static void drive_stat_acct(struct request *rq, int new_io)
{
- struct gendisk *disk = rq->rq_disk;
struct hd_struct *part;
int rw = rq_data_dir(rq);
int cpu;
- if (!blk_fs_request(rq) || !disk || !blk_do_io_stat(disk->queue))
+ if (!blk_do_io_stat(rq))
return;
cpu = part_stat_lock();
- part = disk_map_sector_rcu(rq->rq_disk, rq->sector);
+ part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
if (!new_io)
part_stat_inc(cpu, part, merges[rw]);
INIT_HLIST_NODE(&rq->hash);
RB_CLEAR_NODE(&rq->rb_node);
rq->cmd = rq->__cmd;
+ rq->cmd_len = BLK_MAX_CDB;
rq->tag = -1;
rq->ref_count = 1;
+ rq->start_time = jiffies;
}
EXPORT_SYMBOL(blk_rq_init);
rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type,
rq->cmd_flags);
- printk(KERN_INFO " sector %llu, nr/cnr %lu/%u\n",
- (unsigned long long)rq->sector,
- rq->nr_sectors,
- rq->current_nr_sectors);
- printk(KERN_INFO " bio %p, biotail %p, buffer %p, data %p, len %u\n",
+ printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
+ (unsigned long long)blk_rq_pos(rq),
+ blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
+ printk(KERN_INFO " bio %p, biotail %p, buffer %p, len %u\n",
rq->bio, rq->biotail,
- rq->buffer, rq->data,
- rq->data_len);
+ rq->buffer, rq->data_len);
if (blk_pc_request(rq)) {
printk(KERN_INFO " cdb: ");
}
EXPORT_SYMBOL(blk_unplug);
-static void blk_invoke_request_fn(struct request_queue *q)
-{
- if (unlikely(blk_queue_stopped(q)))
- return;
-
- /*
- * one level of recursion is ok and is much faster than kicking
- * the unplug handling
- */
- if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
- q->request_fn(q);
- queue_flag_clear(QUEUE_FLAG_REENTER, q);
- } else {
- queue_flag_set(QUEUE_FLAG_PLUGGED, q);
- kblockd_schedule_work(q, &q->unplug_work);
- }
-}
-
/**
* blk_start_queue - restart a previously stopped queue
* @q: The &struct request_queue in question
WARN_ON(!irqs_disabled());
queue_flag_clear(QUEUE_FLAG_STOPPED, q);
- blk_invoke_request_fn(q);
+ __blk_run_queue(q);
}
EXPORT_SYMBOL(blk_start_queue);
{
blk_remove_plug(q);
+ if (unlikely(blk_queue_stopped(q)))
+ return;
+
+ if (elv_queue_empty(q))
+ return;
+
/*
* 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))
- blk_invoke_request_fn(q);
+ if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
+ q->request_fn(q);
+ queue_flag_clear(QUEUE_FLAG_REENTER, q);
+ } else {
+ queue_flag_set(QUEUE_FLAG_PLUGGED, q);
+ kblockd_schedule_work(q, &q->unplug_work);
+ }
}
EXPORT_SYMBOL(__blk_run_queue);
*
* Description:
* Invoke request handling on this queue, if it has pending work to do.
- * May be used to restart queueing when a request has completed. Also
- * See @blk_start_queueing.
- *
+ * May be used to restart queueing when a request has completed.
