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mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff()

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Using this helper allows us to avoid the in-kernel calls to the
sys_mmap_pgoff() 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_mmap_pgoff().

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: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Dominik Brodowski
2018-03-11 11:34:46 +01:00
parent 9d5b7c956b
commit a90f590a1b
21 changed files with 60 additions and 41 deletions
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17
mm/nommu.c
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@@ -1423,9 +1423,9 @@ error_getting_region:
return -ENOMEM;
}
SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags,
unsigned long, fd, unsigned long, pgoff)
unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags,
unsigned long fd, unsigned long pgoff)
{
struct file *file = NULL;
unsigned long retval = -EBADF;
@@ -1447,6 +1447,13 @@ out:
return retval;
}
SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags,
unsigned long, fd, unsigned long, pgoff)
{
return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
}
#ifdef __ARCH_WANT_SYS_OLD_MMAP
struct mmap_arg_struct {
unsigned long addr;
@@ -1466,8 +1473,8 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
if (offset_in_page(a.offset))
return -EINVAL;
return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
a.offset >> PAGE_SHIFT);
return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
a.offset >> PAGE_SHIFT);
}
#endif /* __ARCH_WANT_SYS_OLD_MMAP */