Messages in this thread | | | Date | Sat, 09 Jun 2012 09:06:28 +0200 | From | Marco Stornelli <> | Subject | Re: [RFC, PATCH, RESEND] fs: push rcu_barrier() from deactivate_locked_super() to filesystems |
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Il 09/06/2012 02:28, Andrew Morton ha scritto: > On Fri, 8 Jun 2012 16:46:47 -0700 Linus Torvalds<torvalds@linux-foundation.org> wrote: > >> Of course, if you just mean having a VFS wrapper that does >> >> static void vfs_inode_kmem_cache_destroy(struct kmem_cache *cachep) >> { >> rcu_barrier(); >> kmem_cache_destroy(cachep); >> } >> >> then we could do that. Not much better than what Kirill's patch did, >> but at least we could have that comment in just one single place. > > That's conceptually what I meant. But it has the problem that new and > out-of-tree filesystems might forget to do it. Which is why I suggest > adding a kmem_cache* argument to unregister_filesystem() for this. > > It's a bit awkward, and the fs can pass in NULL if it knows what it's > doing. But it's reliable. > --
The call of rcu_barrier should be mandatory for the "unload fs module" problem, right? If the fs is compiled statically maybe we could avoid it, but (eventually) this kind of decision is per-fs, so this could be a clue that the call of rcu_barrier maybe is inside each fs not in VFS.
Marco
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