[GIT PULL] Important fixes for 2.6.38

From: Jens Axboe
Date: Thu Mar 03 2011 - 12:01:46 EST

Hi Linus,

This is a LOT larger than I would like at this point in time,
but all of them are fixing important bugs. Well except the kerneldoc
change, but that is harmless.

- The block BKL conversion introduced a deadlock in loop, since the
mutex isn't recursive like the BKL is. This private mutex isn't
needed, so get rid of it.

- Fix a problem where blktrace does not detect the right request type.
So we miss things like a SYNC tag.

- Fix a bug triggering on IDE due to how we handle flush completions.
This is causing crashes.

- Fix a deadlock in the throttling code due to using kblockd.

Please pull!

git://git.kernel.dk/linux-2.6-block.git for-linus

Ben Hutchings (1):
block: fix kernel-doc format for blkdev_issue_zeroout

Petr Uzel (1):
block: kill loop_mutex

Tao Ma (1):
blktrace: Remove blk_fill_rwbs_rq.

Tejun Heo (2):
block: add @force_kblockd to __blk_run_queue()
block: blk-flush shouldn't call directly into q->request_fn() __blk_run_queue()

Vivek Goyal (1):
blk-throttle: Do not use kblockd workqueue for throtl work

block/blk-core.c | 18 ++++++------------
block/blk-flush.c | 8 +++++---
block/blk-lib.c | 2 +-
block/blk-throttle.c | 29 ++++++++++++++++++-----------
block/cfq-iosched.c | 6 +++---
block/elevator.c | 4 ++--
drivers/block/loop.c | 5 -----
drivers/scsi/scsi_lib.c | 2 +-
drivers/scsi/scsi_transport_fc.c | 2 +-
include/linux/blkdev.h | 5 +----
include/linux/blktrace_api.h | 1 -
include/trace/events/block.h | 6 +++---
kernel/trace/blktrace.c | 16 ----------------
13 files changed, 41 insertions(+), 63 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 2f4002f..518dd42 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -352,7 +352,7 @@ void blk_start_queue(struct request_queue *q)
WARN_ON(!irqs_disabled());

queue_flag_clear(QUEUE_FLAG_STOPPED, q);
- __blk_run_queue(q);
+ __blk_run_queue(q, false);
}
EXPORT_SYMBOL(blk_start_queue);

@@ -403,13 +403,14 @@ EXPORT_SYMBOL(blk_sync_queue);
/**
* __blk_run_queue - run a single device queue
* @q: The queue to run
+ * @force_kblockd: Don't run @q->request_fn directly. Use kblockd.
*
* Description:
* See @blk_run_queue. This variant must be called with the queue lock
* held and interrupts disabled.
*
*/
-void __blk_run_queue(struct request_queue *q)
+void __blk_run_queue(struct request_queue *q, bool force_kblockd)
{
blk_remove_plug(q);

@@ -423,7 +424,7 @@ void __blk_run_queue(struct request_queue *q)
* Only recurse once to avoid overrunning the stack, let the unplug
* handling reinvoke the handler shortly if we already got there.
*/
- if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
+ if (!force_kblockd && !queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
q->request_fn(q);
queue_flag_clear(QUEUE_FLAG_REENTER, q);
} else {
@@ -446,7 +447,7 @@ void blk_run_queue(struct request_queue *q)
unsigned long flags;

spin_lock_irqsave(q->queue_lock, flags);
- __blk_run_queue(q);
+ __blk_run_queue(q, false);
spin_unlock_irqrestore(q->queue_lock, flags);
}
EXPORT_SYMBOL(blk_run_queue);
@@ -1053,7 +1054,7 @@ void blk_insert_request(struct request_queue *q, struct request *rq,

drive_stat_acct(rq, 1);
__elv_add_request(q, rq, where, 0);
- __blk_run_queue(q);
+ __blk_run_queue(q, false);
spin_unlock_irqrestore(q->queue_lock, flags);
}
EXPORT_SYMBOL(blk_insert_request);
@@ -2610,13 +2611,6 @@ int kblockd_schedule_work(struct request_queue *q, struct work_struct *work)
}
EXPORT_SYMBOL(kblockd_schedule_work);

-int kblockd_schedule_delayed_work(struct request_queue *q,
- struct delayed_work *dwork, unsigned long delay)
-{
- return queue_delayed_work(kblockd_workqueue, dwork, delay);
-}
-EXPORT_SYMBOL(kblockd_schedule_delayed_work);
-
int __init blk_dev_init(void)
{
BUILD_BUG_ON(__REQ_NR_BITS > 8 *
diff --git a/block/blk-flush.c b/block/blk-flush.c
index 54b123d..b27d020 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -66,10 +66,12 @@ static void blk_flush_complete_seq_end_io(struct request_queue *q,

