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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-19 17:42:00 -0500
committerMiquel Raynal <miquel.raynal@bootlin.com>2020-03-24 23:02:30 +0100
commitf1ffdbfad00a3c424cadfd307b5bb9c466638532 (patch)
treedd5ecbef4e7eb9745bdd2a7c133c89ae6ddfa602
parent49c64df880570034308e4a9a49c4bc95cf8cdb33 (diff)
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mtd: maps: sa1100-flash: 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> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/linux-mtd/20200319224200.GA25162@embeddedor.com
-rw-r--r--drivers/mtd/maps/sa1100-flash.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/mtd/maps/sa1100-flash.c b/drivers/mtd/maps/sa1100-flash.c
index 47602af4ee34..bb1ef650ffd2 100644
--- a/drivers/mtd/maps/sa1100-flash.c
+++ b/drivers/mtd/maps/sa1100-flash.c
@@ -34,7 +34,7 @@ struct sa_subdev_info {
struct sa_info {
struct mtd_info *mtd;
int num_subdev;
- struct sa_subdev_info subdev[0];
+ struct sa_subdev_info subdev[];
};
static DEFINE_SPINLOCK(sa1100_vpp_lock);