*/
void blk_run_queue(struct request_queue *q)
{
{
struct request_list *rl = &q->rq;
- rl->count[READ] = rl->count[WRITE] = 0;
- rl->starved[READ] = rl->starved[WRITE] = 0;
+ 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[READ]);
- init_waitqueue_head(&rl->wait[WRITE]);
+ 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);
}
static struct request *
-blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask)
+blk_alloc_request(struct request_queue *q, int flags, int priv, gfp_t gfp_mask)
{
struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
blk_rq_init(q, rq);
- rq->cmd_flags = rw | REQ_ALLOCED;
+ rq->cmd_flags = flags | REQ_ALLOCED;
if (priv) {
if (unlikely(elv_set_request(q, rq, gfp_mask))) {
ioc->last_waited = jiffies;
}
-static void __freed_request(struct request_queue *q, int rw)
+static void __freed_request(struct request_queue *q, int sync)
{
struct request_list *rl = &q->rq;
- if (rl->count[rw] < queue_congestion_off_threshold(q))
- blk_clear_queue_congested(q, rw);
+ if (rl->count[sync] < queue_congestion_off_threshold(q))
+ blk_clear_queue_congested(q, sync);
- if (rl->count[rw] + 1 <= q->nr_requests) {
- if (waitqueue_active(&rl->wait[rw]))
- wake_up(&rl->wait[rw]);
+ if (rl->count[sync] + 1 <= q->nr_requests) {
+ if (waitqueue_active(&rl->wait[sync]))
+ wake_up(&rl->wait[sync]);
- blk_clear_queue_full(q, rw);
+ blk_clear_queue_full(q, 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, int rw, int priv)
+static void freed_request(struct request_queue *q, int sync, int priv)
{
struct request_list *rl = &q->rq;
- rl->count[rw]--;
+ rl->count[sync]--;
if (priv)
rl->elvpriv--;
- __freed_request(q, rw);
+ __freed_request(q, sync);
- if (unlikely(rl->starved[rw ^ 1]))
- __freed_request(q, rw ^ 1);
+ if (unlikely(rl->starved[sync ^ 1]))
+ __freed_request(q, sync ^ 1);
}
/*
struct request *rq = NULL;
struct request_list *rl = &q->rq;
struct io_context *ioc = NULL;
- const int rw = rw_flags & 0x01;
+ const bool is_sync = rw_is_sync(rw_flags) != 0;
int may_queue, priv;
may_queue = elv_may_queue(q, rw_flags);
if (may_queue == ELV_MQUEUE_NO)
goto rq_starved;
- if (rl->count[rw]+1 >= queue_congestion_on_threshold(q)) {
- if (rl->count[rw]+1 >= q->nr_requests) {
+ 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
* This process will be allowed to complete a batch of
* requests, others will be blocked.
*/
- if (!blk_queue_full(q, rw)) {
+ if (!blk_queue_full(q, is_sync)) {
ioc_set_batching(q, ioc);
- blk_set_queue_full(q, rw);
+ blk_set_queue_full(q, is_sync);
} else {
if (may_queue != ELV_MQUEUE_MUST
&& !ioc_batching(q, ioc)) {
}
}
}
- blk_set_queue_congested(q, rw);
+ blk_set_queue_congested(q, is_sync);
}
/*
* limit of requests, otherwise we could have thousands of requests
* allocated with any setting of ->nr_requests
*/
- if (rl->count[rw] >= (3 * q->nr_requests / 2))
+ if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
goto out;
- rl->count[rw]++;
- rl->starved[rw] = 0;
+ rl->count[is_sync]++;
+ rl->starved[is_sync] = 0;
priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
if (priv)
rl->elvpriv++;
+ if (blk_queue_io_stat(q))
+ rw_flags |= REQ_IO_STAT;
spin_unlock_irq(q->queue_lock);
rq = blk_alloc_request(q, rw_flags, priv, gfp_mask);
* wait queue, but this is pretty rare.
