linux-kernel - Re: [PATCH] mtd: rawnand: Use proper enum for flctl_dma_fifo0

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAKwvOd=V4n9MXDn3+gX7iQtoCBNEcn3CSueg++QvOMMzD4VDDg@mail.gmail.com>
Date:   Fri, 21 Sep 2018 10:28:22 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Nathan Chancellor <natechancellor@...il.com>
Cc:     boris.brezillon@...tlin.com, miquel.raynal@...tlin.com,
        richard@....at, David Woodhouse <dwmw2@...radead.org>,
        computersforpeace@...il.com, marek.vasut@...il.com,
        linux-mtd@...ts.infradead.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mtd: rawnand: Use proper enum for flctl_dma_fifo0_transfer

On Thu, Sep 20, 2018 at 4:31 PM Nathan Chancellor
<natechancellor@...il.com> wrote:
>
> Clang warns when one enumerated type is converted implicitly to another:
>
> drivers/mtd/nand/raw/sh_flctl.c:483:46: warning: implicit conversion
> from enumeration type 'enum dma_transfer_direction' to different
> enumeration type 'enum dma_data_direction' [-Wenum-conversion]
>                 flctl_dma_fifo0_transfer(flctl, buf, rlen, DMA_DEV_TO_MEM) > 0)
>                 ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
> drivers/mtd/nand/raw/sh_flctl.c:542:46: warning: implicit conversion
> from enumeration type 'enum dma_transfer_direction' to different
> enumeration type 'enum dma_data_direction' [-Wenum-conversion]
>                 flctl_dma_fifo0_transfer(flctl, buf, rlen, DMA_MEM_TO_DEV) > 0)
>                 ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
> 2 warnings generated.
>
> Use the proper enums from dma_data_direction to satisfy Clang.
>
> DMA_MEM_TO_DEV = DMA_TO_DEVICE = 1
> DMA_DEV_TO_MEM = DMA_FROM_DEVICE = 2
>
> Reported-by: Nick Desaulniers <ndesaulniers@...gle.com>
> Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
> ---
>  drivers/mtd/nand/raw/sh_flctl.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/sh_flctl.c b/drivers/mtd/nand/raw/sh_flctl.c
> index c0c0798f268f..4d20d033de7b 100644
> --- a/drivers/mtd/nand/raw/sh_flctl.c
> +++ b/drivers/mtd/nand/raw/sh_flctl.c
> @@ -480,7 +480,7 @@ static void read_fiforeg(struct sh_flctl *flctl, int rlen, int offset)
>
>         /* initiate DMA transfer */
>         if (flctl->chan_fifo0_rx && rlen >= 32 &&
> -               flctl_dma_fifo0_transfer(flctl, buf, rlen, DMA_DEV_TO_MEM) > 0)
> +               flctl_dma_fifo0_transfer(flctl, buf, rlen, DMA_FROM_DEVICE) > 0)

Looks like flctl_dma_fifo0_transfer() expects an `enum
dma_data_direction dir`, not an `enum dma_transfer_direction` as noted
by the warning, and luckily the values specified happened to have the
same value today as you noted.  So this change is no functional
change, but will prevent changes to either enum from potentially
breaking this code.

Reviewed-by: Nick Desaulniers <ndesaulniers@...gle.com>

>                         goto convert;   /* DMA success */
>
>         /* do polling transfer */
> @@ -539,7 +539,7 @@ static void write_ec_fiforeg(struct sh_flctl *flctl, int rlen,
>
>         /* initiate DMA transfer */
>         if (flctl->chan_fifo0_tx && rlen >= 32 &&
> -               flctl_dma_fifo0_transfer(flctl, buf, rlen, DMA_MEM_TO_DEV) > 0)
> +               flctl_dma_fifo0_transfer(flctl, buf, rlen, DMA_TO_DEVICE) > 0)
>                         return; /* DMA success */
>
>         /* do polling transfer */
> --
> 2.19.0
>


-- 
Thanks,
~Nick Desaulniers