Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  Block: use round_jiffies_up()
  Add round_jiffies_up and related routines
  block: fix __blkdev_get() for removable devices
  generic-ipi: fix the smp_mb() placement
  blk: move blk_delete_timer call in end_that_request_last
  block: add timer on blkdev_dequeue_request() not elv_next_request()
  bio: define __BIOVEC_PHYS_MERGEABLE
  block: remove unused ll_new_mergeable()

9 files changed, 143 insertions, 95 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index c3df30c..10e8a64 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1770,8 +1770,6 @@ static void end_that_request_last(struct request *req, int error)
 {
 	struct gendisk *disk = req->rq_disk;
 
-	blk_delete_timer(req);
-
 	if (blk_rq_tagged(req))
 		blk_queue_end_tag(req->q, req);
 
@@ -1781,6 +1779,8 @@ static void end_that_request_last(struct request *req, int error)
 	if (unlikely(laptop_mode) && blk_fs_request(req))
 		laptop_io_completion();
 
+	blk_delete_timer(req);
+
 	/*
 	 * Account IO completion.  bar_rq isn't accounted as a normal
 	 * IO on queueing nor completion.  Accounting the containing
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 8681cd6..b92f5b0 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -222,27 +222,6 @@ new_segment:
 }
 EXPORT_SYMBOL(blk_rq_map_sg);
 
-static inline int ll_new_mergeable(struct request_queue *q,
-				   struct request *req,
-				   struct bio *bio)
-{
-	int nr_phys_segs = bio_phys_segments(q, bio);
-
-	if (req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) {
-		req->cmd_flags |= REQ_NOMERGE;
-		if (req == q->last_merge)
-			q->last_merge = NULL;
-		return 0;
-	}
-
-	/*
-	 * A hw segment is just getting larger, bump just the phys
-	 * counter.
-	 */
-	req->nr_phys_segments += nr_phys_segs;
-	return 1;
-}
-
 static inline int ll_new_hw_segment(struct request_queue *q,
 				    struct request *req,
 				    struct bio *bio)
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 972a63f..69185ea 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -75,14 +75,7 @@ void blk_delete_timer(struct request *req)
 {
 	struct request_queue *q = req->q;
 
-	/*
-	 * Nothing to detach
-	 */
-	if (!q->rq_timed_out_fn || !req->deadline)
-		return;
-
 	list_del_init(&req->timeout_list);
-
 	if (list_empty(&q->timeout_list))
 		del_timer(&q->timeout);
 }
@@ -142,7 +135,7 @@ void blk_rq_timed_out_timer(unsigned long data)
 	}
 
 	if (next_set && !list_empty(&q->timeout_list))
-		mod_timer(&q->timeout, round_jiffies(next));
+		mod_timer(&q->timeout, round_jiffies_up(next));
 
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }
@@ -198,17 +191,10 @@ void blk_add_timer(struct request *req)
 
 	/*
 	 * If the timer isn't already pending or this timeout is earlier
-	 * than an existing one, modify the timer. Round to next nearest
+	 * than an existing one, modify the timer. Round up to next nearest
 	 * second.
 	 */
-	expiry = round_jiffies(req->deadline);
-
-	/*
-	 * We use ->deadline == 0 to detect whether a timer was added or
-	 * not, so just increase to next jiffy for that specific case
-	 */
-	if (unlikely(!req->deadline))
-		req->deadline = 1;
+	expiry = round_jiffies_up(req->deadline);
 
 	if (!timer_pending(&q->timeout) ||
 	    time_before(expiry, q->timeout.expires))
diff --git a/block/elevator.c b/block/elevator.c
index 59173a6..9ac82dd 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -773,12 +773,6 @@ struct request *elv_next_request(struct request_queue *q)
 			 */
 			rq->cmd_flags |= REQ_STARTED;
 			blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
-
-			/*
-			 * We are now handing the request to the hardware,
-			 * add the timeout handler
-			 */
-			blk_add_timer(rq);
 		}
 
 		if (!q->boundary_rq || q->boundary_rq == rq) {
@@ -850,6 +844,12 @@ void elv_dequeue_request(struct request_queue *q, struct request *rq)
 	 */
 	if (blk_account_rq(rq))
 		q->in_flight++;
+
+	/*
+	 * We are now handing the request to the hardware, add the
+	 * timeout handler.
+	 */
+	blk_add_timer(rq);
 }
 EXPORT_SYMBOL(elv_dequeue_request);
 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 88a776f..db831ef 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -986,7 +986,6 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
 static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 {
 	struct gendisk *disk;
-	struct hd_struct *part = NULL;
 	int ret;
 	int partno;
 	int perm = 0;
@@ -1004,24 +1003,25 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 		return ret;
 	}
 
-	ret = -ENXIO;
-
 	lock_kernel();
 
