Re: [PATCH v3 0/2] block,scsi: fixup blk_get_request dead queue scenarios

From: Jens Axboe
Date: Tue Aug 26 2014 - 17:24:32 EST

On 08/26/2014 03:19 PM, Jens Axboe wrote:
> On 08/26/2014 11:24 AM, Jeff Moyer wrote:
>> Joe Lawrence <joe.lawrence@xxxxxxxxxxx> writes:
>>> v2->v3: rebase to 3.16-rc2, consider return values from the
>>> blk_mq_alloc_request leg of the blk_get_request callchain
>>> (noted by Jeff), noted in the second patch changelog.
>>> blk_mq_queue_enter may return 0 or errno, which
>>> blk_mq_alloc_request can propogate out via ERR_PTR.
>>> __blk_mq_alloc_request doesn't include any blk_queue_dying
>>> checks, so I'm assuming that its failures can be attributed
>>> to -EWOULDBLOCK under !GFP_WAIT conditions.
>>> v1->v2: incorporate Jeff's feedback in bsg_map_hdr() and Reviewed-by
>>> tags.
>>> Joe Lawrence (2):
>>> block,scsi: verify return pointer from blk_get_request
>>> block,scsi: fixup blk_get_request dead queue scenarios
>> Jens,
>> Did this patch set fall through the cracks again?
> Falling through the cracks implies that I meant to apply it and did not,
> which was not the case. But I think we're at the point now where I'm
> finally comfortable with applying it. So, Joe, could you ensure that it
> applies to 3.17-rc2, then I will roll it in to the updates for 3.18.

Actually, just audited a few of them, and conversions like this:

- if (!rq)
+ if (IS_ERR(rq))

will break spectacularly if rq == NULL is returned. Should all these be

Jens Axboe

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