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author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-26 16:31:25 -0600 |
---|---|---|
committer | Ulf Hansson <ulf.hansson@linaro.org> | 2020-03-24 14:39:45 +0100 |
commit | 1a91a36aba9c232c73e4a5fce038147f5d29e566 (patch) | |
tree | 556ba35f35e808f13f5f51cc08f47c0a2b2b5d2c /drivers/mmc/host/sdhci-pci.h | |
parent | ea21e9b2b33fd06c131415cc66ca5499ab2aef5f (diff) | |
download | linux-1a91a36aba9c232c73e4a5fce038147f5d29e566.tar.bz2 |
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 'drivers/mmc/host/sdhci-pci.h')
-rw-r--r-- | drivers/mmc/host/sdhci-pci.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/mmc/host/sdhci-pci.h b/drivers/mmc/host/sdhci-pci.h index 981bbbe63aff..42ccd123b046 100644 --- a/drivers/mmc/host/sdhci-pci.h +++ b/drivers/mmc/host/sdhci-pci.h @@ -163,7 +163,7 @@ struct sdhci_pci_slot { bool cd_override_level; void (*hw_reset)(struct sdhci_host *host); - unsigned long private[0] ____cacheline_aligned; + unsigned long private[] ____cacheline_aligned; }; struct sdhci_pci_chip { |