Re: [PATCH] nvmet: fix the use of ZERO_PAGE in nvme_execute_identify_ns_nvm()

[Christoph Hellwig <hch@lst.de>]

On Fri, Nov 22, 2024 at 02:20:36PM +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 value and causes the undesired side effect. This patch
> implements the fix ensuring that we use virtual-address of the
> zero page for copying all zeros to the SG list buffers.

I wonder if using ZERO_PAGE() is simply a little too smart for it's
own sake and it should just use kzalloc like a bunch of other identify
implementation..