Re: [PATCH v2] audit: Avoid excessive dput/dget in audit_context setup and reset paths

[Mateusz Guzik]

On Tue, Feb 17, 2026 at 2:33 PM Christian Brauner <brauner@xxxxxxxxxx> wrote:
>
> On Thu, Feb 05, 2026 at 06:53:34PM +0100, Mateusz Guzik wrote:
> > On Thu, Feb 5, 2026 at 6:20 AM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> > > Mateusz: *is* there a measurable effect?  Because if there isn't, I'm
> > > very tempted to simply revert that thing.  "Churn of adding fs_struct.h
> > > as needed" is not the problem - try "exposing the object internals to
> > > far larger subset of the kernel".  We had interesting bugs with weird
> > > shit deciding to poke in there, locking and refcounting be damned.
> >
> > This one I did not bother benchmarking as it is an obvious change --
> > read a var directly instead of going through a func call.
> >
> > If this is causing trouble then it definitely needs to be reverted,
> > but any woes only speak to the mess in the header files.
>
> Any reason this isn't just stealing the cred.h trick?
>
> diff --git a/include/linux/fs_struct.h b/include/linux/fs_struct.h
> index 0070764b790a..e8b8d073f9e0 100644
> --- a/include/linux/fs_struct.h
> +++ b/include/linux/fs_struct.h
> @@ -2,11 +2,12 @@
>  #ifndef _LINUX_FS_STRUCT_H
>  #define _LINUX_FS_STRUCT_H
>
> -#include <linux/sched.h>
>  #include <linux/path.h>
>  #include <linux/spinlock.h>
>  #include <linux/seqlock.h>
>
> +struct task_struct;
> +
>  struct fs_struct {
>         int users;
>         seqlock_t seq;
> @@ -42,9 +43,6 @@ static inline void get_fs_pwd(struct fs_struct *fs, struct path *pwd)
>
>  extern bool current_chrooted(void);
>
> -static inline int current_umask(void)
> -{
> -       return current->fs->umask;
> -}
> +#define current_umask() (current->fs->umask)
>
>  #endif /* _LINUX_FS_STRUCT_H */
>

This depends on the users having task_struct already provided, which
sooner or later will give someone a build breakage when they work on a
new patch, but perhaps that's just a minor inconvenience and is not
worth worrying about.

That said, if the above is no considered a factor, I'm definitely not
going to protest.