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mm: add kernel_mbind() helper; remove in-kernel call to syscall

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Using the mm-internal kernel_mbind() helper allows us to get rid of the
mm-internal call to the sys_mbind() syscall.

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: linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Dominik Brodowski 2018-03-17 16:12:22 +01:00
parent 7addf44388
commit e7dc9ad6e9
1 changed files with 11 additions and 4 deletions
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15
mm/mempolicy.c
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@ -1336,9 +1336,9 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
}
SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
unsigned long, mode, const unsigned long __user *, nmask,
unsigned long, maxnode, unsigned, flags)
static long kernel_mbind(unsigned long start, unsigned long len,
unsigned long mode, const unsigned long __user *nmask,
unsigned long maxnode, unsigned int flags)
{
nodemask_t nodes;
int err;
@ -1357,6 +1357,13 @@ SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
return do_mbind(start, len, mode, mode_flags, &nodes, flags);
}
SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
unsigned long, mode, const unsigned long __user *, nmask,
unsigned long, maxnode, unsigned int, flags)
{
return kernel_mbind(start, len, mode, nmask, maxnode, flags);
}
/* Set the process memory policy */
SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
unsigned long, maxnode)
@ -1575,7 +1582,7 @@ COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
return -EFAULT;
}
return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
return kernel_mbind(start, len, mode, nm, nr_bits+1, flags);
}
COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,