On Wed, Sep 03 2025, Joanne Koong wrote: > On Wed, Sep 3, 2025 at 1:48 PM Darrick J. Wong <djwong@xxxxxxxxxx> wrote: >> ...because if someone fails to set wpc->wb_ctx, this line will crash the >> kernel at least as much as the WARN_ON would. IOWs, the WARN_ONs aren't >> necessary but I don't think they hurt much. >> > > Oh, I see. Actually, this explanation makes a lot of sense. When I was > looking at the other WARN_ON usages in fuse, I noticed they were also > used even if it's logically proven that the code path can never be > triggered. But I guess what you're saying is that WARN_ONs in general > should be used if it's otherwise somehow undetectable / non-obvious > that the condition is violated? That makes sense to me, and checks out > with the other fuse WARN_ON uses. > > I'm fine with just removing the WARN_ON(!data) here and below. I think > I added some more WARN_ONs in my other fuse iomap patchset, so I'll > remove those as well when I send out a new version. I don't have a preference between v1 and v2 of this patch. v1 removed the WARNs because I don't think they are useful: 1. the assertions are never true, but 2. if they are, they are useless because we'll hit a NULL pointer dereference anyway. v2 tries to fix the code assuming the assertions can be triggered. So, yeah I'll just leave the 3 options (v1, v2, or do nothing) on the table :-) Cheers, -- Luís
