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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-23 16:43:39 -0500
committerGustavo A. R. Silva <gustavo@embeddedor.com>2020-04-18 15:44:54 -0500
commitf36aaf8be421099103193c49796a14213d3be315 (patch)
tree9fca686271a805ea635ee60afc5aa3438385fa3d /include
parent0a368bf00e3a7c57a57efc1bf79b79facb97639c (diff)
blk-mq: 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/blk-mq.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index f389d7c724bd..b45148ba3291 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -173,7 +173,7 @@ struct blk_mq_hw_ctx {
* blocking (BLK_MQ_F_BLOCKING). Must be the last member - see also
* blk_mq_hw_ctx_size().
*/
- struct srcu_struct srcu[0];
+ struct srcu_struct srcu[];
};
/**