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See http://www.infradead.org/rpr.html ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655452845; a=rsa-sha256; cv=none; b=dAwHIR+go9WJx2Vff+NdkBUgSSc5pgbAtgVgb3UhNM7Y7sPnGH/tEz1ZJhz3sI3UVDpDPU DBQJkdjXBvDkV9Q6HDGnpDwgETRjw7tMaKyZ020ndvHyaOuR2mVWx/NTECpvJaEsV/LRa1 FE7AEhVNIZvbMv4cc8OI6E1dk1op9ZU= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=LzkqBO94; dmarc=none; spf=none (imf23.hostedemail.com: domain of BATV+9e01da67fa36993cc8ff+6872+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+9e01da67fa36993cc8ff+6872+infradead.org+hch@bombadil.srs.infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655452845; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=yf7G106I8eNg8huKyNP39rS31x9Ej2FmZ3Uo3WWeHGY=; b=LEF6UULtpLCR+skvLyKp2aldfUW9jGl4Bdm6VRUyFqCqArvYm6NY70gmbeW6l3p6YvSywU 5z35Pzj0C4cDeclj8xjalUEl0uKQJxIs7DfUxVhM62hCThTG4MVNvUIDN6Jd647NVC7jdM aC+uKQq35nZoYjNCkqPy0EPJOC83HTA= X-Rspamd-Queue-Id: 2968B14009A X-Rspam-User: Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=LzkqBO94; dmarc=none; spf=none (imf23.hostedemail.com: domain of BATV+9e01da67fa36993cc8ff+6872+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+9e01da67fa36993cc8ff+6872+infradead.org+hch@bombadil.srs.infradead.org X-Rspamd-Server: rspam06 X-Stat-Signature: yto395g3nkdjffghpztxz49prfbpumck X-HE-Tag: 1655452843-103269 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Jun 17, 2022 at 05:48:11AM +0000, Christophe Leroy wrote: > Is it a good idea to duplicate vm_get_page_prot() in each architecture ? It is a completely trivial array index. And I really like the idea of not having the protection_map in common code - it really is an implementation detail. But what we could do is something like #define DECLARE_VM_GET_PAGE_PROT \ pgprot_t vm_get_page_prot(unsigned long vm_flags) \ { \ return protection_map[vm_flags & \ (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)]; \ } \ EXPORT_SYMBOL(vm_get_page_prot); as a helper for the architectures. > Maybe it is, but it will also mean changing common code like > mm/debug_vm_pgtable.c which accesses protection_map[] directly as of today. That's already gone thanks to the good work from Anshuman.