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Merge branch 'for-3.19/core' of git://git.kernel.dk/linux-block

Browse Source 
Pull block driver core update from Jens Axboe:
 "This is the pull request for the core block IO changes for 3.19.  Not
  a huge round this time, mostly lots of little good fixes:

   - Fix a bug in sysfs blktrace interface causing a NULL pointer
     dereference, when enabled/disabled through that API.  From Arianna
     Avanzini.

   - Various updates/fixes/improvements for blk-mq:

        - A set of updates from Bart, mostly fixing buts in the tag
          handling.

        - Cleanup/code consolidation from Christoph.

        - Extend queue_rq API to be able to handle batching issues of IO
          requests. NVMe will utilize this shortly. From me.

        - A few tag and request handling updates from me.

        - Cleanup of the preempt handling for running queues from Paolo.

        - Prevent running of unmapped hardware queues from Ming Lei.

        - Move the kdump memory limiting check to be in the correct
          location, from Shaohua.

        - Initialize all software queues at init time from Takashi. This
          prevents a kobject warning when CPUs are brought online that
          weren't online when a queue was registered.

   - Single writeback fix for I_DIRTY clearing from Tejun.  Queued with
     the core IO changes, since it's just a single fix.

   - Version X of the __bio_add_page() segment addition retry from
     Maurizio.  Hope the Xth time is the charm.

   - Documentation fixup for IO scheduler merging from Jan.

   - Introduce (and use) generic IO stat accounting helpers for non-rq
     drivers, from Gu Zheng.

   - Kill off artificial limiting of max sectors in a request from
     Christoph"

* 'for-3.19/core' of git://git.kernel.dk/linux-block: (26 commits)
  bio: modify __bio_add_page() to accept pages that don't start a new segment
  blk-mq: Fix uninitialized kobject at CPU hotplugging
  blktrace: don't let the sysfs interface remove trace from running list
  blk-mq: Use all available hardware queues
  blk-mq: Micro-optimize bt_get()
  blk-mq: Fix a race between bt_clear_tag() and bt_get()
  blk-mq: Avoid that __bt_get_word() wraps multiple times
  blk-mq: Fix a use-after-free
  blk-mq: prevent unmapped hw queue from being scheduled
  blk-mq: re-check for available tags after running the hardware queue
  blk-mq: fix hang in bt_get()
  blk-mq: move the kdump check to blk_mq_alloc_tag_set
  blk-mq: cleanup tag free handling
  blk-mq: use 'nr_cpu_ids' as highest CPU ID count for hwq <-> cpu map
  blk: introduce generic io stat accounting help function
  blk-mq: handle the single queue case in blk_mq_hctx_next_cpu
  genhd: check for int overflow in disk_expand_part_tbl()
  blk-mq: add blk_mq_free_hctx_request()
  blk-mq: export blk_mq_free_request()
  blk-mq: use get_cpu/put_cpu instead of preempt_disable/preempt_enable
  ...
This commit is contained in:
Linus Torvalds
2014-12-13 14:14:23 -08:00
parent 8f4385d590 fcbf6a087a
commit caf292ae5b
21 changed files with 255 additions and 146 deletions
Download Patch File Download Diff File Expand all files Collapse all files
block/blk-mq-tag.c
+31 -29
View File
@@ -137,6 +137,7 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
static int __bt_get_word(struct blk_align_bitmap *bm, unsigned int last_tag)
{
int tag, org_last_tag, end;
bool wrap = last_tag != 0;
org_last_tag = last_tag;
end = bm->depth;
@@ -148,15 +149,16 @@ restart:
* We started with an offset, start from 0 to
* exhaust the map.
*/
if (org_last_tag && last_tag) {
end = last_tag;
if (wrap) {
wrap = false;
end = org_last_tag;
last_tag = 0;
goto restart;
}
return -1;
}
last_tag = tag + 1;
} while (test_and_set_bit_lock(tag, &bm->word));
} while (test_and_set_bit(tag, &bm->word));
return tag;
}
@@ -246,14 +248,29 @@ static int bt_get(struct blk_mq_alloc_data *data,
if (!(data->gfp & __GFP_WAIT))
return -1;
bs = bt_wait_ptr(bt, hctx);
do {
bs = bt_wait_ptr(bt, hctx);
prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE);
tag = __bt_get(hctx, bt, last_tag);
if (tag != -1)
break;
/*
* We're out of tags on this hardware queue, kick any
* pending IO submits before going to sleep waiting for
* some to complete.
*/
blk_mq_run_hw_queue(hctx, false);
/*
* Retry tag allocation after running the hardware queue,
* as running the queue may also have found completions.
*/
tag = __bt_get(hctx, bt, last_tag);
if (tag != -1)
break;
blk_mq_put_ctx(data->ctx);
io_schedule();
@@ -268,8 +285,6 @@ static int bt_get(struct blk_mq_alloc_data *data,
hctx = data->hctx;
bt = &hctx->tags->bitmap_tags;
}
finish_wait(&bs->wait, &wait);
bs = bt_wait_ptr(bt, hctx);
} while (1);
finish_wait(&bs->wait, &wait);
@@ -340,11 +355,10 @@ static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag)
struct bt_wait_state *bs;
int wait_cnt;
/*
* The unlock memory barrier need to order access to req in free
* path and clearing tag bit
*/
clear_bit_unlock(TAG_TO_BIT(bt, tag), &bt->map[index].word);
clear_bit(TAG_TO_BIT(bt, tag), &bt->map[index].word);
/* Ensure that the wait list checks occur after clear_bit(). */
smp_mb();
bs = bt_wake_ptr(bt);
if (!bs)
@@ -360,21 +374,6 @@ static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag)
}
}
static void __blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag)
{
BUG_ON(tag >= tags->nr_tags);
bt_clear_tag(&tags->bitmap_tags, tag);
}
static void __blk_mq_put_reserved_tag(struct blk_mq_tags *tags,
unsigned int tag)
{
BUG_ON(tag >= tags->nr_reserved_tags);
bt_clear_tag(&tags->breserved_tags, tag);
}
void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag,
unsigned int *last_tag)
{
@@ -383,10 +382,13 @@ void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag,
if (tag >= tags->nr_reserved_tags) {
const int real_tag = tag - tags->nr_reserved_tags;
__blk_mq_put_tag(tags, real_tag);
BUG_ON(real_tag >= tags->nr_tags);
bt_clear_tag(&tags->bitmap_tags, real_tag);
*last_tag = real_tag;
} else
__blk_mq_put_reserved_tag(tags, tag);
} else {
BUG_ON(tag >= tags->nr_reserved_tags);
bt_clear_tag(&tags->breserved_tags, tag);
}
}
static void bt_for_each(struct blk_mq_hw_ctx *hctx,