Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into fixes

3 files changed, 174 insertions, 103 deletions

diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index 8873b9b439ff..8618d8996fea 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -402,7 +402,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
                  * our current implementations need.  If we'll ever need
                  * more the interface will need revisiting.
                  */
-                page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+                page = alloc_page(gfp_mask | __GFP_ZERO);
                 if (!page)
                         goto out_free_bio;
                 if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index dd1f1e0e196f..d52d4adc440b 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -505,21 +505,30 @@ static unsigned int lcm(unsigned int a, unsigned int b)
 
 /**
  * blk_stack_limits - adjust queue_limits for stacked devices
- * @t:  the stacking driver limits (top)
- * @b:  the underlying queue limits (bottom)
+ * @t:  the stacking driver limits (top device)
+ * @b:  the underlying queue limits (bottom, component device)
  * @offset:  offset to beginning of data within component device
  *
  * Description:
- *    Merges two queue_limit structs.  Returns 0 if alignment didn't
- *    change.  Returns -1 if adding the bottom device caused
- *    misalignment.
+ *    This function is used by stacking drivers like MD and DM to ensure
+ *    that all component devices have compatible block sizes and
+ *    alignments.  The stacking driver must provide a queue_limits
+ *    struct (top) and then iteratively call the stacking function for
+ *    all component (bottom) devices.  The stacking function will
+ *    attempt to combine the values and ensure proper alignment.
+ *
+ *    Returns 0 if the top and bottom queue_limits are compatible.  The
+ *    top device's block sizes and alignment offsets may be adjusted to
+ *    ensure alignment with the bottom device. If no compatible sizes
+ *    and alignments exist, -1 is returned and the resulting top
+ *    queue_limits will have the misaligned flag set to indicate that
+ *    the alignment_offset is undefined.
  */
 int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
                      sector_t offset)
 {
-        int ret;
-
-        ret = 0;
+        sector_t alignment;
+        unsigned int top, bottom;
 
         t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
         t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
@@ -537,6 +546,22 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
         t->max_segment_size = min_not_zero(t->max_segment_size,
                                            b->max_segment_size);
 
+        alignment = queue_limit_alignment_offset(b, offset);
+
+        /* Bottom device has different alignment.  Check that it is
+         * compatible with the current top alignment.
+         */
+        if (t->alignment_offset != alignment) {
+
+                top = max(t->physical_block_size, t->io_min)
+                        + t->alignment_offset;
+                bottom = max(b->physical_block_size, b->io_min) + alignment;
+
+                /* Verify that top and bottom intervals line up */
+                if (max(top, bottom) & (min(top, bottom) - 1))
+                        t->misaligned = 1;
+        }
+
         t->logical_block_size = max(t->logical_block_size,
                                     b->logical_block_size);
 
@@ -544,47 +569,64 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
                                      b->physical_block_size);
 
         t->io_min = max(t->io_min, b->io_min);
+        t->io_opt = lcm(t->io_opt, b->io_opt);
+
         t->no_cluster |= b->no_cluster;
         t->discard_zeroes_data &= b->discard_zeroes_data;
 
-        /* Bottom device offset aligned? */
-        if (offset &&
-            (offset & (b->physical_block_size - 1)) != b->alignment_offset) {
+        /* Physical block size a multiple of the logical block size? */
+        if (t->physical_block_size & (t->logical_block_size - 1)) {
+                t->physical_block_size = t->logical_block_size;
                 t->misaligned = 1;
-                ret = -1;
         }
 
-        if (offset &&
-            (offset & (b->discard_granularity - 1)) != b->discard_alignment) {
-                t->discard_misaligned = 1;
-                ret = -1;
+        /* Minimum I/O a multiple of the physical block size? */
+        if (t->io_min & (t->physical_block_size - 1)) {
+                t->io_min = t->physical_block_size;
+                t->misaligned = 1;
         }
 
