#include <linux/fault-inject.h>
#include <linux/list_sort.h>
#include <linux/delay.h>
+#include <linux/ratelimit.h>
+#include <linux/pm_runtime.h>
#define CREATE_TRACE_POINTS
#include <trace/events/block.h>
#include "blk.h"
+#include "blk-cgroup.h"
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
+EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
+
+DEFINE_IDA(blk_queue_ida);
/*
* For the allocated request tables
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
error = -EIO;
- if (unlikely(nbytes > bio->bi_size)) {
- printk(KERN_ERR "%s: want %u bytes done, %u left\n",
- __func__, nbytes, bio->bi_size);
- nbytes = bio->bi_size;
- }
-
if (unlikely(rq->cmd_flags & REQ_QUIET))
set_bit(BIO_QUIET, &bio->bi_flags);
- bio->bi_size -= nbytes;
- bio->bi_sector += (nbytes >> 9);
-
- if (bio_integrity(bio))
- bio_integrity_advance(bio, nbytes);
+ bio_advance(bio, nbytes);
/* don't actually finish bio if it's part of flush sequence */
if (bio->bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ))
* Description:
* Sometimes queueing needs to be postponed for a little while, to allow
* resources to come back. This function will make sure that queueing is
- * restarted around the specified time.
+ * restarted around the specified time. Queue lock must be held.
*/
void blk_delay_queue(struct request_queue *q, unsigned long msecs)
{
- queue_delayed_work(kblockd_workqueue, &q->delay_work,
- msecs_to_jiffies(msecs));
+ if (likely(!blk_queue_dead(q)))
+ queue_delayed_work(kblockd_workqueue, &q->delay_work,
+ msecs_to_jiffies(msecs));
}
EXPORT_SYMBOL(blk_delay_queue);
**/
void blk_stop_queue(struct request_queue *q)
{
- __cancel_delayed_work(&q->delay_work);
+ cancel_delayed_work(&q->delay_work);
queue_flag_set(QUEUE_FLAG_STOPPED, q);
}
EXPORT_SYMBOL(blk_stop_queue);
*
* This function does not cancel any asynchronous activity arising
* out of elevator or throttling code. That would require elevaotor_exit()
- * and blk_throtl_exit() to be called with queue lock initialized.
+ * and blkcg_exit_queue() to be called with queue lock initialized.
*
*/
void blk_sync_queue(struct request_queue *q)
}
EXPORT_SYMBOL(blk_sync_queue);
+/**
+ * __blk_run_queue_uncond - run a queue whether or not it has been stopped
+ * @q: The queue to run
+ *
+ * Description:
+ * Invoke request handling on a queue if there are any pending requests.
+ * May be used to restart request handling after a request has completed.
+ * This variant runs the queue whether or not the queue has been
+ * stopped. Must be called with the queue lock held and interrupts
+ * disabled. See also @blk_run_queue.
+ */
+inline void __blk_run_queue_uncond(struct request_queue *q)
+{
+ if (unlikely(blk_queue_dead(q)))
+ return;
+
+ /*
+ * Some request_fn implementations, e.g. scsi_request_fn(), unlock
+ * the queue lock internally. As a result multiple threads may be
+ * running such a request function concurrently. Keep track of the
+ * number of active request_fn invocations such that blk_drain_queue()
+ * can wait until all these request_fn calls have finished.
+ */
+ q->request_fn_active++;
+ q->request_fn(q);
+ q->request_fn_active--;
+}
+
/**
* __blk_run_queue - run a single device queue
* @q: The queue to run
if (unlikely(blk_queue_stopped(q)))
return;
- q->request_fn(q);
+ __blk_run_queue_uncond(q);
}
EXPORT_SYMBOL(__blk_run_queue);
*
* Description:
* Tells kblockd to perform the equivalent of @blk_run_queue on behalf
- * of us.
+ * of us. The caller must hold the queue lock.
*/
void blk_run_queue_async(struct request_queue *q)
{
- if (likely(!blk_queue_stopped(q))) {
- __cancel_delayed_work(&q->delay_work);
- queue_delayed_work(kblockd_workqueue, &q->delay_work, 0);
- }
+ if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q)))
+ mod_delayed_work(kblockd_workqueue, &q->delay_work, 0);
}
EXPORT_SYMBOL(blk_run_queue_async);
EXPORT_SYMBOL(blk_put_queue);
/**
- * blk_drain_queue - drain requests from request_queue
+ * __blk_drain_queue - drain requests from request_queue
* @q: queue to drain
* @drain_all: whether to drain all requests or only the ones w/ ELVPRIV
*
* If not, only ELVPRIV requests are drained. The caller is responsible
* for ensuring that no new requests which need to be drained are queued.
*/
-void blk_drain_queue(struct request_queue *q, bool drain_all)
+static void __blk_drain_queue(struct request_queue *q, bool drain_all)
+ __releases(q->queue_lock)
+ __acquires(q->queue_lock)
{
+ int i;
+
+ lockdep_assert_held(q->queue_lock);
+
while (true) {
- int nr_rqs;
+ bool drain = false;
- spin_lock_irq(q->queue_lock);
+ /*
+ * The caller might be trying to drain @q before its
+ * elevator is initialized.
+ */
+ if (q->elevator)
+ elv_drain_elevator(q);
- elv_drain_elevator(q);
- if (drain_all)
- blk_throtl_drain(q);
+ blkcg_drain_queue(q);
- __blk_run_queue(q);
+ /*
+ * This function might be called on a queue which failed
+ * driver init after queue creation or is not yet fully
+ * active yet. Some drivers (e.g. fd and loop) get unhappy
+ * in such cases. Kick queue iff dispatch queue has
+ * something on it and @q has request_fn set.
+ */
+ if (!list_empty(&q->queue_head) && q->request_fn)
+ __blk_run_queue(q);
- if (drain_all)
- nr_rqs = q->rq.count[0] + q->rq.count[1];
- else
- nr_rqs = q->rq.elvpriv;
+ drain |= q->nr_rqs_elvpriv;
+ drain |= q->request_fn_active;
- spin_unlock_irq(q->queue_lock);
+ /*
+ * Unfortunately, requests are queued at and tracked from
+ * multiple places and there's no single counter which can
+ * be drained. Check all the queues and counters.
+ */
+ if (drain_all) {
+ drain |= !list_empty(&q->queue_head);
+ for (i = 0; i < 2; i++) {
+ drain |= q->nr_rqs[i];
+ drain |= q->in_flight[i];
+ drain |= !list_empty(&q->flush_queue[i]);
+ }
+ }
- if (!nr_rqs)
+ if (!drain)
break;
+
+ spin_unlock_irq(q->queue_lock);
+
msleep(10);
+
+ spin_lock_irq(q->queue_lock);
+ }
+
+ /*
+ * With queue marked dead, any woken up waiter will fail the
+ * allocation path, so the wakeup chaining is lost and we're
+ * left with hung waiters. We need to wake up those waiters.