/*
* Moving a request silently to empty queue_head may stall the
- * queue. Kick the queue in those cases.
+ * queue. Kick the queue in those cases. This function is called
+ * from request completion path and calling directly into
+ * request_fn may confuse the driver. Always use kblockd.
*/
if (was_empty && next_rq)
- __blk_run_queue(q);
+ __blk_run_queue(q, true);
}

static void pre_flush_end_io(struct request *rq, int error)
@@ -130,7 +132,7 @@ static struct request *queue_next_fseq(struct request_queue *q)
BUG();
}

- elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
+ elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE);
return rq;
}

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 1a320d2..eec78be 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -132,7 +132,7 @@ static void bio_batch_end_io(struct bio *bio, int err)
}

/**
- * blkdev_issue_zeroout generate number of zero filed write bios
+ * blkdev_issue_zeroout - generate number of zero filed write bios
* @bdev: blockdev to issue
* @sector: start sector
* @nr_sects: number of sectors to write
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index a89043a..e36cc10 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -20,6 +20,11 @@ static int throtl_quantum = 32;
/* Throttling is performed over 100ms slice and after that slice is renewed */
static unsigned long throtl_slice = HZ/10; /* 100 ms */

+/* A workqueue to queue throttle related work */
+static struct workqueue_struct *kthrotld_workqueue;
+static void throtl_schedule_delayed_work(struct throtl_data *td,
+ unsigned long delay);
+
struct throtl_rb_root {
struct rb_root rb;
struct rb_node *left;
@@ -345,10 +350,9 @@ static void throtl_schedule_next_dispatch(struct throtl_data *td)
update_min_dispatch_time(st);

if (time_before_eq(st->min_disptime, jiffies))
- throtl_schedule_delayed_work(td->queue, 0);
+ throtl_schedule_delayed_work(td, 0);
else
- throtl_schedule_delayed_work(td->queue,
- (st->min_disptime - jiffies));
+ throtl_schedule_delayed_work(td, (st->min_disptime - jiffies));
}

static inline void
@@ -815,10 +819,10 @@ void blk_throtl_work(struct work_struct *work)
}

/* Call with queue lock held */
-void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay)
+static void
+throtl_schedule_delayed_work(struct throtl_data *td, unsigned long delay)
{

- struct throtl_data *td = q->td;
struct delayed_work *dwork = &td->throtl_work;

if (total_nr_queued(td) > 0) {
@@ -827,12 +831,11 @@ void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay)
* Cancel that and schedule a new one.
*/
__cancel_delayed_work(dwork);
- kblockd_schedule_delayed_work(q, dwork, delay);
+ queue_delayed_work(kthrotld_workqueue, dwork, delay);
throtl_log(td, "schedule work. delay=%lu jiffies=%lu",
delay, jiffies);
}
}
-EXPORT_SYMBOL(throtl_schedule_delayed_work);

static void
throtl_destroy_tg(struct throtl_data *td, struct throtl_grp *tg)
@@ -920,7 +923,7 @@ static void throtl_update_blkio_group_read_bps(void *key,
smp_mb__after_atomic_inc();

/* Schedule a work now to process the limit change */
- throtl_schedule_delayed_work(td->queue, 0);
+ throtl_schedule_delayed_work(td, 0);
}

static void throtl_update_blkio_group_write_bps(void *key,
@@ -934,7 +937,7 @@ static void throtl_update_blkio_group_write_bps(void *key,
smp_mb__before_atomic_inc();
atomic_inc(&td->limits_changed);
smp_mb__after_atomic_inc();
- throtl_schedule_delayed_work(td->queue, 0);
+ throtl_schedule_delayed_work(td, 0);
}

static void throtl_update_blkio_group_read_iops(void *key,
@@ -948,7 +951,7 @@ static void throtl_update_blkio_group_read_iops(void *key,
smp_mb__before_atomic_inc();
atomic_inc(&td->limits_changed);
smp_mb__after_atomic_inc();
- throtl_schedule_delayed_work(td->queue, 0);
+ throtl_schedule_delayed_work(td, 0);
}

static void throtl_update_blkio_group_write_iops(void *key,
@@ -962,7 +965,7 @@ static void throtl_update_blkio_group_write_iops(void *key,
smp_mb__before_atomic_inc();
atomic_inc(&td->limits_changed);
smp_mb__after_atomic_inc();
- throtl_schedule_delayed_work(td->queue, 0);
+ throtl_schedule_delayed_work(td, 0);
}

