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

Using the fs-internal do_vmsplice() helper allows us to get rid of the
fs-internal call to the sys_vmsplice() 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 15:00:24 +01:00
parent 98e5f7bd2c
commit 30cfe4ef8b
1 changed files with 9 additions and 3 deletions
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12
fs/splice.c
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@ -1331,8 +1331,8 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
* Currently we punt and implement it as a normal copy, see pipe_to_user(). * Currently we punt and implement it as a normal copy, see pipe_to_user().
* *
*/ */
SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, iov, static long do_vmsplice(int fd, const struct iovec __user *iov,
unsigned long, nr_segs, unsigned int, flags) unsigned long nr_segs, unsigned int flags)
{ {
struct fd f; struct fd f;
long error; long error;
@ -1358,6 +1358,12 @@ SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, iov,
return error; return error;
} }
SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, iov,
unsigned long, nr_segs, unsigned int, flags)
{
return do_vmsplice(fd, iov, nr_segs, flags);
}
#ifdef CONFIG_COMPAT #ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(vmsplice, int, fd, const struct compat_iovec __user *, iov32, COMPAT_SYSCALL_DEFINE4(vmsplice, int, fd, const struct compat_iovec __user *, iov32,
unsigned int, nr_segs, unsigned int, flags) unsigned int, nr_segs, unsigned int, flags)
@ -1375,7 +1381,7 @@ COMPAT_SYSCALL_DEFINE4(vmsplice, int, fd, const struct compat_iovec __user *, io
put_user(v.iov_len, &iov[i].iov_len)) put_user(v.iov_len, &iov[i].iov_len))
return -EFAULT; return -EFAULT;
} }
return sys_vmsplice(fd, iov, nr_segs, flags); return do_vmsplice(fd, iov, nr_segs, flags);
} }
#endif #endif