+ */
+ if (q->request_fn) {
+ struct request_list *rl;
+
+ blk_queue_for_each_rl(rl, q)
+ for (i = 0; i < ARRAY_SIZE(rl->wait); i++)
+ wake_up_all(&rl->wait[i]);
+ }
+}
+
+/**
+ * blk_queue_bypass_start - enter queue bypass mode
+ * @q: queue of interest
+ *
+ * In bypass mode, only the dispatch FIFO queue of @q is used. This
+ * function makes @q enter bypass mode and drains all requests which were
+ * throttled or issued before. On return, it's guaranteed that no request
+ * is being throttled or has ELVPRIV set and blk_queue_bypass() %true
+ * inside queue or RCU read lock.
+ */
+void blk_queue_bypass_start(struct request_queue *q)
+{
+ bool drain;
+
+ spin_lock_irq(q->queue_lock);
+ drain = !q->bypass_depth++;
+ queue_flag_set(QUEUE_FLAG_BYPASS, q);
+ spin_unlock_irq(q->queue_lock);
+
+ if (drain) {
+ spin_lock_irq(q->queue_lock);
+ __blk_drain_queue(q, false);
+ spin_unlock_irq(q->queue_lock);
+
+ /* ensure blk_queue_bypass() is %true inside RCU read lock */
+ synchronize_rcu();
}
}
+EXPORT_SYMBOL_GPL(blk_queue_bypass_start);
+
+/**
+ * blk_queue_bypass_end - leave queue bypass mode
+ * @q: queue of interest
+ *
+ * Leave bypass mode and restore the normal queueing behavior.
+ */
+void blk_queue_bypass_end(struct request_queue *q)
+{
+ spin_lock_irq(q->queue_lock);
+ if (!--q->bypass_depth)
+ queue_flag_clear(QUEUE_FLAG_BYPASS, q);
+ WARN_ON_ONCE(q->bypass_depth < 0);
+ spin_unlock_irq(q->queue_lock);
+}
+EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
/**
* blk_cleanup_queue - shutdown a request queue
* @q: request queue to shutdown
*
- * Mark @q DEAD, drain all pending requests, destroy and put it. All
- * future requests will be failed immediately with -ENODEV.
+ * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
+ * put it. All future requests will be failed immediately with -ENODEV.
*/
void blk_cleanup_queue(struct request_queue *q)
{
spinlock_t *lock = q->queue_lock;
- /* mark @q DEAD, no new request or merges will be allowed afterwards */
+ /* mark @q DYING, no new request or merges will be allowed afterwards */
mutex_lock(&q->sysfs_lock);
- queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
-
+ queue_flag_set_unlocked(QUEUE_FLAG_DYING, q);
spin_lock_irq(lock);
- queue_flag_set(QUEUE_FLAG_NOMERGES, q);
- queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
- queue_flag_set(QUEUE_FLAG_DEAD, q);
- if (q->queue_lock != &q->__queue_lock)
- q->queue_lock = &q->__queue_lock;
+ /*
+ * A dying queue is permanently in bypass mode till released. Note
+ * that, unlike blk_queue_bypass_start(), we aren't performing
+ * synchronize_rcu() after entering bypass mode to avoid the delay
+ * as some drivers create and destroy a lot of queues while
+ * probing. This is still safe because blk_release_queue() will be
+ * called only after the queue refcnt drops to zero and nothing,
+ * RCU or not, would be traversing the queue by then.
+ */
+ q->bypass_depth++;
+ queue_flag_set(QUEUE_FLAG_BYPASS, q);
+ queue_flag_set(QUEUE_FLAG_NOMERGES, q);
+ queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
+ queue_flag_set(QUEUE_FLAG_DYING, q);
spin_unlock_irq(lock);
mutex_unlock(&q->sysfs_lock);
- /* drain all requests queued before DEAD marking */
- blk_drain_queue(q, true);
+ /*
+ * Drain all requests queued before DYING marking. Set DEAD flag to
+ * prevent that q->request_fn() gets invoked after draining finished.
+ */
+ spin_lock_irq(lock);
+ __blk_drain_queue(q, true);
+ queue_flag_set(QUEUE_FLAG_DEAD, q);
+ spin_unlock_irq(lock);
/* @q won't process any more request, flush async actions */
del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
blk_sync_queue(q);
+ spin_lock_irq(lock);
+ if (q->queue_lock != &q->__queue_lock)
+ q->queue_lock = &q->__queue_lock;
+ spin_unlock_irq(lock);
+
/* @q is and will stay empty, shutdown and put */
blk_put_queue(q);
}
EXPORT_SYMBOL(blk_cleanup_queue);
-static int blk_init_free_list(struct request_queue *q)
+int blk_init_rl(struct request_list *rl, struct request_queue *q,
+ gfp_t gfp_mask)
{
- struct request_list *rl = &q->rq;
-
if (unlikely(rl->rq_pool))
return 0;
+ rl->q = q;
rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
- rl->elvpriv = 0;
init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);
rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
- mempool_free_slab, request_cachep, q->node);
-
+ mempool_free_slab, request_cachep,
+ gfp_mask, q->node);
if (!rl->rq_pool)
return -ENOMEM;
return 0;
}
+void blk_exit_rl(struct request_list *rl)
+{
+ if (rl->rq_pool)
+ mempool_destroy(rl->rq_pool);
+}
+
struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
{
- return blk_alloc_queue_node(gfp_mask, -1);
+ return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE);
}
EXPORT_SYMBOL(blk_alloc_queue);
if (!q)
return NULL;
+ q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask);
+ if (q->id < 0)
+ goto fail_q;
+
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;
q->backing_dev_info.name = "block";
+ q->node = node_id;
err = bdi_init(&q->backing_dev_info);
- if (err) {
- kmem_cache_free(blk_requestq_cachep, q);
- return NULL;
- }
-
- if (blk_throtl_init(q)) {
- kmem_cache_free(blk_requestq_cachep, q);
- return NULL;
- }
+ if (err)
+ goto fail_id;
setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
laptop_mode_timer_fn, (unsigned long) q);
setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
+ INIT_LIST_HEAD(&q->queue_head);
INIT_LIST_HEAD(&q->timeout_list);
+ INIT_LIST_HEAD(&q->icq_list);
+#ifdef CONFIG_BLK_CGROUP
+ INIT_LIST_HEAD(&q->blkg_list);
+#endif
INIT_LIST_HEAD(&q->flush_queue[0]);
INIT_LIST_HEAD(&q->flush_queue[1]);
INIT_LIST_HEAD(&q->flush_data_in_flight);
*/
q->queue_lock = &q->__queue_lock;
+ /*
+ * A queue starts its life with bypass turned on to avoid
+ * unnecessary bypass on/off overhead and nasty surprises during
+ * init. The initial bypass will be finished when the queue is
+ * registered by blk_register_queue().
