Commit 69894718 authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

ipc: add semget syscall wrapper 

Provide ksys_semget() wrapper to avoid in-kernel calls to this syscall.
The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_semget().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net



Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
parent 41f4f0e2

ipc/sem.c

+6 −1
Original line number Diff line number Diff line
@@ -556,7 +556,7 @@ static inline int sem_more_checks(struct kern_ipc_perm *ipcp, 
	return 0;

}



SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg)

long ksys_semget(key_t key, int nsems, int semflg)

{

	struct ipc_namespace *ns;

	static const struct ipc_ops sem_ops = {
@@ -578,6 +578,11 @@ SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg) 
	return ipcget(ns, &sem_ids(ns), &sem_ops, &sem_params);

}



SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg)

{

	return ksys_semget(key, nsems, semflg);

}



/**

 * perform_atomic_semop[_slow] - Attempt to perform semaphore

 *                               operations on a given array.

ipc/syscall.c

+2 −2
Original line number Diff line number Diff line
@@ -35,7 +35,7 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second, 
				       (const struct timespec __user *)fifth);



	case SEMGET:

		return sys_semget(first, second, third);

		return ksys_semget(first, second, third);

	case SEMCTL: {

		unsigned long arg;

		if (!ptr)
@@ -132,7 +132,7 @@ COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second, 
		return compat_ksys_semtimedop(first, compat_ptr(ptr), second,

						compat_ptr(fifth));

	case SEMGET:

		return sys_semget(first, second, third);

		return ksys_semget(first, second, third);

	case SEMCTL:

		if (!ptr)

			return -EINVAL;

ipc/util.h

+1 −0
Original line number Diff line number Diff line
@@ -240,6 +240,7 @@ static inline int compat_ipc_parse_version(int *cmd) 
long ksys_semtimedop(int semid, struct sembuf __user *tsops,

		     unsigned int nsops,

		     const struct timespec __user *timeout);

long ksys_semget(key_t key, int nsems, int semflg);



/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */

#ifdef CONFIG_COMPAT