X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=drivers%2Fmd%2Fdm.c;h=bca448e118786a78a5e07b54f3cb3a7e3aca85d5;hb=d3a47e82b6bc3724dd60f3ee4e84fe4479104382;hp=11f422ecfda000a6ee35ead97dbf8d4c0d433e08;hpb=94d6351e147231b2c5a9512d69693ee8ac0c204d;p=~andy%2Flinux

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 11f422ecfda..bca448e1187 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -37,8 +37,8 @@ static DEFINE_SPINLOCK(_minor_lock);
 struct dm_io {
 	struct mapped_device *md;
 	int error;
-	struct bio *bio;
 	atomic_t io_count;
+	struct bio *bio;
 	unsigned long start_time;
 };
 
@@ -71,6 +71,19 @@ union map_info *dm_get_mapinfo(struct bio *bio)
 #define DMF_DELETING 4
 #define DMF_NOFLUSH_SUSPENDING 5
 
+/*
+ * Work processed by per-device workqueue.
+ */
+struct dm_wq_req {
+	enum {
+		DM_WQ_FLUSH_ALL,
+		DM_WQ_FLUSH_DEFERRED,
+	} type;
+	struct work_struct work;
+	struct mapped_device *md;
+	void *context;
+};
+
 struct mapped_device {
 	struct rw_semaphore io_lock;
 	struct mutex suspend_lock;
@@ -95,6 +108,11 @@ struct mapped_device {
 	struct bio_list deferred;
 	struct bio_list pushback;
 
+	/*
+	 * Processing queue (flush/barriers)
+	 */
+	struct workqueue_struct *wq;
+
 	/*
 	 * The current mapping.
 	 */
@@ -186,6 +204,7 @@ static int (*_inits[])(void) __initdata = {
 	dm_target_init,
 	dm_linear_init,
 	dm_stripe_init,
+	dm_kcopyd_init,
 	dm_interface_init,
 };
 
@@ -194,6 +213,7 @@ static void (*_exits[])(void) = {
 	dm_target_exit,
 	dm_linear_exit,
 	dm_stripe_exit,
+	dm_kcopyd_exit,
 	dm_interface_exit,
 };
 
@@ -809,6 +829,49 @@ static int __split_bio(struct mapped_device *md, struct bio *bio)
  * CRUD END
  *---------------------------------------------------------------*/
 
+static int dm_merge_bvec(struct request_queue *q,
+			 struct bvec_merge_data *bvm,
+			 struct bio_vec *biovec)
+{
+	struct mapped_device *md = q->queuedata;
+	struct dm_table *map = dm_get_table(md);
+	struct dm_target *ti;
+	sector_t max_sectors;
+	int max_size;
+
+	if (unlikely(!map))
+		return 0;
+
+	ti = dm_table_find_target(map, bvm->bi_sector);
+
+	/*
+	 * Find maximum amount of I/O that won't need splitting
+	 */
+	max_sectors = min(max_io_len(md, bvm->bi_sector, ti),
+			  (sector_t) BIO_MAX_SECTORS);
+	max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
+	if (max_size < 0)
+		max_size = 0;
+
+	/*
+	 * merge_bvec_fn() returns number of bytes
+	 * it can accept at this offset
+	 * max is precomputed maximal io size
+	 */
+	if (max_size && ti->type->merge)
+		max_size = ti->type->merge(ti, bvm, biovec, max_size);
+
+	/*
+	 * Always allow an entire first page
+	 */
+	if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
+		max_size = biovec->bv_len;
+
+	dm_table_put(map);
+
+	return max_size;
+}
+
 /*
  * The request function that just remaps the bio built up by
  * dm_merge_bvec.
@@ -904,7 +967,7 @@ static void free_minor(int minor)
 /*
  * See if the device with a specific minor # is free.
  */
-static int specific_minor(struct mapped_device *md, int minor)
+static int specific_minor(int minor)
 {
 	int r, m;
 
@@ -937,7 +1000,7 @@ out:
 	return r;
 }
 
-static int next_free_minor(struct mapped_device *md, int *minor)
+static int next_free_minor(int *minor)
 {
 	int r, m;
 
@@ -948,9 +1011,8 @@ static int next_free_minor(struct mapped_device *md, int *minor)
 	spin_lock(&_minor_lock);
 
 	r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
-	if (r) {
+	if (r)
 		goto out;
-	}
 
 	if (m >= (1 << MINORBITS)) {
 		idr_remove(&_minor_idr, m);
@@ -973,7 +1035,7 @@ static struct block_device_operations dm_blk_dops;
 static struct mapped_device *alloc_dev(int minor)
 {
 	int r;
-	struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
+	struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
 	void *old_md;
 
 	if (!md) {
@@ -986,13 +1048,12 @@ static struct mapped_device *alloc_dev(int minor)
 
 	/* get a minor number for the dev */
 	if (minor == DM_ANY_MINOR)
-		r = next_free_minor(md, &minor);
+		r = next_free_minor(&minor);
 	else
-		r = specific_minor(md, minor);
+		r = specific_minor(minor);
 	if (r < 0)
 		goto bad_minor;
 
-	memset(md, 0, sizeof(*md));
 	init_rwsem(&md->io_lock);
 	mutex_init(&md->suspend_lock);
 	spin_lock_init(&md->pushback_lock);
@@ -1014,6 +1075,7 @@ static struct mapped_device *alloc_dev(int minor)
 	blk_queue_make_request(md->queue, dm_request);
 	blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
 	md->queue->unplug_fn = dm_unplug_all;
+	blk_queue_merge_bvec(md->queue, dm_merge_bvec);
 
 	md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
 	if (!md->io_pool)
@@ -1044,6 +1106,10 @@ static struct mapped_device *alloc_dev(int minor)
 	add_disk(md->disk);
 	format_dev_t(md->name, MKDEV(_major, minor));
 
