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From: Laurent Vivier <laurent@vivier.eu>
To: qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
	Laurent Vivier <laurent@vivier.eu>
Subject: [Qemu-devel] [PULL 04/13] linux-user: Don't use CMSG_ALIGN(sizeof struct cmsghdr)
Date: Tue, 23 Jan 2018 15:47:58 +0100	[thread overview]
Message-ID: <20180123144807.5618-5-laurent@vivier.eu> (raw)
In-Reply-To: <20180123144807.5618-1-laurent@vivier.eu>

From: Peter Maydell <peter.maydell@linaro.org>

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: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <1513345976-22958-3-git-send-email-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/syscall.c      | 4 ++--
 linux-user/syscall_defs.h | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index a1b9772a85..39553c81b6 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -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;
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index bec3680b94..a35c52a60a 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -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,
-- 
2.14.3

  parent reply	other threads:[~2018-01-23 14:48 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-23 14:47 [Qemu-devel] [PULL 00/13] Linux user for 2.12 patches Laurent Vivier
2018-01-23 14:47 ` [Qemu-devel] [PULL 01/13] linux-user: Fix locking order in fork_start() Laurent Vivier
2018-01-23 14:47 ` [Qemu-devel] [PULL 02/13] linux-user: wrap fork() in a start/end exclusive section Laurent Vivier
2018-01-23 14:47 ` [Qemu-devel] [PULL 03/13] linux-user: Fix length calculations in host_to_target_cmsg() Laurent Vivier
2018-01-23 14:47 ` Laurent Vivier [this message]
2018-01-23 14:47 ` [Qemu-devel] [PULL 05/13] linux-user: Translate flags argument to dup3 syscall Laurent Vivier
2018-01-23 14:48 ` [Qemu-devel] [PULL 06/13] linux-user/mmap.c: Avoid choosing NULL as start address Laurent Vivier
2018-01-23 14:48 ` [Qemu-devel] [PULL 07/13] linux-user: Fix sched_get/setaffinity conversion Laurent Vivier
2018-01-26 18:23   ` Peter Maydell
2018-01-26 18:33     ` Samuel Thibault
2018-01-23 14:48 ` [Qemu-devel] [PULL 08/13] linux-user: Add AT_SECURE auxval Laurent Vivier
2018-01-23 14:48 ` [Qemu-devel] [PULL 09/13] linux-user: Add getcpu() support Laurent Vivier
2018-01-23 14:48 ` [Qemu-devel] [PULL 10/13] linux-user: remove nmi.c and fw-path-provider.c Laurent Vivier
2018-01-23 14:48 ` [Qemu-devel] [PULL 11/13] linux-user: Propagate siginfo_t through to handle_cpu_signal() Laurent Vivier
2018-01-23 14:48 ` [Qemu-devel] [PULL 12/13] page_unprotect(): handle calls to pages that are PAGE_WRITE Laurent Vivier
2018-03-22  1:52   ` Laurent Vivier
2018-03-22 10:36     ` Laurent Vivier
2018-03-22 11:05       ` Peter Maydell
2018-03-22 11:07         ` Peter Maydell
2018-03-22 11:13           ` Laurent Vivier
2018-03-22 16:47             ` Laurent Vivier
2018-03-22 11:07         ` Laurent Vivier
2018-03-22 11:10           ` Peter Maydell
2018-01-23 14:48 ` [Qemu-devel] [PULL 13/13] linux-user: implement renameat2 Laurent Vivier
2018-01-23 19:13   ` Palmer Dabbelt
2018-01-23 20:13     ` Laurent Vivier
2018-01-23 20:55       ` Palmer Dabbelt
2018-01-25 11:37 ` [Qemu-devel] [PULL 00/13] Linux user for 2.12 patches Peter Maydell

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