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author | David S. Miller <davem@davemloft.net> | 2019-10-20 08:51:25 +0300 |
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committer | David S. Miller <davem@davemloft.net> | 2019-10-20 20:43:00 +0300 |
commit | 2f184393e0c2d409c62262f57f2a57efdf9370b8 (patch) | |
tree | 25b96db2550014d7f888605abfabb67a7f40a5d3 /Documentation/process/deprecated.rst | |
parent | ebcd670d05d54ff8d17a1a51bba1ec1e4069d949 (diff) | |
parent | 531e93d11470aa2e14e6a3febef50d9bc7bab7a1 (diff) | |
download | linux-2f184393e0c2d409c62262f57f2a57efdf9370b8.tar.xz |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Several cases of overlapping changes which were for the most
part trivially resolvable.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/process/deprecated.rst')
-rw-r--r-- | Documentation/process/deprecated.rst | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst index 053b24a6dd38..179f2a5625a0 100644 --- a/Documentation/process/deprecated.rst +++ b/Documentation/process/deprecated.rst @@ -122,14 +122,27 @@ memory adjacent to the stack (when built without `CONFIG_VMAP_STACK=y`) Implicit switch case fall-through --------------------------------- -The C language allows switch cases to "fall through" when -a "break" statement is missing at the end of a case. This, -however, introduces ambiguity in the code, as it's not always -clear if the missing break is intentional or a bug. As there -have been a long list of flaws `due to missing "break" statements +The C language allows switch cases to "fall-through" when a "break" statement +is missing at the end of a case. This, however, introduces ambiguity in the +code, as it's not always clear if the missing break is intentional or a bug. + +As there have been a long list of flaws `due to missing "break" statements <https://cwe.mitre.org/data/definitions/484.html>`_, we no longer allow -"implicit fall-through". In order to identify an intentional fall-through -case, we have adopted the marking used by static analyzers: a comment -saying `/* Fall through */`. Once the C++17 `__attribute__((fallthrough))` -is more widely handled by C compilers, static analyzers, and IDEs, we can -switch to using that instead. +"implicit fall-through". + +In order to identify intentional fall-through cases, we have adopted a +pseudo-keyword macro 'fallthrough' which expands to gcc's extension +__attribute__((__fallthrough__)). `Statement Attributes +<https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html>`_ + +When the C17/C18 [[fallthrough]] syntax is more commonly supported by +C compilers, static analyzers, and IDEs, we can switch to using that syntax +for the macro pseudo-keyword. + +All switch/case blocks must end in one of: + + break; + fallthrough; + continue; + goto <label>; + return [expression]; |