysfs dir)
*/
elevator_exit(e);
- e = NULL;
-fail:
q->elevator = old_elevator;
elv_register_queue(q);
clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
- kfree(e);
-error:
- elevator_put(new_e);
- printk(KERN_ERR "elevator: switch to %s failed\n",new_e->elevator_name);
+ return 0;
}
ssize_t elv_iosched_store(request_queue_t *q, const char *name, size_t count)
return count;
}
- elevator_switch(q, e);
+ if (!elevator_switch(q, e))
+ printk(KERN_ERR "elevator: switch to %s failed\n",elevator_name);
return count;
}
return len;
}
-EXPORT_SYMBOL(elv_dispatch_sort);
-EXPORT_SYMBOL(elv_add_request);
-EXPORT_SYMBOL(__elv_add_request);
-EXPORT_SYMBOL(elv_requeue_request);
-EXPORT_SYMBOL(elv_next_request);
-EXPORT_SYMBOL(elv_dequeue_request);
-EXPORT_SYMBOL(elv_queue_empty);
-EXPORT_SYMBOL(elv_completed_request);
-EXPORT_SYMBOL(elevator_exit);
-EXPORT_SYMBOL(elevator_init);
+struct request *elv_rb_former_request(request_queue_t *q, struct request *rq)
+{
+ struct rb_node *rbprev = rb_prev(&rq->rb_node);
+
+ if (rbprev)
+ return rb_entry_rq(rbprev);
+
+ return NULL;
+}
+
+EXPORT_SYMBOL(elv_rb_former_request);
+
+struct request *elv_rb_latter_request(request_queue_t *q, struct request *rq)
+{
+ struct rb_node *rbnext = rb_next(&rq->rb_node);
+
+ if (rbnext)
+ return rb_entry_rq(rbnext);
+
+ return NULL;
+}
+
+EXPORT_SYMBOL(elv_rb_latter_request);
git://git.onelab.eu / linux-2.6.git / blobdiff