Messages in this thread | | | Subject | Re: [PATCH v2 04/10] block: revert back to synchronous request_queue removal | From | Bart Van Assche <> | Date | Mon, 20 Apr 2020 14:11:13 -0700 |
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On 4/20/20 11:59 AM, Luis Chamberlain wrote: > On Sun, Apr 19, 2020 at 03:23:31PM -0700, Bart Van Assche wrote: >> On 4/19/20 12:45 PM, Luis Chamberlain wrote: >>> + * Decrements the refcount to the request_queue kobject, when this reaches >>> + * 0 we'll have blk_release_queue() called. You should avoid calling >>> + * this function in atomic context but if you really have to ensure you >>> + * first refcount the block device with bdgrab() / bdput() so that the >>> + * last decrement happens in blk_cleanup_queue(). >>> + */ >> >> Is calling bdgrab() and bdput() an option from a context in which it is not >> guaranteed that the block device is open? > > If the block device is not open, nope. For that blk_get_queue() can > be used, and is used by the block layer. This begs the question: > > Do we have *drivers* which requires access to the request_queue from > atomic context when the block device is not open?
Instead of trying to answer that question, how about changing the references to bdgrab() and bdput() into references to blk_get_queue() and blk_put_queue()? I think if that change is made that we won't have to research what the answer to the bdgrab()/bdput() question is.
Thanks,
Bart.
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