*/
spin_lock_irq(q->queue_lock);
- freed_request(q, rw, priv);
+ freed_request(q, is_sync, priv);
/*
* in the very unlikely event that allocation failed and no
* rq mempool into READ and WRITE
*/
rq_starved:
- if (unlikely(rl->count[rw] == 0))
- rl->starved[rw] = 1;
+ if (unlikely(rl->count[is_sync] == 0))
+ rl->starved[is_sync] = 1;
goto out;
}
if (ioc_batching(q, ioc))
ioc->nr_batch_requests--;
- trace_block_getrq(q, bio, rw);
+ trace_block_getrq(q, bio, rw_flags & 1);
out:
return rq;
}
static struct request *get_request_wait(struct request_queue *q, int rw_flags,
struct bio *bio)
{
- const int rw = rw_flags & 0x01;
+ const bool is_sync = rw_is_sync(rw_flags) != 0;
struct request *rq;
rq = get_request(q, rw_flags, bio, GFP_NOIO);
struct io_context *ioc;
struct request_list *rl = &q->rq;
- prepare_to_wait_exclusive(&rl->wait[rw], &wait,
+ prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
TASK_UNINTERRUPTIBLE);
- trace_block_sleeprq(q, bio, rw);
+ trace_block_sleeprq(q, bio, rw_flags & 1);
__generic_unplug_device(q);
spin_unlock_irq(q->queue_lock);
ioc_set_batching(q, ioc);
spin_lock_irq(q->queue_lock);
- finish_wait(&rl->wait[rw], &wait);
+ finish_wait(&rl->wait[is_sync], &wait);
rq = get_request(q, rw_flags, bio, GFP_NOIO);
};
}
EXPORT_SYMBOL(blk_get_request);
-/**
- * blk_start_queueing - initiate dispatch of requests to device
- * @q: request queue to kick into gear
- *
- * This is basically a helper to remove the need to know whether a queue
- * is plugged or not if someone just wants to initiate dispatch of requests
- * for this queue. Should be used to start queueing on a device outside
- * of ->request_fn() context. Also see @blk_run_queue.
- *
- * The queue lock must be held with interrupts disabled.
- */
-void blk_start_queueing(struct request_queue *q)
-{
- if (!blk_queue_plugged(q)) {
- if (unlikely(blk_queue_stopped(q)))
- return;
- q->request_fn(q);
- } else
- __generic_unplug_device(q);
-}
-EXPORT_SYMBOL(blk_start_queueing);
-
/**
* blk_requeue_request - put a request back on queue
* @q: request queue where request should be inserted
* barrier
*/
rq->cmd_type = REQ_TYPE_SPECIAL;
- rq->cmd_flags |= REQ_SOFTBARRIER;
rq->special = data;
drive_stat_acct(rq, 1);
__elv_add_request(q, rq, where, 0);
- blk_start_queueing(q);
+ __blk_run_queue(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
EXPORT_SYMBOL(blk_insert_request);
* it didn't come out of our reserved rq pools
*/
if (req->cmd_flags & REQ_ALLOCED) {
- int rw = rq_data_dir(req);
+ int is_sync = rq_is_sync(req) != 0;
int priv = req->cmd_flags & REQ_ELVPRIV;
BUG_ON(!list_empty(&req->queuelist));
BUG_ON(!hlist_unhashed(&req->hash));
blk_free_request(q, req);
- freed_request(q, rw, priv);
+ freed_request(q, is_sync, priv);
}
}
EXPORT_SYMBOL_GPL(__blk_put_request);
if (bio_failfast_driver(bio))
req->cmd_flags |= REQ_FAILFAST_DRIVER;
- /*
- * REQ_BARRIER implies no merging, but lets make it explicit
- */
if (unlikely(bio_discard(bio))) {
req->cmd_flags |= REQ_DISCARD;
if (bio_barrier(bio))
req->cmd_flags |= REQ_SOFTBARRIER;
req->q->prepare_discard_fn(req->q, req);
} else if (unlikely(bio_barrier(bio)))
- req->cmd_flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
+ req->cmd_flags |= REQ_HARDBARRIER;
if (bio_sync(bio))
req->cmd_flags |= REQ_RW_SYNC;
- if (bio_unplug(bio))
- req->cmd_flags |= REQ_UNPLUG;
if (bio_rw_meta(bio))
req->cmd_flags |= REQ_RW_META;
+ if (bio_noidle(bio))
+ req->cmd_flags |= REQ_NOIDLE;
req->errors = 0;
req->hard_sector = req->sector = bio->bi_sector;
