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From: Nick Desaulniers <ndesaulniers@google.com>
To: Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>
Cc: "Gustavo A . R . Silva" <gustavo@embeddedor.com>,
	Joe Perches <joe@perches.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	"Gustavo A . R . Silva" <gustavoars@kernel.org>,
	Miaohe Lin <linmiaohe@huawei.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Hongxiang Lou <louhongxiang@huawei.com>,
	linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com
Subject: [PATCH v3] nfs: remove incorrect fallthrough label
Date: Thu, 17 Sep 2020 14:45:45 -0700	[thread overview]
Message-ID: <20200917214545.199463-1-ndesaulniers@google.com> (raw)
In-Reply-To: <ce28bb9bc25cb3f1197f75950a0cfe14947f9002.camel@perches.com>

There is no case after the default from which to fallthrough to. Clang
will error in this case (unhelpfully without context, see link below)
and GCC will with -Wswitch-unreachable.

The previous commit should have just replaced the comment with a break
statement.

If we consider implicit fallthrough to be a design mistake of C, then
all case statements should be terminated with one of the following
statements:
* break
* continue
* return
* fallthrough
* goto
* (call of function with __attribute__(__noreturn__))

Fixes: 2a1390c95a69 ("nfs: Convert to use the preferred fallthrough macro")
Link: https://bugs.llvm.org/show_bug.cgi?id=47539
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
Changes v3:
* update the commit message as per Joe.
* collect tags.

Changes v2:
* add break rather than no terminating statement as per Joe.
* add Joe's suggested by tag.
* add blurb about acceptable terminal statements.

 fs/nfs/super.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index d20326ee0475..eb2401079b04 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -889,7 +889,7 @@ static struct nfs_server *nfs_try_mount_request(struct fs_context *fc)
 		default:
 			if (rpcauth_get_gssinfo(flavor, &info) != 0)
 				continue;
-			fallthrough;
+			break;
 		}
 		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
 		ctx->selected_flavor = flavor;
-- 
2.28.0.681.g6f77f65b4e-goog


  parent reply	other threads:[~2020-09-17 21:46 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-15 22:57 [PATCH] " Nick Desaulniers
2020-09-15 23:29 ` Joe Perches
2020-09-15 23:51   ` Gustavo A. R. Silva
2020-09-16  0:01     ` Gustavo A. R. Silva
2020-09-16  0:33       ` Joe Perches
2020-09-16 20:02   ` [PATCH v2] " Nick Desaulniers
2020-09-16 20:18     ` Gustavo A. R. Silva
2020-09-16 20:19     ` Joe Perches
2020-09-17 21:41       ` Nick Desaulniers
2020-09-18  1:36         ` Joe Perches
2020-09-17 21:45       ` Nick Desaulniers [this message]
2020-09-24 17:19         ` [PATCH v3] " Nick Desaulniers
2020-09-24 17:40           ` Joe Perches
2020-09-24 18:07             ` Joe Perches
2020-09-24 18:11               ` Anna Schumaker
2020-09-25 11:27                 ` Mark Brown
2020-09-24 18:08           ` Gustavo A. R. Silva
2020-09-17  4:35     ` [PATCH v2] " Nathan Chancellor

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