Re: [PATCH] drivers/base - fix sparse warnings
From: Linus Torvalds
Date: Thu Oct 13 2005 - 13:11:08 EST
On Thu, 13 Oct 2005, Ben Dooks wrote:
> The patch does not solve all the sparse errors generated,
> but reduces the count significantly.
Well, you should also then remove the _bad_ declarations.
For example, attribute_container_init() right now is defined in
attribute_container.c, but then it's _declared_ (with no checking) where
it's used in init.c.
The sparse warnign is appropriate: it was not declared where that
declaration is actually visible to the definition, so the code basically
isn't type-safe at all (since there's nothing that enforces the
declaration actually matching the definition).
You made the declaration properly visible, but you should also remove the
bogus declaration. A declaration that isn't visible to the definition is
always bad - since in the absense of a compiler with global visibility it
may or may not actually match what it supposedly declares.
I wonder if I should make sparse warn about multiple declarations..
These days, sparse actually has some limited support for checking _global_
visibility, and we could do cross-checking across thousands of files.
However, the build environment isn't really very amenable to that, so
doing a global sparse check is pretty hard in practice.
We could possibly do a per-directory global check, which might be better
than nothing (ie if you were to have incorrect declaration in a C file
that is in the same directory as another C file, then we could
But the kernel kbuild environment is pretty hairy, and I wouldn't even
know where to begin trying to do that. It's also fundamentally hard to do
if there are per-file pre-defines (since to do a cross-check, sparse wants
to see all C files together on the command line).
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