+ */
+ q->bypass_depth = 1;
+ __set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
+
+ if (blkcg_init_queue(q))
+ goto fail_id;
+
return q;
+
+fail_id:
+ ida_simple_remove(&blk_queue_ida, q->id);
+fail_q:
+ kmem_cache_free(blk_requestq_cachep, q);
+ return NULL;
}
EXPORT_SYMBOL(blk_alloc_queue_node);
struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock)
{
- return blk_init_queue_node(rfn, lock, -1);
+ return blk_init_queue_node(rfn, lock, NUMA_NO_NODE);
}
EXPORT_SYMBOL(blk_init_queue);
if (!uninit_q)
return NULL;
- q = blk_init_allocated_queue_node(uninit_q, rfn, lock, node_id);
+ q = blk_init_allocated_queue(uninit_q, rfn, lock);
if (!q)
blk_cleanup_queue(uninit_q);
struct request_queue *
blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
spinlock_t *lock)
-{
- return blk_init_allocated_queue_node(q, rfn, lock, -1);
-}
-EXPORT_SYMBOL(blk_init_allocated_queue);
-
-struct request_queue *
-blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn,
- spinlock_t *lock, int node_id)
{
if (!q)
return NULL;
- q->node = node_id;
- if (blk_init_free_list(q))
+ if (blk_init_rl(&q->root_rl, q, GFP_KERNEL))
return NULL;
q->request_fn = rfn;
q->prep_rq_fn = NULL;
q->unprep_rq_fn = NULL;
- q->queue_flags = QUEUE_FLAG_DEFAULT;
+ q->queue_flags |= QUEUE_FLAG_DEFAULT;
/* Override internal queue lock with supplied lock pointer */
if (lock)
q->sg_reserved_size = INT_MAX;
- /*
- * all done
- */
- if (!elevator_init(q, NULL)) {
- blk_queue_congestion_threshold(q);
- return q;
- }
-
- return NULL;
+ /* init elevator */
+ if (elevator_init(q, NULL))
+ return NULL;
+ return q;
}
-EXPORT_SYMBOL(blk_init_allocated_queue_node);
+EXPORT_SYMBOL(blk_init_allocated_queue);
-int blk_get_queue(struct request_queue *q)
+bool blk_get_queue(struct request_queue *q)
{
- if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
- kobject_get(&q->kobj);
- return 0;
+ if (likely(!blk_queue_dying(q))) {
+ __blk_get_queue(q);
+ return true;
}
- return 1;
+ return false;
}
EXPORT_SYMBOL(blk_get_queue);
-static inline void blk_free_request(struct request_queue *q, struct request *rq)
-{
- if (rq->cmd_flags & REQ_ELVPRIV)
- elv_put_request(q, rq);
- mempool_free(rq, q->rq.rq_pool);
-}
-
-static struct request *
-blk_alloc_request(struct request_queue *q, unsigned int flags, gfp_t gfp_mask)
+static inline void blk_free_request(struct request_list *rl, struct request *rq)
{
- struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
-
- if (!rq)
- return NULL;
-
- blk_rq_init(q, rq);
-
- rq->cmd_flags = flags | REQ_ALLOCED;
-
- if ((flags & REQ_ELVPRIV) &&
- unlikely(elv_set_request(q, rq, gfp_mask))) {
- mempool_free(rq, q->rq.rq_pool);
- return NULL;
+ if (rq->cmd_flags & REQ_ELVPRIV) {
+ elv_put_request(rl->q, rq);
+ if (rq->elv.icq)
+ put_io_context(rq->elv.icq->ioc);
}
- return rq;
+ mempool_free(rq, rl->rq_pool);
}
/*
ioc->last_waited = jiffies;
}
-static void __freed_request(struct request_queue *q, int sync)
+static void __freed_request(struct request_list *rl, int sync)
{
- struct request_list *rl = &q->rq;
+ struct request_queue *q = rl->q;
- if (rl->count[sync] < queue_congestion_off_threshold(q))
+ /*
+ * bdi isn't aware of blkcg yet. As all async IOs end up root
+ * blkcg anyway, just use root blkcg state.
+ */
+ if (rl == &q->root_rl &&
+ rl->count[sync] < queue_congestion_off_threshold(q))
blk_clear_queue_congested(q, sync);
if (rl->count[sync] + 1 <= q->nr_requests) {
if (waitqueue_active(&rl->wait[sync]))
wake_up(&rl->wait[sync]);
- blk_clear_queue_full(q, sync);
+ blk_clear_rl_full(rl, sync);
}
}
* A request has just been released. Account for it, update the full and
* congestion status, wake up any waiters. Called under q->queue_lock.
*/
-static void freed_request(struct request_queue *q, unsigned int flags)
+static void freed_request(struct request_list *rl, unsigned int flags)
{
- struct request_list *rl = &q->rq;
+ struct request_queue *q = rl->q;
int sync = rw_is_sync(flags);
+ q->nr_rqs[sync]--;
rl->count[sync]--;
if (flags & REQ_ELVPRIV)
- rl->elvpriv--;
+ q->nr_rqs_elvpriv--;
- __freed_request(q, sync);
+ __freed_request(rl, sync);
if (unlikely(rl->starved[sync ^ 1]))
- __freed_request(q, sync ^ 1);
+ __freed_request(rl, sync ^ 1);
}
/*
}
/**
- * get_request - get a free request
- * @q: request_queue to allocate request from
+ * rq_ioc - determine io_context for request allocation
+ * @bio: request being allocated is for this bio (can be %NULL)
+ *
+ * Determine io_context to use for request allocation for @bio. May return
+ * %NULL if %current->io_context doesn't exist.
+ */
+static struct io_context *rq_ioc(struct bio *bio)
+{
+#ifdef CONFIG_BLK_CGROUP
+ if (bio && bio->bi_ioc)
+ return bio->bi_ioc;
+#endif
+ return current->io_context;
+}
+
+/**
+ * __get_request - get a free request
+ * @rl: request list to allocate from
* @rw_flags: RW and SYNC flags
* @bio: bio to allocate request for (can be %NULL)
* @gfp_mask: allocation mask
* Returns %NULL on failure, with @q->queue_lock held.
* Returns !%NULL on success, with @q->queue_lock *not held*.