req->ioprio = bio_prio(bio);
- req->start_time = jiffies;
blk_rq_bio_prep(req->q, req, bio);
}
+/*
+ * Only disabling plugging for non-rotational devices if it does tagging
+ * as well, otherwise we do need the proper merging
+ */
+static inline bool queue_should_plug(struct request_queue *q)
+{
+ return !(blk_queue_nonrot(q) && blk_queue_tagged(q));
+}
+
static int __make_request(struct request_queue *q, struct bio *bio)
{
struct request *req;
if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) ||
bio_flagged(bio, BIO_CPU_AFFINE))
req->cpu = blk_cpu_to_group(smp_processor_id());
- if (!blk_queue_nonrot(q) && elv_queue_empty(q))
+ if (queue_should_plug(q) && elv_queue_empty(q))
blk_plug_device(q);
add_request(q, req);
out:
- if (unplug || blk_queue_nonrot(q))
+ if (unplug || !queue_should_plug(q))
__generic_unplug_device(q);
spin_unlock_irq(q->queue_lock);
return 0;
*/
int blk_rq_check_limits(struct request_queue *q, struct request *rq)
{
- if (rq->nr_sectors > q->max_sectors ||
+ if (blk_rq_sectors(rq) > q->max_sectors ||
rq->data_len > q->max_hw_sectors << 9) {
printk(KERN_ERR "%s: over max size limit.\n", __func__);
return -EIO;
static void blk_account_io_completion(struct request *req, unsigned int bytes)
{
- struct gendisk *disk = req->rq_disk;
-
- if (!disk || !blk_do_io_stat(disk->queue))
- return;
-
- if (blk_fs_request(req)) {
+ if (blk_do_io_stat(req)) {
const int rw = rq_data_dir(req);
struct hd_struct *part;
int cpu;
cpu = part_stat_lock();
- part = disk_map_sector_rcu(req->rq_disk, req->sector);
+ part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
part_stat_add(cpu, part, sectors[rw], bytes >> 9);
part_stat_unlock();
}
static void blk_account_io_done(struct request *req)
{
- struct gendisk *disk = req->rq_disk;
-
- if (!disk || !blk_do_io_stat(disk->queue))
- return;
-
/*
* Account IO completion. bar_rq isn't accounted as a normal
* IO on queueing nor completion. Accounting the containing
* request is enough.
*/
- if (blk_fs_request(req) && req != &req->q->bar_rq) {
+ if (blk_do_io_stat(req) && req != &req->q->bar_rq) {
unsigned long duration = jiffies - req->start_time;
const int rw = rq_data_dir(req);
struct hd_struct *part;
int cpu;
cpu = part_stat_lock();
- part = disk_map_sector_rcu(disk, req->sector);
+ part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
part_stat_inc(cpu, part, ios[rw]);
part_stat_add(cpu, part, ticks[rw], duration);
}
/**
- * __end_that_request_first - end I/O on a request
- * @req: the request being processed
+ * blk_rq_bytes - Returns bytes left to complete in the entire request
+ * @rq: the request being processed
+ **/
+unsigned int blk_rq_bytes(struct request *rq)
+{
+ if (blk_fs_request(rq))
+ return blk_rq_sectors(rq) << 9;
+
+ return rq->data_len;
+}
+EXPORT_SYMBOL_GPL(blk_rq_bytes);
+
+/**
+ * blk_rq_cur_bytes - Returns bytes left to complete in the current segment
+ * @rq: the request being processed
+ **/
+unsigned int blk_rq_cur_bytes(struct request *rq)
+{
+ if (blk_fs_request(rq))
+ return rq->current_nr_sectors << 9;
+
+ if (rq->bio)
+ return rq->bio->bi_size;
+
+ return rq->data_len;
+}
+EXPORT_SYMBOL_GPL(blk_rq_cur_bytes);
+
+struct request *elv_next_request(struct request_queue *q)
+{
+ struct request *rq;
+ int ret;
+
+ while ((rq = __elv_next_request(q)) != NULL) {
+ if (!(rq->cmd_flags & REQ_STARTED)) {
+ /*
+ * This is the first time the device driver
+ * sees this request (possibly after
+ * requeueing). Notify IO scheduler.
