From eb571eeade2598635f813b3284d02c13a380301e Mon Sep 17 00:00:00 2001 From: Joe Lawrence Date: Wed, 2 Jul 2014 15:35:16 -0400 Subject: block,scsi: verify return pointer from blk_get_request The blk-core dead queue checks introduce an error scenario to blk_get_request that returns NULL if the request queue has been shutdown. This affects the behavior for __GFP_WAIT callers, who should verify the return value before dereferencing. Signed-off-by: Joe Lawrence Acked-by: Jiri Kosina [for pktdvd] Reviewed-by: Jeff Moyer Signed-off-by: Jens Axboe --- drivers/block/paride/pd.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/block/paride') diff --git a/drivers/block/paride/pd.c b/drivers/block/paride/pd.c index fea7e76a00de..ca831f741d89 100644 --- a/drivers/block/paride/pd.c +++ b/drivers/block/paride/pd.c @@ -722,6 +722,8 @@ static int pd_special_command(struct pd_unit *disk, int err = 0; rq = blk_get_request(disk->gd->queue, READ, __GFP_WAIT); + if (!rq) + return -ENODEV; rq->cmd_type = REQ_TYPE_SPECIAL; rq->special = func; -- cgit v1.2.3 From a492f075450f3ba87de36e5ffe92a9d0c7af9723 Mon Sep 17 00:00:00 2001 From: Joe Lawrence Date: Thu, 28 Aug 2014 08:15:21 -0600 Subject: block,scsi: fixup blk_get_request dead queue scenarios The blk_get_request function may fail in low-memory conditions or during device removal (even if __GFP_WAIT is set). To distinguish between these errors, modify the blk_get_request call stack to return the appropriate ERR_PTR. Verify that all callers check the return status and consider IS_ERR instead of a simple NULL pointer check. For consistency, make a similar change to the blk_mq_alloc_request leg of blk_get_request. It may fail if the queue is dead, or the caller was unwilling to wait. Signed-off-by: Joe Lawrence Acked-by: Jiri Kosina [for pktdvd] Acked-by: Boaz Harrosh [for osd] Reviewed-by: Jeff Moyer Signed-off-by: Jens Axboe --- drivers/block/paride/pd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/block/paride') diff --git a/drivers/block/paride/pd.c b/drivers/block/paride/pd.c index ca831f741d89..d48715b287e6 100644 --- a/drivers/block/paride/pd.c +++ b/drivers/block/paride/pd.c @@ -722,8 +722,8 @@ static int pd_special_command(struct pd_unit *disk, int err = 0; rq = blk_get_request(disk->gd->queue, READ, __GFP_WAIT); - if (!rq) - return -ENODEV; + if (IS_ERR(rq)) + return PTR_ERR(rq); rq->cmd_type = REQ_TYPE_SPECIAL; rq->special = func; -- cgit v1.2.3