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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-26 16:31:25 -0600
committerUlf Hansson <ulf.hansson@linaro.org>2020-03-24 14:39:45 +0100
commit1a91a36aba9c232c73e4a5fce038147f5d29e566 (patch)
tree556ba35f35e808f13f5f51cc08f47c0a2b2b5d2c /include/linux/mmc
parentea21e9b2b33fd06c131415cc66ca5499ab2aef5f (diff)
mmc: Replace zero-length array with flexible-array member
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] 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 <gustavo@embeddedor.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Link: https://lore.kernel.org/r/20200226223125.GA20630@embeddedor Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'include/linux/mmc')
-rw-r--r--include/linux/mmc/host.h2
-rw-r--r--include/linux/mmc/sdio_func.h2
2 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index f5db24a6a860..c318fb5b6a94 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -468,7 +468,7 @@ struct mmc_host {
/* Host Software Queue support */
bool hsq_enabled;
- unsigned long private[0] ____cacheline_aligned;
+ unsigned long private[] ____cacheline_aligned;
};
struct device_node;
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
index 5a177f7a83c3..fa2aaab5e57a 100644
--- a/include/linux/mmc/sdio_func.h
+++ b/include/linux/mmc/sdio_func.h
@@ -25,7 +25,7 @@ struct sdio_func_tuple {
struct sdio_func_tuple *next;
unsigned char code;
unsigned char size;
- unsigned char data[0];
+ unsigned char data[];
};
/*