+ */
+ if (blk_sorted_rq(rq))
+ elv_activate_rq(q, rq);
+
+ /*
+ * just mark as started even if we don't start
+ * it, a request that has been delayed should
+ * not be passed by new incoming requests
+ */
+ rq->cmd_flags |= REQ_STARTED;
+ trace_block_rq_issue(q, rq);
+ }
+
+ if (!q->boundary_rq || q->boundary_rq == rq) {
+ q->end_sector = rq_end_sector(rq);
+ q->boundary_rq = NULL;
+ }
+
+ if (rq->cmd_flags & REQ_DONTPREP)
+ break;
+
+ if (q->dma_drain_size && rq->data_len) {
+ /*
+ * make sure space for the drain appears we
+ * know we can do this because max_hw_segments
+ * has been adjusted to be one fewer than the
+ * device can handle
+ */
+ rq->nr_phys_segments++;
+ }
+
+ if (!q->prep_rq_fn)
+ break;
+
+ ret = q->prep_rq_fn(q, rq);
+ if (ret == BLKPREP_OK) {
+ break;
+ } else if (ret == BLKPREP_DEFER) {
+ /*
+ * the request may have been (partially) prepped.
+ * we need to keep this request in the front to
+ * avoid resource deadlock. REQ_STARTED will
+ * prevent other fs requests from passing this one.
+ */
+ if (q->dma_drain_size && rq->data_len &&
+ !(rq->cmd_flags & REQ_DONTPREP)) {
+ /*
+ * remove the space for the drain we added
+ * so that we don't add it again
+ */
+ --rq->nr_phys_segments;
+ }
+
+ rq = NULL;
+ break;
+ } else if (ret == BLKPREP_KILL) {
+ rq->cmd_flags |= REQ_QUIET;
+ __blk_end_request_all(rq, -EIO);
+ } else {
+ printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
+ break;
+ }
+ }
+
+ return rq;
+}
+EXPORT_SYMBOL(elv_next_request);
+
+void elv_dequeue_request(struct request_queue *q, struct request *rq)
+{
+ BUG_ON(list_empty(&rq->queuelist));
+ BUG_ON(ELV_ON_HASH(rq));
+
+ list_del_init(&rq->queuelist);
+
+ /*
+ * the time frame between a request being removed from the lists
+ * and to it is freed is accounted as io that is in progress at
+ * the driver side.
+ */
+ if (blk_account_rq(rq))
+ q->in_flight++;
+}
+
+/**
+ * blk_update_request - Special helper function for request stacking drivers
+ * @rq: the request being processed
* @error: %0 for success, < %0 for error
- * @nr_bytes: number of bytes to complete
+ * @nr_bytes: number of bytes to complete @rq
*
* Description:
- * Ends I/O on a number of bytes attached to @req, and sets it up
- * for the next range of segments (if any) in the cluster.
+ * Ends I/O on a number of bytes attached to @rq, but doesn't complete
+ * the request structure even if @rq doesn't have leftover.
+ * If @rq has leftover, sets it up for the next range of segments.
+ *
+ * This special helper function is only for request stacking drivers
+ * (e.g. request-based dm) so that they can handle partial completion.
+ * Actual device drivers should use blk_end_request instead.
+ *
+ * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
+ * %false return from this function.
*
* Return:
- * %0 - we are done with this request, call end_that_request_last()
- * %1 - still buffers pending for this request
+ * %false - this request doesn't have any more data
+ * %true - this request has more data
**/
-static int __end_that_request_first(struct request *req, int error,
- int nr_bytes)
+bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
{
int total_bytes, bio_nbytes, next_idx = 0;
struct bio *bio;
+ if (!req->bio)
+ return false;
+
trace_block_rq_complete(req->q, req);
/*
- * for a REQ_TYPE_BLOCK_PC request, we want to carry any eventual
- * sense key with us all the way through
+ * For fs requests, rq is just carrier of independent bio's
+ * and each partial completion should be handled separately.
