From patchwork Fri Aug 25 21:00:09 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Jiang X-Patchwork-Id: 9922845 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id AE52460349 for ; Fri, 25 Aug 2017 21:00:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7DE07284AA for ; Fri, 25 Aug 2017 21:00:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7C7E82853E; Fri, 25 Aug 2017 21:00:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 9B0F228546 for ; Fri, 25 Aug 2017 21:00:11 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 0E0422095DC99; Fri, 25 Aug 2017 13:57:35 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id B764E2095B9C1 for ; Fri, 25 Aug 2017 13:57:33 -0700 (PDT) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Aug 2017 14:00:09 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos; i="5.41,426,1498546800"; d="scan'208"; a="1188223265" Received: from djiang5-desk3.ch.intel.com ([143.182.137.38]) by fmsmga001.fm.intel.com with ESMTP; 25 Aug 2017 14:00:09 -0700 Subject: [PATCH v6 8/8] libnvdimm: Add blk-mq pmem driver From: Dave Jiang To: vinod.koul@intel.com, dan.j.williams@intel.com Date: Fri, 25 Aug 2017 14:00:09 -0700 Message-ID: <150369480912.6962.5373358327146419354.stgit@djiang5-desk3.ch.intel.com> In-Reply-To: <150369446130.6962.4195769527575520889.stgit@djiang5-desk3.ch.intel.com> References: <150369446130.6962.4195769527575520889.stgit@djiang5-desk3.ch.intel.com> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dmaengine@vger.kernel.org, hch@infradead.org, linux-nvdimm@lists.01.org Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP Adding a DMA supported blk-mq driver for pmem. This provides significant CPU utilization reduction at the cost of some increased latency and bandwidth reduction in some cases. By default the current cpu-copy based pmem driver will load, but this driver can be manually selected with a modprobe configuration. The pmem driver will be using blk-mq with DMA through the dmaengine API. Numbers below are measured against pmem simulated via DRAM using memmap=NN!SS. DMA engine used is the ioatdma on Intel Skylake Xeon platform. Keep in mind the performance for persistent memory will differ. Fio 2.21 was used. 64k: 1 task queuedepth=1 CPU Read: 7631 MB/s 99.7% CPU DMA Read: 2415 MB/s 54% CPU CPU Write: 3552 MB/s 100% CPU DMA Write 2173 MB/s 54% CPU 64k: 16 tasks queuedepth=16 CPU Read: 36800 MB/s 1593% CPU DMA Read: 29100 MB/s 607% CPU CPU Write 20900 MB/s 1589% CPU DMA Write: 23400 MB/s 585% CPU 2M: 1 task queuedepth=1 CPU Read: 6013 MB/s 99.3% CPU DMA Read: 7986 MB/s 59.3% CPU CPU Write: 3579 MB/s 100% CPU DMA Write: 5211 MB/s 58.3% CPU 2M: 16 tasks queuedepth=16 CPU Read: 18100 MB/s 1588% CPU DMA Read: 21300 MB/s 180.9% CPU CPU Write: 14100 MB/s 1594% CPU DMA Write: 20400 MB/s 446.9% CPU Also, due to a significant portion of the code being shared with the pmem driver, the common code are broken out into a kernel module called pmem_core to be shared between the two drivers. Signed-off-by: Dave Jiang Reviewed-by: Ross Zwisler --- drivers/nvdimm/Kconfig | 21 ++ drivers/nvdimm/Makefile | 6 drivers/nvdimm/pmem.c | 264 ------------------- drivers/nvdimm/pmem.h | 48 +++ drivers/nvdimm/pmem_core.c | 298 ++++++++++++++++++++++ drivers/nvdimm/pmem_dma.c | 606 ++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 979 insertions(+), 264 deletions(-) create mode 100644 drivers/nvdimm/pmem_core.c create mode 100644 drivers/nvdimm/pmem_dma.c diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig index 5bdd499..bb0f8a8 100644 --- a/drivers/nvdimm/Kconfig +++ b/drivers/nvdimm/Kconfig @@ -17,12 +17,16 @@ menuconfig LIBNVDIMM if LIBNVDIMM +config