*/
-static struct request *get_request(struct request_queue *q, int rw_flags,
- struct bio *bio, gfp_t gfp_mask)
+static struct request *__get_request(struct request_list *rl, int rw_flags,
+ struct bio *bio, gfp_t gfp_mask)
{
- struct request *rq = NULL;
- struct request_list *rl = &q->rq;
- struct io_context *ioc = NULL;
+ struct request_queue *q = rl->q;
+ struct request *rq;
+ struct elevator_type *et = q->elevator->type;
+ struct io_context *ioc = rq_ioc(bio);
+ struct io_cq *icq = NULL;
const bool is_sync = rw_is_sync(rw_flags) != 0;
int may_queue;
- if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
+ if (unlikely(blk_queue_dying(q)))
return NULL;
may_queue = elv_may_queue(q, rw_flags);
if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) {
if (rl->count[is_sync]+1 >= q->nr_requests) {
- ioc = current_io_context(GFP_ATOMIC, q->node);
/*
* The queue will fill after this allocation, so set
* it as full, and mark this process as "batching".
* This process will be allowed to complete a batch of
* requests, others will be blocked.
*/
- if (!blk_queue_full(q, is_sync)) {
+ if (!blk_rl_full(rl, is_sync)) {
ioc_set_batching(q, ioc);
- blk_set_queue_full(q, is_sync);
+ blk_set_rl_full(rl, is_sync);
} else {
if (may_queue != ELV_MQUEUE_MUST
&& !ioc_batching(q, ioc)) {
* process is not a "batcher", and not
* exempted by the IO scheduler
*/
- goto out;
+ return NULL;
}
}
}
- blk_set_queue_congested(q, is_sync);
+ /*
+ * bdi isn't aware of blkcg yet. As all async IOs end up
+ * root blkcg anyway, just use root blkcg state.
+ */
+ if (rl == &q->root_rl)
+ blk_set_queue_congested(q, is_sync);
}
/*
* allocated with any setting of ->nr_requests
*/
if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
- goto out;
+ return NULL;
+ q->nr_rqs[is_sync]++;
rl->count[is_sync]++;
rl->starved[is_sync] = 0;
- if (blk_rq_should_init_elevator(bio) &&
- !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags)) {
+ /*
+ * Decide whether the new request will be managed by elevator. If
+ * so, mark @rw_flags and increment elvpriv. Non-zero elvpriv will
+ * prevent the current elevator from being destroyed until the new
+ * request is freed. This guarantees icq's won't be destroyed and
+ * makes creating new ones safe.
+ *
+ * Also, lookup icq while holding queue_lock. If it doesn't exist,
+ * it will be created after releasing queue_lock.
+ */
+ if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
rw_flags |= REQ_ELVPRIV;
- rl->elvpriv++;
+ q->nr_rqs_elvpriv++;
+ if (et->icq_cache && ioc)
+ icq = ioc_lookup_icq(ioc, q);
}
if (blk_queue_io_stat(q))
rw_flags |= REQ_IO_STAT;
spin_unlock_irq(q->queue_lock);
- rq = blk_alloc_request(q, rw_flags, gfp_mask);
- if (unlikely(!rq)) {
- /*
- * Allocation failed presumably due to memory. Undo anything
- * we might have messed up.
- *
- * Allocating task should really be put onto the front of the
- * wait queue, but this is pretty rare.
- */
- spin_lock_irq(q->queue_lock);
- freed_request(q, rw_flags);
+ /* allocate and init request */
+ rq = mempool_alloc(rl->rq_pool, gfp_mask);
+ if (!rq)
+ goto fail_alloc;
- /*
- * in the very unlikely event that allocation failed and no
- * requests for this direction was pending, mark us starved
- * so that freeing of a request in the other direction will
- * notice us. another possible fix would be to split the
- * rq mempool into READ and WRITE
- */
-rq_starved:
- if (unlikely(rl->count[is_sync] == 0))
- rl->starved[is_sync] = 1;
+ blk_rq_init(q, rq);
+ blk_rq_set_rl(rq, rl);
+ rq->cmd_flags = rw_flags | REQ_ALLOCED;
+
+ /* init elvpriv */
+ if (rw_flags & REQ_ELVPRIV) {
+ if (unlikely(et->icq_cache && !icq)) {
+ if (ioc)
+ icq = ioc_create_icq(ioc, q, gfp_mask);
+ if (!icq)
+ goto fail_elvpriv;
+ }
- goto out;
- }
+ rq->elv.icq = icq;
+ if (unlikely(elv_set_request(q, rq, bio, gfp_mask)))
+ goto fail_elvpriv;
+ /* @rq->elv.icq holds io_context until @rq is freed */
+ if (icq)
+ get_io_context(icq->ioc);
+ }
+out:
/*
* ioc may be NULL here, and ioc_batching will be false. That's
* OK, if the queue is under the request limit then requests need
ioc->nr_batch_requests--;
trace_block_getrq(q, bio, rw_flags & 1);
-out:
return rq;
+
+fail_elvpriv:
+ /*
+ * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed
+ * and may fail indefinitely under memory pressure and thus
+ * shouldn't stall IO. Treat this request as !elvpriv. This will
+ * disturb iosched and blkcg but weird is bettern than dead.
+ */
+ printk_ratelimited(KERN_WARNING "%s: request aux data allocation failed, iosched may be disturbed\n",
+ dev_name(q->backing_dev_info.dev));
+
+ rq->cmd_flags &= ~REQ_ELVPRIV;
+ rq->elv.icq = NULL;
+
+ spin_lock_irq(q->queue_lock);
+ q->nr_rqs_elvpriv--;
+ spin_unlock_irq(q->queue_lock);
+ goto out;
+
+fail_alloc:
+ /*
+ * Allocation failed presumably due to memory. Undo anything we
+ * might have messed up.
+ *
+ * Allocating task should really be put onto the front of the wait
+ * queue, but this is pretty rare.
+ */
+ spin_lock_irq(q->queue_lock);
+ freed_request(rl, rw_flags);
+
+ /*
+ * in the very unlikely event that allocation failed and no
+ * requests for this direction was pending, mark us starved so that
+ * freeing of a request in the other direction will notice
+ * us. another possible fix would be to split the rq mempool into
+ * READ and WRITE
+ */
+rq_starved:
+ if (unlikely(rl->count[is_sync] == 0))
+ rl->starved[is_sync] = 1;
+ return NULL;
}
/**
- * get_request_wait - get a free request with retry
+ * get_request - get a free request
* @q: request_queue to allocate request from
* @rw_flags: RW and SYNC flags
* @bio: bio to allocate request for (can be %NULL)
+ * @gfp_mask: allocation mask
*
- * Get a free request from @q. This function keeps retrying under memory
- * pressure and fails iff @q is dead.
+ * Get a free request from @q. If %__GFP_WAIT is set in @gfp_mask, this
+ * function keeps retrying under memory pressure and fails iff @q is dead.
