9 files changed, 143 insertions, 95 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index c3df30cfb3fc..10e8a64a5a5b 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 8681cd6f9911..b92f5b0866b0 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 972a63f848fb..69185ea9fae2 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 59173a69ebdf..9ac82dde99dd 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 88a776fa0ef6..db831efbdbbd 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 1c91a176b9ae..6a642098e5c3 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 d4ba79248a27..daf9685b861c 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 f362a8553777..75c8dde58c55 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 56becf373c58..dbd50fabe4c7 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)