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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-24 01:43:59 +0300
committerGustavo A. R. Silva <gustavo@embeddedor.com>2020-04-18 23:44:54 +0300
commit89f60a5d9bf5a6b9b16dfdd56a91c4a2d7b8830d (patch)
tree877c993e896e98a34b72551970b2d42509448e65 /include
parent5299a11a9378e8c68e3b8e2040f7aa7e401d50b7 (diff)
downloadlinux-89f60a5d9bf5a6b9b16dfdd56a91c4a2d7b8830d.tar.xz
genalloc.h: 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>
Diffstat (limited to 'include')
-rw-r--r--include/linux/genalloc.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
index 5b14a0f38124..0bd581003cd5 100644
--- a/include/linux/genalloc.h
+++ b/include/linux/genalloc.h
@@ -76,7 +76,7 @@ struct gen_pool_chunk {
void *owner; /* private data to retrieve at alloc time */
unsigned long start_addr; /* start address of memory chunk */
unsigned long end_addr; /* end address of memory chunk (inclusive) */
- unsigned long bits[0]; /* bitmap for allocating memory chunk */
+ unsigned long bits[]; /* bitmap for allocating memory chunk */
};
/*