Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
[pandora-kernel.git] / block / ll_rw_blk.c
index 0ef2971..eee03a3 100644 (file)
@@ -28,6 +28,7 @@
 #include <linux/writeback.h>
 #include <linux/interrupt.h>
 #include <linux/cpu.h>
+#include <linux/blktrace_api.h>
 
 /*
  * for max sense size
@@ -637,7 +638,7 @@ void blk_queue_bounce_limit(request_queue_t *q, u64 dma_addr)
        /* 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 < (0xffffffff>>PAGE_SHIFT))
+       if (bounce_pfn < (min_t(u64,0xffffffff,BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
                dma = 1;
        q->bounce_pfn = max_low_pfn;
 #else
@@ -784,6 +785,8 @@ void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b)
        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);
@@ -905,17 +908,15 @@ init_tag_map(request_queue_t *q, struct blk_queue_tag *tags, int depth)
                                __FUNCTION__, depth);
        }
 
-       tag_index = kmalloc(depth * sizeof(struct request *), GFP_ATOMIC);
+       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 = kmalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC);
+       tag_map = kzalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC);
        if (!tag_map)
                goto fail;
 
-       memset(tag_index, 0, depth * sizeof(struct request *));
-       memset(tag_map, 0, nr_ulongs * sizeof(unsigned long));
        tags->real_max_depth = depth;
        tags->max_depth = depth;
        tags->tag_index = tag_index;
@@ -1553,11 +1554,13 @@ void blk_plug_device(request_queue_t *q)
         * don't plug a stopped queue, it must be paired with blk_start_queue()
         * which will restart the queueing
         */
-       if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
+       if (blk_queue_stopped(q))
                return;
 
-       if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
+       if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) {
                mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
+               blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG);
+       }
 }
 
 EXPORT_SYMBOL(blk_plug_device);
@@ -1584,7 +1587,7 @@ EXPORT_SYMBOL(blk_remove_plug);
  */
 void __generic_unplug_device(request_queue_t *q)
 {
-       if (unlikely(test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)))
+       if (unlikely(blk_queue_stopped(q)))
                return;
 
        if (!blk_remove_plug(q))
@@ -1621,14 +1624,21 @@ static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
        /*
         * devices don't necessarily have an ->unplug_fn defined
         */
-       if (q->unplug_fn)
+       if (q->unplug_fn) {
+               blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
+                                       q->rq.count[READ] + q->rq.count[WRITE]);
+
                q->unplug_fn(q);
+       }
 }
 
 static void blk_unplug_work(void *data)
 {
        request_queue_t *q = data;
 
+       blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
+                               q->rq.count[READ] + q->rq.count[WRITE]);
+
        q->unplug_fn(q);
 }
 
@@ -1636,6 +1646,9 @@ static void blk_unplug_timeout(unsigned long data)
 {
        request_queue_t *q = (request_queue_t *)data;
 
+       blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL,
+                               q->rq.count[READ] + q->rq.count[WRITE]);
+
        kblockd_schedule_work(&q->unplug_work);
 }
 
@@ -1650,6 +1663,8 @@ static void blk_unplug_timeout(unsigned long data)
  **/
 void blk_start_queue(request_queue_t *q)
 {
+       WARN_ON(!irqs_disabled());
+
        clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags);
 
        /*
@@ -1719,15 +1734,28 @@ void blk_run_queue(struct request_queue *q)
 
        spin_lock_irqsave(q->queue_lock, flags);
        blk_remove_plug(q);
-       if (!elv_queue_empty(q))
-               q->request_fn(q);
+
+       /*
+        * Only recurse once to avoid overrunning the stack, let the unplug
+        * handling reinvoke the handler shortly if we already got there.
+        */
+       if (!elv_queue_empty(q)) {
+               if (!test_and_set_bit(QUEUE_FLAG_REENTER, &q->queue_flags)) {
+                       q->request_fn(q);
+                       clear_bit(QUEUE_FLAG_REENTER, &q->queue_flags);
+               } else {
+                       blk_plug_device(q);
+                       kblockd_schedule_work(&q->unplug_work);
+               }
+       }
+
        spin_unlock_irqrestore(q->queue_lock, flags);
 }
 EXPORT_SYMBOL(blk_run_queue);
 
 /**
  * blk_cleanup_queue: - release a &request_queue_t when it is no longer needed
- * @q:    the request queue to be released
+ * @kobj:    the kobj belonging of the request queue to be released
  *
  * Description:
  *     blk_cleanup_queue is the pair to blk_init_queue() or
@@ -1740,16 +1768,11 @@ EXPORT_SYMBOL(blk_run_queue);
  *     Hopefully the low level driver will have finished any
  *     outstanding requests first...
  **/
-void blk_cleanup_queue(request_queue_t * q)
+static void blk_release_queue(struct kobject *kobj)
 {
+       request_queue_t *q = container_of(kobj, struct request_queue, kobj);
        struct request_list *rl = &q->rq;
 