-        /* If top has no alignment offset, inherit from bottom */
-        if (!t->alignment_offset)
-                t->alignment_offset =
-                        b->alignment_offset & (b->physical_block_size - 1);
-
-        if (!t->discard_alignment)
-                t->discard_alignment =
-                        b->discard_alignment & (b->discard_granularity - 1);
-
-        /* Top device aligned on logical block boundary? */
-        if (t->alignment_offset & (t->logical_block_size - 1)) {
+        /* Optimal I/O a multiple of the physical block size? */
+        if (t->io_opt & (t->physical_block_size - 1)) {
+                t->io_opt = 0;
                 t->misaligned = 1;
-                ret = -1;
         }
 
-        /* Find lcm() of optimal I/O size and granularity */
-        t->io_opt = lcm(t->io_opt, b->io_opt);
-        t->discard_granularity = lcm(t->discard_granularity,
-                                     b->discard_granularity);
+        /* Find lowest common alignment_offset */
+        t->alignment_offset = lcm(t->alignment_offset, alignment)
+                & (max(t->physical_block_size, t->io_min) - 1);
+
+        /* Verify that new alignment_offset is on a logical block boundary */
+        if (t->alignment_offset & (t->logical_block_size - 1))
+                t->misaligned = 1;
 
-        /* Verify that optimal I/O size is a multiple of io_min */
-        if (t->io_min && t->io_opt % t->io_min)
-                ret = -1;
+        /* Discard alignment and granularity */
+        if (b->discard_granularity) {
+                unsigned int granularity = b->discard_granularity;
+                offset &= granularity - 1;
+
+                alignment = (granularity + b->discard_alignment - offset)
+                        & (granularity - 1);
+
+                if (t->discard_granularity != 0 &&
+                    t->discard_alignment != alignment) {
+                        top = t->discard_granularity + t->discard_alignment;
+                        bottom = b->discard_granularity + alignment;
+
+                        /* Verify that top and bottom intervals line up */
+                        if (max(top, bottom) & (min(top, bottom) - 1))
+                                t->discard_misaligned = 1;
+                }
+
+                t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
+                                                      b->max_discard_sectors);
+                t->discard_granularity = max(t->discard_granularity,
+                                             b->discard_granularity);
+                t->discard_alignment = lcm(t->discard_alignment, alignment) &
+                        (t->discard_granularity - 1);
+        }
 
-        return ret;
+        return t->misaligned ? -1 : 0;
 }
 EXPORT_SYMBOL(blk_stack_limits);
 
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index cfb0b2f5f63d..918c7fd9aeb1 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -208,8 +208,6 @@ struct cfq_data {
         /* Root service tree for cfq_groups */
         struct cfq_rb_root grp_service_tree;
         struct cfq_group root_group;
-        /* Number of active cfq groups on group service tree */
-        int nr_groups;
 
         /*
          * The priority currently being served
@@ -283,7 +281,7 @@ struct cfq_data {
          */
         struct cfq_queue oom_cfqq;
 
-        unsigned long last_end_sync_rq;
+        unsigned long last_delayed_sync;
 
         /* List of cfq groups being managed on this device*/
         struct hlist_head cfqg_list;
@@ -294,8 +292,7 @@ static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd);
 
 static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg,
                                             enum wl_prio_t prio,
-                                            enum wl_type_t type,
-                                            struct cfq_data *cfqd)
+                                            enum wl_type_t type)
 {
         if (!cfqg)
                 return NULL;
@@ -319,7 +316,6 @@ enum cfqq_state_flags {
         CFQ_CFQQ_FLAG_coop,             /* cfqq is shared */
         CFQ_CFQQ_FLAG_deep,             /* sync cfqq experienced large depth */
         CFQ_CFQQ_FLAG_wait_busy,        /* Waiting for next request */
-        CFQ_CFQQ_FLAG_wait_busy_done,   /* Got new request. Expire the queue */
 };
 
 #define CFQ_CFQQ_FNS(name)                                              \
@@ -348,7 +344,6 @@ CFQ_CFQQ_FNS(sync);
 CFQ_CFQQ_FNS(coop);
 CFQ_CFQQ_FNS(deep);
 CFQ_CFQQ_FNS(wait_busy);
-CFQ_CFQQ_FNS(wait_busy_done);
 #undef CFQ_CFQQ_FNS
 
