diff options
author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-19 14:50:46 -0500 |
---|---|---|
committer | Dan Williams <dan.j.williams@intel.com> | 2020-03-25 17:08:42 -0700 |
commit | 4b566406085bc1fd5b6ba309fae70e6f6d6fa94e (patch) | |
tree | 6c3bf42a20bc4c0670e840a9e5b972084a3b2d58 | |
parent | 11a48a5a18c63fd7621bb050228cebf13566e4d8 (diff) |
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>
-rw-r--r-- | drivers/acpi/nfit/nfit.h | 12 |
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 { |