Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756677Ab3CEOXd (ORCPT ); Tue, 5 Mar 2013 09:23:33 -0500 Received: from mail-qe0-f42.google.com ([209.85.128.42]:33773 "EHLO mail-qe0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752847Ab3CEOXa (ORCPT ); Tue, 5 Mar 2013 09:23:30 -0500 Date: Tue, 5 Mar 2013 22:23:26 +0800 (HKT) From: Nicolas Pitre To: Joonsoo Kim cc: Russell King , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ARM: mm: clean-up in order to reduce to call kmap_high_get() In-Reply-To: <1362372609-877-1-git-send-email-iamjoonsoo.kim@lge.com> Message-ID: References: <1362372609-877-1-git-send-email-iamjoonsoo.kim@lge.com> User-Agent: Alpine 2.03 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2518 Lines: 77 On Mon, 4 Mar 2013, Joonsoo Kim wrote: > In kmap_atomic(), kmap_high_get() is invoked for checking already > mapped area. In __flush_dcache_page() and dma_cache_maint_page(), > we explicitly call kmap_high_get() before kmap_atomic() > when cache_is_vipt(), so kmap_high_get() can be invoked twice. > This is useless operation, so remove one. > > Signed-off-by: Joonsoo Kim Acked-by: Nicolas Pitre > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > index c7e3759..b7711be 100644 > --- a/arch/arm/mm/dma-mapping.c > +++ b/arch/arm/mm/dma-mapping.c > @@ -822,16 +822,16 @@ static void dma_cache_maint_page(struct page *page, unsigned long offset, > if (PageHighMem(page)) { > if (len + offset > PAGE_SIZE) > len = PAGE_SIZE - offset; > - vaddr = kmap_high_get(page); > - if (vaddr) { > - vaddr += offset; > - op(vaddr, len, dir); > - kunmap_high(page); > - } else if (cache_is_vipt()) { > - /* unmapped pages might still be cached */ > + if (cache_is_vipt()) { > vaddr = kmap_atomic(page); > op(vaddr + offset, len, dir); > kunmap_atomic(vaddr); > + } else { > + vaddr = kmap_high_get(page); > + if (vaddr) { > + op(vaddr + offset, len, dir); > + kunmap_high(page); > + } > } > } else { > vaddr = page_address(page) + offset; > diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c > index 1c8f7f5..e6a03d0 100644 > --- a/arch/arm/mm/flush.c > +++ b/arch/arm/mm/flush.c > @@ -170,15 +170,18 @@ void __flush_dcache_page(struct address_space *mapping, struct page *page) > if (!PageHighMem(page)) { > __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE); > } else { > - void *addr = kmap_high_get(page); > - if (addr) { > - __cpuc_flush_dcache_area(addr, PAGE_SIZE); > - kunmap_high(page); > - } else if (cache_is_vipt()) { > - /* unmapped pages might still be cached */ > + void *addr; > + > + if (cache_is_vipt()) { > addr = kmap_atomic(page); > __cpuc_flush_dcache_area(addr, PAGE_SIZE); > kunmap_atomic(addr); > + } else { > + addr = kmap_high_get(page); > + if (addr) { > + __cpuc_flush_dcache_area(addr, PAGE_SIZE); > + kunmap_high(page); > + } > } > } > > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/