On 03/19/12 17:04, Tejun Heo wrote:
> I don't think it's a good idea to push requests out to stopped queue.
> Wouldn't aborting all pending requests be better? Thanks.
How about the (lightly tested) patch below ? It combines three separate
changes:
- Making blk_drain_queue() ignore the stopped state of a queue.
- Add request_queue.kill_all_requests_fn.
- Fix a null pointer dereference triggered by sd during device removal.
Thanks,
Bart.
diff --git a/block/blk-core.c b/block/blk-core.c
index 3a78b00..9429f1b 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -375,8 +375,12 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
* (e.g. fd) get unhappy in such cases. Kick queue iff
* dispatch queue has something on it.
*/
- if (!list_empty(&q->queue_head))
- __blk_run_queue(q);
+ if (!list_empty(&q->queue_head)) {
+ if (blk_queue_dead(q) && q->kill_all_requests_fn)
+ q->kill_all_requests_fn(q);
+ else
+ q->request_fn(q);
+ }
drain |= q->rq.elvpriv;
diff --git a/block/blk-settings.c b/block/blk-settings.c
index d3234fc..9ce3df6 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -191,6 +191,13 @@ void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)
}
EXPORT_SYMBOL(blk_queue_make_request);
+void blk_queue_kill_all_requests(struct request_queue *q,
+ kill_all_requests_fn *kfn)
+{
+ q->kill_all_requests_fn = kfn;
+}
+EXPORT_SYMBOL(blk_queue_kill_all_requests);
+
/**
* blk_queue_bounce_limit - set bounce buffer limit for queue
* @q: the request queue for the device
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 351dc0b..5cf3a92 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -296,6 +296,12 @@ static void scsi_host_dev_release(struct device *dev)
destroy_workqueue(shost->work_q);
q = shost->uspace_req_q;
if (q) {
+ /*
+ * Note: freeing queuedata before invoking scsi_free_queue()
+ * is safe here because no request function is associated with
+ * uspace_req_q. See also the __scsi_alloc_queue() call in
+ * drivers/scsi/scsi_tgt_lib.c.
+ */
kfree(q->queuedata);
q->queuedata = NULL;
scsi_free_queue(q);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index b2c95db..21ede38 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1468,6 +1468,14 @@ static void scsi_softirq_done(struct request *rq)
}
}
+static void scsi_kill_all_requests(struct request_queue *q)
+{
+ struct request *req;
+
+ while ((req = blk_peek_request(q)) != NULL)
+ scsi_kill_request(req, q);
+}
+
/*
* Function: scsi_request_fn()
*
@@ -1486,11 +1494,7 @@ static void scsi_request_fn(struct request_queue *q)
struct scsi_cmnd *cmd;
struct request *req;
- if (!sdev) {
- while ((req = blk_peek_request(q)) != NULL)
- scsi_kill_request(req, q);
- return;
- }
+ BUG_ON(!sdev);
if(!get_device(&sdev->sdev_gendev))
/* We must be tearing the block queue down already */
@@ -1686,6 +1690,7 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
if (!q)
return NULL;
+ blk_queue_kill_all_requests(q, scsi_kill_all_requests);
blk_queue_prep_rq(q, scsi_prep_fn);
blk_queue_softirq_done(q, scsi_softirq_done);
blk_queue_rq_timed_out(q, scsi_times_out);
@@ -1695,15 +1700,6 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
void scsi_free_queue(struct request_queue *q)
{
- unsigned long flags;
-
- WARN_ON(q->queuedata);
-
- /* cause scsi_request_fn() to kill all non-finished requests */
- spin_lock_irqsave(q->queue_lock, flags);
- q->request_fn(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
-
blk_cleanup_queue(q);
}
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 04c2a27..65801e9 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -971,9 +971,6 @@ void __scsi_remove_device(struct scsi_device *sdev)
sdev->host->hostt->slave_destroy(sdev);
transport_destroy_device(dev);
- /* cause the request function to reject all I/O requests */
- sdev->request_queue->queuedata = NULL;
-
/* Freeing the queue signals to block that we're done */
scsi_free_queue(sdev->request_queue);
put_device(dev);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 606cf33..5a31e4c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -200,6 +200,7 @@ struct request_pm_state
typedef void (request_fn_proc) (struct request_queue *q);
typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
+typedef void (kill_all_requests_fn) (struct request_queue *q);
typedef int (prep_rq_fn) (struct request_queue *, struct request *);
typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
@@ -282,6 +283,7 @@ struct request_queue {
request_fn_proc *request_fn;
make_request_fn *make_request_fn;
+ kill_all_requests_fn *kill_all_requests_fn;
prep_rq_fn *prep_rq_fn;
unprep_rq_fn *unprep_rq_fn;
merge_bvec_fn *merge_bvec_fn;
@@ -825,6 +827,8 @@ extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
request_fn_proc *, spinlock_t *);
extern void blk_cleanup_queue(struct request_queue *);
extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
+extern void blk_queue_kill_all_requests(struct request_queue *,
+ kill_all_requests_fn *);
extern void blk_queue_bounce_limit(struct request_queue *, u64);
extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
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