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fs: add do_compat_select() helper; remove in-kernel call to compat syscall 

Using the fs-internal do_compat_select() helper allows us to get rid of
the fs-internal call to the compat_sys_select() 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Dominik Brodowski 2018-03-20 19:33:48 +01:00
parent e02af2ff65
commit 05585e4495
1 changed files with 12 additions and 5 deletions
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17
fs/select.c
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@ -1265,9 +1265,9 @@ static int compat_core_sys_select(int n, compat_ulong_t __user *inp,
return ret;
}
COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp,
compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
struct compat_timeval __user *, tvp)
static int do_compat_select(int n, compat_ulong_t __user *inp,
compat_ulong_t __user *outp, compat_ulong_t __user *exp,
struct compat_timeval __user *tvp)
{
struct timespec64 end_time, *to = NULL;
struct compat_timeval tv;
@ -1290,6 +1290,13 @@ COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp,
return ret;
}
COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp,
compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
struct compat_timeval __user *, tvp)
{
return do_compat_select(n, inp, outp, exp, tvp);
}
struct compat_sel_arg_struct {
compat_ulong_t n;
compat_uptr_t inp;
@ -1304,8 +1311,8 @@ COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg)
if (copy_from_user(&a, arg, sizeof(a)))
return -EFAULT;
return compat_sys_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp),
compat_ptr(a.exp), compat_ptr(a.tvp));
return do_compat_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp),
compat_ptr(a.exp), compat_ptr(a.tvp));
}
static long do_compat_pselect(int n, compat_ulong_t __user *inp,