linux-kernel - Re: [PATCH] libnvdimm, pmem: Fix memcpy_mcsafe() return code handling in nsio_rw

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Message-ID: <x49bmc792df.fsf@segfault.boston.devel.redhat.com>
Date:   Mon, 18 Jun 2018 18:05:48 -0400
From:   Jeff Moyer <jmoyer@...hat.com>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     linux-nvdimm@...ts.01.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] libnvdimm, pmem: Fix memcpy_mcsafe() return code handling in nsio_rw_bytes()

Dan Williams <dan.j.williams@...el.com> writes:

> Commit 60622d68227d "x86/asm/memcpy_mcsafe: Return bytes remaining"
> converted callers of memcpy_mcsafe() to expect a positive 'bytes
> remaining' value rather than a negative error code. The nsio_rw_bytes()
> conversion failed to return success. The failure is benign in that
> nsio_rw_bytes() will end up writing back what it just read.
>
> Fixes: 60622d68227d ("x86/asm/memcpy_mcsafe: Return bytes remaining")
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: Vishal Verma <vishal.l.verma@...el.com>
> Signed-off-by: Dan Williams <dan.j.williams@...el.com>
> ---
>  drivers/nvdimm/claim.c |    1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
> index 2e96b34bc936..fb667bf469c7 100644
> --- a/drivers/nvdimm/claim.c
> +++ b/drivers/nvdimm/claim.c
> @@ -278,6 +278,7 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns,
>  			return -EIO;
>  		if (memcpy_mcsafe(buf, nsio->addr + offset, size) != 0)
>  			return -EIO;
> +		return 0;
>  	}
>  
>  	if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align))) {

Reviewed-by: Jeff Moyer <jmoyer@...hat.com>