void throtl_shutdown_timer_wq(struct request_queue *q)
@@ -1135,6 +1138,10 @@ void blk_throtl_exit(struct request_queue *q)

static int __init throtl_init(void)
{
+ kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0);
+ if (!kthrotld_workqueue)
+ panic("Failed to create kthrotld\n");
+
blkio_policy_register(&blkio_policy_throtl);
return 0;
}
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 7be4c79..ea83a4f 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3355,7 +3355,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfqd->busy_queues > 1) {
cfq_del_timer(cfqd, cfqq);
cfq_clear_cfqq_wait_request(cfqq);
- __blk_run_queue(cfqd->queue);
+ __blk_run_queue(cfqd->queue, false);
} else {
cfq_blkiocg_update_idle_time_stats(
&cfqq->cfqg->blkg);
@@ -3370,7 +3370,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
* this new queue is RT and the current one is BE
*/
cfq_preempt_queue(cfqd, cfqq);
- __blk_run_queue(cfqd->queue);
+ __blk_run_queue(cfqd->queue, false);
}
}

@@ -3731,7 +3731,7 @@ static void cfq_kick_queue(struct work_struct *work)
struct request_queue *q = cfqd->queue;

spin_lock_irq(q->queue_lock);
- __blk_run_queue(cfqd->queue);
+ __blk_run_queue(cfqd->queue, false);
spin_unlock_irq(q->queue_lock);
}

diff --git a/block/elevator.c b/block/elevator.c
index 2569512..236e93c 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -602,7 +602,7 @@ void elv_quiesce_start(struct request_queue *q)
*/
elv_drain_elevator(q);
while (q->rq.elvpriv) {
- __blk_run_queue(q);
+ __blk_run_queue(q, false);
spin_unlock_irq(q->queue_lock);
msleep(10);
spin_lock_irq(q->queue_lock);
@@ -651,7 +651,7 @@ void elv_insert(struct request_queue *q, struct request *rq, int where)
* with anything. There's no point in delaying queue
* processing.
*/
- __blk_run_queue(q);
+ __blk_run_queue(q, false);
break;

case ELEVATOR_INSERT_SORT:
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 49e6a54..dbf31ec 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -78,7 +78,6 @@

#include <asm/uaccess.h>

-static DEFINE_MUTEX(loop_mutex);
static LIST_HEAD(loop_devices);
static DEFINE_MUTEX(loop_devices_mutex);

@@ -1501,11 +1500,9 @@ static int lo_open(struct block_device *bdev, fmode_t mode)
{
struct loop_device *lo = bdev->bd_disk->private_data;

- mutex_lock(&loop_mutex);
mutex_lock(&lo->lo_ctl_mutex);
lo->lo_refcnt++;
mutex_unlock(&lo->lo_ctl_mutex);
- mutex_unlock(&loop_mutex);

return 0;
}
@@ -1515,7 +1512,6 @@ static int lo_release(struct gendisk *disk, fmode_t mode)
struct loop_device *lo = disk->private_data;
int err;

- mutex_lock(&loop_mutex);
mutex_lock(&lo->lo_ctl_mutex);

if (--lo->lo_refcnt)
@@ -1540,7 +1536,6 @@ static int lo_release(struct gendisk *disk, fmode_t mode)
out:
mutex_unlock(&lo->lo_ctl_mutex);
out_unlocked:
- mutex_unlock(&loop_mutex);
return 0;
}

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9045c52..fb2bb35 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -443,7 +443,7 @@ static void scsi_run_queue(struct request_queue *q)
&sdev->request_queue->queue_flags);
if (flagset)
queue_flag_set(QUEUE_FLAG_REENTER, sdev->request_queue);
- __blk_run_queue(sdev->request_queue);
+ __blk_run_queue(sdev->request_queue, false);
if (flagset)
queue_flag_clear(QUEUE_FLAG_REENTER, sdev->request_queue);
spin_unlock(sdev->request_queue->queue_lock);
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 998c01b..5c3ccfc 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -3829,7 +3829,7 @@ fc_bsg_goose_queue(struct fc_rport *rport)
!test_bit(QUEUE_FLAG_REENTER, &rport->rqst_q->queue_flags);
if (flagset)
queue_flag_set(QUEUE_FLAG_REENTER, rport->rqst_q);
- __blk_run_queue(rport->rqst_q);
+ __blk_run_queue(rport->rqst_q, false);
if (flagset)
queue_flag_clear(QUEUE_FLAG_REENTER, rport->rqst_q);
spin_unlock_irqrestore(rport->rqst_q->queue_lock, flags);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 4d18ff3..d5063e1 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -699,7 +699,7 @@ extern void blk_start_queue(struct request_queue *q);
extern void blk_stop_queue(struct request_queue *q);
extern void blk_sync_queue(struct request_queue *q);
extern void __blk_stop_queue(struct request_queue *q);
-extern void __blk_run_queue(struct request_queue *);
+extern void __blk_run_queue(struct request_queue *q, bool force_kblockd);
extern void blk_run_queue(struct request_queue *);
extern int blk_rq_map_user(struct request_queue *, struct request *,
struct rq_map_data *, void __user *, unsigned long,
@@ -1088,7 +1088,6 @@ static inline void put_dev_sector(Sector p)