BLK_DEV_PMEM_CORE + tristate + config BLK_DEV_PMEM tristate "PMEM: Persistent memory block device support" default LIBNVDIMM select DAX select ND_BTT if BTT select ND_PFN if NVDIMM_PFN + select BLK_DEV_PMEM_CORE help Memory ranges for PMEM are described by either an NFIT (NVDIMM Firmware Interface Table, see CONFIG_NFIT_ACPI), a @@ -36,6 +40,23 @@ config BLK_DEV_PMEM Say Y if you want to use an NVDIMM +config BLK_DEV_PMEM_DMA + tristate "PMEM: Persistent memory block device multi-queue support" + depends on DMA_ENGINE + depends on BLK_DEV_PMEM=m || !BLK_DEV_PMEM + default LIBNVDIMM + select DAX + select ND_BTT if BTT + select ND_PFN if NVDIMM_PFN + select BLK_DEV_PMEM_CORE + help + This driver utilizes block layer multi-queue in order to support + using DMA engines to help offload the data copying. The desire for + this driver is to reduce CPU utilization with some sacrifice in + latency and performance. + + Say Y if you want to use an NVDIMM + config ND_BLK tristate "BLK: Block data window (aperture) device support" default LIBNVDIMM diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile index 909554c..cecc280 100644 --- a/drivers/nvdimm/Makefile +++ b/drivers/nvdimm/Makefile @@ -1,11 +1,17 @@ obj-$(CONFIG_LIBNVDIMM) += libnvdimm.o +obj-$(CONFIG_BLK_DEV_PMEM_CORE) += nd_pmem_core.o obj-$(CONFIG_BLK_DEV_PMEM) += nd_pmem.o +obj-$(CONFIG_BLK_DEV_PMEM_DMA) += nd_pmem_dma.o obj-$(CONFIG_ND_BTT) += nd_btt.o obj-$(CONFIG_ND_BLK) += nd_blk.o obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o +nd_pmem_core-y := pmem_core.o + nd_pmem-y := pmem.o +nd_pmem_dma-y := pmem_dma.o + nd_btt-y := btt.o nd_blk-y := blk.o diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index f7099ada..20e8502 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -35,120 +35,6 @@ #include "pfn.h" #include "nd.h" -static struct device *to_dev(struct pmem_device *pmem) -{ - /* - * nvdimm bus services need a 'dev' parameter, and we record the device - * at init in bb.dev. - */ - return pmem->bb.dev; -} - -static struct nd_region *to_region(struct pmem_device *pmem) -{ - return to_nd_region(to_dev(pmem)->parent); -} - -static blk_status_t pmem_clear_poison(struct pmem_device *pmem, - phys_addr_t offset, unsigned int len) -{ - struct device *dev = to_dev(pmem); - sector_t sector; - long cleared; - blk_status_t rc = BLK_STS_OK; - - sector = (offset - pmem->data_offset) / 512; - - cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len); - if (cleared < len) - rc = BLK_STS_IOERR; - if (cleared > 0 && cleared / 512) { - cleared /= 512; - dev_dbg(dev, "%s: %#llx clear %ld sector%s\n", __func__, - (unsigned long long) sector, cleared, - cleared > 1 ? "s" : ""); - badblocks_clear(&pmem->bb, sector, cleared); - if (pmem->bb_state) - sysfs_notify_dirent(pmem->bb_state); - } - - arch_invalidate_pmem(pmem->virt_addr + offset, len); - - return rc; -} - -static void write_pmem(void *pmem_addr, struct page *page, - unsigned int off, unsigned int len) -{ - void *mem = kmap_atomic(page); - - memcpy_flushcache(pmem_addr, mem + off, len); - kunmap_atomic(mem); -} - -static blk_status_t read_pmem(struct page *page, unsigned int off, - void *pmem_addr, unsigned int len) -{ - int rc; - void *mem = kmap_atomic(page); - - rc = memcpy_mcsafe(mem + off, pmem_addr, len); - kunmap_atomic(mem); - if (rc) - return BLK_STS_IOERR; - return BLK_STS_OK; -} - -static blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page, - unsigned int len, unsigned int off, bool is_write, - sector_t sector) -{ - blk_status_t rc = BLK_STS_OK; - bool bad_pmem = false; - phys_addr_t pmem_off = sector * 512 + pmem->data_offset; - void *pmem_addr = pmem->virt_addr + pmem_off; - - if (unlikely(is_bad_pmem(&pmem->bb, sector, len))) - bad_pmem = true; - - if (!is_write) { - if (unlikely(bad_pmem)) - rc = BLK_STS_IOERR; - else { - rc = read_pmem(page, off, pmem_addr, len); - flush_dcache_page(page); - } - } else { - /* - * Note that we write the data both before and after - * clearing poison. The write before clear poison - * handles situations where the latest written data is - * preserved and the clear poison operation simply marks - * the address range as valid without changing the data. - * In this case application software can assume that an - * interrupted write will either return the new good - * data or an error. - * - * However, if pmem_clear_poison() leaves the data in an - * indeterminate state we need to perform the write - * after clear poison. - */ - flush_dcache_page(page); - write_pmem(pmem_addr, page, off, len); - if (unlikely(bad_pmem)) { - rc = pmem_clear_poison(pmem, pmem_off, len); - write_pmem(pmem_addr, page, off, len); - } - } - - return rc; -} - -/* account for REQ_FLUSH rename, replace with REQ_PREFLUSH after v4.8-rc1 */ -#ifndef REQ_FLUSH -#define REQ_FLUSH REQ_PREFLUSH -#endif - static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio) { blk_status_t rc = 0; @@ -182,73 +68,12 @@ static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio) return BLK_QC_T_NONE; } -static int pmem_rw_page(struct block_device *bdev, sector_t sector, - struct page *page, bool is_write) -{ - struct pmem_device *pmem = bdev->bd_queue->queuedata; - blk_status_t rc; - - rc = pmem_do_bvec(pmem, page, PAGE_SIZE, 0, is_write, sector); - - /* - * The ->rw_page interface is subtle and tricky. The core - * retries on any error, so we can only invoke page_endio() in - * the successful completion case. Otherwise, we'll see crashes - * caused by double completion. - */ - if (rc == 0) - page_endio(page, is_write, 0); - - return blk_status_to_errno(rc); -} - -/* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */ -__weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff, - long nr_pages, void **kaddr, pfn_t *pfn) -{ - resource_size_t offset = PFN_PHYS(pgoff) + pmem->data_offset; - - if (unlikely(is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512, - PFN_PHYS(nr_pages)))) - return -EIO; - *kaddr = pmem->virt_addr + offset; - *pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags); - - /* - * If badblocks are present, limit known good range to the - * requested range. - */ - if (unlikely(pmem->bb.count)) - return nr_pages; - return PHYS_PFN(pmem->size - pmem->pfn_pad - offset); -} - static const struct block_device_operations pmem_fops = { .owner = THIS_MODULE, .rw_page = pmem_rw_page, .revalidate_disk = nvdimm_revalidate_disk, }; -static long pmem_dax_direct_access(struct dax_device *dax_dev, - pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn) -{ - struct pmem_device *pmem = dax_get_private(dax_dev); - - return __pmem_direct_access(pmem, pgoff, nr_pages, kaddr, pfn); -} - -static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, - void *addr, size_t bytes, struct iov_iter *i) -{ - return copy_from_iter_flushcache(addr, bytes, i); -} - -static void pmem_dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, - void *addr, size_t size) -{ - arch_wb_cache_pmem(addr, size); -} - static const struct dax_operations pmem_dax_ops = { .direct_access = pmem_dax_direct_access, .copy_from_iter = pmem_copy_from_iter, @@ -265,21 +90,6 @@ static void pmem_release_queue(void *q) blk_cleanup_queue(q); } -static void pmem_freeze_queue(void *q) -{ - blk_freeze_queue_start(q); -} - -static void pmem_release_disk(void *__pmem) -{ - struct pmem_device *pmem = __pmem; - - kill_dax(pmem->dax_dev); - put_dax(pmem->dax_dev); - del_gendisk(pmem->disk); - put_disk(pmem->disk); -} - static int pmem_attach_disk(struct device *dev, struct nd_namespace_common *ndns) { @@ -441,80 +251,6 @@ static int nd_pmem_probe(struct device *dev) return pmem_attach_disk(dev, ndns); } -static int nd_pmem_remove(struct device *dev) -{ - struct pmem_device *pmem = dev_get_drvdata(dev); - - if (is_nd_btt(dev)) - nvdimm_namespace_detach_btt(to_nd_btt(dev)); - else { - /* - * Note, this assumes device_lock() context to not race - * nd_pmem_notify() - */ - sysfs_put(pmem->bb_state); - pmem->bb_state = NULL; - } - nvdimm_flush(to_nd_region(dev->parent)); - - return 0; -} - -static void nd_pmem_shutdown(struct device *dev) -{ - nvdimm_flush(to_nd_region(dev->parent)); -} - -static void nd_pmem_notify(struct device *dev, enum nvdimm_event event) -{ - struct nd_region *nd_region; - resource_size_t offset = 0, end_trunc = 0; - struct nd_namespace_common *ndns; - struct nd_namespace_io *nsio; - struct resource res; - struct badblocks *bb; - struct kernfs_node *bb_state; - - if (event != NVDIMM_REVALIDATE_POISON) - return; - - if (is_nd_btt(dev)) { - struct nd_btt *nd_btt = to_nd_btt(dev); - - ndns = nd_btt->ndns; - nd_region = to_nd_region(ndns->dev.parent); - nsio = to_nd_namespace_io(&ndns->dev); - bb = &nsio->bb; - bb_state = NULL; - } else { - struct pmem_device *pmem = dev_get_drvdata(dev); - - nd_region = to_region(pmem); - bb = &pmem->bb; - bb_state = pmem->bb_state; - - if (is_nd_pfn(dev)) { - struct nd_pfn *nd_pfn = to_nd_pfn(dev); - struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb; - - ndns = nd_pfn->ndns; - offset = pmem->data_offset + - __le32_to_cpu(pfn_sb->start_pad); - end_trunc = __le32_to_cpu(pfn_sb->end_trunc); - } else { - ndns = to_ndns(dev); - } - - nsio = to_nd_namespace_io(&ndns->dev); - } - - res.start = nsio->res.start + offset; - res.end = nsio->res.end - end_trunc; - nvdimm_badblocks_populate(nd_region, bb, &res); - if (bb_state) - sysfs_notify_dirent(bb_state); -} - MODULE_ALIAS("pmem"); MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO); MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM); diff --git a/drivers/nvdimm/pmem.h b/drivers/nvdimm/pmem.h index 5434321..7e363fc 100644 --- a/drivers/nvdimm/pmem.h +++ b/drivers/nvdimm/pmem.h @@ -4,6 +4,13 @@ #include #include #include +#include +#include "nd.h" + +/* account for REQ_FLUSH rename, replace with REQ_PREFLUSH after v4.8-rc1 */ +#ifndef REQ_FLUSH +#define REQ_FLUSH REQ_PREFLUSH +#endif #ifdef CONFIG_ARCH_HAS_PMEM_API #define ARCH_MEMREMAP_PMEM MEMREMAP_WB @@ -35,8 +42,49 @@ struct pmem_device { struct badblocks bb; struct dax_device *dax_dev; struct gendisk *disk; + struct blk_mq_tag_set tag_set; + struct request_queue *q; }; +static inline struct device *to_dev(struct pmem_device *pmem) +{ + /* + * nvdimm bus services need a 'dev' parameter, and we record the device + * at init in bb.dev. + */ + return pmem->bb.dev; +} + +static inline struct nd_region *to_region(struct pmem_device *pmem) +{ + return to_nd_region(to_dev(pmem)->parent); +} + +struct device *to_dev(struct pmem_device *pmem); +struct nd_region *to_region(struct pmem_device *pmem); +blk_status_t pmem_clear_poison(struct pmem_device *pmem, + phys_addr_t offset, unsigned int len); +void write_pmem(void *pmem_addr, struct page *page, + unsigned int off, unsigned int len); +blk_status_t read_pmem(struct page *page, unsigned int off, + void *pmem_addr, unsigned int len); +blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page, + unsigned int len, unsigned int off, bool is_write, + sector_t sector); +int pmem_rw_page(struct block_device *bdev, sector_t sector, + struct