 #ifdef CONFIG_DEBUG_CFQ_IOSCHED
@@ -844,7 +839,6 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
 
         __cfq_group_service_tree_add(st, cfqg);
         cfqg->on_st = true;
-        cfqd->nr_groups++;
         st->total_weight += cfqg->weight;
 }
 
@@ -865,7 +859,6 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
 
         cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");
         cfqg->on_st = false;
-        cfqd->nr_groups--;
         st->total_weight -= cfqg->weight;
         if (!RB_EMPTY_NODE(&cfqg->rb_node))
                 cfq_rb_erase(&cfqg->rb_node, st);
@@ -1152,7 +1145,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 #endif
 
         service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq),
-                                                cfqq_type(cfqq), cfqd);
+                                                cfqq_type(cfqq));
         if (cfq_class_idle(cfqq)) {
                 rb_key = CFQ_IDLE_DELAY;
                 parent = rb_last(&service_tree->rb);
@@ -1515,9 +1508,6 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
         struct cfq_io_context *cic;
         struct cfq_queue *cfqq;
 
-        /* Deny merge if bio and rq don't belong to same cfq group */
-        if ((RQ_CFQQ(rq))->cfqg != cfq_get_cfqg(cfqd, 0))
-                return false;
         /*
          * Disallow merge of a sync bio into an async request.
          */
@@ -1574,7 +1564,6 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 
         cfq_clear_cfqq_wait_request(cfqq);
         cfq_clear_cfqq_wait_busy(cfqq);
-        cfq_clear_cfqq_wait_busy_done(cfqq);
 
         /*
          * store what was left of this slice, if the queue idled/timed out
@@ -1619,7 +1608,7 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
 {
         struct cfq_rb_root *service_tree =
                 service_tree_for(cfqd->serving_group, cfqd->serving_prio,
-                                        cfqd->serving_type, cfqd);
+                                        cfqd->serving_type);
 
         if (!cfqd->rq_queued)
                 return NULL;
@@ -1678,13 +1667,17 @@ static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
 #define CFQQ_SEEKY(cfqq)        ((cfqq)->seek_mean > CFQQ_SEEK_THR)
 
 static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-                               struct request *rq)
+                               struct request *rq, bool for_preempt)
 {
         sector_t sdist = cfqq->seek_mean;
 
         if (!sample_valid(cfqq->seek_samples))
                 sdist = CFQQ_SEEK_THR;
 
+        /* if seek_mean is big, using it as close criteria is meaningless */
+        if (sdist > CFQQ_SEEK_THR && !for_preempt)
+                sdist = CFQQ_SEEK_THR;
+
         return cfq_dist_from_last(cfqd, rq) <= sdist;
 }
 
@@ -1712,7 +1705,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
          * will contain the closest sector.
          */
         __cfqq = rb_entry(parent, struct cfq_queue, p_node);
-        if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
+        if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false))
                 return __cfqq;
 
         if (blk_rq_pos(__cfqq->next_rq) < sector)
@@ -1723,7 +1716,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
                 return NULL;
 
         __cfqq = rb_entry(node, struct cfq_queue, p_node);
-        if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
+        if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false))
                 return __cfqq;
 
         return NULL;
@@ -1750,6 +1743,12 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
                 return NULL;
 
         /*
+         * Don't search priority tree if it's the only queue in the group.
+         */
+        if (cur_cfqq->cfqg->nr_cfqq == 1)
+                return NULL;
+
+        /*
          * We should notice if some of the queues are cooperating, eg
          * working closely on the same area of the disk. In that case,
          * we can group them together and don't waste time idling.
@@ -1960,8 +1959,7 @@ static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
 }
 
 static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd,
-                                struct cfq_group *cfqg, enum wl_prio_t prio,
-                                bool prio_changed)
+                                struct cfq_group *cfqg, enum wl_prio_t prio)
 {
         struct cfq_queue *queue;
         int i;
@@ -1969,24 +1967,9 @@ static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd,
         unsigned long lowest_key = 0;
         enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD;
 
