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From: Keith Busch <kbusch@kernel.org>
To: Nilay Shroff <nilay@linux.ibm.com>
Cc: linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
	hch@lst.de, sagi@grimberg.me, axboe@fb.com,
	chaitanyak@nvidia.com, yi.zhang@redhat.com,
	shinichiro.kawasaki@wdc.com, mlombard@redhat.com,
	gjoyce@linux.ibm.com
Subject: Re: [PATCHv2] nvmet: use kzalloc instead of ZERO_PAGE in nvme_execute_identify_ns_nvm()
Date: Mon, 2 Dec 2024 11:03:35 -0700	[thread overview]
Message-ID: <Z032dx3uDu-m1j9i@kbusch-mbp> (raw)
In-Reply-To: <20241124125628.2532658-1-nilay@linux.ibm.com>

On Sun, Nov 24, 2024 at 06:25:53PM +0530, Nilay Shroff wrote:
> The nvme_execute_identify_ns_nvm function uses ZERO_PAGE for copying
> SG list with all zeros. As ZERO_PAGE would not necessarily return the
> virtual-address of the zero page, we need to first convert the page
> address to kernel virtual-address and then use it as source address
> for copying the data to SG list with all zeros. Using return address
> of ZERO_PAGE(0) as source address for copying data to SG list would
> fill the target buffer with random/garbage value and causes the
> undesired side effect.
> 
> As other identify implemenations uses kzalloc for allocating a zero
> filled buffer, we decided use kzalloc for allocating a zero filled
> buffer in nvme_execute_identify_ns_nvm function and then use this
> buffer for copying all zeros to SG list buffers. So esentially, we
> now avoid using ZERO_PAGE.

Thanks, applied to nvme-6.13.

      parent reply	other threads:[~2024-12-02 18:03 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-24 12:55 [PATCHv2] nvmet: use kzalloc instead of ZERO_PAGE in nvme_execute_identify_ns_nvm() Nilay Shroff
2024-11-25  6:47 ` Christoph Hellwig
2024-11-25 12:56 ` Yi Zhang
2024-11-26  2:49 ` Chaitanya Kulkarni
2024-12-02 18:03 ` Keith Busch [this message]

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