Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752337AbbBQUwQ (ORCPT ); Tue, 17 Feb 2015 15:52:16 -0500 Received: from mga03.intel.com ([134.134.136.65]:32969 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751522AbbBQUwP (ORCPT ); Tue, 17 Feb 2015 15:52:15 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,595,1418112000"; d="scan'208";a="667707537" Message-ID: <1424206333.12687.8.camel@theros.lm.intel.com> Subject: Re: [PATCH 3/3] pmem: Allow request_mem to fail, (CONFIG_BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET) From: Ross Zwisler To: Boaz Harrosh Cc: Ingo Molnar , x86@kernel.org, linux-kernel , "Roger C. Pao" , Dan Williams , Thomas Gleixner , Linus Torvalds , linux-nvdimm , "H. Peter Anvin" Date: Tue, 17 Feb 2015 13:52:13 -0700 In-Reply-To: <54E1D36B.4000905@plexistor.com> References: <54E1CF5B.9020905@plexistor.com> <54E1D36B.4000905@plexistor.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-4.fc20.rez) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2990 Lines: 85 On Mon, 2015-02-16 at 13:24 +0200, Boaz Harrosh wrote: > With old Kernels there was a bug in x86 where any unknown > memory chip type would come up BUSY when calling > request_mem_region_exclusive(). > > So for pmem to work with old Kernels and real NvDIMM chips > we have a new Kconfig option CONFIG_BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET. > > People have been running with hacked up pmem that will ignore > the return code from request_mem_region_exclusive. So here it is > official > > Signed-off-by: Boaz Harrosh I'm confused - I thought that this behavior was fixed by patch 1/3? With that patch this memory reservation should not fail, correct? If so, why do we need this patch? > --- > drivers/block/Kconfig | 12 ++++++++++++ > drivers/block/pmem.c | 11 +++++++---- > 2 files changed, 19 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig > index 3b3200f..10879b8 100644 > --- a/drivers/block/Kconfig > +++ b/drivers/block/Kconfig > @@ -430,6 +430,18 @@ config BLK_DEV_PMEM_USE_PAGES > to other devices in the system, then you must say "Yes" here. > If unsure leave as Yes. > > +config BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET > + bool "Ignore the return code from request_mem_region_exclusive" > + depends on BLK_DEV_PMEM > + help > + In Old Kernels type-12 Memory type which is used by NvDIMM > + chips Comes out busy when calling request_mem_region_exclusive, > + because of a bug. > + If this option is set to "yes". The pmem will ignore the > + failure, and continue as usual. If you have an old Kernel and > + a real NvDIMM chip you must say yes here. > + (Ignored if BLK_DEV_PMEM_USE_PAGES=y) > + > config CDROM_PKTCDVD > tristate "Packet writing on CD/DVD media" > depends on !UML > diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c > index 9eb7ffe..f84d033 100644 > --- a/drivers/block/pmem.c > +++ b/drivers/block/pmem.c > @@ -197,10 +197,12 @@ int pmem_mapmem(struct pmem_device *pmem) > > res_mem = request_mem_region_exclusive(pmem->phys_addr, pmem->size, > "pmem"); > - if (!res_mem) { > + if (unlikely(!res_mem)) { > pr_warn("pmem: request_mem_region_exclusive phys=0x%llx size=0x%zx failed\n", > - pmem->phys_addr, pmem->size); > - return -EINVAL; > + pmem->phys_addr, pmem->size); > +#ifndef CONFIG_BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET > + return -EBUSY; > +#endif > } > > pmem->virt_addr = ioremap_cache(pmem->phys_addr, pmem->size); > @@ -211,7 +213,8 @@ int pmem_mapmem(struct pmem_device *pmem) > return 0; > > out_release: > - release_mem_region(pmem->phys_addr, pmem->size); > + if (res_mem) > + release_mem_region(pmem->phys_addr, pmem->size); > return err; > } > -- 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/