[PATCH v2] net: introduce helper macro for_each_cmsghdr

[PATCH v2] net: introduce helper macro for_each_cmsghdr

[Gu Zheng]

Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
cmsghdr from msghdr, just cleanup. 


Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
---
v2: use the lower-case macro name as Joe suggested.
---
 .../networking/timestamping/timestamping.c         |    4 +---
 .../networking/timestamping/txtimestamp.c          |    4 +---
 crypto/af_alg.c                                    |    2 +-
 include/linux/socket.h                             |    4 ++++
 net/core/scm.c                                     |    3 +--
 net/dccp/proto.c                                   |    5 ++---
 net/ipv4/ip_sockglue.c                             |    2 +-
 net/ipv6/datagram.c                                |    2 +-
 net/iucv/af_iucv.c                                 |    4 +---
 net/rds/send.c                                     |    4 ++--
 net/rxrpc/ar-output.c                              |    2 +-
 net/sctp/socket.c                                  |    3 +--
 12 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/Documentation/networking/timestamping/timestamping.c b/Documentation/networking/timestamping/timestamping.c
index 5cdfd74..3106e88 100644
--- 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/Documentation/networking/timestamping/txtimestamp.c b/Documentation/networking/timestamping/txtimestamp.c
index b32fc2a..e44ef35 100644
--- a/Documentation/networking/timestamping/txtimestamp.c
+++ b/Documentation/networking/timestamping/txtimestamp.c
@@ -149,9 +149,7 @@ static void __recv_errmsg_cmsg(struct msghdr *msg, int payload_len)
 	struct scm_timestamping *tss = NULL;
 	struct cmsghdr *cm;
 
-	for (cm = CMSG_FIRSTHDR(msg);
-	     cm && cm->cmsg_len;
-	     cm = CMSG_NXTHDR(msg, cm)) {
+	for_each_cmsghdr(cmsg, msg) {
 		if (cm->cmsg_level == SOL_SOCKET &&
 		    cm->cmsg_type == SCM_TIMESTAMPING) {
 			tss = (void *) CMSG_DATA(cm);
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 6a3ad80..3df7d53 100644
--- 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
index bb9b836..d4b592f 100644
--- 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))
 
 /*
  *	Get the next cmsg header
diff --git a/net/core/scm.c b/net/core/scm.c
index b442e7e..e938c49 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -129,8 +129,7 @@ int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *p)
 	struct cmsghdr *cmsg;
 	int err;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg))
-	{
+	for_each_cmsghdr(cmsg, msg) {
 		err = -EINVAL;
 
 		/* Verify that cmsg_len is at least sizeof(struct cmsghdr) */
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 5ab6627..d449cc5 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -703,7 +703,7 @@ EXPORT_SYMBOL_GPL(compat_dccp_getsockopt);
 
 static int dccp_msghdr_parse(struct msghdr *msg, struct sk_buff *skb)
 {
-	struct cmsghdr *cmsg = CMSG_FIRSTHDR(msg);
+	struct cmsghdr *cmsg;
 
 	/*
 	 * Assign an (opaque) qpolicy priority value to skb->priority.
@@ -717,8 +717,7 @@ static int dccp_msghdr_parse(struct msghdr *msg, struct sk_buff *skb)
 	 */
 	skb->priority = 0;
 
-	for (; cmsg != NULL; cmsg = CMSG_NXTHDR(msg, cmsg)) {
-
+	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg))
 			return -EINVAL;
 
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 9daf217..14a6f71 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -192,7 +192,7 @@ int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc,
 	int err, val;
 	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 IS_ENABLED(CONFIG_IPV6)
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 2cdc383..9895b98 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -640,7 +640,7 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk,
 	int len;
 	int err = 0;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
+	for_each_cmsghdr(cmsg, msg) {
 		int addr_type;
 
 		if (!CMSG_OK(msg, cmsg)) {
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index a089b6b..eae4e08 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -1070,9 +1070,7 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
 	txmsg.class = 0;
 
