Re: [PATCH 14/15] kernel: convert futex_pi_state.refcount from atomic_t to refcount_t

From: Thomas Gleixner
Date: Mon Jul 17 2017 - 10:25:52 EST


On Mon, 17 Jul 2017, Elena Reshetova wrote:

> Subject: kernel: convert futex_pi_state.refcount from atomic_t to refcount_t

Several people including myself told you already, that subjects consist of

SUBSYSTEMPREFIX: Concise description

It's easy enough to figure the prefix out by looking at the output of 'git
log path/of/changed/file'.

Concise descriptions are not lengthy sentences with implementation
details. They should merily describe the problem/concept of change. The
details go into the changelog. IOW, something like:

"PROPERPREFIX: Convert to refcount API"

would be sufficient.

> refcount_t type and corresponding API should be
> used instead of atomic_t when the variable is used as
> a reference counter. This allows to avoid accidental
> refcounter overflows that might lead to use-after-free
> situations.

Copying the same sentence over and over avoids thinking about a proper
changelog, right? You fail to explain, how you come to the conclusion that
futex_pi_state.refcount is a pure reference counter (aside of the name) and
therefor can be safely converted to refcount_t.

Other than that, the patch itself is fine.

Thanks,

tglx