-       if (!atomic_dec_and_test(&q->refcnt))
-               return;
-
-       if (q->elevator)
-               elevator_exit(q->elevator);
-
        blk_sync_queue(q);
 
        if (rl->rq_pool)
@@ -1758,9 +1781,30 @@ void blk_cleanup_queue(request_queue_t * q)
        if (q->queue_tags)
                __blk_queue_free_tags(q);
 
+       if (q->blk_trace)
+               blk_trace_shutdown(q);
+
        kmem_cache_free(requestq_cachep, q);
 }
 
+void blk_put_queue(request_queue_t *q)
+{
+       kobject_put(&q->kobj);
+}
+EXPORT_SYMBOL(blk_put_queue);
+
+void blk_cleanup_queue(request_queue_t * q)
+{
+       mutex_lock(&q->sysfs_lock);
+       set_bit(QUEUE_FLAG_DEAD, &q->queue_flags);
+       mutex_unlock(&q->sysfs_lock);
+
+       if (q->elevator)
+               elevator_exit(q->elevator);
+
+       blk_put_queue(q);
+}
+
 EXPORT_SYMBOL(blk_cleanup_queue);
 
 static int blk_init_free_list(request_queue_t *q)
@@ -1788,6 +1832,8 @@ request_queue_t *blk_alloc_queue(gfp_t gfp_mask)
 }
 EXPORT_SYMBOL(blk_alloc_queue);
 
+static struct kobj_type queue_ktype;
+
 request_queue_t *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 {
        request_queue_t *q;
@@ -1798,11 +1844,16 @@ request_queue_t *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 
        memset(q, 0, sizeof(*q));
        init_timer(&q->unplug_timer);
-       atomic_set(&q->refcnt, 1);
+
+       snprintf(q->kobj.name, KOBJ_NAME_LEN, "%s", "queue");
+       q->kobj.ktype = &queue_ktype;
+       kobject_init(&q->kobj);
 
        q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug;
        q->backing_dev_info.unplug_io_data = q;
 
+       mutex_init(&q->sysfs_lock);
+
        return q;
 }
 EXPORT_SYMBOL(blk_alloc_queue_node);
@@ -1829,7 +1880,8 @@ EXPORT_SYMBOL(blk_alloc_queue_node);
  *    get dealt with eventually.
  *
  *    The queue spin lock must be held while manipulating the requests on the
- *    request queue.
+ *    request queue; this lock will be taken also from interrupt context, so irq
+ *    disabling is needed for it.
  *
  *    Function returns a pointer to the initialized request queue, or NULL if
  *    it didn't succeed.
@@ -1854,8 +1906,10 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
                return NULL;
 
        q->node = node_id;
-       if (blk_init_free_list(q))
-               goto out_init;
+       if (blk_init_free_list(q)) {
+               kmem_cache_free(requestq_cachep, q);
+               return NULL;
+       }
 
        /*
         * if caller didn't supply a lock, they get per-queue locking with
@@ -1891,9 +1945,7 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
                return q;
        }
 
-       blk_cleanup_queue(q);
-out_init:
-       kmem_cache_free(requestq_cachep, q);
+       blk_put_queue(q);
        return NULL;
 }
 EXPORT_SYMBOL(blk_init_queue_node);
@@ -1901,7 +1953,7 @@ EXPORT_SYMBOL(blk_init_queue_node);
 int blk_get_queue(request_queue_t *q)
 {
        if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
-               atomic_inc(&q->refcnt);
+               kobject_get(&q->kobj);
                return 0;
        }
 
@@ -2109,6 +2161,8 @@ rq_starved:
        
        rq_init(q, rq);
        rq->rl = rl;
+
+       blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ);
 out:
        return rq;
 }
@@ -2137,6 +2191,8 @@ static struct request *get_request_wait(request_queue_t *q, int rw,
                if (!rq) {
                        struct io_context *ioc;
 
+                       blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
+
                        __generic_unplug_device(q);
                        spin_unlock_irq(q->queue_lock);
                        io_schedule();
@@ -2190,6 +2246,8 @@ EXPORT_SYMBOL(blk_get_request);
  */
 void blk_requeue_request(request_queue_t *q, struct request *rq)
 {
+       blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
+
        if (blk_rq_tagged(rq))
                blk_queue_end_tag(q, rq);
 
@@ -2437,10 +2495,12 @@ void blk_execute_rq_nowait(request_queue_t *q, struct gendisk *bd_disk,
        rq->rq_disk = bd_disk;
        rq->flags |= REQ_NOMERGE;
        rq->end_io = done;
-       elv_add_request(q, rq, where, 1);
-       generic_unplug_device(q);
+       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);
 