+ * Reset per-request error on each partial completion.
+ *
+ * TODO: tj: This is too subtle. It would be better to let
+ * low level drivers do what they see fit.
*/
- if (!blk_pc_request(req))
+ if (blk_fs_request(req))
req->errors = 0;
if (error && (blk_fs_request(req) && !(req->cmd_flags & REQ_QUIET))) {
printk(KERN_ERR "end_request: I/O error, dev %s, sector %llu\n",
req->rq_disk ? req->rq_disk->disk_name : "?",
- (unsigned long long)req->sector);
+ (unsigned long long)blk_rq_pos(req));
}
blk_account_io_completion(req, nr_bytes);
/*
* completely done
*/
- if (!req->bio)
- return 0;
+ if (!req->bio) {
+ /*
+ * Reset counters so that the request stacking driver
+ * can find how many bytes remain in the request
+ * later.
+ */
+ req->nr_sectors = req->hard_nr_sectors = 0;
+ req->current_nr_sectors = req->hard_cur_sectors = 0;
+ return false;
+ }
/*
* if the request wasn't completed, update state
blk_recalc_rq_sectors(req, total_bytes >> 9);
blk_recalc_rq_segments(req);
- return 1;
+ return true;
+}
+EXPORT_SYMBOL_GPL(blk_update_request);
+
+static bool blk_update_bidi_request(struct request *rq, int error,
+ unsigned int nr_bytes,
+ unsigned int bidi_bytes)
+{
+ if (blk_update_request(rq, error, nr_bytes))
+ return true;
+
+ /* Bidi request must be completed as a whole */
+ if (unlikely(blk_bidi_rq(rq)) &&
+ blk_update_request(rq->next_rq, error, bidi_bytes))
+ return true;
+
+ add_disk_randomness(rq->rq_disk);
+
+ return false;
}
/*
* queue lock must be held
*/
-static void end_that_request_last(struct request *req, int error)
+static void blk_finish_request(struct request *req, int error)
{
if (blk_rq_tagged(req))
blk_queue_end_tag(req->q, req);
}
/**
- * blk_rq_bytes - Returns bytes left to complete in the entire request
- * @rq: the request being processed
- **/
-unsigned int blk_rq_bytes(struct request *rq)
-{
- if (blk_fs_request(rq))
- return rq->hard_nr_sectors << 9;
-
- return rq->data_len;
-}
-EXPORT_SYMBOL_GPL(blk_rq_bytes);
-
-/**
- * blk_rq_cur_bytes - Returns bytes left to complete in the current segment
- * @rq: the request being processed
- **/
-unsigned int blk_rq_cur_bytes(struct request *rq)
-{
- if (blk_fs_request(rq))
- return rq->current_nr_sectors << 9;
-
- if (rq->bio)
- return rq->bio->bi_size;
-
- return rq->data_len;
-}
-EXPORT_SYMBOL_GPL(blk_rq_cur_bytes);
-
-/**
- * end_request - end I/O on the current segment of the request
- * @req: the request being processed
- * @uptodate: error value or %0/%1 uptodate flag
- *
- * Description:
- * Ends I/O on the current segment of a request. If that is the only
- * remaining segment, the request is also completed and freed.
- *
- * This is a remnant of how older block drivers handled I/O completions.
- * Modern drivers typically end I/O on the full request in one go, unless
- * they have a residual value to account for. For that case this function
- * isn't really useful, unless the residual just happens to be the
- * full current segment. In other words, don't use this function in new
- * code. Use blk_end_request() or __blk_end_request() to end a request.
