[GIT PULL] block fixes for 3.0-rc4

From: Jens Axboe
Date: Fri Jun 24 2011 - 02:59:04 EST

Hi Linus,

A small collection of fixes for the current cycle. Most of these
are stable material as well.

- Fix a long standing race around the ioc lookup cache in cfq-iosched.
Very elusive bug, as the window is really small. Seemed to reproduce
most easily on single CPU systems.

- Add REQ_SECURE to the shared bio/rq mask.

- Bad types in throtl_log() prints.

- A small series of continued fixes disk event notification and bdev
claiming from Tejun.


Please pull.


git://git.kernel.dk/linux-block.git for-linus

Jens Axboe (1):
cfq-iosched: fix locking around ioc->ioc_data assignment

Joe Perches (1):
block: Add __attribute__((format(printf...) and fix fallout

Namhyung Kim (1):
block: add REQ_SECURE to REQ_COMMON_MASK

Tejun Heo (4):
block: don't use non-syncing event blocking in disk_check_events()
block: remove non-syncing __disk_block_events() and fold it into disk_block_events()
block: make disk_block_events() properly wait for work cancellation
block: use the passed in @bdev when claiming if partno is zero

block/blk-throttle.c | 4 +-
block/cfq-iosched.c | 16 +++++---
block/genhd.c | 79 ++++++++++++++++++++++++------------------
fs/block_dev.c | 14 +++++++-
include/linux/blk_types.h | 2 +-
include/linux/blktrace_api.h | 3 +-
6 files changed, 73 insertions(+), 45 deletions(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index a62be8d..3689f83 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -927,7 +927,7 @@ static int throtl_dispatch(struct request_queue *q)

bio_list_init(&bio_list_on_stack);

- throtl_log(td, "dispatch nr_queued=%lu read=%u write=%u",
+ throtl_log(td, "dispatch nr_queued=%d read=%u write=%u",
total_nr_queued(td), td->nr_queued[READ],
td->nr_queued[WRITE]);

@@ -1204,7 +1204,7 @@ int blk_throtl_bio(struct request_queue *q, struct bio **biop)
}

queue_bio:
- throtl_log_tg(td, tg, "[%c] bio. bdisp=%u sz=%u bps=%llu"
+ throtl_log_tg(td, tg, "[%c] bio. bdisp=%llu sz=%u bps=%llu"
" iodisp=%u iops=%u queued=%d/%d",
rw == READ ? 'R' : 'W',
tg->bytes_disp[rw], bio->bi_size, tg->bps[rw],
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 3c7b537..f379943 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -988,9 +988,10 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,

cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime,
st->min_vdisktime);
- cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u disp=%u charge=%u iops=%u"
- " sect=%u", used_sl, cfqq->slice_dispatch, charge,
- iops_mode(cfqd), cfqq->nr_sectors);
+ cfq_log_cfqq(cfqq->cfqd, cfqq,
+ "sl_used=%u disp=%u charge=%u iops=%u sect=%lu",
+ used_sl, cfqq->slice_dispatch, charge,
+ iops_mode(cfqd), cfqq->nr_sectors);
cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl,
unaccounted_sl);
cfq_blkiocg_set_start_empty_time(&cfqg->blkg);
@@ -2023,8 +2024,8 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
*/
if (sample_valid(cic->ttime_samples) &&
(cfqq->slice_end - jiffies < cic->ttime_mean)) {
- cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%d",
- cic->ttime_mean);
+ cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%lu",
+ cic->ttime_mean);
return;
}

@@ -2772,8 +2773,11 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
smp_wmb();
cic->key = cfqd_dead_key(cfqd);

- if (ioc->ioc_data == cic)
+ if (rcu_dereference(ioc->ioc_data) == cic) {
+ spin_lock(&ioc->lock);
rcu_assign_pointer(ioc->ioc_data, NULL);
+ spin_unlock(&ioc->lock);
+ }

if (cic->cfqq[BLK_RW_ASYNC]) {
cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);
diff --git a/block/genhd.c b/block/genhd.c
index 95822ae..3608289 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1371,6 +1371,7 @@ struct disk_events {
struct gendisk *disk; /* the associated disk */
spinlock_t lock;

+ struct mutex block_mutex; /* protects blocking */
int block; /* event blocking depth */
unsigned int pending; /* events already sent out */
unsigned int clearing; /* events being cleared */
@@ -1414,22 +1415,44 @@ static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
return msecs_to_jiffies(intv_msecs);
}

-static void __disk_block_events(struct gendisk *disk, bool sync)
+/**
+ * disk_block_events - block and flush disk event checking
+ * @disk: disk to block events for
+ *
+ * On return from this function, it is guaranteed that event checking
+ * isn't in progress and won't happen until unblocked by
+ * disk_unblock_events(). Events blocking is counted and the actual
+ * unblocking happens after the matching number of unblocks are done.
+ *
+ * Note that this intentionally does not block event checking from
+ * disk_clear_events().
+ *
+ * CONTEXT:
+ * Might sleep.
+ */
+void disk_block_events(struct gendisk *disk)
{
struct disk_events *ev = disk->ev;
unsigned long flags;
bool cancel;

