[U-Boot] [PATCH v4] arm: socfpga: mailbox: Fix off-by-one error on command length checking

[Marek Vasut]

On 4/24/19 7:21 AM, Ley Foon Tan wrote:
> A mailbox command contains 1-u32 header + arguments. The "len" variable
> only contains the length of the arguments, but not the 1-u32 header.
> Include the length of header when checking the ring buffer space to
> prevent off-by-one error.
> 
> Signed-off-by: Ley Foon Tan <ley.foon.tan at intel.com>
> Signed-off-by: Chee Hong Ang <chee.hong.ang at intel.com>
> ---
> v3->v4:
> - Change DWORD to u32 in commit message
> - Add note len is in u32 unit in code
> 
> v2->v3:
> - Update commit description.
> ---
>  arch/arm/mach-socfpga/mailbox_s10.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mach-socfpga/mailbox_s10.c b/arch/arm/mach-socfpga/mailbox_s10.c
> index 3c33223936..4498ab55df 100644
> --- a/arch/arm/mach-socfpga/mailbox_s10.c
> +++ b/arch/arm/mach-socfpga/mailbox_s10.c
> @@ -55,11 +55,11 @@ static __always_inline int mbox_fill_cmd_circular_buff(u32 header, u32 len,
>  	cout = MBOX_READL(MBOX_COUT) % MBOX_CMD_BUFFER_SIZE;
>  
>  	/* if command buffer is full or not enough free space
> -	 * to fit the data
> +	 * to fit the data. Note, len is in u32 unit.
>  	 */
>  	if (((cin + 1) % MBOX_CMD_BUFFER_SIZE) == cout ||
>  	    ((MBOX_CMD_BUFFER_SIZE - cin + cout - 1) %
> -	     MBOX_CMD_BUFFER_SIZE) < len)
> +	     MBOX_CMD_BUFFER_SIZE) < (len + 1))
>  		return -ENOMEM;
>  
>  	/* write header to circular buffer */
> 

Applied, thanks.

-- 
Best regards,
Marek Vasut