*
* Must be callled with @q->queue_lock held and,
* Returns %NULL on failure, with @q->queue_lock held.
* Returns !%NULL on success, with @q->queue_lock *not held*.
*/
-static struct request *get_request_wait(struct request_queue *q, int rw_flags,
- struct bio *bio)
+static struct request *get_request(struct request_queue *q, int rw_flags,
+ struct bio *bio, gfp_t gfp_mask)
{
const bool is_sync = rw_is_sync(rw_flags) != 0;
+ DEFINE_WAIT(wait);
+ struct request_list *rl;
struct request *rq;
- rq = get_request(q, rw_flags, bio, GFP_NOIO);
- while (!rq) {
- DEFINE_WAIT(wait);
- struct io_context *ioc;
- struct request_list *rl = &q->rq;
-
- if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
- return NULL;
+ rl = blk_get_rl(q, bio); /* transferred to @rq on success */
+retry:
+ rq = __get_request(rl, rw_flags, bio, gfp_mask);
+ if (rq)
+ return rq;
- prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
- TASK_UNINTERRUPTIBLE);
+ if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dying(q))) {
+ blk_put_rl(rl);
+ return NULL;
+ }
- trace_block_sleeprq(q, bio, rw_flags & 1);
+ /* wait on @rl and retry */
+ prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
+ TASK_UNINTERRUPTIBLE);
- spin_unlock_irq(q->queue_lock);
- io_schedule();
+ trace_block_sleeprq(q, bio, rw_flags & 1);
- /*
- * After sleeping, we become a "batching" process and
- * will be able to allocate at least one request, and
- * up to a big batch of them for a small period time.
- * See ioc_batching, ioc_set_batching
- */
- ioc = current_io_context(GFP_NOIO, q->node);
- ioc_set_batching(q, ioc);
+ spin_unlock_irq(q->queue_lock);
+ io_schedule();
- spin_lock_irq(q->queue_lock);
- finish_wait(&rl->wait[is_sync], &wait);
+ /*
+ * After sleeping, we become a "batching" process and will be able
+ * to allocate at least one request, and up to a big batch of them
+ * for a small period time. See ioc_batching, ioc_set_batching
+ */
+ ioc_set_batching(q, current->io_context);
- rq = get_request(q, rw_flags, bio, GFP_NOIO);
- };
+ spin_lock_irq(q->queue_lock);
+ finish_wait(&rl->wait[is_sync], &wait);
- return rq;
+ goto retry;
}
struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
BUG_ON(rw != READ && rw != WRITE);
+ /* create ioc upfront */
+ create_io_context(gfp_mask, q->node);
+
spin_lock_irq(q->queue_lock);
- if (gfp_mask & __GFP_WAIT)
- rq = get_request_wait(q, rw, NULL);
- else
- rq = get_request(q, rw, NULL, gfp_mask);
+ rq = get_request(q, rw, NULL, gfp_mask);
if (!rq)
spin_unlock_irq(q->queue_lock);
/* q->queue_lock is unlocked at this point */
__elv_add_request(q, rq, where);
}
-/**
- * blk_insert_request - insert a special request into a request queue
- * @q: request queue where request should be inserted
- * @rq: request to be inserted
- * @at_head: insert request at head or tail of queue
- * @data: private data
- *
- * Description:
- * Many block devices need to execute commands asynchronously, so they don't
- * block the whole kernel from preemption during request execution. This is
- * accomplished normally by inserting aritficial requests tagged as
- * REQ_TYPE_SPECIAL in to the corresponding request queue, and letting them
- * be scheduled for actual execution by the request queue.
- *
- * We have the option of inserting the head or the tail of the queue.
- * Typically we use the tail for new ioctls and so forth. We use the head
- * of the queue for things like a QUEUE_FULL message from a device, or a
- * host that is unable to accept a particular command.
- */
-void blk_insert_request(struct request_queue *q, struct request *rq,
- int at_head, void *data)
-{
- int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
- unsigned long flags;
-
- /*
- * tell I/O scheduler that this isn't a regular read/write (ie it
- * must not attempt merges on this) and that it acts as a soft
- * barrier
- */
- rq->cmd_type = REQ_TYPE_SPECIAL;
-
- rq->special = data;
-
- spin_lock_irqsave(q->queue_lock, flags);
-
- /*
- * If command is tagged, release the tag
- */
- if (blk_rq_tagged(rq))
- blk_queue_end_tag(q, rq);
-
- add_acct_request(q, rq, where);
- __blk_run_queue(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
-}
-EXPORT_SYMBOL(blk_insert_request);
-
static void part_round_stats_single(int cpu, struct hd_struct *part,
unsigned long now)
{
}
EXPORT_SYMBOL_GPL(part_round_stats);
+#ifdef CONFIG_PM_RUNTIME
+static void blk_pm_put_request(struct request *rq)
+{
+ if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && !--rq->q->nr_pending)
+ pm_runtime_mark_last_busy(rq->q->dev);
+}
+#else
+static inline void blk_pm_put_request(struct request *rq) {}
+#endif
+
/*
* queue lock must be held
*/
if (unlikely(--req->ref_count))
return;
+ blk_pm_put_request(req);
+
elv_completed_request(q, req);
/* this is a bio leak */
*/
if (req->cmd_flags & REQ_ALLOCED) {
unsigned int flags = req->cmd_flags;
+ struct request_list *rl = blk_rq_rl(req);
BUG_ON(!list_empty(&req->queuelist));
BUG_ON(!hlist_unhashed(&req->hash));
- blk_free_request(q, req);
- freed_request(q, flags);
+ blk_free_request(rl, req);
+ freed_request(rl, flags);
+ blk_put_rl(rl);
}
}
EXPORT_SYMBOL_GPL(__blk_put_request);
if (!ll_back_merge_fn(q, req, bio))
return false;
- trace_block_bio_backmerge(q, bio);
+ trace_block_bio_backmerge(q, req, bio);
if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
blk_rq_set_mixed_merge(req);
req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
drive_stat_acct(req, 0);
- elv_bio_merged(q, req, bio);
return true;
}
if (!ll_front_merge_fn(q, req, bio))
return false;
- trace_block_bio_frontmerge(q, bio);
+ trace_block_bio_frontmerge(q, req, bio);
if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
blk_rq_set_mixed_merge(req);
req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
drive_stat_acct(req, 0);
- elv_bio_merged(q, req, bio);
return true;
}
* on %current's plugged list. Returns %true if merge was successful,
* otherwise %false.
*
- * This function is called without @q->queue_lock; however, elevator is
- * accessed iff there already are requests on the plugged list which in
- * turn guarantees validity of the elevator.
- *
- * Note that, on successful merge, elevator operation
- * elevator_bio_merged_fn() will be called without queue lock. Elevator
- * must be ready for this.