+	ret = -ENXIO;
 	disk = get_gendisk(bdev->bd_dev, &partno);
 	if (!disk)
 		goto out_unlock_kernel;
-	part = disk_get_part(disk, partno);
-	if (!part)
-		goto out_unlock_kernel;
 
 	mutex_lock_nested(&bdev->bd_mutex, for_part);
 	if (!bdev->bd_openers) {
 		bdev->bd_disk = disk;
-		bdev->bd_part = part;
 		bdev->bd_contains = bdev;
 		if (!partno) {
 			struct backing_dev_info *bdi;
+
+			ret = -ENXIO;
+			bdev->bd_part = disk_get_part(disk, partno);
+			if (!bdev->bd_part)
+				goto out_clear;
+
 			if (disk->fops->open) {
 				ret = disk->fops->open(bdev, mode);
 				if (ret)
@@ -1049,18 +1049,17 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 			bdev->bd_contains = whole;
 			bdev->bd_inode->i_data.backing_dev_info =
 			   whole->bd_inode->i_data.backing_dev_info;
+			bdev->bd_part = disk_get_part(disk, partno);
 			if (!(disk->flags & GENHD_FL_UP) ||
-			    !part || !part->nr_sects) {
+			    !bdev->bd_part || !bdev->bd_part->nr_sects) {
 				ret = -ENXIO;
 				goto out_clear;
 			}
-			bd_set_size(bdev, (loff_t)part->nr_sects << 9);
+			bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
 		}
 	} else {
-		disk_put_part(part);
 		put_disk(disk);
 		module_put(disk->fops->owner);
-		part = NULL;
 		disk = NULL;
 		if (bdev->bd_contains == bdev) {
 			if (bdev->bd_disk->fops->open) {
@@ -1080,6 +1079,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 	return 0;
 
  out_clear:
+	disk_put_part(bdev->bd_part);
 	bdev->bd_disk = NULL;
 	bdev->bd_part = NULL;
 	bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
@@ -1091,7 +1091,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
  out_unlock_kernel:
 	unlock_kernel();
 
-	disk_put_part(part);
 	if (disk)
 		module_put(disk->fops->owner);
 	put_disk(disk);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 1c91a17..6a64209 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -236,12 +236,16 @@ static inline void *bio_data(struct bio *bio)
 #define __BVEC_END(bio)		bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
 #define __BVEC_START(bio)	bio_iovec_idx((bio), (bio)->bi_idx)
 
+/* Default implementation of BIOVEC_PHYS_MERGEABLE */
+#define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
+	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
+
 /*
  * allow arch override, for eg virtualized architectures (put in asm/io.h)
  */
 #ifndef BIOVEC_PHYS_MERGEABLE
 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
-	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
+	__BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 #endif
 
 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
diff --git a/include/linux/timer.h b/include/linux/timer.h
index d4ba792..daf9685 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -186,4 +186,9 @@ unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 unsigned long round_jiffies(unsigned long j);
 unsigned long round_jiffies_relative(unsigned long j);
 
+unsigned long __round_jiffies_up(unsigned long j, int cpu);
+unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
+unsigned long round_jiffies_up(unsigned long j);
+unsigned long round_jiffies_up_relative(unsigned long j);
+
 #endif
diff --git a/kernel/smp.c b/kernel/smp.c
index f362a85..75c8dde 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -51,10 +51,6 @@ static void csd_flag_wait(struct call_single_data *data)
 {
 	/* Wait for response */
 	do {
-		/*
-		 * We need to see the flags store in the IPI handler
-		 */
-		smp_mb();
 		if (!(data->flags & CSD_FLAG_WAIT))
 			break;
 		cpu_relax();
@@ -76,6 +72,11 @@ static void generic_exec_single(int cpu, struct call_single_data *data)
 	list_add_tail(&data->list, &dst->list);
 	spin_unlock_irqrestore(&dst->lock, flags);
 
+	/*
+	 * Make the list addition visible before sending the ipi.
+	 */
+	smp_mb();
+
 	if (ipi)
 		arch_send_call_function_single_ipi(cpu);
 
@@ -157,7 +158,7 @@ void generic_smp_call_function_single_interrupt(void)
 	 * Need to see other stores to list head for checking whether
 	 * list is empty without holding q->lock
 	 */
-	smp_mb();
+	smp_read_barrier_depends();
 	while (!list_empty(&q->list)) {
 		unsigned int data_flags;
 
@@ -191,7 +192,7 @@ void generic_smp_call_function_single_interrupt(void)
 		/*
 		 * See comment on outer loop
 		 */
-		smp_mb();
+		smp_read_barrier_depends();
 	}
 }
 
@@ -370,6 +371,11 @@ int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info,
 	list_add_tail_rcu(&data->csd.list, &call_function_queue);
 	spin_unlock_irqrestore(&call_function_lock, flags);
 
+	/*
+	 * Make the list addition visible before sending the ipi.
+	 */
+	smp_mb();
+
 	/* Send a message to all CPUs in the map */
 	arch_send_call_function_ipi(mask);
 
diff --git a/kernel/timer.c b/kernel/timer.c
index 56becf3..dbd50fa 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -112,27 +112,8 @@ timer_set_base(struct timer_list *timer, struct tvec_base *new_base)
 				      tbase_get_deferrable(timer->base));
 }
 
