Messages in this thread |  | | Subject | Re: [PATCH] Initial support for struct vfs_cred [0/1] | From | Luca Barbieri <> | Date | 01 Sep 2002 20:42:57 +0200 |
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On Sun, 2002-09-01 at 18:38, Trond Myklebust wrote: > >>>>> " " == Luca Barbieri <ldb@ldb.ods.org> writes: > > > That's what the code did, unless I misunderstood it. Anyway if > > you want to give a different fsuid to a filesystem function, > > you either pass credentials as a parameter (that means that you > > change all the functions in the call chain to do that) or you > > If you read through the beginning of the thread, you will see that > this is *exactly* what I'm proposing to do. Just not in this one > already very large patch. But you'll need to modify the declaration of the various function pointers whose implementations might need credentials and modify all functions that call them and deal with permissions. Instead with my proposal the credentials are automatically immutable across the syscall without needing to worry at all about locks, counts and sharing.
And remember that passing parameters has a cost since you need to push them and the stack will be larger, occupy more cachelines, and thus cause more cache misses. All this without any particular reason to do since normally the credentials are always the same.
Of course, if you have reason to think that we'll need to call VFS functions with a lot of differential credential then you are right, but otherwise you would add just a lot of useless overhead and code modifications.
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