Commit ad762b99 authored by Peter Maydell's avatar Peter Maydell Committed by Laurent Vivier
Browse files

linux-user: Don't use CMSG_ALIGN(sizeof struct cmsghdr) 



The Linux struct cmsghdr is already guaranteed to be sufficiently
aligned that CMSG_ALIGN(sizeof struct cmsghdr) is always equal
to sizeof struct cmsghdr. Stop doing the unnecessary alignment
arithmetic for host and target cmsghdr.

This follows kernel commit 1ff8cebf49ed9e9ca2 and brings our
TARGET_CMSG_* macros back into line with the kernel ones,
as well as making them easier to understand.

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: default avatarLaurent Vivier <laurent@vivier.eu>
Message-Id: <1513345976-22958-3-git-send-email-peter.maydell@linaro.org>
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
parent 7174970a

linux-user/syscall.c

+2 −2
Original line number Diff line number Diff line
@@ -1692,7 +1692,7 @@ static inline abi_long target_to_host_cmsg(struct msghdr *msgh, 
        void *target_data = TARGET_CMSG_DATA(target_cmsg);



        int len = tswapal(target_cmsg->cmsg_len)

                  - TARGET_CMSG_ALIGN(sizeof (struct target_cmsghdr));

            - sizeof(struct target_cmsghdr);



        space += CMSG_SPACE(len);

        if (space > msgh->msg_controllen) {
@@ -1773,7 +1773,7 @@ static inline abi_long host_to_target_cmsg(struct target_msghdr *target_msgh, 
        void *data = CMSG_DATA(cmsg);

        void *target_data = TARGET_CMSG_DATA(target_cmsg);



        int len = cmsg->cmsg_len - CMSG_ALIGN(sizeof (struct cmsghdr));

        int len = cmsg->cmsg_len - sizeof(struct cmsghdr);

        int tgt_len, tgt_space;



        /* We never copy a half-header but may copy half-data;

linux-user/syscall_defs.h

+3 −3
Original line number Diff line number Diff line
@@ -303,9 +303,9 @@ struct target_cmsghdr { 
                               __target_cmsg_nxthdr(mhdr, cmsg, cmsg_start)

#define TARGET_CMSG_ALIGN(len) (((len) + sizeof (abi_long) - 1) \

                               & (size_t) ~(sizeof (abi_long) - 1))

#define TARGET_CMSG_SPACE(len) (TARGET_CMSG_ALIGN (len) \

                               + TARGET_CMSG_ALIGN (sizeof (struct target_cmsghdr)))

#define TARGET_CMSG_LEN(len)   (TARGET_CMSG_ALIGN (sizeof (struct target_cmsghdr)) + (len))

#define TARGET_CMSG_SPACE(len) (sizeof(struct target_cmsghdr) + \

                                TARGET_CMSG_ALIGN(len))

#define TARGET_CMSG_LEN(len) (sizeof(struct target_cmsghdr) + (len))



static __inline__ struct target_cmsghdr *

__target_cmsg_nxthdr(struct target_msghdr *__mhdr,