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fs: add kern_select() helper; remove in-kernel call to sys_select() 

Using this helper allows us to avoid the in-kernel call to the sys_umount()
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>
hifive-unleashed-5.1
Dominik Brodowski 2018-03-18 07:53:04 +01:00
parent 30cfe4ef8b
commit 4bdb9acabf
1 changed files with 9 additions and 3 deletions
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12
fs/select.c
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@ -675,8 +675,8 @@ out_nofds:
return ret;
}
SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
fd_set __user *, exp, struct timeval __user *, tvp)
static int kern_select(int n, fd_set __user *inp, fd_set __user *outp,
fd_set __user *exp, struct timeval __user *tvp)
{
struct timespec64 end_time, *to = NULL;
struct timeval tv;
@ -699,6 +699,12 @@ SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
return ret;
}
SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
fd_set __user *, exp, struct timeval __user *, tvp)
{
return kern_select(n, inp, outp, exp, tvp);
}
static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
fd_set __user *exp, struct timespec __user *tsp,
const sigset_t __user *sigmask, size_t sigsetsize)
@ -784,7 +790,7 @@ SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
if (copy_from_user(&a, arg, sizeof(a)))
return -EFAULT;
return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
return kern_select(a.n, a.inp, a.outp, a.exp, a.tvp);
}
#endif