linux-kernel - Re: [PATCH v2] fs: Replace kmap{,_atomic}() with kmap_local

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Message-Id: <166067718637.5584.14452180962626793627.b4-ty@chromium.org>
Date:   Tue, 16 Aug 2022 12:13:08 -0700
From:   Kees Cook <keescook@...omium.org>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        fmdefrancesco@...il.com, linux-fsdevel@...r.kernel.org,
        ebiederm@...ssion.com, Al Viro <viro@...iv.linux.org.uk>
Cc:     Kees Cook <keescook@...omium.org>, ira.weiny@...el.com
Subject: Re: [PATCH v2] fs: Replace kmap{,_atomic}() with kmap_local_page()

On Wed, 3 Aug 2022 20:28:56 +0200, Fabio M. De Francesco wrote:
> The use of kmap() and kmap_atomic() are being deprecated in favor of
> kmap_local_page().
> 
> There are two main problems with kmap(): (1) It comes with an overhead as
> mapping space is restricted and protected by a global lock for
> synchronization and (2) it also requires global TLB invalidation when the
> kmap’s pool wraps and it might block when the mapping space is fully
> utilized until a slot becomes available.
> 
> [...]

Applied to for-next/execve, thanks!

[1/1] fs: Replace kmap{,_atomic}() with kmap_local_page()
      https://git.kernel.org/kees/c/3a608cfee97e

-- 
Kees Cook