Subject: Re: [PATCH v2] net: introduce helper macro for_each_cmsghdr

From: Joe Perches <[email-masked]>
Date: Tue, 09 Dec 2014 18:01:04 -0800

On Wed, 2014-12-10 at 09:39 +0800, Gu Zheng wrote:
> Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
> cmsghdr from msghdr, just cleanup. 

Does this even compile?

So which is it?

	for_each_cmsghdr
or
	for_each_cmsg_hdr?

The .h #defines for_each_cmsg_hdr
but all the uses are for_each_cmsghdr

> diff --git a/Documentation/networking/timestamping/timestamping.c b/Documentation/networking/timestamping/timestamping.c
[]
> @@ -169,9 +169,7 @@ static void printpacket(struct msghdr *msg, int res,
>  	       res,
>  	       inet_ntoa(from_addr->sin_addr),
>  	       msg->msg_controllen);
> -	for (cmsg = CMSG_FIRSTHDR(msg);
> -	     cmsg;
> -	     cmsg = CMSG_NXTHDR(msg, cmsg)) {
> +	for_each_cmsghdr(cmsg, msg) {
>  		printf("   cmsg len %zu: ", cmsg->cmsg_len);
>  		switch (cmsg->cmsg_level) {
>  		case SOL_SOCKET:
> diff --git a/crypto/af_alg.c b/crypto/af_alg.c
[]
> @@ -399,7 +399,7 @@ int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
>  {
>  	struct cmsghdr *cmsg;
>  
> -	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
> +	for_each_cmsghdr(cmsg, msg) {
>  		if (!CMSG_OK(msg, cmsg))
>  			return -EINVAL;
>  		if (cmsg->cmsg_level != SOL_ALG)
> diff --git a/include/linux/socket.h b/include/linux/socket.h
[]
> @@ -94,6 +94,10 @@ struct cmsghdr {
>  			     (cmsg)->cmsg_len <= (unsigned long) \
>  			     ((mhdr)->msg_controllen - \
>  			      ((char *)(cmsg) - (char *)(mhdr)->msg_control)))
> +#define for_each_cmsg_hdr(cmsg, msg)  \
> +	for (cmsg = CMSG_FIRSTHDR(msg); \
> +	     cmsg; \
> +	     cmsg = CMSG_NXTHDR(msg, cmsg))