[PATCH] readv.2: Fix wrong errno for an unknown flag

[Xiao Yang <yangx.jy@xxxxxxxxxxxxxx>]

According to the following kernel code, preadv2(2)/pwritev2(2) with
an unknown flag actually returned EOPNOTSUPP instead of EINVAL:
----------------------------------------------------------------
static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags)
{
	if (unlikely(flags & ~RWF_SUPPORTED)) {
		return -EOPNOTSUPP;
	}
	...
}

static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
		loff_t *ppos, int type, rwf_t flags)
{
	...
	if (flags & ~RWF_HIPRI)
		return -EOPNOTSUPP;
	...
}

Signed-off-by: Xiao Yang <yangx.jy@xxxxxxxxxxxxxx>
---
 man2/readv.2 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/man2/readv.2 b/man2/readv.2
index 4441e92..2d73007 100644
--- a/man2/readv.2
+++ b/man2/readv.2
@@ -312,7 +312,7 @@ The vector count,
 .IR iovcnt ,
 is less than zero or greater than the permitted maximum.
 .TP
-.B EINVAL
+.B EOPNOTSUPP
 An unknown flag is specified in \fIflags\fP.
 .SH VERSIONS
 .BR preadv ()
-- 
1.8.3.1