From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Russell King (Oracle)" Date: Wed, 02 Mar 2022 11:19:22 +0000 Subject: Re: [PATCH V3 09/30] arm/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT Message-Id: List-Id: References: <1646045273-9343-10-git-send-email-anshuman.khandual@arm.com> <542fa048-131e-240b-cc3a-fd4fff7ce4ba@arm.com> <52866c88-59f9-2d1c-6f5a-5afcaf23f2bb@csgroup.eu> <9caa90f5-c10d-75dd-b403-1388b7a3d296@arm.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Anshuman Khandual Cc: Geert Uytterhoeven , Christophe Leroy , "linux-ia64@vger.kernel.org" , "linux-sh@vger.kernel.org" , "linux-mips@vger.kernel.org" , "linux-mm@kvack.org" , "sparclinux@vger.kernel.org" , "linux-riscv@lists.infradead.org" , "linux-arch@vger.kernel.org" , "linux-s390@vger.kernel.org" , "linux-hexagon@vger.kernel.org" , "linux-csky@vger.kernel.org" , Christoph Hellwig , "linux-snps-arc@lists.infradead.org" , "linux-xtensa@linux-xtensa.org" , Arnd Bergmann , "linux-um@lists.infradead.org" , "linux-m68k@lists.linux-m68k.org" , "openrisc@lists.librecores.org" , "linux-arm-kernel@lists.infradead.org" , "linux-parisc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-alpha@vger.kernel.org" , "akpm@linux-foundation.org" , "linuxppc-dev@lists.ozlabs.org" On Wed, Mar 02, 2022 at 04:36:52PM +0530, Anshuman Khandual wrote: > On 3/2/22 3:35 PM, Geert Uytterhoeven wrote: > > I doubt the switch() variant would give better code on any platform. > > > > What about using tables everywhere, using designated initializers > > to improve readability? > > Designated initializers ? Could you please be more specific. A table look > up on arm platform would be something like this and arm_protection_map[] > needs to be updated with user_pgprot like before. There is *absolutely* nothing wrong with that. Updating it once during boot is way more efficient than having to compute the value each time vm_get_page_prot() gets called. Thanks. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!