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authorGustavo A. R. Silva <gustavoars@kernel.org>2020-05-07 14:22:28 -0500
committerMark Brown <broonie@kernel.org>2020-05-08 11:28:48 +0100
commit2d6201ee1123325c089008570bd5ddea3c5b131a (patch)
tree4ac2c8319be946bce42a20bce7c919418769a526 /include/sound
parent28d4adc4257cd2e119df17aa7e9d18cdf607f23d (diff)
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.h2
-rw-r--r--include/sound/soc.h2
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]