 	/* iterate over control messages */
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg;
-		cmsg = CMSG_NXTHDR(msg, cmsg)) {
-
+	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg)) {
 			err = -EINVAL;
 			goto out;
diff --git a/net/rds/send.c b/net/rds/send.c
index 0a64541..1accb3e 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -826,7 +826,7 @@ static int rds_rm_size(struct msghdr *msg, int data_len)
 	int cmsg_groups = 0;
 	int retval;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
+	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg))
 			return -EINVAL;
 
@@ -878,7 +878,7 @@ static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 	struct cmsghdr *cmsg;
 	int ret = 0;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
+	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg))
 			return -EINVAL;
 
diff --git a/net/rxrpc/ar-output.c b/net/rxrpc/ar-output.c
index 0b4b9a7..f915e7e 100644
--- a/net/rxrpc/ar-output.c
+++ b/net/rxrpc/ar-output.c
@@ -45,7 +45,7 @@ static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 	if (msg->msg_controllen == 0)
 		return -EINVAL;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
+	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg))
 			return -EINVAL;
 
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 634a2ab..58834d7 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6592,8 +6592,7 @@ static int sctp_msghdr_parse(const struct msghdr *msg, sctp_cmsgs_t *cmsgs)
 	struct cmsghdr *cmsg;
 	struct msghdr *my_msg = (struct msghdr *)msg;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg != NULL;
-	     cmsg = CMSG_NXTHDR(my_msg, cmsg)) {
+	for_each_cmsghdr(cmsg, my_msg) {
 		if (!CMSG_OK(my_msg, cmsg))
 			return -EINVAL;
 
-- 
1.7.7

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

[Gu Zheng]

There's a mistake in this patch, please ignore it.
Sorry for the noise.

Regards,
Gu
On 12/10/2014 09:39 AM, Gu Zheng wrote:

> Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
> cmsghdr from msghdr, just cleanup. 
> 
> 
> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> ---
> v2: use the lower-case macro name as Joe suggested.
> ---
>  .../networking/timestamping/timestamping.c         |    4 +---
>  .../networking/timestamping/txtimestamp.c          |    4 +---
>  crypto/af_alg.c                                    |    2 +-
>  include/linux/socket.h                             |    4 ++++
>  net/core/scm.c                                     |    3 +--
>  net/dccp/proto.c                                   |    5 ++---
>  net/ipv4/ip_sockglue.c                             |    2 +-
>  net/ipv6/datagram.c                                |    2 +-
>  net/iucv/af_iucv.c                                 |    4 +---
>  net/rds/send.c                                     |    4 ++--
>  net/rxrpc/ar-output.c                              |    2 +-
>  net/sctp/socket.c                                  |    3 +--
>  12 files changed, 17 insertions(+), 22 deletions(-)
> 
> diff --git a/Documentation/networking/timestamping/timestamping.c b/Documentation/networking/timestamping/timestamping.c
> index 5cdfd74..3106e88 100644
> --- 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/Documentation/networking/timestamping/txtimestamp.c b/Documentation/networking/timestamping/txtimestamp.c
> index b32fc2a..e44ef35 100644
> --- a/Documentation/networking/timestamping/txtimestamp.c
> +++ b/Documentation/networking/timestamping/txtimestamp.c
> @@ -149,9 +149,7 @@ static void __recv_errmsg_cmsg(struct msghdr *msg, int payload_len)
>  	struct scm_timestamping *tss = NULL;
>  	struct cmsghdr *cm;
>  
> -	for (cm = CMSG_FIRSTHDR(msg);
> -	     cm && cm->cmsg_len;
> -	     cm = CMSG_NXTHDR(msg, cm)) {
> +	for_each_cmsghdr(cmsg, msg) {
>  		if (cm->cmsg_level == SOL_SOCKET &&
>  		    cm->cmsg_type == SCM_TIMESTAMPING) {
>  			tss = (void *) CMSG_DATA(cm);
> diff --git a/crypto/af_alg.c b/crypto/af_alg.c
> index 6a3ad80..3df7d53 100644
> --- 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
> index bb9b836..d4b592f 100644
> --- 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))
>  
>  /*
>   *	Get the next cmsg header
> diff --git a/net/core/scm.c b/net/core/scm.c
> index b442e7e..e938c49 100644
> --- a/net/core/scm.c
> +++ b/net/core/scm.c
> @@ -129,8 +129,7 @@ int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *p)
>  	struct cmsghdr *cmsg;
>  	int err;
>  
> -	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg))
> -	{
> +	for_each_cmsghdr(cmsg, msg) {
>  		err = -EINVAL;
>  
>  		/* Verify that cmsg_len is at least sizeof(struct cmsghdr) */
> diff --git a/net/dccp/proto.c b/net/dccp/proto.c
> index 5ab6627..d449cc5 100644
> --- a/net/dccp/proto.c
> +++ b/net/dccp/proto.c
> @@ -703,7 +703,7 @@ EXPORT_SYMBOL_GPL(compat_dccp_getsockopt);
>  
>  static int dccp_msghdr_parse(struct msghdr *msg, struct sk_buff *skb)
>  {
> -	struct cmsghdr *cmsg = CMSG_FIRSTHDR(msg);
> +	struct cmsghdr *cmsg;
>  
>  	/*
>  	 * Assign an (opaque) qpolicy priority value to skb->priority.
> @@ -717,8 +717,7 @@ static int dccp_msghdr_parse(struct msghdr *msg, struct sk_buff *skb)
>  	 */
>  	skb->priority = 0;
>  
> -	for (; cmsg != NULL; cmsg = CMSG_NXTHDR(msg, cmsg)) {
> -
> +	for_each_cmsghdr(cmsg, msg) {
>  		if (!CMSG_OK(msg, cmsg))
>  			return -EINVAL;
>  
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index 9daf217..14a6f71 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -192,7 +192,7 @@ int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc,
>  	int err, val;
>  	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 IS_ENABLED(CONFIG_IPV6)
> diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
> index 2cdc383..9895b98 100644
> --- a/net/ipv6/datagram.c
> +++ b/net/ipv6/datagram.c
> @@ -640,7 +640,7 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk,
>  	int len;
>  	int err = 0;
>  
> -	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
> +	for_each_cmsghdr(cmsg, msg) {
>  		int addr_type;
>  
>  		if (!CMSG_OK(msg, cmsg)) {
> diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
> index a089b6b..eae4e08 100644
> --- a/net/iucv/af_iucv.c
> +++ b/net/iucv/af_iucv.c
> @@ -1070,9 +1070,7 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
>  	txmsg.class = 0;
>  
>  	/* iterate over control messages */
> -	for (cmsg = CMSG_FIRSTHDR(msg); cmsg;
> -		cmsg = CMSG_NXTHDR(msg, cmsg)) {
> -
> +	for_each_cmsghdr(cmsg, msg) {
>  		if (!CMSG_OK(msg, cmsg)) {
>  			err = -EINVAL;
>  			goto out;
> diff --git a/net/rds/send.c b/net/rds/send.c
> index 0a64541..1accb3e 100644
> --- a/net/rds/send.c
> +++ b/net/rds/send.c
> @@ -826,7 +826,7 @@ static int rds_rm_size(struct msghdr *msg, int data_len)
>  	int cmsg_groups = 0;
>  	int retval;
>  
> -	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
> +	for_each_cmsghdr(cmsg, msg) {
>  		if (!CMSG_OK(msg, cmsg))
>  			return -EINVAL;
>  
> @@ -878,7 +878,7 @@ static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
>  	struct cmsghdr *cmsg;
>  	int ret = 0;
>  
> -	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
> +	for_each_cmsghdr(cmsg, msg) {
>  		if (!CMSG_OK(msg, cmsg))
>  			return -EINVAL;
>  
> diff --git a/net/rxrpc/ar-output.c b/net/rxrpc/ar-output.c
> index 0b4b9a7..f915e7e 100644
> --- a/net/rxrpc/ar-output.c
> +++ b/net/rxrpc/ar-output.c
> @@ -45,7 +45,7 @@ static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
>  	if (msg->msg_controllen == 0)
>  		return -EINVAL;
>  
> -	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
> +	for_each_cmsghdr(cmsg, msg) {
>  		if (!CMSG_OK(msg, cmsg))
>  			return -EINVAL;
>  
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 634a2ab..58834d7 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -6592,8 +6592,7 @@ static int sctp_msghdr_parse(const struct msghdr *msg, sctp_cmsgs_t *cmsgs)
>  	struct cmsghdr *cmsg;
>  	struct msghdr *my_msg = (struct msghdr *)msg;
>  
> -	for (cmsg = CMSG_FIRSTHDR(msg); cmsg != NULL;
> -	     cmsg = CMSG_NXTHDR(my_msg, cmsg)) {
> +	for_each_cmsghdr(cmsg, my_msg) {
>  		if (!CMSG_OK(my_msg, cmsg))
>  			return -EINVAL;
>  

