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 <20201111174902.GK517454@elver.google.com>
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From:   Andrey Konovalov <andreyknvl@google.com>
Date:   Thu, 12 Nov 2020 20:45:18 +0100
Message-ID: <CAAeHK+wvvkYko=tM=NHODkKas13h5Jvsswvg05jhv9LqE0jSjQ@mail.gmail.com>
Subject: Re: [PATCH v2 10/20] kasan: inline and rename kasan_unpoison_memory
To:     Marco Elver <elver@google.com>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Wed, Nov 11, 2020 at 6:49 PM Marco Elver <elver@google.com> wrote:
>
> On Tue, Nov 10, 2020 at 11:20PM +0100, Andrey Konovalov wrote:
> > Currently kasan_unpoison_memory() is used as both an external annotation
> > and as an internal memory poisoning helper. Rename external annotation to
> > kasan_unpoison_data() and inline the internal helper for hardware
> > tag-based mode to avoid undeeded function calls.
>
> I don't understand why this needs to be renamed again. The users of
> kasan_unpoison_memory() outweigh those of kasan_unpoison_slab(), of
> which there seems to be only 1!

The idea is to make kasan_(un)poison_memory() functions inlinable for
internal use. It doesn't have anything to do with the number of times
they are used.

Perhaps we can drop the kasan_ prefix for the internal implementations
though, and keep using kasan_unpoison_memory() externally.

> So can't we just get rid of kasan_unpoison_slab() and just open-code it
> in mm/mempool.c:kasan_unpoison_element()? That function is already
> kasan-prefixed, so we can even place a small comment there (which would
> also be an improvement over current interface, since
> kasan_unpoison_slab() is not documented and its existence not quite
> justified).

We can, but this is a change unrelated to this patch.