-        if (prio_changed) {
-                /*
-                 * When priorities switched, we prefer starting
-                 * from SYNC_NOIDLE (first choice), or just SYNC
-                 * over ASYNC
-                 */
-                if (service_tree_for(cfqg, prio, cur_best, cfqd)->count)
-                        return cur_best;
-                cur_best = SYNC_WORKLOAD;
-                if (service_tree_for(cfqg, prio, cur_best, cfqd)->count)
-                        return cur_best;
-
-                return ASYNC_WORKLOAD;
-        }
-
-        for (i = 0; i < 3; ++i) {
-                /* otherwise, select the one with lowest rb_key */
-                queue = cfq_rb_first(service_tree_for(cfqg, prio, i, cfqd));
+        for (i = 0; i <= SYNC_WORKLOAD; ++i) {
+                /* select the one with lowest rb_key */
+                queue = cfq_rb_first(service_tree_for(cfqg, prio, i));
                 if (queue &&
                     (!key_valid || time_before(queue->rb_key, lowest_key))) {
                         lowest_key = queue->rb_key;
@@ -2000,8 +1983,6 @@ static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd,
 
 static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
 {
-        enum wl_prio_t previous_prio = cfqd->serving_prio;
-        bool prio_changed;
         unsigned slice;
         unsigned count;
         struct cfq_rb_root *st;
@@ -2029,24 +2010,19 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
          * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
          * expiration time
          */
-        prio_changed = (cfqd->serving_prio != previous_prio);
-        st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type,
-                                cfqd);
+        st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type);
         count = st->count;
 
         /*
-         * If priority didn't change, check workload expiration,
-         * and that we still have other queues ready
+         * check workload expiration, and that we still have other queues ready
          */
-        if (!prio_changed && count &&
-            !time_after(jiffies, cfqd->workload_expires))
+        if (count && !time_after(jiffies, cfqd->workload_expires))
                 return;
 
         /* otherwise select new workload type */
         cfqd->serving_type =
-                cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio, prio_changed);
-        st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type,
-                                cfqd);
+                cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio);
+        st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type);
         count = st->count;
 
         /*
@@ -2110,7 +2086,9 @@ static void cfq_choose_cfqg(struct cfq_data *cfqd)
                 cfqd->workload_expires = jiffies + cfqg->saved_workload_slice;
                 cfqd->serving_type = cfqg->saved_workload;
                 cfqd->serving_prio = cfqg->saved_serving_prio;
-        }
+        } else
+                cfqd->workload_expires = jiffies - 1;
+
         choose_service_tree(cfqd, cfqg);
 }
 
@@ -2128,14 +2106,35 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
 
         if (!cfqd->rq_queued)
                 return NULL;
+
         /*
-         * The active queue has run out of time, expire it and select new.
+         * We were waiting for group to get backlogged. Expire the queue
          */
-        if ((cfq_slice_used(cfqq) || cfq_cfqq_wait_busy_done(cfqq))
-             && !cfq_cfqq_must_dispatch(cfqq))
+        if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list))
                 goto expire;
 
         /*
+         * The active queue has run out of time, expire it and select new.
+         */
+        if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) {
+                /*
+                 * If slice had not expired at the completion of last request
+                 * we might not have turned on wait_busy flag. Don't expire
+                 * the queue yet. Allow the group to get backlogged.
+                 *
+                 * The very fact that we have used the slice, that means we
+                 * have been idling all along on this queue and it should be
+                 * ok to wait for this request to complete.
+                 */
+                if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list)
+                    && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) {
+                        cfqq = NULL;
+                        goto keep_queue;
+                } else
+                        goto expire;
+        }
+
+        /*
          * The active queue has requests and isn't expired, allow it to
          * dispatch.
          */
@@ -2264,7 +2263,7 @@ static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
          * based on the last sync IO we serviced
          */
         if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) {
-                unsigned long last_sync = jiffies - cfqd->last_end_sync_rq;
+                unsigned long last_sync = jiffies - cfqd->last_delayed_sync;
                 unsigned int depth;
 