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

[Joe Perches]

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))

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

[Gu Zheng]

Hi Joe,
On 12/10/2014 10:01 AM, Joe Perches wrote:

> 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

Thanks for your quick feedback.
There seems some problems with my send-patch script, it sent out the patch
before the test completed.

Thanks,
Gu

> 
>> 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))
> 
> 
> 
> .
> 

[PATCH v2] net: introduce helper macro for_each_cmsghdr

[Gu Zheng]

Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
cmsghdr from msghdr, just cleanup. 

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
---
v2: use the lower-case macro name as Joe suggested.
---
 .../networking/timestamping/timestamping.c         |    4 +---
 .../networking/timestamping/txtimestamp.c          |    4 +---
 crypto/af_alg.c                                    |    2 +-
 include/linux/socket.h                             |    4 ++++
 net/core/scm.c                                     |    3 +--
 net/dccp/proto.c                                   |    5 ++---
 net/ipv4/ip_sockglue.c                             |    2 +-
 net/ipv6/datagram.c                                |    2 +-
 net/iucv/af_iucv.c                                 |    4 +---
 net/rds/send.c                                     |    4 ++--
 net/rxrpc/ar-output.c                              |    2 +-
 net/sctp/socket.c                                  |    3 +--
 12 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/Documentation/networking/timestamping/timestamping.c b/Documentation/networking/timestamping/timestamping.c
index 5cdfd74..635a43a 100644
--- 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/Documentation/networking/timestamping/txtimestamp.c b/Documentation/networking/timestamping/txtimestamp.c
index b32fc2a..f4fd9a2 100644
--- a/Documentation/networking/timestamping/txtimestamp.c
+++ b/Documentation/networking/timestamping/txtimestamp.c
@@ -149,9 +149,7 @@ static void __recv_errmsg_cmsg(struct msghdr *msg, int payload_len)
 	struct scm_timestamping *tss = NULL;
 	struct cmsghdr *cm;
 
-	for (cm = CMSG_FIRSTHDR(msg);
-	     cm && cm->cmsg_len;
-	     cm = CMSG_NXTHDR(msg, cm)) {
+	for_each_cmsghdr(cmsg, msg) {
 		if (cm->cmsg_level == SOL_SOCKET &&
 		    cm->cmsg_type == SCM_TIMESTAMPING) {
 			tss = (void *) CMSG_DATA(cm);
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 6a3ad80..bc21f52 100644
--- 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
index bb9b836..0e71278 100644
--- 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_cmsghdr(cmsg, msg) \
+	for (cmsg = CMSG_FIRSTHDR(msg); \
+	     cmsg; \
+	     cmsg = CMSG_NXTHDR(msg, cmsg))
 
 /*
  *	Get the next cmsg header
diff --git a/net/core/scm.c b/net/core/scm.c
index b442e7e..3b6899b 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -129,8 +129,7 @@ int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *p)
 	struct cmsghdr *cmsg;
 	int err;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg))
-	{
+	for_each_cmsghdr(cmsg, msg) {
 		err = -EINVAL;
 
 		/* Verify that cmsg_len is at least sizeof(struct cmsghdr) */
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 5ab6627..e7413a9 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -703,7 +703,7 @@ EXPORT_SYMBOL_GPL(compat_dccp_getsockopt);
 
 static int dccp_msghdr_parse(struct msghdr *msg, struct sk_buff *skb)
 {
-	struct cmsghdr *cmsg = CMSG_FIRSTHDR(msg);
+	struct cmsghdr *cmsg;
 
 	/*
 	 * Assign an (opaque) qpolicy priority value to skb->priority.
@@ -717,8 +717,7 @@ static int dccp_msghdr_parse(struct msghdr *msg, struct sk_buff *skb)
 	 */
 	skb->priority = 0;
 
