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Date:   Mon, 25 Oct 2021 09:07:55 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Daejun Park <daejun7.park@samsung.com>
Cc:     James Bottomley <James.Bottomley@HansenPartnership.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        Jaegeuk Kim <jaegeuk@kernel.org>
Subject: Re: please revert the UFS HPB support
Message-ID: <20211025070755.GA7742@lst.de>
References: <571fc7393fb043e3c34bca57402bd098a56ea8ac.camel@HansenPartnership.com> <20211021144210.GA28195@lst.de> <84fac5a3-135a-2ac8-5929-a1031a311cb7@kernel.dk> <20211021151520.GA31407@lst.de> <20211021151728.GA31600@lst.de> <2cba13c3-bcd5-2a47-e4cb-54fa1ca088f3@acm.org> <CGME20211023154316epcas2p208f95cf1e4a87a4b61d2daf1a2b3c725@epcms2p3> <20211025051654epcms2p36b259d237eb2b8b885210148118c5d3f@epcms2p3>
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On Mon, Oct 25, 2021 at 02:16:54PM +0900, Daejun Park wrote:
> > before the kernel is due to go final.  Can the problems identified by
> > Christoph be fixed within that timeframe?
> 
> I'm checking to see if I can replace blk_execute_rq_nowait with
> blk_insert_cloned_request in the HPB code.

blk_insert_cloned_request is part of the problem.  You can't just fan
out one request into two on the same queue.

FYI, 5.15 is supposed to be released end of this week (unless an -rc8)
happens.  I don't think we can sit this out, we need to revert (or at
least disable) the code now.