From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: Areca driver recap + status Date: Tue, 27 Jun 2006 16:51:40 +0100 Message-ID: <1151423500.32186.39.camel@localhost.localdomain> References: <09be01c695b3$2ed8c2c0$c100a8c0@robm> <20060621222826.ff080422.akpm@osdl.org> <1151333338.2673.4.camel@mulgrave.il.steeleye.com> <057801c69970$70b45090$0e00cb0a@robm> <1151422074.3340.25.camel@mulgrave.il.steeleye.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:42725 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S1161111AbWF0PgK (ORCPT ); Tue, 27 Jun 2006 11:36:10 -0400 In-Reply-To: <1151422074.3340.25.camel@mulgrave.il.steeleye.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: Robert Mueller , Andrew Morton , rdunlap@xenotime.net, hch@infradead.org, erich@areca.com.tw, brong@fastmail.fm, dax@gurulabs.com, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Ar Maw, 2006-06-27 am 10:27 -0500, ysgrifennodd James Bottomley: > On a PAE platform, dma_addr_t is u64 and unsigned long is u32, so any > address > 4GB will be truncated by these operations. > > I think all this does is cause a slow leak of dma mappings, and on any > kernel > 2.6.16 the leak should be even smaller, since we've severely > restricted the use_sg == 0 case. It probably is only significant on > x86_64 with the gart iommu enabled. On x86_64 the dma_addr_t and the ulong are both 64bit so the problem doesn't arise. Alan