-	for (; cmsg != NULL; cmsg = CMSG_NXTHDR(msg, cmsg)) {
-
+	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg))
 			return -EINVAL;
 
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 9daf217..839db9d 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -192,7 +192,7 @@ int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc,
 	int err, val;
 	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 IS_ENABLED(CONFIG_IPV6)
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 2cdc383..7252965 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -640,7 +640,7 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk,
 	int len;
 	int err = 0;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
+	for_each_cmsghdr(cmsg, msg) {
 		int addr_type;
 
 		if (!CMSG_OK(msg, cmsg)) {
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index a089b6b..b69d87e 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -1070,9 +1070,7 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
 	txmsg.class = 0;
 
 	/* iterate over control messages */
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg;
-		cmsg = CMSG_NXTHDR(msg, cmsg)) {
-
+	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg)) {
 			err = -EINVAL;
 			goto out;
diff --git a/net/rds/send.c b/net/rds/send.c
index 0a64541..b23e7b8 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -826,7 +826,7 @@ static int rds_rm_size(struct msghdr *msg, int data_len)
 	int cmsg_groups = 0;
 	int retval;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
+	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg))
 			return -EINVAL;
 
@@ -878,7 +878,7 @@ static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 	struct cmsghdr *cmsg;
 	int ret = 0;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
+	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg))
 			return -EINVAL;
 
diff --git a/net/rxrpc/ar-output.c b/net/rxrpc/ar-output.c
index 0b4b9a7..83b4616 100644
--- a/net/rxrpc/ar-output.c
+++ b/net/rxrpc/ar-output.c
@@ -45,7 +45,7 @@ static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 	if (msg->msg_controllen == 0)
 		return -EINVAL;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
+	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg))
 			return -EINVAL;
 
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 634a2ab..a3802ed 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6592,8 +6592,7 @@ static int sctp_msghdr_parse(const struct msghdr *msg, sctp_cmsgs_t *cmsgs)
 	struct cmsghdr *cmsg;
 	struct msghdr *my_msg = (struct msghdr *)msg;
 
-	for (cmsg = CMSG_FIRSTHDR(msg); cmsg != NULL;
-	     cmsg = CMSG_NXTHDR(my_msg, cmsg)) {
+	for_each_cmsghdr(cmsg, my_msg) {
 		if (!CMSG_OK(my_msg, cmsg))
 			return -EINVAL;
 
-- 
1.7.7

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

[Joe Perches]

On Wed, 2014-12-10 at 13:36 +0800, Gu Zheng wrote:
> Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
> cmsghdr from msghdr, just cleanup. 

This looks nicer.
Ideally this would have used: [PATCH V3] as the subject

> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> ---
> v2: use the lower-case macro name as Joe suggested.

And a description of the v2->v3 change here.

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

[Gu Zheng]

Hi Joe,
On 12/10/2014 02:56 PM, Joe Perches wrote:

> On Wed, 2014-12-10 at 13:36 +0800, Gu Zheng wrote:
>> Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
>> cmsghdr from msghdr, just cleanup. 
> 
> This looks nicer.
> Ideally this would have used: [PATCH V3] as the subject

Thanks for your review.
The previous v2 thread was marked as mistake, so this is the really active
v2 version.

Regards,
Gu

> 
>> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
>> ---
>> v2: use the lower-case macro name as Joe suggested.
> 
> And a description of the v2->v3 change here.
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 

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

[Joe Perches]

On Wed, 2014-12-10 at 16:15 +0800, Gu Zheng wrote:
> On 12/10/2014 02:56 PM, Joe Perches wrote:
> > On Wed, 2014-12-10 at 13:36 +0800, Gu Zheng wrote:
> >> Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
> >> cmsghdr from msghdr, just cleanup. 
> > 
> > This looks nicer.
> > Ideally this would have used: [PATCH V3] as the subject
> 
> The previous v2 thread was marked as mistake, so this is the really active
> v2 version.

A buggy submitted version is still a version.
Using an incremented version number helps.

