Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031273AbbD1WaX (ORCPT ); Tue, 28 Apr 2015 18:30:23 -0400 Received: from mail-wi0-f175.google.com ([209.85.212.175]:36372 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030978AbbD1WaV (ORCPT ); Tue, 28 Apr 2015 18:30:21 -0400 MIME-Version: 1.0 In-Reply-To: References: <20150428181203.35812.60474.stgit@dwillia2-desk3.amr.corp.intel.com> <20150428182602.35812.78599.stgit@dwillia2-desk3.amr.corp.intel.com> Date: Tue, 28 Apr 2015 15:30:19 -0700 Message-ID: Subject: Re: [PATCH v2 20/20] libnd, nd_acpi, nd_blk: driver for BLK-mode access persistent memory From: Dan Williams To: Andy Lutomirski Cc: linux-nvdimm , Boaz Harrosh , "linux-kernel@vger.kernel.org" , Jens Axboe , "H. Peter Anvin" , Ross Zwisler , Christoph Hellwig , Ingo Molnar Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3732 Lines: 78 On Tue, Apr 28, 2015 at 2:10 PM, Andy Lutomirski wrote: > On Tue, Apr 28, 2015 at 11:26 AM, Dan Williams wrote: >> From: Ross Zwisler >> >> The libnd implementation handles allocating dimm address space (DPA) >> between PMEM and BLK mode interfaces. After DPA has been allocated from >> a BLK-region to a BLK-namespace the nd_blk driver attaches to handle I/O >> as a struct bio based block device. Unlike PMEM, BLK is required to >> handle platform specific details like mmio register formats and memory >> controller interleave. For this reason the libnd generic nd_blk driver >> calls back into the bus provider to carry out the I/O. >> >> This initial implementation handles the BLK interface defined by the >> ACPI 6 NFIT [1] and the NVDIMM DSM Interface Example [2] composed from >> DCR (dimm control region), BDW (block data window), IDT (interleave >> descriptor) NFIT structures and the hardware register format. >> [1]: http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf >> [2]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf >> >> Cc: Andy Lutomirski >> Cc: Boaz Harrosh >> Cc: H. Peter Anvin >> Cc: Jens Axboe >> Cc: Ingo Molnar >> Cc: Christoph Hellwig >> Signed-off-by: Ross Zwisler >> Signed-off-by: Dan Williams >> --- >> drivers/block/nd/Kconfig | 12 + >> drivers/block/nd/Makefile | 3 >> drivers/block/nd/acpi.c | 422 +++++++++++++++++++++++++++++++++++-- >> drivers/block/nd/acpi_nfit.h | 47 ++++ >> drivers/block/nd/blk.c | 264 +++++++++++++++++++++++ >> drivers/block/nd/libnd.h | 11 + >> drivers/block/nd/namespace_devs.c | 47 ++++ >> drivers/block/nd/nd-private.h | 3 >> drivers/block/nd/nd.h | 16 + >> drivers/block/nd/region.c | 8 + >> drivers/block/nd/region_devs.c | 65 +++++- >> drivers/block/nd/test/nfit.c | 29 +++ >> drivers/block/nd/test/nfit_test.h | 2 >> 13 files changed, 891 insertions(+), 38 deletions(-) >> create mode 100644 drivers/block/nd/blk.c >> >> diff --git a/drivers/block/nd/Kconfig b/drivers/block/nd/Kconfig >> index 612bf2b14283..bac4290129fc 100644 >> --- a/drivers/block/nd/Kconfig >> +++ b/drivers/block/nd/Kconfig >> @@ -95,6 +95,18 @@ config BLK_DEV_PMEM >> >> Say Y if you want to use a NVDIMM described by ACPI, E820, etc... >> >> +config ND_BLK >> + tristate "BLK: Block data window (aperture) device support" >> + depends on LIBND >> + default ND_ACPI >> + help >> + This driver performs I/O using a set of mmio windows on a >> + dimm. The set of apertures will all access the one DIMM. >> + Multiple windows allow multiple threads to have a different >> + portions of the dimm open at one time. >> + >> + Say Y if you want to use a NVDIMM with BLK-mode capability >> + > > This describes how it works, not what it is. How about: > > This driver exposes NVDIMM BLK regions as block devices. BLK regions > are regions of NVDIMM storage that are sector-addressable, not > byte-addressible, and do not support DAX. They *are* byte-addressable albeit through an indirection window. The indirection windows are too small for DAX to be a viable access mode. -- 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/