struct work_struct;
int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
-int kblockd_schedule_delayed_work(struct request_queue *q, struct delayed_work *dwork, unsigned long delay);

#ifdef CONFIG_BLK_CGROUP
/*
@@ -1136,7 +1135,6 @@ static inline uint64_t rq_io_start_time_ns(struct request *req)
extern int blk_throtl_init(struct request_queue *q);
extern void blk_throtl_exit(struct request_queue *q);
extern int blk_throtl_bio(struct request_queue *q, struct bio **bio);
-extern void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay);
extern void throtl_shutdown_timer_wq(struct request_queue *q);
#else /* CONFIG_BLK_DEV_THROTTLING */
static inline int blk_throtl_bio(struct request_queue *q, struct bio **bio)
@@ -1146,7 +1144,6 @@ static inline int blk_throtl_bio(struct request_queue *q, struct bio **bio)

static inline int blk_throtl_init(struct request_queue *q) { return 0; }
static inline int blk_throtl_exit(struct request_queue *q) { return 0; }
-static inline void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay) {}
static inline void throtl_shutdown_timer_wq(struct request_queue *q) {}
#endif /* CONFIG_BLK_DEV_THROTTLING */

diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index 3395cf7..b22fb0d 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -245,7 +245,6 @@ static inline int blk_cmd_buf_len(struct request *rq)

extern void blk_dump_cmd(char *buf, struct request *rq);
extern void blk_fill_rwbs(char *rwbs, u32 rw, int bytes);
-extern void blk_fill_rwbs_rq(char *rwbs, struct request *rq);

#endif /* CONFIG_EVENT_TRACING && CONFIG_BLOCK */

diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index aba421d..78f18ad 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -31,7 +31,7 @@ DECLARE_EVENT_CLASS(block_rq_with_error,
0 : blk_rq_sectors(rq);
__entry->errors = rq->errors;

- blk_fill_rwbs_rq(__entry->rwbs, rq);
+ blk_fill_rwbs(__entry->rwbs, rq->cmd_flags, blk_rq_bytes(rq));
blk_dump_cmd(__get_str(cmd), rq);
),

@@ -118,7 +118,7 @@ DECLARE_EVENT_CLASS(block_rq,
__entry->bytes = (rq->cmd_type == REQ_TYPE_BLOCK_PC) ?
blk_rq_bytes(rq) : 0;

- blk_fill_rwbs_rq(__entry->rwbs, rq);
+ blk_fill_rwbs(__entry->rwbs, rq->cmd_flags, blk_rq_bytes(rq));
blk_dump_cmd(__get_str(cmd), rq);
memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
),
@@ -563,7 +563,7 @@ TRACE_EVENT(block_rq_remap,
__entry->nr_sector = blk_rq_sectors(rq);
__entry->old_dev = dev;
__entry->old_sector = from;
- blk_fill_rwbs_rq(__entry->rwbs, rq);
+ blk_fill_rwbs(__entry->rwbs, rq->cmd_flags, blk_rq_bytes(rq));
),

TP_printk("%d,%d %s %llu + %u <- (%d,%d) %llu",
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index d95721f..cbafed7 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1827,21 +1827,5 @@ void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
rwbs[i] = '\0';
}

-void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
-{
- int rw = rq->cmd_flags & 0x03;
- int bytes;
-
- if (rq->cmd_flags & REQ_DISCARD)
- rw |= REQ_DISCARD;
-
- if (rq->cmd_flags & REQ_SECURE)
- rw |= REQ_SECURE;
-
- bytes = blk_rq_bytes(rq);
-
- blk_fill_rwbs(rwbs, rw, bytes);
-}
-
#endif /* CONFIG_EVENT_TRACING */


--
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/