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 <joe.lawrence@stratus.com>
Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Joe Lawrence 2014-07-02 15:35:16 -04:00 committed by Jens Axboe
parent 52addcf9d6
commit eb571eeade
4 changed files with 14 additions and 1 deletions

View File

@ -448,6 +448,10 @@ int sg_scsi_ioctl(struct request_queue *q, struct gendisk *disk, fmode_t mode,
}
rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT);
if (!rq) {
err = -ENODEV;
goto error_free_buffer;
}
cmdlen = COMMAND_SIZE(opcode);
@ -520,8 +524,9 @@ out:
}
error:
kfree(buffer);
blk_put_request(rq);
error_free_buffer:
kfree(buffer);
return err;
}
EXPORT_SYMBOL_GPL(sg_scsi_ioctl);
@ -534,6 +539,8 @@ static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk,
int err;
rq = blk_get_request(q, WRITE, __GFP_WAIT);
if (!rq)
return -ENODEV;
blk_rq_set_block_pc(rq);
rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
rq->cmd[0] = cmd;

View File

@ -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;

View File

@ -704,6 +704,8 @@ static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command *
rq = blk_get_request(q, (cgc->data_direction == CGC_DATA_WRITE) ?
WRITE : READ, __GFP_WAIT);
if (!rq)
return -ENODEV;
blk_rq_set_block_pc(rq);
if (cgc->buflen) {

View File

@ -1960,6 +1960,8 @@ static void scsi_eh_lock_door(struct scsi_device *sdev)
* request becomes available
*/
req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
if (!req)
return;
blk_rq_set_block_pc(req);