- **/
-void end_request(struct request *req, int uptodate)
-{
- int error = 0;
-
- if (uptodate <= 0)
- error = uptodate ? uptodate : -EIO;
-
- __blk_end_request(req, error, req->hard_cur_sectors << 9);
-}
-EXPORT_SYMBOL(end_request);
-
-static int end_that_request_data(struct request *rq, int error,
- unsigned int nr_bytes, unsigned int bidi_bytes)
-{
- if (rq->bio) {
- if (__end_that_request_first(rq, error, nr_bytes))
- return 1;
-
- /* Bidi request must be completed as a whole */
- if (blk_bidi_rq(rq) &&
- __end_that_request_first(rq->next_rq, error, bidi_bytes))
- return 1;
- }
-
- return 0;
-}
-
-/**
- * blk_end_io - Generic end_io function to complete a request.
- * @rq: the request being processed
- * @error: %0 for success, < %0 for error
- * @nr_bytes: number of bytes to complete @rq
- * @bidi_bytes: number of bytes to complete @rq->next_rq
- * @drv_callback: function called between completion of bios in the request
- * and completion of the request.
- * If the callback returns non %0, this helper returns without
- * completion of the request.
+ * blk_end_bidi_request - Complete a bidi request
+ * @rq: the request to complete
+ * @error: %0 for success, < %0 for error
+ * @nr_bytes: number of bytes to complete @rq
+ * @bidi_bytes: number of bytes to complete @rq->next_rq
*
* Description:
* Ends I/O on a number of bytes attached to @rq and @rq->next_rq.
- * If @rq has leftover, sets it up for the next range of segments.
+ * Drivers that supports bidi can safely call this member for any
+ * type of request, bidi or uni. In the later case @bidi_bytes is
+ * just ignored.
*
* Return:
- * %0 - we are done with this request
- * %1 - this request is not freed yet, it still has pending buffers.
+ * %false - we are done with this request
+ * %true - still buffers pending for this request
**/
-static int blk_end_io(struct request *rq, int error, unsigned int nr_bytes,
- unsigned int bidi_bytes,
- int (drv_callback)(struct request *))
+bool blk_end_bidi_request(struct request *rq, int error,
+ unsigned int nr_bytes, unsigned int bidi_bytes)
{
struct request_queue *q = rq->q;
- unsigned long flags = 0UL;
-
- if (end_that_request_data(rq, error, nr_bytes, bidi_bytes))
- return 1;
+ unsigned long flags;
- /* Special feature for tricky drivers */
- if (drv_callback && drv_callback(rq))
- return 1;
-
- add_disk_randomness(rq->rq_disk);
+ if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
+ return true;
spin_lock_irqsave(q->queue_lock, flags);
- end_that_request_last(rq, error);
+ blk_finish_request(rq, error);
spin_unlock_irqrestore(q->queue_lock, flags);
- return 0;
-}
-
-/**
- * blk_end_request - Helper function for drivers to complete the request.
- * @rq: the request being processed
- * @error: %0 for success, < %0 for error
- * @nr_bytes: number of bytes to complete
- *
- * Description:
- * Ends I/O on a number of bytes attached to @rq.
- * If @rq has leftover, sets it up for the next range of segments.
- *
- * Return:
- * %0 - we are done with this request
- * %1 - still buffers pending for this request
- **/
-int blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
-{
- return blk_end_io(rq, error, nr_bytes, 0, NULL);
-}
-EXPORT_SYMBOL_GPL(blk_end_request);
-
-/**
- * __blk_end_request - Helper function for drivers to complete the request.
- * @rq: the request being processed
- * @error: %0 for success, < %0 for error
- * @nr_bytes: number of bytes to complete
- *
- * Description:
- * Must be called with queue lock held unlike blk_end_request().
- *
- * Return:
- * %0 - we are done with this request
- * %1 - still buffers pending for this request
- **/
-int __blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
-{
- if (rq->bio && __end_that_request_first(rq, error, nr_bytes))
- return 1;
-
- add_disk_randomness(rq->rq_disk);
-
- end_that_request_last(rq, error);
-
- return 0;
+ return false;
}
-EXPORT_SYMBOL_GPL(__blk_end_request);
+EXPORT_SYMBOL_GPL(blk_end_bidi_request);
/**
- * blk_end_bidi_request - Helper function for drivers to complete bidi request.