+	md->wq = create_singlethread_workqueue("kdmflush");
+	if (!md->wq)
+		goto bad_thread;
+
 	/* Populate the mapping, nobody knows we exist yet */
 	spin_lock(&_minor_lock);
 	old_md = idr_replace(&_minor_idr, md, minor);
@@ -1053,6 +1119,8 @@ static struct mapped_device *alloc_dev(int minor)
 
 	return md;
 
+bad_thread:
+	put_disk(md->disk);
 bad_disk:
 	bioset_free(md->bs);
 bad_no_bioset:
@@ -1080,6 +1148,7 @@ static void free_dev(struct mapped_device *md)
 		unlock_fs(md);
 		bdput(md->suspended_bdev);
 	}
+	destroy_workqueue(md->wq);
 	mempool_destroy(md->tio_pool);
 	mempool_destroy(md->io_pool);
 	bioset_free(md->bs);
@@ -1259,6 +1328,29 @@ void dm_put(struct mapped_device *md)
 }
 EXPORT_SYMBOL_GPL(dm_put);
 
+static int dm_wait_for_completion(struct mapped_device *md)
+{
+	int r = 0;
+
+	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		smp_mb();
+		if (!atomic_read(&md->pending))
+			break;
+
+		if (signal_pending(current)) {
+			r = -EINTR;
+			break;
+		}
+
+		io_schedule();
+	}
+	set_current_state(TASK_RUNNING);
+
+	return r;
+}
+
 /*
  * Process the deferred bios
  */
@@ -1285,6 +1377,44 @@ static void __merge_pushback_list(struct mapped_device *md)
 	spin_unlock_irqrestore(&md->pushback_lock, flags);
 }
 
+static void dm_wq_work(struct work_struct *work)
+{
+	struct dm_wq_req *req = container_of(work, struct dm_wq_req, work);
+	struct mapped_device *md = req->md;
+
+	down_write(&md->io_lock);
+	switch (req->type) {
+	case DM_WQ_FLUSH_ALL:
+		__merge_pushback_list(md);
+		/* pass through */
+	case DM_WQ_FLUSH_DEFERRED:
+		__flush_deferred_io(md);
+		break;
+	default:
+		DMERR("dm_wq_work: unrecognised work type %d", req->type);
+		BUG();
+	}
+	up_write(&md->io_lock);
+}
+
+static void dm_wq_queue(struct mapped_device *md, int type, void *context,
+			struct dm_wq_req *req)
+{
+	req->type = type;
+	req->md = md;
+	req->context = context;
+	INIT_WORK(&req->work, dm_wq_work);
+	queue_work(md->wq, &req->work);
+}
+
+static void dm_queue_flush(struct mapped_device *md, int type, void *context)
+{
+	struct dm_wq_req req;
+
+	dm_wq_queue(md, type, context, &req);
+	flush_workqueue(md->wq);
+}
+
 /*
  * Swap in a new table (destroying old one).
  */
@@ -1357,7 +1487,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
 {
 	struct dm_table *map = NULL;
 	DECLARE_WAITQUEUE(wait, current);
-	int pending, r = 0;
+	int r = 0;
 	int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
 	int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
 
@@ -1414,20 +1544,9 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
 		dm_table_unplug_all(map);
 
 	/*
-	 * Then we wait for the already mapped ios to
-	 * complete.
+	 * Wait for the already-mapped ios to complete.
 	 */
-	while (1) {
-		set_current_state(TASK_INTERRUPTIBLE);
-
-		smp_mb();
-		pending = atomic_read(&md->pending);
-		if (!pending || signal_pending(current))
-			break;
-
-		io_schedule();
-	}
-	set_current_state(TASK_RUNNING);
+	r = dm_wait_for_completion(md);
 
 	down_write(&md->io_lock);
 	remove_wait_queue(&md->wait, &wait);
@@ -1437,13 +1556,10 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
 	up_write(&md->io_lock);
 
 	/* were we interrupted ? */
-	if (pending) {
-		down_write(&md->io_lock);
-		__flush_deferred_io(md);
-		up_write(&md->io_lock);
+	if (r < 0) {
+		dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
 
 		unlock_fs(md);
-		r = -EINTR;
 		goto out; /* pushback list is already flushed, so skip flush */
 	}
 
@@ -1452,16 +1568,12 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
 	set_bit(DMF_SUSPENDED, &md->flags);
 
 flush_and_out:
-	if (r && noflush) {
+	if (r && noflush)
 		/*
 		 * Because there may be already I/Os in the pushback list,
 		 * flush them before return.
 		 */
-		down_write(&md->io_lock);
-		__merge_pushback_list(md);
-		__flush_deferred_io(md);
-		up_write(&md->io_lock);
-	}
+		dm_queue_flush(md, DM_WQ_FLUSH_ALL, NULL);
 
 out:
 	if (r && md->suspended_bdev) {
@@ -1493,9 +1605,7 @@ int dm_resume(struct mapped_device *md)
 	if (r)
 		goto out;
 
-	down_write(&md->io_lock);
-	__flush_deferred_io(md);
-	up_write(&md->io_lock);
+	dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
 
 	unlock_fs(md);