+ * Plugging coalesces IOs from the same issuer for the same purpose without
+ * going through @q->queue_lock. As such it's more of an issuing mechanism
+ * than scheduling, and the request, while may have elvpriv data, is not
+ * added on the elevator at this point. In addition, we don't have
+ * reliable access to the elevator outside queue lock. Only check basic
+ * merging parameters without querying the elevator.
*/
static bool attempt_plug_merge(struct request_queue *q, struct bio *bio,
unsigned int *request_count)
list_for_each_entry_reverse(rq, &plug->list, queuelist) {
int el_ret;
- (*request_count)++;
+ if (rq->q == q)
+ (*request_count)++;
- if (rq->q != q)
+ if (rq->q != q || !blk_rq_merge_ok(rq, bio))
continue;
- el_ret = elv_try_merge(rq, bio);
+ el_ret = blk_try_merge(rq, bio);
if (el_ret == ELEVATOR_BACK_MERGE) {
ret = bio_attempt_back_merge(q, rq, bio);
if (ret)
*/
blk_queue_bounce(q, &bio);
+ if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
+ bio_endio(bio, -EIO);
+ return;
+ }
+
if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
spin_lock_irq(q->queue_lock);
where = ELEVATOR_INSERT_FLUSH;
el_ret = elv_merge(q, &req, bio);
if (el_ret == ELEVATOR_BACK_MERGE) {
if (bio_attempt_back_merge(q, req, bio)) {
+ elv_bio_merged(q, req, bio);
if (!attempt_back_merge(q, req))
elv_merged_request(q, req, el_ret);
goto out_unlock;
}
} else if (el_ret == ELEVATOR_FRONT_MERGE) {
if (bio_attempt_front_merge(q, req, bio)) {
+ elv_bio_merged(q, req, bio);
if (!attempt_front_merge(q, req))
elv_merged_request(q, req, el_ret);
goto out_unlock;
* Grab a free request. This is might sleep but can not fail.
* Returns with the queue unlocked.
*/
- req = get_request_wait(q, rw_flags, bio);
+ req = get_request(q, rw_flags, bio, GFP_NOIO);
if (unlikely(!req)) {
bio_endio(bio, -ENODEV); /* @q is dead */
goto out_unlock;
*/
if (list_empty(&plug->list))
trace_block_plug(q);
- else if (!plug->should_sort) {
- struct request *__rq;
-
- __rq = list_entry_rq(plug->list.prev);
- if (__rq->q != q)
- plug->should_sort = 1;
+ else {
+ if (request_count >= BLK_MAX_REQUEST_COUNT) {
+ blk_flush_plug_list(plug, false);
+ trace_block_plug(q);
+ }
}
- if (request_count >= BLK_MAX_REQUEST_COUNT)
- blk_flush_plug_list(plug, false);
list_add_tail(&req->queuelist, &plug->list);
drive_stat_acct(req, 1);
} else {
printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n",
bdevname(bio->bi_bdev, b),
bio->bi_rw,
- (unsigned long long)bio->bi_sector + bio_sectors(bio),
+ (unsigned long long)bio_end_sector(bio),
(long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9));
set_bit(BIO_EOF, &bio->bi_flags);
goto end_io;
}
- if (unlikely(!(bio->bi_rw & REQ_DISCARD) &&
- nr_sectors > queue_max_hw_sectors(q))) {
+ if (likely(bio_is_rw(bio) &&
+ nr_sectors > queue_max_hw_sectors(q))) {
printk(KERN_ERR "bio too big device %s (%u > %u)\n",
bdevname(bio->bi_bdev, b),
bio_sectors(bio),
*/
blk_partition_remap(bio);
- if (bio_integrity_enabled(bio) && bio_integrity_prep(bio))
- goto end_io;
-
if (bio_check_eod(bio, nr_sectors))
goto end_io;
if ((bio->bi_rw & REQ_DISCARD) &&
(!blk_queue_discard(q) ||
- ((bio->bi_rw & REQ_SECURE) &&
- !blk_queue_secdiscard(q)))) {
+ ((bio->bi_rw & REQ_SECURE) && !blk_queue_secdiscard(q)))) {
+ err = -EOPNOTSUPP;
+ goto end_io;
+ }
+
+ if (bio->bi_rw & REQ_WRITE_SAME && !bdev_write_same(bio->bi_bdev)) {
err = -EOPNOTSUPP;
goto end_io;
}
+ /*
+ * Various block parts want %current->io_context and lazy ioc
+ * allocation ends up trading a lot of pain for a small amount of
+ * memory. Just allocate it upfront. This may fail and block
+ * layer knows how to live with it.
+ */
+ create_io_context(GFP_ATOMIC, q->node);
+
if (blk_throtl_bio(q, bio))
return false; /* throttled, will be resubmitted later */
*/
void submit_bio(int rw, struct bio *bio)
{
- int count = bio_sectors(bio);
-
bio->bi_rw |= rw;
/*
* If it's a regular read/write or a barrier with data attached,
* go through the normal accounting stuff before submission.
*/
- if (bio_has_data(bio) && !(rw & REQ_DISCARD)) {
+ if (bio_has_data(bio)) {
+ unsigned int count;
+
+ if (unlikely(rw & REQ_WRITE_SAME))
+ count = bdev_logical_block_size(bio->bi_bdev) >> 9;
+ else
+ count = bio_sectors(bio);
+
if (rw & WRITE) {
count_vm_events(PGPGOUT, count);
} else {
*/
int blk_rq_check_limits(struct request_queue *q, struct request *rq)
{
- if (rq->cmd_flags & REQ_DISCARD)
+ if (!rq_mergeable(rq))
return 0;
- if (blk_rq_sectors(rq) > queue_max_sectors(q) ||
- blk_rq_bytes(rq) > queue_max_hw_sectors(q) << 9) {
+ if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) {
printk(KERN_ERR "%s: over max size limit.\n", __func__);
return -EIO;
}
return -EIO;
spin_lock_irqsave(q->queue_lock, flags);
+ if (unlikely(blk_queue_dying(q))) {
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ return -ENODEV;
+ }
/*
* Submitting request must be dequeued before calling this function
where = ELEVATOR_INSERT_FLUSH;
add_acct_request(q, rq, where);
+ if (where == ELEVATOR_INSERT_FLUSH)
+ __blk_run_queue(q);
spin_unlock_irqrestore(q->queue_lock, flags);
return 0;
}
}
+#ifdef CONFIG_PM_RUNTIME
+/*
+ * Don't process normal requests when queue is suspended
+ * or in the process of suspending/resuming
+ */
+static struct request *blk_pm_peek_request(struct request_queue *q,
+ struct request *rq)
+{
+ if (q->dev && (q->rpm_status == RPM_SUSPENDED ||
+ (q->rpm_status != RPM_ACTIVE && !(rq->cmd_flags & REQ_PM))))
+ return NULL;
+ else
+ return rq;
+}
+#else
+static inline struct request *blk_pm_peek_request(struct request_queue *q,
+ struct request *rq)
+{
+ return rq;
+}
+#endif
+
/**
* blk_peek_request - peek at the top of a request queue
* @q: request queue to peek at
int ret;
while ((rq = __elv_next_request(q)) != NULL) {
+
+ rq = blk_pm_peek_request(q, rq);
+ if (!rq)
+ break;
+
if (!(rq->cmd_flags & REQ_STARTED)) {
/*
* This is the first time the device driver
**/
bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
{
- int total_bytes, bio_nbytes, next_idx = 0;
- struct bio *bio;
+ int total_bytes;
if (!req->bio)
return false;
error_type = "I/O";
break;
}
- printk(KERN_ERR "end_request: %s error, dev %s, sector %llu\n",
- error_type, req->rq_disk ? req->rq_disk->disk_name : "?",
- (unsigned long long)blk_rq_pos(req));
+ printk_ratelimited(KERN_ERR "end_request: %s error, dev %s, sector %llu\n",
+ error_type, req->rq_disk ?
