Messages in this thread Patch in this message | | | Date | Wed, 16 Apr 2008 13:59:24 -0500 | From | scameron@beardog ... | Subject | Re: [patch] cciss: Fix race between disk-adding code and interrupt handler |
| |
Fix race condition between cciss_init_one(), cciss_update_drive_info(), and cciss_check_queues().
Signed-off-by: Stephen M. Cameron <scameron@beardog.cca.cpqcorp.net>
---
linux-2.6.25-rc9/drivers/block/cciss.c | 17 ++++++++++++++++- drivers/block/cciss.h | 0 2 files changed, 16 insertions(+), 1 deletion(-)
diff -puN linux-2.6.25-rc9/drivers/block/cciss.c~cciss_init_one_race linux-2.6.25-rc9/drivers/block/cciss.c --- linux-2.6.25-rc9/linux-2.6.25-rc9/drivers/block/cciss.c~cciss_init_one_race 2008-04-14 08:21:03.000000000 -0500 +++ linux-2.6.25-rc9-scameron/linux-2.6.25-rc9/drivers/block/cciss.c 2008-04-16 08:15:38.000000000 -0500 @@ -1349,6 +1349,10 @@ static void cciss_update_drive_info(int spin_lock_irqsave(CCISS_LOCK(h->ctlr), flags); h->drv[drv_index].busy_configuring = 1; spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags); + + /* deregister_disk sets h->drv[drv_index].queue = NULL */ + /* which keeps the interrupt handler from starting */ + /* the queue. */ ret = deregister_disk(h->gendisk[drv_index], &h->drv[drv_index], 0); h->drv[drv_index].busy_configuring = 0; @@ -1419,6 +1423,10 @@ geo_inq: blk_queue_hardsect_size(disk->queue, hba[ctlr]->drv[drv_index].block_size); + /* Make sure all queue data is written out before */ + /* setting h->drv[drv_index].queue, as setting this */ + /* allows the interrupt handler to start the queue */ + wmb(); h->drv[drv_index].queue = disk->queue; add_disk(disk); } @@ -3520,10 +3528,17 @@ static int __devinit cciss_init_one(stru continue; blk_queue_hardsect_size(q, drv->block_size); set_capacity(disk, drv->nr_blocks); - add_disk(disk); j++; } while (j <= hba[i]->highest_lun); + /* Make sure all queue data is written out before */ + /* interrupt handler, triggered by add_disk, */ + /* is allowed to start them. */ + wmb(); + + for (j = 0; j <= hba[i]->highest_lun; j++) + add_disk(hba[i]->gendisk[j]); + return 1; clean4: diff -puN linux-2.6.25-rc9/drivers/block/cciss.h~cciss_init_one_race linux-2.6.25-rc9/drivers/block/cciss.h _
| |