Re: [PATCH] vfs: workaround gcc <4.6 build error in link_path_walk()

From: Al Viro
Date: Tue Sep 16 2014 - 13:40:11 EST


On Tue, Sep 16, 2014 at 01:07:35PM +0100, James Hogan wrote:
> Commit d6bb3e9075bb (vfs: simplify and shrink stack frame of
> link_path_walk()) introduced build problems with GCC versions older than
> 4.6 due to the initialisation of a member of an anonymous union in
> struct qstr without enclosing braces.
>
> This hits GCC bug 10676 [1] (which was fixed in GCC 4.6 by [2]), and
> causes the following build error:
> fs/namei.c: In function 'link_path_walk':
> fs/namei.c:1778: error: unknown field 'hash_len' specified in initializer
>
> This is worked around by adding explicit braces.

IOW, the same thing QSTR_INIT is doing... BTW, after looking at the commit
in question, what the hell was this
+ name = this.name;
in link_path_walk() about? Granted, none of the ->d_hash() instances in
the tree reassign qstr->name, and out-of-tree ones are unlikely to do it
either, so it's harmless but... why bother rereading this.name at all?
Linus?
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