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

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Using the fs-internal do_lookup_dcookie() helper allows us to get rid of
fs-internal calls to the sys_lookup_dcookie() 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 2018-03-17 14:53:38 +01:00
parent 2fc96f8331
commit 98e5f7bd2c
1 changed files with 8 additions and 3 deletions
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11
fs/dcookies.c
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@ -146,7 +146,7 @@ int get_dcookie(const struct path *path, unsigned long *cookie)
/* And here is where the userspace process can look up the cookie value
* to retrieve the path.
*/
SYSCALL_DEFINE3(lookup_dcookie, u64, cookie64, char __user *, buf, size_t, len)
static int do_lookup_dcookie(u64 cookie64, char __user *buf, size_t len)
{
unsigned long cookie = (unsigned long)cookie64;
int err = -EINVAL;
@ -203,13 +203,18 @@ SYSCALL_DEFINE3(lookup_dcookie, u64, cookie64, char __user *, buf, size_t, len)
return err;
}
SYSCALL_DEFINE3(lookup_dcookie, u64, cookie64, char __user *, buf, size_t, len)
{
return do_lookup_dcookie(cookie64, buf, len);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(lookup_dcookie, u32, w0, u32, w1, char __user *, buf, compat_size_t, len)
{
#ifdef __BIG_ENDIAN
return sys_lookup_dcookie(((u64)w0 << 32) | w1, buf, len);
return do_lookup_dcookie(((u64)w0 << 32) | w1, buf, len);
#else
return sys_lookup_dcookie(((u64)w1 << 32) | w0, buf, len);
return do_lookup_dcookie(((u64)w1 << 32) | w0, buf, len);
#endif
}
#endif