From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f175.google.com (mail-ig0-f175.google.com [209.85.213.175]) by kanga.kvack.org (Postfix) with ESMTP id 2FB446B003A for ; Fri, 8 Aug 2014 18:45:59 -0400 (EDT) Received: by mail-ig0-f175.google.com with SMTP id uq10so1775238igb.2 for ; Fri, 08 Aug 2014 15:45:59 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id cm8si18843012icc.80.2014.08.08.15.45.58 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Aug 2014 15:45:58 -0700 (PDT) Date: Fri, 8 Aug 2014 15:45:56 -0700 From: Andrew Morton Subject: Re: [PATCHv6 3/5] common: dma-mapping: Introduce common remapping functions Message-Id: <20140808154556.11c7bf68d1bcf2714c148e3b@linux-foundation.org> In-Reply-To: <1407529397-6642-3-git-send-email-lauraa@codeaurora.org> References: <1407529397-6642-1-git-send-email-lauraa@codeaurora.org> <1407529397-6642-3-git-send-email-lauraa@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Laura Abbott Cc: Will Deacon , Catalin Marinas , Russell King , David Riley , linux-arm-kernel@lists.infradead.org, Ritesh Harjain , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Thierry Reding , Arnd Bergmann On Fri, 8 Aug 2014 13:23:15 -0700 Laura Abbott wrote: > > For architectures without coherent DMA, memory for DMA may > need to be remapped with coherent attributes. Factor out > the the remapping code from arm and put it in a > common location to reduce code duplication. > > As part of this, the arm APIs are now migrated away from > ioremap_page_range to the common APIs which use map_vm_area for remapping. > This should be an equivalent change and using map_vm_area is more > correct as ioremap_page_range is intended to bring in io addresses > into the cpu space and not regular kernel managed memory. > > ... > > @@ -267,3 +269,68 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, > return ret; > } > EXPORT_SYMBOL(dma_common_mmap); > + > +/* > + * remaps an allocated contiguous region into another vm_area. > + * Cannot be used in non-sleeping contexts > + */ > + > +void *dma_common_contiguous_remap(struct page *page, size_t size, > + unsigned long vm_flags, > + pgprot_t prot, const void *caller) > +{ > + int i; > + struct page **pages; > + void *ptr; > + > + pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL); > + if (!pages) > + return NULL; > + > + for (i = 0; i < (size >> PAGE_SHIFT); i++) > + pages[i] = page + i; Assumes a single mem_map[] array. That's not the case for sparsemem (at least). > + ptr = dma_common_pages_remap(pages, size, vm_flags, prot, caller); > + > + kfree(pages); > + > + return ptr; > +} > + -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org