+ req->rq_disk->disk_name : "?",
+ (unsigned long long)blk_rq_pos(req));
+
}
blk_account_io_completion(req, nr_bytes);
- total_bytes = bio_nbytes = 0;
- while ((bio = req->bio) != NULL) {
- int nbytes;
+ total_bytes = 0;
+ while (req->bio) {
+ struct bio *bio = req->bio;
+ unsigned bio_bytes = min(bio->bi_size, nr_bytes);
- if (nr_bytes >= bio->bi_size) {
+ if (bio_bytes == bio->bi_size)
req->bio = bio->bi_next;
- nbytes = bio->bi_size;
- req_bio_endio(req, bio, nbytes, error);
- next_idx = 0;
- bio_nbytes = 0;
- } else {
- int idx = bio->bi_idx + next_idx;
-
- if (unlikely(idx >= bio->bi_vcnt)) {
- blk_dump_rq_flags(req, "__end_that");
- printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n",
- __func__, idx, bio->bi_vcnt);
- break;
- }
- nbytes = bio_iovec_idx(bio, idx)->bv_len;
- BIO_BUG_ON(nbytes > bio->bi_size);
+ req_bio_endio(req, bio, bio_bytes, error);
- /*
- * not a complete bvec done
- */
- if (unlikely(nbytes > nr_bytes)) {
- bio_nbytes += nr_bytes;
- total_bytes += nr_bytes;
- break;
- }
-
- /*
- * advance to the next vector
- */
- next_idx++;
- bio_nbytes += nbytes;
- }
-
- total_bytes += nbytes;
- nr_bytes -= nbytes;
+ total_bytes += bio_bytes;
+ nr_bytes -= bio_bytes;
- bio = req->bio;
- if (bio) {
- /*
- * end more in this run, or just return 'not-done'
- */
- if (unlikely(nr_bytes <= 0))
- break;
- }
+ if (!nr_bytes)
+ break;
}
/*
return false;
}
- /*
- * if the request wasn't completed, update state
- */
- if (bio_nbytes) {
- req_bio_endio(req, bio, bio_nbytes, error);
- bio->bi_idx += next_idx;
- bio_iovec(bio)->bv_offset += nr_bytes;
- bio_iovec(bio)->bv_len -= nr_bytes;
- }
-
req->__data_len -= total_bytes;
req->buffer = bio_data(req->bio);
/* update sector only for requests with clear definition of sector */
- if (req->cmd_type == REQ_TYPE_FS || (req->cmd_flags & REQ_DISCARD))
+ if (req->cmd_type == REQ_TYPE_FS)
req->__sector += total_bytes >> 9;
/* mixed attributes always follow the first bio */
blk_rq_init(NULL, rq);
__rq_for_each_bio(bio_src, rq_src) {
- bio = bio_alloc_bioset(gfp_mask, bio_src->bi_max_vecs, bs);
+ bio = bio_clone_bioset(bio_src, gfp_mask, bs);
if (!bio)
goto free_and_out;
- __bio_clone(bio, bio_src);
-
- if (bio_integrity(bio_src) &&
- bio_integrity_clone(bio, bio_src, gfp_mask, bs))
- goto free_and_out;
-
if (bio_ctr && bio_ctr(bio, bio_src, data))
goto free_and_out;
free_and_out:
if (bio)
- bio_free(bio, bs);
+ bio_put(bio);
blk_rq_unprep_clone(rq);
return -ENOMEM;
plug->magic = PLUG_MAGIC;
INIT_LIST_HEAD(&plug->list);
INIT_LIST_HEAD(&plug->cb_list);
- plug->should_sort = 0;
/*
* If this is a nested plug, don't actually assign it. It will be
struct request *rqa = container_of(a, struct request, queuelist);
struct request *rqb = container_of(b, struct request, queuelist);
- return !(rqa->q <= rqb->q);
+ return !(rqa->q < rqb->q ||
+ (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb)));
}
/*
{
trace_block_unplug(q, depth, !from_schedule);
- /*
- * If we are punting this to kblockd, then we can safely drop
- * the queue_lock before waking kblockd (which needs to take
- * this lock).