                 depth = last_sync / cfqd->cfq_slice[1];
@@ -3117,7 +3116,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
          * if this request is as-good as one we would expect from the
          * current cfqq, let it preempt
          */
-        if (cfq_rq_close(cfqd, cfqq, rq))
+        if (cfq_rq_close(cfqd, cfqq, rq, true))
                 return true;
 
         return false;
@@ -3165,10 +3164,6 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
         cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);
 
         if (cfqq == cfqd->active_queue) {
-                if (cfq_cfqq_wait_busy(cfqq)) {
-                        cfq_clear_cfqq_wait_busy(cfqq);
-                        cfq_mark_cfqq_wait_busy_done(cfqq);
-                }
                 /*
                  * Remember that we saw a request from this process, but
                  * don't start queuing just yet. Otherwise we risk seeing lots
@@ -3183,6 +3178,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                         if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE ||
                             cfqd->busy_queues > 1) {
                                 del_timer(&cfqd->idle_slice_timer);
+                                cfq_clear_cfqq_wait_request(cfqq);
                                 __blk_run_queue(cfqd->queue);
                         } else
                                 cfq_mark_cfqq_must_dispatch(cfqq);
@@ -3251,6 +3247,35 @@ static void cfq_update_hw_tag(struct cfq_data *cfqd)
                 cfqd->hw_tag = 0;
 }
 
+static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+        struct cfq_io_context *cic = cfqd->active_cic;
+
+        /* If there are other queues in the group, don't wait */
+        if (cfqq->cfqg->nr_cfqq > 1)
+                return false;
+
+        if (cfq_slice_used(cfqq))
+                return true;
+
+        /* if slice left is less than think time, wait busy */
+        if (cic && sample_valid(cic->ttime_samples)
+            && (cfqq->slice_end - jiffies < cic->ttime_mean))
+                return true;
+
+        /*
+         * If think times is less than a jiffy than ttime_mean=0 and above
+         * will not be true. It might happen that slice has not expired yet
+         * but will expire soon (4-5 ns) during select_queue(). To cover the
+         * case where think time is less than a jiffy, mark the queue wait
+         * busy if only 1 jiffy is left in the slice.
+         */
+        if (cfqq->slice_end - jiffies == 1)
+                return true;
+
+        return false;
+}
+
 static void cfq_completed_request(struct request_queue *q, struct request *rq)
 {
         struct cfq_queue *cfqq = RQ_CFQQ(rq);
@@ -3273,7 +3298,8 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
 
         if (sync) {
                 RQ_CIC(rq)->last_end_request = now;
-                cfqd->last_end_sync_rq = now;
+                if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now))
+                        cfqd->last_delayed_sync = now;
         }
 
         /*
@@ -3289,11 +3315,10 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
                 }
 
                 /*
-                 * If this queue consumed its slice and this is last queue
-                 * in the group, wait for next request before we expire
-                 * the queue
+                 * Should we wait for next request to come in before we expire
+                 * the queue.
                  */
-                if (cfq_slice_used(cfqq) && cfqq->cfqg->nr_cfqq == 1) {
+                if (cfq_should_wait_busy(cfqd, cfqq)) {
                         cfqq->slice_end = jiffies + cfqd->cfq_slice_idle;
                         cfq_mark_cfqq_wait_busy(cfqq);
                 }
@@ -3711,7 +3736,11 @@ static void *cfq_init_queue(struct request_queue *q)
         cfqd->cfq_latency = 1;
         cfqd->cfq_group_isolation = 0;
         cfqd->hw_tag = -1;
-        cfqd->last_end_sync_rq = jiffies;
+        /*
+         * we optimistically start assuming sync ops weren't delayed in last
+         * second, in order to have larger depth for async operations.
+         */
+        cfqd->last_delayed_sync = jiffies - HZ;
         INIT_RCU_HEAD(&cfqd->rcu);
         return cfqd;
 }