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

[Gu Zheng]

Hi Joe,
On 12/10/2014 10:51 PM, Joe Perches wrote:

> On Wed, 2014-12-10 at 16:15 +0800, Gu Zheng wrote:
>> On 12/10/2014 02:56 PM, Joe Perches wrote:
>>> On Wed, 2014-12-10 at 13:36 +0800, Gu Zheng wrote:
>>>> Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
>>>> cmsghdr from msghdr, just cleanup. 
>>>
>>> This looks nicer.
>>> Ideally this would have used: [PATCH V3] as the subject
>>
>> The previous v2 thread was marked as mistake, so this is the really active
>> v2 version.
> 
> A buggy submitted version is still a version.
> Using an incremented version number helps.

Got it, this can also avoid some unnecessary misreading.
Thanks for your suggestion.

Regards,
Gu

> 
> 

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

[David Miller]

From: Gu Zheng <guz.fnst@cn.fujitsu.com>
Date: Wed, 10 Dec 2014 13:36:25 +0800

> Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
> cmsghdr from msghdr, just cleanup. 
> 
> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>

Applied, thanks.

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

[David Miller]

From: David Miller <davem@davemloft.net>
Date: Wed, 10 Dec 2014 13:48:04 -0500 (EST)

> From: Gu Zheng <guz.fnst@cn.fujitsu.com>
> Date: Wed, 10 Dec 2014 13:36:25 +0800
> 
>> Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
>> cmsghdr from msghdr, just cleanup. 
>> 
>> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> 
> Applied, thanks.

This breaks the build, I'm reverting.

You cannot use your new macros in
Documentation/networking/timestamping/txtimestamp.c, that is a
userland program and the header you are adding your helper to is not
available to userspace.

This also means you didn't sufficiently test the build of your
changes.

Documentation/networking/timestamping/timestamping.c: In function ‘printpacket’:
Documentation/networking/timestamping/timestamping.c:172:2: warning: implicit declaration of function ‘for_each_cmsghdr’ [-Wimplicit-function-declaration]
Documentation/networking/timestamping/timestamping.c:172:30: error: expected ‘;’ before ‘{’ token
Documentation/networking/timestamping/timestamping.c:161:18: warning: unused variable ‘ts’ [-Wunused-variable]
Documentation/networking/timestamping/timestamping.c:160:17: warning: unused variable ‘tv’ [-Wunused-variable]
make[3]: *** [Documentation/networking/timestamping/timestamping] Error 1
make[3]: *** Waiting for unfinished jobs....
Documentation/networking/timestamping/txtimestamp.c: In function ‘__recv_errmsg_cmsg’:
Documentation/networking/timestamping/txtimestamp.c:187:2: warning: implicit declaration of function ‘for_each_cmsghdr’ [-Wimplicit-function-declaration]
Documentation/networking/timestamping/txtimestamp.c:187:19: error: ‘cmsg’ undeclared (first use in this function)
Documentation/networking/timestamping/txtimestamp.c:187:19: note: each undeclared identifier is reported only once for each function it appears in
Documentation/networking/timestamping/txtimestamp.c:187:30: error: expected ‘;’ before ‘{’ token
Documentation/networking/timestamping/txtimestamp.c:185:18: warning: unused variable ‘cm’ [-Wunused-variable]
Documentation/networking/timestamping/txtimestamp.c:184:27: warning: unused variable ‘tss’ [-Wunused-variable]
Documentation/networking/timestamping/txtimestamp.c:183:28: warning: unused variable ‘serr’ [-Wunused-variable]
Documentation/networking/timestamping/txtimestamp.c: At top level:
Documentation/networking/timestamping/txtimestamp.c:123:13: warning: ‘print_timestamp’ defined but not used [-Wunused-function]
Documentation/networking/timestamping/txtimestamp.c:159:13: warning: ‘print_pktinfo’ defined but not used [-Wunused-function]

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

[Gu Zheng]

Hi David,
On 12/11/2014 03:44 AM, David Miller wrote:

> From: David Miller <davem@davemloft.net>
> Date: Wed, 10 Dec 2014 13:48:04 -0500 (EST)
> 
>> From: Gu Zheng <guz.fnst@cn.fujitsu.com>
>> Date: Wed, 10 Dec 2014 13:36:25 +0800
>>
>>> Introduce helper macro for_each_cmsghdr as a wrapper of the enumerating
>>> cmsghdr from msghdr, just cleanup. 
>>>
>>> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
>>
>> Applied, thanks.
> 
> This breaks the build, I'm reverting.

