Re: [PATCH][next] treewide: uapi: Replace zero-length arrays with flexible-array members
From: Jason Gunthorpe <jgg@ziepe.ca>
Date: 2022-06-28 13:38:15
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On Tue, Jun 28, 2022 at 04:21:29AM +0200, Gustavo A. R. Silva wrote:
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Though maybe we could just switch off -Wgnu-variable-sized-type-not-at-end during configuration ?
We need to think in a different strategy.
I think we will need to switch off the warning in userspace - this is doable for rdma-core. On the other hand, if the goal is to enable the array size check compiler warning I would suggest focusing only on those structs that actually hit that warning in the kernel. IIRC infiniband doesn't trigger it because it just pointer casts the flex array to some other struct. It isn't actually an array it is a placeholder for a trailing structure, so it is never indexed. This is also why we hit the warning because the convient way for userspace to compose the message is to squash the header and trailer structs together in a super struct on the stack, then invoke the ioctl. Jason