ipc: add shmdt syscall wrapper

Provide ksys_shmdt() 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_shmdt().

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: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Dominik Brodowski 2018-03-20 20:09:48 +01:00
parent 65749e0bb5
commit da1e274434
3 changed files with 9 additions and 3 deletions

View File

@ -1481,7 +1481,7 @@ COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
* detach and kill segment if marked destroyed.
* The work is done in shm_close.
*/
SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
long ksys_shmdt(char __user *shmaddr)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
@ -1588,6 +1588,11 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
return retval;
}
SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
{
return ksys_shmdt(shmaddr);
}
#ifdef CONFIG_PROC_FS
static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
{

View File

@ -90,7 +90,7 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
return -EINVAL;
}
case SHMDT:
return sys_shmdt((char __user *)ptr);
return ksys_shmdt((char __user *)ptr);
case SHMGET:
return ksys_shmget(first, second, third);
case SHMCTL:
@ -178,7 +178,7 @@ COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second,
return put_user(raddr, (compat_ulong_t __user *)compat_ptr(third));
}
case SHMDT:
return sys_shmdt(compat_ptr(ptr));
return ksys_shmdt(compat_ptr(ptr));
case SHMGET:
return ksys_shmget(first, (unsigned int)second, third);
case SHMCTL:

View File

@ -244,6 +244,7 @@ long ksys_semget(key_t key, int nsems, int semflg);
long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg);
long ksys_msgget(key_t key, int msgflg);
long ksys_shmget(key_t key, size_t size, int shmflg);
long ksys_shmdt(char __user *shmaddr);
/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */
#ifdef CONFIG_COMPAT