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author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-26 23:31:25 +0100 |
---|---|---|
committer | Ulf Hansson <ulf.hansson@linaro.org> | 2020-03-24 14:39:45 +0100 |
commit | 1a91a36aba9c232c73e4a5fce038147f5d29e566 (patch) | |
tree | 556ba35f35e808f13f5f51cc08f47c0a2b2b5d2c /drivers/mmc | |
parent | mmc: mmc_test: Pass different sg lists for non-blocking requests (diff) | |
download | linux-1a91a36aba9c232c73e4a5fce038147f5d29e566.tar.xz linux-1a91a36aba9c232c73e4a5fce038147f5d29e566.zip |
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')
-rw-r--r-- | drivers/mmc/host/sdhci-acpi.c | 2 | ||||
-rw-r--r-- | drivers/mmc/host/sdhci-cadence.c | 2 | ||||
-rw-r--r-- | drivers/mmc/host/sdhci-pci.h | 2 | ||||
-rw-r--r-- | drivers/mmc/host/sdhci-pltfm.h | 2 | ||||
-rw-r--r-- | drivers/mmc/host/sdhci.h | 2 | ||||
-rw-r--r-- | drivers/mmc/host/vub300.c | 2 |
6 files changed, 6 insertions, 6 deletions
diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c index 2a2173d953f5..68cf41747fa5 100644 --- a/drivers/mmc/host/sdhci-acpi.c +++ b/drivers/mmc/host/sdhci-acpi.c @@ -75,7 +75,7 @@ struct sdhci_acpi_host { bool use_runtime_pm; bool is_intel; bool reset_signal_volt_on_suspend; - unsigned long private[0] ____cacheline_aligned; + unsigned long private[] ____cacheline_aligned; }; enum { diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c index e573495f8726..6da6d4fb5edd 100644 --- a/drivers/mmc/host/sdhci-cadence.c +++ b/drivers/mmc/host/sdhci-cadence.c @@ -68,7 +68,7 @@ struct sdhci_cdns_priv { void __iomem *hrs_addr; bool enhanced_strobe; unsigned int nr_phy_params; - struct sdhci_cdns_phy_param phy_params[0]; + struct sdhci_cdns_phy_param phy_params[]; }; struct sdhci_cdns_phy_cfg { 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 { diff --git a/drivers/mmc/host/sdhci-pltfm.h b/drivers/mmc/host/sdhci-pltfm.h index 2af445b8c325..6301b81cf573 100644 --- a/drivers/mmc/host/sdhci-pltfm.h +++ b/drivers/mmc/host/sdhci-pltfm.h @@ -25,7 +25,7 @@ struct sdhci_pltfm_host { unsigned int clock; u16 xfer_mode_shadow; - unsigned long private[0] ____cacheline_aligned; + unsigned long private[] ____cacheline_aligned; }; #ifdef CONFIG_MMC_SDHCI_BIG_ENDIAN_32BIT_BYTE_SWAPPER diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index cac2d97782e6..249635692112 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -614,7 +614,7 @@ struct sdhci_host { u64 data_timeout; - unsigned long private[0] ____cacheline_aligned; + unsigned long private[] ____cacheline_aligned; }; struct sdhci_ops { diff --git a/drivers/mmc/host/vub300.c b/drivers/mmc/host/vub300.c index 6ced1b7f642f..a5a90d133f1f 100644 --- a/drivers/mmc/host/vub300.c +++ b/drivers/mmc/host/vub300.c @@ -95,7 +95,7 @@ struct sd_response_header { u8 port_number; u8 command_type; u8 command_index; - u8 command_response[0]; + u8 command_response[]; } __packed; struct sd_status_header { |