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Date:   Wed, 16 Feb 2022 09:05:02 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Chaitanya Kulkarni <chaitanyak@nvidia.com>
Cc:     Haimin Zhang <tcs.kernel@gmail.com>, Jens Axboe <axboe@kernel.dk>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: Re: [PATCH] block-map: add __GFP_ZERO flag for alloc_page in
 function bio_copy_kern
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References: <20220216084038.15635-1-tcs.kernel@gmail.com>
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On Wed, Feb 16, 2022 at 09:12:21AM +0000, Chaitanya Kulkarni wrote:
> but blk_rq_map_kern() does accept gfp_mask for exactly this same case
> and that is passed on to the bio_copy_kern() unless I'm wrong here,
> so you need to pass the __GFP_ZERO flag in the step 3 above
> (sg_scsi_ioctl) and not force zzeroed allocation the generic API..

We only want the zeroing for the payload, and other callers have the
same issue, so I think this patch is the right thing to do.