[PATCH 3/7] lib/iov_iter: fix misplaced parenthesis in iov_iter_restore() kvec check

[Josh Law <objecting@objecting.org>]

When restoring a kvec-backed iterator after a short write in a kernel
socket sendmsg path (e.g. an NFS client resending an RPC call), the
WARN_ON_ONCE guard fires a spurious warning on every first call.

The closing parenthesis of WARN_ON_ONCE is after !iter_is_ubuf(i),
leaving !iov_iter_is_kvec(i) as a separate && operand outside the
macro:

  WARN_ON_ONCE(!bvec && !iovec && !ubuf) && !kvec

For kvec iterators this evaluates as WARN_ON_ONCE(true) && false — the
warning fires but the return is skipped, so execution proceeds correctly.
The warning is the only visible symptom, but it is confusing and may
mask real issues.

Found through code review of the operator precedence in the condition
expression and confirmed by tracing the macro expansion.

Move the closing parenthesis to include the kvec check inside
WARN_ON_ONCE so the warning only fires for genuinely unsupported
iterator types.

Signed-off-by: Josh Law <objecting@objecting.org>
---
 lib/iov_iter.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 325669b103ed..6a7959bfc849 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1471,7 +1471,7 @@ EXPORT_SYMBOL_GPL(import_ubuf);
 void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state)
 {
 	if (WARN_ON_ONCE(!iov_iter_is_bvec(i) && !iter_is_iovec(i) &&
-			 !iter_is_ubuf(i)) && !iov_iter_is_kvec(i))
+			 !iter_is_ubuf(i) && !iov_iter_is_kvec(i)))
 		return;
 	i->iov_offset = state->iov_offset;
 	i->count = state->count;
-- 
2.34.1