From: Paolo 'Blaisorblade' Giarrusso <[email protected]>
The queue lock can be taken from interrupts so it must always be taken with irq
disabling primitives. Some primitives already verify this.
blk_start_queue() is called under this lock, so interrupts must be disabled.
Also document this requirement clearly in blk_init_queue(), where the queue
spinlock is set.
Cc: Jens Axboe <[email protected]>
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <[email protected]>
---
block/ll_rw_blk.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index e5041a0..11872d1 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1663,6 +1663,8 @@ static void blk_unplug_timeout(unsigned
**/
void blk_start_queue(request_queue_t *q)
{
+ WARN_ON(!irqs_disabled());
+
clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags);
/*
@@ -1865,7 +1867,8 @@ EXPORT_SYMBOL(blk_alloc_queue_node);
* get dealt with eventually.
*
* The queue spin lock must be held while manipulating the requests on the
- * request queue.
+ * request queue; this lock will be taken also from interrupt context, so irq
+ * disabling is needed for it.
*
* Function returns a pointer to the initialized request queue, or NULL if
* it didn't succeed.
-
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