-/**
- * __round_jiffies - function to round jiffies to a full second
- * @j: the time in (absolute) jiffies that should be rounded
- * @cpu: the processor number on which the timeout will happen
- *
- * __round_jiffies() rounds an absolute time in the future (in jiffies)
- * up or down to (approximately) full seconds. This is useful for timers
- * for which the exact time they fire does not matter too much, as long as
- * they fire approximately every X seconds.
- *
- * By rounding these timers to whole seconds, all such timers will fire
- * at the same time, rather than at various times spread out. The goal
- * of this is to have the CPU wake up less, which saves power.
- *
- * The exact rounding is skewed for each processor to avoid all
- * processors firing at the exact same time, which could lead
- * to lock contention or spurious cache line bouncing.
- *
- * The return value is the rounded version of the @j parameter.
- */
-unsigned long __round_jiffies(unsigned long j, int cpu)
+static unsigned long round_jiffies_common(unsigned long j, int cpu,
+		bool force_up)
 {
 	int rem;
 	unsigned long original = j;
@@ -154,8 +135,9 @@ unsigned long __round_jiffies(unsigned long j, int cpu)
 	 * due to delays of the timer irq, long irq off times etc etc) then
 	 * we should round down to the whole second, not up. Use 1/4th second
 	 * as cutoff for this rounding as an extreme upper bound for this.
+	 * But never round down if @force_up is set.
 	 */
-	if (rem < HZ/4) /* round down */
+	if (rem < HZ/4 && !force_up) /* round down */
 		j = j - rem;
 	else /* round up */
 		j = j - rem + HZ;
@@ -167,6 +149,31 @@ unsigned long __round_jiffies(unsigned long j, int cpu)
 		return original;
 	return j;
 }
+
+/**
+ * __round_jiffies - function to round jiffies to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * __round_jiffies() rounds an absolute time in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The exact rounding is skewed for each processor to avoid all
+ * processors firing at the exact same time, which could lead
+ * to lock contention or spurious cache line bouncing.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long __round_jiffies(unsigned long j, int cpu)
+{
+	return round_jiffies_common(j, cpu, false);
+}
 EXPORT_SYMBOL_GPL(__round_jiffies);
 
 /**
@@ -191,13 +198,10 @@ EXPORT_SYMBOL_GPL(__round_jiffies);
  */
 unsigned long __round_jiffies_relative(unsigned long j, int cpu)
 {
-	/*
-	 * In theory the following code can skip a jiffy in case jiffies
-	 * increments right between the addition and the later subtraction.
-	 * However since the entire point of this function is to use approximate
-	 * timeouts, it's entirely ok to not handle that.
-	 */
-	return  __round_jiffies(j + jiffies, cpu) - jiffies;
+	unsigned long j0 = jiffies;
+
+	/* Use j0 because jiffies might change while we run */
+	return round_jiffies_common(j + j0, cpu, false) - j0;
 }
 EXPORT_SYMBOL_GPL(__round_jiffies_relative);
 
@@ -218,7 +222,7 @@ EXPORT_SYMBOL_GPL(__round_jiffies_relative);
  */
 unsigned long round_jiffies(unsigned long j)
 {
-	return __round_jiffies(j, raw_smp_processor_id());
+	return round_jiffies_common(j, raw_smp_processor_id(), false);
 }
 EXPORT_SYMBOL_GPL(round_jiffies);
 
@@ -243,6 +247,71 @@ unsigned long round_jiffies_relative(unsigned long j)
 }
 EXPORT_SYMBOL_GPL(round_jiffies_relative);
 
+/**
+ * __round_jiffies_up - function to round jiffies up to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * This is the same as __round_jiffies() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long __round_jiffies_up(unsigned long j, int cpu)
+{
+	return round_jiffies_common(j, cpu, true);
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_up);
+
+/**
+ * __round_jiffies_up_relative - function to round jiffies up to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * This is the same as __round_jiffies_relative() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
+{
+	unsigned long j0 = jiffies;
+
+	/* Use j0 because jiffies might change while we run */
+	return round_jiffies_common(j + j0, cpu, true) - j0;
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);
+
+/**
+ * round_jiffies_up - function to round jiffies up to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ *
+ * This is the same as round_jiffies() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long round_jiffies_up(unsigned long j)
+{
+	return round_jiffies_common(j, raw_smp_processor_id(), true);
+}
+EXPORT_SYMBOL_GPL(round_jiffies_up);
+
+/**
+ * round_jiffies_up_relative - function to round jiffies up to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ *
+ * This is the same as round_jiffies_relative() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long round_jiffies_up_relative(unsigned long j)
+{
+	return __round_jiffies_up_relative(j, raw_smp_processor_id());
+}
+EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
+
 
 static inline void set_running_timer(struct tvec_base *base,
 					struct timer_list *timer)