 /**
@@ -2685,7 +2745,7 @@ static int attempt_merge(request_queue_t *q, struct request *req,
                return 0;
 
        /*
-        * not contigious
+        * not contiguous
         */
        if (req->sector + req->nr_sectors != next->sector)
                return 0;
@@ -2767,6 +2827,9 @@ static void init_request_from_bio(struct request *req, struct bio *bio)
        if (unlikely(bio_barrier(bio)))
                req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
 
+       if (bio_sync(bio))
+               req->flags |= REQ_RW_SYNC;
+
        req->errors = 0;
        req->hard_sector = req->sector = bio->bi_sector;
        req->hard_nr_sectors = req->nr_sectors = bio_sectors(bio);
@@ -2824,6 +2887,8 @@ static int __make_request(request_queue_t *q, struct bio *bio)
                        if (!q->back_merge_fn(q, req, bio))
                                break;
 
+                       blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
+
                        req->biotail->bi_next = bio;
                        req->biotail = bio;
                        req->nr_sectors = req->hard_nr_sectors += nr_sectors;
@@ -2839,6 +2904,8 @@ static int __make_request(request_queue_t *q, struct bio *bio)
                        if (!q->front_merge_fn(q, req, bio))
                                break;
 
+                       blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
+
                        bio->bi_next = req->bio;
                        req->bio = bio;
 
@@ -2956,6 +3023,7 @@ void generic_make_request(struct bio *bio)
        request_queue_t *q;
        sector_t maxsector;
        int ret, nr_sectors = bio_sectors(bio);
+       dev_t old_dev;
 
        might_sleep();
        /* Test device or partition size, when known. */
@@ -2982,6 +3050,8 @@ void generic_make_request(struct bio *bio)
         * NOTE: we don't repeat the blk_size check for each new device.
         * Stacking drivers are expected to know what they are doing.
         */
+       maxsector = -1;
+       old_dev = 0;
        do {
                char b[BDEVNAME_SIZE];
 
@@ -3014,6 +3084,15 @@ end_io:
                 */
                blk_partition_remap(bio);
 
+               if (maxsector != -1)
+                       blk_add_trace_remap(q, bio, old_dev, bio->bi_sector, 
+                                           maxsector);
+
+               blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
+
+               maxsector = bio->bi_sector;
+               old_dev = bio->bi_bdev->bd_dev;
+
                ret = q->make_request_fn(q, bio);
        } while (ret);
 }
@@ -3133,6 +3212,8 @@ static int __end_that_request_first(struct request *req, int uptodate,
        int total_bytes, bio_nbytes, error, next_idx = 0;
        struct bio *bio;
 
+       blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE);
+
        /*
         * extend uptodate bool to allow < 0 value to be direct io error
         */
@@ -3284,12 +3365,11 @@ EXPORT_SYMBOL(end_that_request_chunk);
  */
 static void blk_done_softirq(struct softirq_action *h)
 {
-       struct list_head *cpu_list;
-       LIST_HEAD(local_list);
+       struct list_head *cpu_list, local_list;
 
        local_irq_disable();
        cpu_list = &__get_cpu_var(blk_cpu_done);
-       list_splice_init(cpu_list, &local_list);
+       list_replace_init(cpu_list, &local_list);
        local_irq_enable();
 
        while (!list_empty(&local_list)) {
@@ -3335,7 +3415,7 @@ static struct notifier_block __devinitdata blk_cpu_notifier = {
  *
  * Description:
  *     Ends all I/O on a request. It does not handle partial completions,
- *     unless the driver actually implements this in its completionc callback
+ *     unless the driver actually implements this in its completion callback
  *     through requeueing. Theh actual completion happens out-of-order,
  *     through a softirq handler. The user must have registered a completion
  *     callback through blk_queue_softirq_done().
@@ -3377,7 +3457,12 @@ void end_that_request_last(struct request *req, int uptodate)
        if (unlikely(laptop_mode) && blk_fs_request(req))
                laptop_io_completion();
 
-       if (disk && blk_fs_request(req)) {
+       /*
+        * Account IO completion.  bar_rq isn't accounted as a normal
+        * IO on queueing nor completion.  Accounting the containing
+        * request is enough.
+        */
+       if (disk && blk_fs_request(req) && req != &req->q->bar_rq) {
                unsigned long duration = jiffies - req->start_time;
                const int rw = rq_data_dir(req);
 
@@ -3452,13 +3537,11 @@ int __init blk_dev_init(void)
        iocontext_cachep = kmem_cache_create("blkdev_ioc",
                        sizeof(struct io_context), 0, SLAB_PANIC, NULL, NULL);
 
