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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id l6-20020a170903120600b0017272667a56sm3734063plh.196.2022.08.16.12.13.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Aug 2022 12:13:17 -0700 (PDT) From: Kees Cook To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, fmdefrancesco@gmail.com, linux-fsdevel@vger.kernel.org, ebiederm@xmission.com, Al Viro Cc: Kees Cook , ira.weiny@intel.com Subject: Re: [PATCH v2] fs: Replace kmap{,_atomic}() with kmap_local_page() Date: Tue, 16 Aug 2022 12:13:08 -0700 Message-Id: <166067718637.5584.14452180962626793627.b4-ty@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220803182856.28246-1-fmdefrancesco@gmail.com> References: <20220803182856.28246-1-fmdefrancesco@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=kcRvnsyQ; spf=pass (imf08.hostedemail.com: domain of keescook@chromium.org designates 209.85.214.179 as permitted sender) smtp.mailfrom=keescook@chromium.org; dmarc=pass (policy=none) header.from=chromium.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660677199; a=rsa-sha256; cv=none; b=SviyVO4HxS21LFpZ1OkfibHZwXnoOyq0OozJWWCLM/UW+jivme3EgnBN5hQKt54UuGdTfZ QRfco1mUmXSK+aMK9XaHn1Lhcz3uLeRoVJ90gy73mmYVUHF1FjuVjUUh/MyzSe1XSm6EqM YfbsEc5j6zWFlHh9j0bt9EGqyoQZtkE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660677199; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Wjb5AIGvJ0V/NRfbnr8gg1CmISm7LqELqnVgTQyStiY=; b=U01tZR1dyVBaWnRHOPk23ou+HngZiekML2+Ks2rVaAovGRKC/+oRlbCNYfd6JoHT07jhfV b8sCHMKBZPgA2EdgB6XyLz7lcWSH+Zddoc41Ymez5KTTYNQbwH2q0oWFI08PCIsNzYHkTr jlJrm9xJKCBUgGArjGr4Gp3GXKu4vXk= Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=kcRvnsyQ; spf=pass (imf08.hostedemail.com: domain of keescook@chromium.org designates 209.85.214.179 as permitted sender) smtp.mailfrom=keescook@chromium.org; dmarc=pass (policy=none) header.from=chromium.org X-Stat-Signature: eriqitnae4ttfbbnfrcbadeukwxz1toa X-Rspamd-Server: rspam09 X-Rspam-User: X-Rspamd-Queue-Id: 2330E1601D8 X-HE-Tag: 1660677198-162838 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000112, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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