Re: [Outreachy kernel] [RESEND PATCH v2 2/2] Staging: rtl8723au: Use put_unaligned_le16

[Arnd Bergmann <arnd@arndb.de>]

On Friday 20 February 2015 14:18:45 Vaishali Thakkar wrote:
> Using byte ordering functions and then memcpy() is risky and
> prone to hide errors which are hard to track down. So, this
> patch introduces the use of function put_unaligned_le16 which
> makes the code clear. Here, use of variable tim_bitmap_le
> and variable itself is removed. Also, to be compatible with the
> changes header file is added too.
> 
> Coccinelle is used to do this change and semantic patch used for
> this is as follows:
> 
> @a@
> typedef __le16;
> __le16 e16;
> identifier tmp;
> expression ptr;
> expression y,e;
> type T;
> @@
> 
> - tmp = cpu_to_le16(y);
> 
> <+... when != tmp
> (
> - memcpy(ptr, (T)&tmp, \(2\|sizeof(__le16)\|sizeof(e16)\));
> + put_unaligned_le16(y,ptr);
> |
> - memcpy(ptr, (T)&tmp, ...);
> + put_unaligned_le16(y,ptr);
> )
> ...+>
> ? tmp = e
> 
> @@ type T; identifier a.tmp; @@
> 
> - T tmp;
> ...when != tmp
> 
> Signed-off-by: Vaishali Thakkar <vthakkar1994@gmail.com>
> 

Reviewed-by: Arnd Bergmann <arnd@arndb.de>