+ if (!ev)
+ return;
+
+ /*
+ * Outer mutex ensures that the first blocker completes canceling
+ * the event work before further blockers are allowed to finish.
+ */
+ mutex_lock(&ev->block_mutex);
+
spin_lock_irqsave(&ev->lock, flags);
cancel = !ev->block++;
spin_unlock_irqrestore(&ev->lock, flags);

- if (cancel) {
- if (sync)
- cancel_delayed_work_sync(&disk->ev->dwork);
- else
- cancel_delayed_work(&disk->ev->dwork);
- }
+ if (cancel)
+ cancel_delayed_work_sync(&disk->ev->dwork);
+
+ mutex_unlock(&ev->block_mutex);
}

static void __disk_unblock_events(struct gendisk *disk, bool check_now)
@@ -1461,27 +1484,6 @@ out_unlock:
}

/**
- * disk_block_events - block and flush disk event checking
- * @disk: disk to block events for
- *
- * On return from this function, it is guaranteed that event checking
- * isn't in progress and won't happen until unblocked by
- * disk_unblock_events(). Events blocking is counted and the actual
- * unblocking happens after the matching number of unblocks are done.
- *
- * Note that this intentionally does not block event checking from
- * disk_clear_events().
- *
- * CONTEXT:
- * Might sleep.
- */
-void disk_block_events(struct gendisk *disk)
-{
- if (disk->ev)
- __disk_block_events(disk, true);
-}
-
-/**
* disk_unblock_events - unblock disk event checking
* @disk: disk to unblock events for
*
@@ -1508,10 +1510,18 @@ void disk_unblock_events(struct gendisk *disk)
*/
void disk_check_events(struct gendisk *disk)
{
- if (disk->ev) {
- __disk_block_events(disk, false);
- __disk_unblock_events(disk, true);
+ struct disk_events *ev = disk->ev;
+ unsigned long flags;
+
+ if (!ev)
+ return;
+
+ spin_lock_irqsave(&ev->lock, flags);
+ if (!ev->block) {
+ cancel_delayed_work(&ev->dwork);
+ queue_delayed_work(system_nrt_wq, &ev->dwork, 0);
}
+ spin_unlock_irqrestore(&ev->lock, flags);
}
EXPORT_SYMBOL_GPL(disk_check_events);

@@ -1546,7 +1556,7 @@ unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
spin_unlock_irq(&ev->lock);

/* uncondtionally schedule event check and wait for it to finish */
- __disk_block_events(disk, true);
+ disk_block_events(disk);
queue_delayed_work(system_nrt_wq, &ev->dwork, 0);
flush_delayed_work(&ev->dwork);
__disk_unblock_events(disk, false);
@@ -1664,7 +1674,7 @@ static ssize_t disk_events_poll_msecs_store(struct device *dev,
if (intv < 0 && intv != -1)
return -EINVAL;

- __disk_block_events(disk, true);
+ disk_block_events(disk);
disk->ev->poll_msecs = intv;
__disk_unblock_events(disk, true);

@@ -1750,6 +1760,7 @@ static void disk_add_events(struct gendisk *disk)
INIT_LIST_HEAD(&ev->node);
ev->disk = disk;
spin_lock_init(&ev->lock);
+ mutex_init(&ev->block_mutex);
ev->block = 1;
ev->poll_msecs = -1;
INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
@@ -1770,7 +1781,7 @@ static void disk_del_events(struct gendisk *disk)
if (!disk->ev)
return;

- __disk_block_events(disk, true);
+ disk_block_events(disk);

mutex_lock(&disk_events_mutex);
list_del_init(&disk->ev->node);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1a2421f..610e8e0 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -762,7 +762,19 @@ static struct block_device *bd_start_claiming(struct block_device *bdev,
if (!disk)
return ERR_PTR(-ENXIO);

- whole = bdget_disk(disk, 0);
+ /*
+ * Normally, @bdev should equal what's returned from bdget_disk()
+ * if partno is 0; however, some drivers (floppy) use multiple
+ * bdev's for the same physical device and @bdev may be one of the
+ * aliases. Keep @bdev if partno is 0. This means claimer
+ * tracking is broken for those devices but it has always been that
+ * way.
+ */
+ if (partno)
+ whole = bdget_disk(disk, 0);
+ else
+ whole = bdgrab(bdev);
+
module_put(disk->fops->owner);
put_disk(disk);
if (!whole)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 2a7cea5..6395692 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -167,7 +167,7 @@ enum rq_flag_bits {
(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
#define REQ_COMMON_MASK \
(REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_DISCARD | \
- REQ_NOIDLE | REQ_FLUSH | REQ_FUA)
+ REQ_NOIDLE | REQ_FLUSH | REQ_FUA | REQ_SECURE)
#define REQ_CLONE_MASK REQ_COMMON_MASK

#define REQ_RAHEAD (1 << __REQ_RAHEAD)
diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index b22fb0d..8c7c2de 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -169,7 +169,8 @@ extern void blk_trace_shutdown(struct request_queue *);
extern int do_blk_trace_setup(struct request_queue *q, char *name,
dev_t dev, struct block_device *bdev,
struct blk_user_trace_setup *buts);
-extern void __trace_note_message(struct blk_trace *, const char *fmt, ...);
+extern __attribute__((format(printf, 2, 3)))
+void __trace_note_message(struct blk_trace *, const char *fmt, ...);

/**
* blk_add_trace_msg - Add a (simple) message to the blktrace stream

--
Jens Axboe

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/