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Date:   Thu, 28 Oct 2021 10:10:24 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Bart Van Assche <bvanassche@acm.org>
Cc:     Christoph Hellwig <hch@infradead.org>,
        James Bottomley <jejb@linux.ibm.com>, daejun7.park@samsung.com,
        ALIM AKHTAR <alim.akhtar@samsung.com>,
        "avri.altman@wdc.com" <avri.altman@wdc.com>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
        "huobean@gmail.com" <huobean@gmail.com>,
        Keoseong Park <keosung.park@samsung.com>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] scsi: ufs: Fix proper API to send HPB pre-request
Message-ID: <YXrZgC7mYVQS+CE6@infradead.org>
References: <CGME20211027223619epcms2p60bbc74c9ba9757c58709a99acd0892ff@epcms2p6>
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 <0f9229c3c4c7859524411a47db96a3b53ac89c90.camel@linux.ibm.com>
 <YXrBTHmu/fiAaZH5@infradead.org>
 <54b45df9-9339-c69d-73b5-9c293449b849@acm.org>
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On Thu, Oct 28, 2021 at 10:07:52AM -0700, Bart Van Assche wrote:
> I spent some time looking around for other examples of allocating and
> inserting a request from inside block layer callbacks. I only found one
> such example, namely in the NVMe core. nvme_timeout() calls
> nvme_alloc_request() and blk_execute_rq_nowait(). The difference between
> what the UFS HPB code is doing and what nvme_timeout() does doesn't seem
> that big to me.

The difference is that nvme_timeout allocates a request on the
admin queue, and only does so for commands on the I/O queues.