- * @rq: the bidi request being processed
+ * __blk_end_bidi_request - Complete a bidi request with queue lock held
+ * @rq: the request to complete
* @error: %0 for success, < %0 for error
* @nr_bytes: number of bytes to complete @rq
* @bidi_bytes: number of bytes to complete @rq->next_rq
*
* Description:
- * Ends I/O on a number of bytes attached to @rq and @rq->next_rq.
+ * Identical to blk_end_bidi_request() except that queue lock is
+ * assumed to be locked on entry and remains so on return.
*
* Return:
- * %0 - we are done with this request
- * %1 - still buffers pending for this request
+ * %false - we are done with this request
+ * %true - still buffers pending for this request
**/
-int blk_end_bidi_request(struct request *rq, int error, unsigned int nr_bytes,
- unsigned int bidi_bytes)
+bool __blk_end_bidi_request(struct request *rq, int error,
+ unsigned int nr_bytes, unsigned int bidi_bytes)
{
- return blk_end_io(rq, error, nr_bytes, bidi_bytes, NULL);
-}
-EXPORT_SYMBOL_GPL(blk_end_bidi_request);
+ if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
+ return true;
-/**
- * blk_update_request - Special helper function for request stacking drivers
- * @rq: the request being processed
- * @error: %0 for success, < %0 for error
- * @nr_bytes: number of bytes to complete @rq
- *
- * Description:
- * Ends I/O on a number of bytes attached to @rq, but doesn't complete
- * the request structure even if @rq doesn't have leftover.
- * If @rq has leftover, sets it up for the next range of segments.
- *
- * This special helper function is only for request stacking drivers
- * (e.g. request-based dm) so that they can handle partial completion.
- * Actual device drivers should use blk_end_request instead.
- */
-void blk_update_request(struct request *rq, int error, unsigned int nr_bytes)
-{
- if (!end_that_request_data(rq, error, nr_bytes, 0)) {
- /*
- * These members are not updated in end_that_request_data()
- * when all bios are completed.
- * Update them so that the request stacking driver can find
- * how many bytes remain in the request later.
- */
- rq->nr_sectors = rq->hard_nr_sectors = 0;
- rq->current_nr_sectors = rq->hard_cur_sectors = 0;
- }
-}
-EXPORT_SYMBOL_GPL(blk_update_request);
+ blk_finish_request(rq, error);
-/**
- * blk_end_request_callback - Special helper function for tricky drivers
- * @rq: the request being processed
- * @error: %0 for success, < %0 for error
- * @nr_bytes: number of bytes to complete
- * @drv_callback: function called between completion of bios in the request
- * and completion of the request.
- * If the callback returns non %0, this helper returns without
- * completion of the request.
- *
- * Description:
- * Ends I/O on a number of bytes attached to @rq.
- * If @rq has leftover, sets it up for the next range of segments.
- *
- * This special helper function is used only for existing tricky drivers.
- * (e.g. cdrom_newpc_intr() of ide-cd)
- * This interface will be removed when such drivers are rewritten.
- * Don't use this interface in other places anymore.
- *
- * Return:
- * %0 - we are done with this request
- * %1 - this request is not freed yet.
- * this request still has pending buffers or
- * the driver doesn't want to finish this request yet.
- **/
-int blk_end_request_callback(struct request *rq, int error,
- unsigned int nr_bytes,
- int (drv_callback)(struct request *))
-{
- return blk_end_io(rq, error, nr_bytes, 0, drv_callback);
+ return false;
}
-EXPORT_SYMBOL_GPL(blk_end_request_callback);
+EXPORT_SYMBOL_GPL(__blk_end_bidi_request);
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
struct bio *bio)
int __init blk_dev_init(void)
{
+ BUILD_BUG_ON(__REQ_NR_BITS > 8 *
+ sizeof(((struct request *)0)->cmd_flags));
+
kblockd_workqueue = create_workqueue("kblockd");
if (!kblockd_workqueue)
panic("Failed to create kblockd\n");
projects / linux-block.git / blobdiff