-       for_each_cpu(i)
+       for_each_possible_cpu(i)
                INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
 
        open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
-#ifdef CONFIG_HOTPLUG_CPU
-       register_cpu_notifier(&blk_cpu_notifier);
-#endif
+       register_hotcpu_notifier(&blk_cpu_notifier);
 
        blk_max_low_pfn = max_low_pfn;
        blk_max_pfn = max_pfn;
@@ -3477,10 +3560,18 @@ void put_io_context(struct io_context *ioc)
        BUG_ON(atomic_read(&ioc->refcount) == 0);
 
        if (atomic_dec_and_test(&ioc->refcount)) {
+               struct cfq_io_context *cic;
+
+               rcu_read_lock();
                if (ioc->aic && ioc->aic->dtor)
                        ioc->aic->dtor(ioc->aic);
-               if (ioc->cic && ioc->cic->dtor)
-                       ioc->cic->dtor(ioc->cic);
+               if (ioc->cic_root.rb_node != NULL) {
+                       struct rb_node *n = rb_first(&ioc->cic_root);
+
+                       cic = rb_entry(n, struct cfq_io_context, rb_node);
+                       cic->dtor(ioc);
+               }
+               rcu_read_unlock();
 
                kmem_cache_free(iocontext_cachep, ioc);
        }
@@ -3492,6 +3583,7 @@ void exit_io_context(void)
 {
        unsigned long flags;
        struct io_context *ioc;
+       struct cfq_io_context *cic;
 
        local_irq_save(flags);
        task_lock(current);
@@ -3503,9 +3595,11 @@ void exit_io_context(void)
 
        if (ioc->aic && ioc->aic->exit)
                ioc->aic->exit(ioc->aic);
-       if (ioc->cic && ioc->cic->exit)
-               ioc->cic->exit(ioc->cic);
-
+       if (ioc->cic_root.rb_node != NULL) {
+               cic = rb_entry(rb_first(&ioc->cic_root), struct cfq_io_context, rb_node);
+               cic->exit(ioc);
+       }
        put_io_context(ioc);
 }
 
@@ -3534,7 +3628,7 @@ struct io_context *current_io_context(gfp_t gfp_flags)
                ret->last_waited = jiffies; /* doesn't matter... */
                ret->nr_batch_requests = 0; /* because this is 0 */
                ret->aic = NULL;
-               ret->cic = NULL;
+               ret->cic_root.rb_node = NULL;
                tsk->io_context = ret;
        }
 
@@ -3614,10 +3708,13 @@ 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;
 
-       int ret = queue_var_store(&q->nr_requests, page, count);
-       if (q->nr_requests < BLKDEV_MIN_RQ)
-               q->nr_requests = 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))
@@ -3643,6 +3740,7 @@ queue_requests_store(struct request_queue *q, const char *page, size_t count)
                blk_clear_queue_full(q, WRITE);
                wake_up(&rl->wait[WRITE]);
        }
+       spin_unlock_irq(q->queue_lock);
        return ret;
 }
 
@@ -3758,13 +3856,19 @@ 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;
+       request_queue_t *q = container_of(kobj, struct request_queue, kobj);
+       ssize_t res;
 
-       q = container_of(kobj, struct request_queue, kobj);
        if (!entry->show)
                return -EIO;
-
-       return entry->show(q, page);
+       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
@@ -3772,13 +3876,20 @@ 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;
+       request_queue_t *q = container_of(kobj, struct request_queue, kobj);
+
+       ssize_t res;
 
-       q = container_of(kobj, struct request_queue, kobj);
        if (!entry->store)
                return -EIO;
-
-       return entry->store(q, page, length);
+       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 = {
@@ -3789,6 +3900,7 @@ static struct sysfs_ops queue_sysfs_ops = {
 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)
@@ -3801,19 +3913,17 @@ int blk_register_queue(struct gendisk *disk)
                return -ENXIO;
 
        q->kobj.parent = kobject_get(&disk->kobj);
-       if (!q->kobj.parent)
-               return -EBUSY;
 
-       snprintf(q->kobj.name, KOBJ_NAME_LEN, "%s", "queue");
-       q->kobj.ktype = &queue_ktype;
-
-       ret = kobject_register(&q->kobj);
+       ret = kobject_add(&q->kobj);
        if (ret < 0)
                return ret;
 
+       kobject_uevent(&q->kobj, KOBJ_ADD);
+
        ret = elv_register_queue(q);
        if (ret) {
-               kobject_unregister(&q->kobj);
+               kobject_uevent(&q->kobj, KOBJ_REMOVE);
+               kobject_del(&q->kobj);
                return ret;
        }
 
@@ -3827,7 +3937,8 @@ void blk_unregister_queue(struct gendisk *disk)
        if (q && q->request_fn) {
                elv_unregister_queue(q);
 
-               kobject_unregister(&q->kobj);
+               kobject_uevent(&q->kobj, KOBJ_REMOVE);
+               kobject_del(&q->kobj);
                kobject_put(&disk->kobj);
        }
 }