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authorTejun Heo <tj@kernel.org>2009-04-28 07:38:33 +0400
committerJens Axboe <jens.axboe@oracle.com>2009-04-28 09:36:56 +0400
commite93b9fb7d85da4fd9d5171649e5ddcac1dd572bf (patch)
tree72671e9cad1d1fa6acadd7e389515f3579f3ff26 /drivers/block/hd.c
parent7090a0a97f55cbf47547a140fcc5a349f32c598c (diff)
downloadlinux-e93b9fb7d85da4fd9d5171649e5ddcac1dd572bf.tar.xz
hd: fix locking
hd dance around local irq and HD_IRQ enable without achieving much. It ends up transferring data from irq handler with both local irq and HD_IRQ disabled. The only place it actually does something is while transferring the first block of a request which it does with HD_IRQ disabled but local irq enabled. Unfortunately, the dancing is horribly broken from locking POV. IRQ and timeout handlers access block queue without grabbing the queue lock and running the driver in SMP configuration crashes the whole machine pretty quickly. Remove meaningless irq enable/disable dancing and add proper locking in issue, irq and timeout paths. Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'drivers/block/hd.c')
-rw-r--r--drivers/block/hd.c17
1 files changed, 7 insertions, 10 deletions
diff --git a/drivers/block/hd.c b/drivers/block/hd.c
index 3c11f062a18c..baaa9e486e50 100644
--- a/drivers/block/hd.c
+++ b/drivers/block/hd.c
@@ -509,7 +509,6 @@ ok_to_write:
if (i > 0) {
SET_HANDLER(&write_intr);
outsw(HD_DATA, req->buffer, 256);
- local_irq_enable();
} else {
#if (HD_DELAY > 0)
last_req = read_timer();
@@ -541,8 +540,7 @@ static void hd_times_out(unsigned long dummy)
if (!CURRENT)
return;
- disable_irq(HD_IRQ);
- local_irq_enable();
+ spin_lock_irq(hd_queue->queue_lock);
reset = 1;
name = CURRENT->rq_disk->disk_name;
printk("%s: timeout\n", name);
@@ -552,9 +550,8 @@ static void hd_times_out(unsigned long dummy)
#endif
end_request(CURRENT, 0);
}
- local_irq_disable();
hd_request();
- enable_irq(HD_IRQ);
+ spin_unlock_irq(hd_queue->queue_lock);
}
static int do_special_op(struct hd_i_struct *disk, struct request *req)
@@ -592,7 +589,6 @@ static void hd_request(void)
return;
repeat:
del_timer(&device_timer);
- local_irq_enable();
req = CURRENT;
if (!req) {
@@ -601,7 +597,6 @@ repeat:
}
if (reset) {
- local_irq_disable();
reset_hd();
return;
}
@@ -660,9 +655,7 @@ repeat:
static void do_hd_request(struct request_queue *q)
{
- disable_irq(HD_IRQ);
hd_request();
- enable_irq(HD_IRQ);
}
static int hd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
@@ -684,12 +677,16 @@ static irqreturn_t hd_interrupt(int irq, void *dev_id)
{
void (*handler)(void) = do_hd;
+ spin_lock(hd_queue->queue_lock);
+
do_hd = NULL;
del_timer(&device_timer);
if (!handler)
handler = unexpected_hd_interrupt;
handler();
- local_irq_enable();
+
+ spin_unlock(hd_queue->queue_lock);
+
return IRQ_HANDLED;
}