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 <joe.lawrence@stratus.com>
Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
Acked-by: Boaz Harrosh <bharrosh@panasas.com> [for osd]
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 29d0567..a8b0d02 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -318,8 +318,8 @@
at_head = 1;
rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL);
- if (!rq)
- return -ENOMEM;
+ if (IS_ERR(rq))
+ return PTR_ERR(rq);
blk_rq_set_block_pc(rq);
if (blk_fill_sghdr_rq(q, rq, hdr, mode)) {
@@ -448,8 +448,8 @@
}
rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT);
- if (!rq) {
- err = -ENODEV;
+ if (IS_ERR(rq)) {
+ err = PTR_ERR(rq);
goto error_free_buffer;
}
@@ -539,8 +539,8 @@
int err;
rq = blk_get_request(q, WRITE, __GFP_WAIT);
- if (!rq)
- return -ENODEV;
+ if (IS_ERR(rq))
+ return PTR_ERR(rq);
blk_rq_set_block_pc(rq);
rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
rq->cmd[0] = cmd;