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authorTejun Heo <tj@kernel.org>2009-04-28 12:38:33 +0900
committerJens Axboe <jens.axboe@oracle.com>2009-04-28 20:24:20 +0200
commit0191944282e84931f92915b5f06b348a92dac7e1 (patch)
tree5459927f8545c1a666913ee327c4f25c6994c6eb
parent0d9f346fb0cd6d6fc70827c5396a0d83939530e4 (diff)
downloadlinux-stericsson-0191944282e84931f92915b5f06b348a92dac7e1.tar.gz
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>
-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;
}