- */
- if (from_schedule) {
- spin_unlock(q->queue_lock);
+ if (from_schedule)
blk_run_queue_async(q);
- } else {
+ else
__blk_run_queue(q);
- spin_unlock(q->queue_lock);
- }
-
+ spin_unlock(q->queue_lock);
}
-static void flush_plug_callbacks(struct blk_plug *plug)
+static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
{
LIST_HEAD(callbacks);
- if (list_empty(&plug->cb_list))
- return;
-
- list_splice_init(&plug->cb_list, &callbacks);
+ while (!list_empty(&plug->cb_list)) {
+ list_splice_init(&plug->cb_list, &callbacks);
- while (!list_empty(&callbacks)) {
- struct blk_plug_cb *cb = list_first_entry(&callbacks,
+ while (!list_empty(&callbacks)) {
+ struct blk_plug_cb *cb = list_first_entry(&callbacks,
struct blk_plug_cb,
list);
- list_del(&cb->list);
- cb->callback(cb);
+ list_del(&cb->list);
+ cb->callback(cb, from_schedule);
+ }
+ }
+}
+
+struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
+ int size)
+{
+ struct blk_plug *plug = current->plug;
+ struct blk_plug_cb *cb;
+
+ if (!plug)
+ return NULL;
+
+ list_for_each_entry(cb, &plug->cb_list, list)
+ if (cb->callback == unplug && cb->data == data)
+ return cb;
+
+ /* Not currently on the callback list */
+ BUG_ON(size < sizeof(*cb));
+ cb = kzalloc(size, GFP_ATOMIC);
+ if (cb) {
+ cb->data = data;
+ cb->callback = unplug;
+ list_add(&cb->list, &plug->cb_list);
}
+ return cb;
}
+EXPORT_SYMBOL(blk_check_plugged);
void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
{
BUG_ON(plug->magic != PLUG_MAGIC);
- flush_plug_callbacks(plug);
+ flush_plug_callbacks(plug, from_schedule);
if (list_empty(&plug->list))
return;
list_splice_init(&plug->list, &list);
- if (plug->should_sort) {
- list_sort(NULL, &list, plug_rq_cmp);
- plug->should_sort = 0;
- }
+ list_sort(NULL, &list, plug_rq_cmp);
q = NULL;
depth = 0;
depth = 0;
spin_lock(q->queue_lock);
}
+
+ /*
+ * Short-circuit if @q is dead
+ */
+ if (unlikely(blk_queue_dying(q))) {
+ __blk_end_request_all(rq, -ENODEV);
+ continue;
+ }
+
/*
* rq is already accounted, so use raw insert
*/
}
EXPORT_SYMBOL(blk_finish_plug);
+#ifdef CONFIG_PM_RUNTIME
+/**
+ * blk_pm_runtime_init - Block layer runtime PM initialization routine
+ * @q: the queue of the device
+ * @dev: the device the queue belongs to
+ *
+ * Description:
+ * Initialize runtime-PM-related fields for @q and start auto suspend for
+ * @dev. Drivers that want to take advantage of request-based runtime PM
+ * should call this function after @dev has been initialized, and its
+ * request queue @q has been allocated, and runtime PM for it can not happen
+ * yet(either due to disabled/forbidden or its usage_count > 0). In most
+ * cases, driver should call this function before any I/O has taken place.
+ *
+ * This function takes care of setting up using auto suspend for the device,
+ * the autosuspend delay is set to -1 to make runtime suspend impossible
+ * until an updated value is either set by user or by driver. Drivers do
+ * not need to touch other autosuspend settings.
+ *
+ * The block layer runtime PM is request based, so only works for drivers
+ * that use request as their IO unit instead of those directly use bio's.
+ */
+void blk_pm_runtime_init(struct request_queue *q, struct device *dev)
+{
+ q->dev = dev;
+ q->rpm_status = RPM_ACTIVE;
+ pm_runtime_set_autosuspend_delay(q->dev, -1);
+ pm_runtime_use_autosuspend(q->dev);
+}
+EXPORT_SYMBOL(blk_pm_runtime_init);
+
+/**
+ * blk_pre_runtime_suspend - Pre runtime suspend check
+ * @q: the queue of the device
+ *
+ * Description:
+ * This function will check if runtime suspend is allowed for the device
+ * by examining if there are any requests pending in the queue. If there
+ * are requests pending, the device can not be runtime suspended; otherwise,
+ * the queue's status will be updated to SUSPENDING and the driver can
+ * proceed to suspend the device.
+ *
+ * For the not allowed case, we mark last busy for the device so that
+ * runtime PM core will try to autosuspend it some time later.
+ *
+ * This function should be called near the start of the device's
+ * runtime_suspend callback.
+ *
+ * Return:
+ * 0 - OK to runtime suspend the device
+ * -EBUSY - Device should not be runtime suspended
+ */
+int blk_pre_runtime_suspend(struct request_queue *q)
+{
+ int ret = 0;
+
+ spin_lock_irq(q->queue_lock);
+ if (q->nr_pending) {
+ ret = -EBUSY;
+ pm_runtime_mark_last_busy(q->dev);
+ } else {
+ q->rpm_status = RPM_SUSPENDING;
+ }
+ spin_unlock_irq(q->queue_lock);
+ return ret;
+}
+EXPORT_SYMBOL(blk_pre_runtime_suspend);
+
+/**
+ * blk_post_runtime_suspend - Post runtime suspend processing
+ * @q: the queue of the device
+ * @err: return value of the device's runtime_suspend function
+ *
+ * Description:
+ * Update the queue's runtime status according to the return value of the
+ * device's runtime suspend function and mark last busy for the device so
+ * that PM core will try to auto suspend the device at a later time.
+ *
+ * This function should be called near the end of the device's
+ * runtime_suspend callback.
+ */
+void blk_post_runtime_suspend(struct request_queue *q, int err)
+{
+ spin_lock_irq(q->queue_lock);
+ if (!err) {
+ q->rpm_status = RPM_SUSPENDED;
+ } else {
+ q->rpm_status = RPM_ACTIVE;
+ pm_runtime_mark_last_busy(q->dev);
+ }
+ spin_unlock_irq(q->queue_lock);
+}
+EXPORT_SYMBOL(blk_post_runtime_suspend);
+
+/**
+ * blk_pre_runtime_resume - Pre runtime resume processing
+ * @q: the queue of the device
+ *
+ * Description:
+ * Update the queue's runtime status to RESUMING in preparation for the
+ * runtime resume of the device.
+ *
+ * This function should be called near the start of the device's
+ * runtime_resume callback.
+ */
+void blk_pre_runtime_resume(struct request_queue *q)
+{
+ spin_lock_irq(q->queue_lock);
+ q->rpm_status = RPM_RESUMING;
+ spin_unlock_irq(q->queue_lock);
+}
+EXPORT_SYMBOL(blk_pre_runtime_resume);
+
+/**
+ * blk_post_runtime_resume - Post runtime resume processing
+ * @q: the queue of the device
+ * @err: return value of the device's runtime_resume function
+ *
+ * Description:
+ * Update the queue's runtime status according to the return value of the
+ * device's runtime_resume function. If it is successfully resumed, process
+ * the requests that are queued into the device's queue when it is resuming
+ * and then mark last busy and initiate autosuspend for it.
+ *
+ * This function should be called near the end of the device's
+ * runtime_resume callback.
+ */
+void blk_post_runtime_resume(struct request_queue *q, int err)
+{
+ spin_lock_irq(q->queue_lock);
+ if (!err) {
+ q->rpm_status = RPM_ACTIVE;
+ __blk_run_queue(q);
+ pm_runtime_mark_last_busy(q->dev);
+ pm_request_autosuspend(q->dev);
+ } else {
+ q->rpm_status = RPM_SUSPENDED;
+ }
+ spin_unlock_irq(q->queue_lock);
+}
+EXPORT_SYMBOL(blk_post_runtime_resume);
+#endif
+
int __init blk_dev_init(void)
{
BUILD_BUG_ON(__REQ_NR_BITS > 8 *
Code Review / linux-3.10.git / blobdiff