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Subject[PATCH 39/45] ipc: add msgsnd syscall/compat_syscall wrappers
Date
Provide ksys_msgsnd() and compat_ksys_msgsnd() wrappers to avoid in-kernel
calls to these syscalls. The ksys_ prefix denotes that these functions are
meant as a drop-in replacement for the syscalls. In particular, they use
the same calling convention as sys_msgsnd() and compat_sys_msgsnd().

This patch is part of a series which tries to remove in-kernel calls to
syscalls. On this basis, the syscall entry path can be streamlined.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
ipc/msg.c | 20 ++++++++++++++++----
ipc/syscall.c | 4 ++--
ipc/util.h | 4 ++++
3 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/ipc/msg.c b/ipc/msg.c
index abc5826270a6..9de48065c1ac 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -867,8 +867,8 @@ static long do_msgsnd(int msqid, long mtype, void __user *mtext,
return err;
}

-SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
- int, msgflg)
+long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
+ int msgflg)
{
long mtype;

@@ -877,6 +877,12 @@ SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
}

+SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
+ int, msgflg)
+{
+ return ksys_msgsnd(msqid, msgp, msgsz, msgflg);
+}
+
#ifdef CONFIG_COMPAT

struct compat_msgbuf {
@@ -884,8 +890,8 @@ struct compat_msgbuf {
char mtext[1];
};

-COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
- compat_ssize_t, msgsz, int, msgflg)
+long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
+ compat_ssize_t msgsz, int msgflg)
{
struct compat_msgbuf __user *up = compat_ptr(msgp);
compat_long_t mtype;
@@ -894,6 +900,12 @@ COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
return -EFAULT;
return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg);
}
+
+COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
+ compat_ssize_t, msgsz, int, msgflg)
+{
+ return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg);
+}
#endif

static inline int convert_mode(long *msgtyp, int msgflg)
diff --git a/ipc/syscall.c b/ipc/syscall.c
index 0228c7afd882..77a883ef2eca 100644
--- a/ipc/syscall.c
+++ b/ipc/syscall.c
@@ -46,7 +46,7 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
}

case MSGSND:
- return sys_msgsnd(first, (struct msgbuf __user *) ptr,
+ return ksys_msgsnd(first, (struct msgbuf __user *) ptr,
second, third);
case MSGRCV:
switch (version) {
@@ -142,7 +142,7 @@ COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second,
return compat_ksys_semctl(first, second, third, pad);

case MSGSND:
- return compat_sys_msgsnd(first, ptr, second, third);
+ return compat_ksys_msgsnd(first, ptr, second, third);

case MSGRCV: {
void __user *uptr = compat_ptr(ptr);
diff --git a/ipc/util.h b/ipc/util.h
index c16aceb1bdec..51853dc2f340 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -246,6 +246,8 @@ long ksys_msgget(key_t key, int msgflg);
long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf);
long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
long msgtyp, int msgflg);
+long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
+ int msgflg);
long ksys_shmget(key_t key, size_t size, int shmflg);
long ksys_shmdt(char __user *shmaddr);
long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf);
@@ -259,6 +261,8 @@ long compat_ksys_semctl(int semid, int semnum, int cmd, int arg);
long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr);
long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
compat_long_t msgtyp, int msgflg);
+long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
+ compat_ssize_t msgsz, int msgflg);
long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr);
#endif /* CONFIG_COMPAT */

--
2.16.2
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