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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-19 14:50:46 -0500
committerDan Williams <dan.j.williams@intel.com>2020-03-25 17:08:42 -0700
commit4b566406085bc1fd5b6ba309fae70e6f6d6fa94e (patch)
tree6c3bf42a20bc4c0670e840a9e5b972084a3b2d58 /drivers/acpi
parent11a48a5a18c63fd7621bb050228cebf13566e4d8 (diff)
downloadlinux-4b566406085bc1fd5b6ba309fae70e6f6d6fa94e.tar.bz2
ACPI: NFIT: 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> Link: https://lore.kernel.org/r/20200319195046.GA452@embeddedor.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/nfit/nfit.h12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h
index 24241941181c..af09143ce403 100644
--- a/drivers/acpi/nfit/nfit.h
+++ b/drivers/acpi/nfit/nfit.h
@@ -144,32 +144,32 @@ struct nfit_spa {
unsigned long ars_state;
u32 clear_err_unit;
u32 max_ars;
- struct acpi_nfit_system_address spa[0];
+ struct acpi_nfit_system_address spa[];
};
struct nfit_dcr {
struct list_head list;
- struct acpi_nfit_control_region dcr[0];
+ struct acpi_nfit_control_region dcr[];
};
struct nfit_bdw {
struct list_head list;
- struct acpi_nfit_data_region bdw[0];
+ struct acpi_nfit_data_region bdw[];
};
struct nfit_idt {
struct list_head list;
- struct acpi_nfit_interleave idt[0];
+ struct acpi_nfit_interleave idt[];
};
struct nfit_flush {
struct list_head list;
- struct acpi_nfit_flush_address flush[0];
+ struct acpi_nfit_flush_address flush[];
};
struct nfit_memdev {
struct list_head list;
- struct acpi_nfit_memory_map memdev[0];
+ struct acpi_nfit_memory_map memdev[];
};
enum nfit_mem_flags {