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| author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 14:22:28 -0500 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2020-05-08 11:28:48 +0100 |
| commit | 2d6201ee1123325c089008570bd5ddea3c5b131a (patch) | |
| tree | 4ac2c8319be946bce42a20bce7c919418769a526 /include/sound | |
| parent | 28d4adc4257cd2e119df17aa7e9d18cdf607f23d (diff) | |
| download | linux-2d6201ee1123325c089008570bd5ddea3c5b131a.tar.bz2 | |
ASoC: soc-core: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200507192228.GA16355@embeddedor
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'include/sound')
| -rw-r--r-- | include/sound/soc-dapm.h | 2 | ||||
| -rw-r--r-- | include/sound/soc.h | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/include/sound/soc-dapm.h b/include/sound/soc-dapm.h index 08495f8d86dc..cc3dcb815282 100644 --- a/include/sound/soc-dapm.h +++ b/include/sound/soc-dapm.h @@ -689,7 +689,7 @@ struct snd_soc_dapm_context { /* A list of widgets associated with an object, typically a snd_kcontrol */ struct snd_soc_dapm_widget_list { int num_widgets; - struct snd_soc_dapm_widget *widgets[0]; + struct snd_soc_dapm_widget *widgets[]; }; #define for_each_dapm_widgets(list, i, widget) \ diff --git a/include/sound/soc.h b/include/sound/soc.h index 1288a87f9ccb..69a82487fa9b 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -1172,7 +1172,7 @@ struct snd_soc_pcm_runtime { unsigned int fe_compr:1; /* for Dynamic PCM */ int num_components; - struct snd_soc_component *components[0]; /* CPU/Codec/Platform */ + struct snd_soc_component *components[]; /* CPU/Codec/Platform */ }; /* see soc_new_pcm_runtime() */ #define asoc_rtd_to_cpu(rtd, n) (rtd)->dais[n] |