I'm very sorry.

> 
> You cannot use your new macros in
> Documentation/networking/timestamping/txtimestamp.c, that is a
> userland program and the header you are adding your helper to is not
> available to userspace.

IMO, the user-land programs need to be build with the matched headers separately.
I split the kernel codes and the user-land programs, build and install the kernel first,
and then build the user-land ones. 

> 
> This also means you didn't sufficiently test the build of your
> changes.

To be honest, I do the test as I mentioned above.

Thanks,
Gu

> 
> Documentation/networking/timestamping/timestamping.c: In function ‘printpacket’:
> Documentation/networking/timestamping/timestamping.c:172:2: warning: implicit declaration of function ‘for_each_cmsghdr’ [-Wimplicit-function-declaration]
> Documentation/networking/timestamping/timestamping.c:172:30: error: expected ‘;’ before ‘{’ token
> Documentation/networking/timestamping/timestamping.c:161:18: warning: unused variable ‘ts’ [-Wunused-variable]
> Documentation/networking/timestamping/timestamping.c:160:17: warning: unused variable ‘tv’ [-Wunused-variable]
> make[3]: *** [Documentation/networking/timestamping/timestamping] Error 1
> make[3]: *** Waiting for unfinished jobs....
> Documentation/networking/timestamping/txtimestamp.c: In function ‘__recv_errmsg_cmsg’:
> Documentation/networking/timestamping/txtimestamp.c:187:2: warning: implicit declaration of function ‘for_each_cmsghdr’ [-Wimplicit-function-declaration]
> Documentation/networking/timestamping/txtimestamp.c:187:19: error: ‘cmsg’ undeclared (first use in this function)
> Documentation/networking/timestamping/txtimestamp.c:187:19: note: each undeclared identifier is reported only once for each function it appears in
> Documentation/networking/timestamping/txtimestamp.c:187:30: error: expected ‘;’ before ‘{’ token
> Documentation/networking/timestamping/txtimestamp.c:185:18: warning: unused variable ‘cm’ [-Wunused-variable]
> Documentation/networking/timestamping/txtimestamp.c:184:27: warning: unused variable ‘tss’ [-Wunused-variable]
> Documentation/networking/timestamping/txtimestamp.c:183:28: warning: unused variable ‘serr’ [-Wunused-variable]
> Documentation/networking/timestamping/txtimestamp.c: At top level:
> Documentation/networking/timestamping/txtimestamp.c:123:13: warning: ‘print_timestamp’ defined but not used [-Wunused-function]
> Documentation/networking/timestamping/txtimestamp.c:159:13: warning: ‘print_pktinfo’ defined but not used [-Wunused-function]
> 

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

[David Miller]

From: Gu Zheng <guz.fnst@cn.fujitsu.com>
Date: Thu, 11 Dec 2014 09:05:59 +0800

> IMO, the user-land programs need to be build with the matched
> headers separately.

You absolutely cannot provide this new interface to userland and
expect programs to be able to just use it, it's non-standard and does
not exist in older headers.

I do not want this new interface available to userland programs.
They can just open-code the list traversal just like every program
in history has had to do since BSD UNIX.

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

[Gu Zheng]

Hi David,
On 12/11/2014 09:47 AM, David Miller wrote:

> From: Gu Zheng <guz.fnst@cn.fujitsu.com>
> Date: Thu, 11 Dec 2014 09:05:59 +0800
> 
>> IMO, the user-land programs need to be build with the matched
>> headers separately.
> 
> You absolutely cannot provide this new interface to userland and
> expect programs to be able to just use it, it's non-standard and does
> not exist in older headers.

Got it, sorry for my mistake, and thanks for your correction.

> 
> I do not want this new interface available to userland programs.
> They can just open-code the list traversal just like every program
> in history has had to do since BSD UNIX.

Agree. Let's leave the user-land ones as they are.
I'll send a new version (without changing user-land ones) soon.

Best regards,
Gu

> .
>