page *page, bool is_write); +void nd_pmem_notify(struct device *dev, enum nvdimm_event event); +long pmem_dax_direct_access(struct dax_device *dax_dev, + pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn); +size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, + void *addr, size_t bytes, struct iov_iter *i); +void pmem_dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, + void *addr, size_t size); long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn); +int nd_pmem_remove(struct device *dev); +void nd_pmem_shutdown(struct device *dev); +void pmem_freeze_queue(void *q); +void pmem_release_disk(void *__pmem); + #endif /* __NVDIMM_PMEM_H__ */ diff --git a/drivers/nvdimm/pmem_core.c b/drivers/nvdimm/pmem_core.c new file mode 100644 index 0000000..1b6471a --- /dev/null +++ b/drivers/nvdimm/pmem_core.c @@ -0,0 +1,298 @@ +/* + * Persistent Memory Block Driver shared code + * Copyright (c) 2014-2017, Intel Corporation. + * Copyright (c) 2015, Christoph Hellwig . + * Copyright (c) 2015, Boaz Harrosh . + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "pmem.h" +#include "pfn.h" +#include "nd.h" + +blk_status_t pmem_clear_poison(struct pmem_device *pmem, + phys_addr_t offset, unsigned int len) +{ + struct device *dev = to_dev(pmem); + sector_t sector; + long cleared; + blk_status_t rc = BLK_STS_OK; + + sector = (offset - pmem->data_offset) / 512; + + cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len); + if (cleared < len) + rc = BLK_STS_IOERR; + if (cleared > 0 && cleared / 512) { + cleared /= 512; + dev_dbg(dev, "%s: %#llx clear %ld sector%s\n", __func__, + (unsigned long long) sector, cleared, + cleared > 1 ? "s" : ""); + badblocks_clear(&pmem->bb, sector, cleared); + if (pmem->bb_state) + sysfs_notify_dirent(pmem->bb_state); + } + + arch_invalidate_pmem(pmem->virt_addr + offset, len); + + return rc; +} +EXPORT_SYMBOL_GPL(pmem_clear_poison); + +void write_pmem(void *pmem_addr, struct page *page, + unsigned int off, unsigned int len) +{ + void *mem = kmap_atomic(page); + + memcpy_flushcache(pmem_addr, mem + off, len); + kunmap_atomic(mem); +} +EXPORT_SYMBOL_GPL(write_pmem); + +blk_status_t read_pmem(struct page *page, unsigned int off, + void *pmem_addr, unsigned int len) +{ + int rc; + void *mem = kmap_atomic(page); + + rc = memcpy_mcsafe(mem + off, pmem_addr, len); + kunmap_atomic(mem); + if (rc) + return BLK_STS_IOERR; + return BLK_STS_OK; +} +EXPORT_SYMBOL_GPL(read_pmem); + +blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page, + unsigned int len, unsigned int off, bool is_write, + sector_t sector) +{ + blk_status_t rc = BLK_STS_OK; + bool bad_pmem = false; + phys_addr_t pmem_off = sector * 512 + pmem->data_offset; + void *pmem_addr = pmem->virt_addr + pmem_off; + + if (unlikely(is_bad_pmem(&pmem->bb, sector, len))) + bad_pmem = true; + + if (!is_write) { + if (unlikely(bad_pmem)) + rc = BLK_STS_IOERR; + else { + rc = read_pmem(page, off, pmem_addr, len); + flush_dcache_page(page); + } + } else { + /* + * Note that we write the data both before and after + * clearing poison. The write before clear poison + * handles situations where the latest written data is + * preserved and the clear poison operation simply marks + * the address range as valid without changing the data. + * In this case application software can assume that an + * interrupted write will either return the new good + * data or an error. + * + * However, if pmem_clear_poison() leaves the data in an + * indeterminate state we need to perform the write + * after clear poison. + */ + flush_dcache_page(page); + write_pmem(pmem_addr, page, off, len); + if (unlikely(bad_pmem)) { + rc = pmem_clear_poison(pmem, pmem_off, len); + write_pmem(pmem_addr, page, off, len); + } + } + + return rc; +} +EXPORT_SYMBOL_GPL(pmem_do_bvec); + +int pmem_rw_page(struct block_device *bdev, sector_t sector, + struct page *page, bool is_write) +{ + struct pmem_device *pmem = bdev->bd_queue->queuedata; + blk_status_t rc; + + rc = pmem_do_bvec(pmem, page, PAGE_SIZE, 0, is_write, sector); + + /* + * The ->rw_page interface is subtle and tricky. The core + * retries on any error, so we can only invoke page_endio() in + * the successful completion case. Otherwise, we'll see crashes + * caused by double completion. + */ + if (rc == 0) + page_endio(page, is_write, 0); + + return blk_status_to_errno(rc); +} +EXPORT_SYMBOL_GPL(pmem_rw_page); + +/* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */ +__weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff, + long nr_pages, void **kaddr, pfn_t *pfn) +{ + resource_size_t offset = PFN_PHYS(pgoff) + pmem->data_offset; + + if (unlikely(is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512, + PFN_PHYS(nr_pages)))) + return -EIO; + *kaddr = pmem->virt_addr + offset; + *pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags); + + /* + * If badblocks are present, limit known good range to the + * requested range. + */ + if (unlikely(pmem->bb.count)) + return nr_pages; + return PHYS_PFN(pmem->size - pmem->pfn_pad - offset); +} + +long pmem_dax_direct_access(struct dax_device *dax_dev, + pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn) +{ + struct pmem_device *pmem = dax_get_private(dax_dev); + + return __pmem_direct_access(pmem, pgoff, nr_pages, kaddr, pfn); +} +EXPORT_SYMBOL_GPL(pmem_dax_direct_access); + +size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, + void *addr, size_t bytes, struct iov_iter *i) +{ + return copy_from_iter_flushcache(addr, bytes, i); +} +EXPORT_SYMBOL_GPL(pmem_copy_from_iter); + +void pmem_dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, + void *addr, size_t size) +{ + arch_wb_cache_pmem(addr, size); +} +EXPORT_SYMBOL_GPL(pmem_dax_flush); + +void nd_pmem_notify(struct device *dev, enum nvdimm_event event) +{ + struct nd_region *nd_region; + resource_size_t offset = 0, end_trunc = 0; + struct nd_namespace_common *ndns; + struct nd_namespace_io *nsio; + struct resource res; + struct badblocks *bb; + struct kernfs_node *bb_state; + + if (event != NVDIMM_REVALIDATE_POISON) + return; + + if (is_nd_btt(dev)) { + struct nd_btt *nd_btt = to_nd_btt(dev); + + ndns = nd_btt->ndns; + nd_region = to_nd_region(ndns->dev.parent); + nsio = to_nd_namespace_io(&ndns->dev); + bb = &nsio->bb; + bb_state = NULL; + } else { + struct pmem_device *pmem = dev_get_drvdata(dev); + + nd_region = to_region(pmem); + bb = &pmem->bb; + bb_state = pmem->bb_state; + + if (is_nd_pfn(dev)) { + struct nd_pfn *nd_pfn = to_nd_pfn(dev); + struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb; + + ndns = nd_pfn->ndns; + offset = pmem->data_offset + + __le32_to_cpu(pfn_sb->start_pad); + end_trunc = __le32_to_cpu(pfn_sb->end_trunc); + } else { + ndns = to_ndns(dev); + } + + nsio = to_nd_namespace_io(&ndns->dev); + } + + res.start = nsio->res.start + offset; + res.end = nsio->res.end - end_trunc; + nvdimm_badblocks_populate(nd_region, bb, &res); + if (bb_state) + sysfs_notify_dirent(bb_state); +} +EXPORT_SYMBOL_GPL(nd_pmem_notify); + +int nd_pmem_remove(struct device *dev) +{ + struct pmem_device *pmem = dev_get_drvdata(dev); + + if (is_nd_btt(dev)) + nvdimm_namespace_detach_btt(to_nd_btt(dev)); + else { + /* + * Note, this assumes device_lock() context to not race + * nd_pmem_notify() + */ + sysfs_put(pmem->bb_state); + pmem->bb_state = NULL; + } + nvdimm_flush(to_nd_region(dev->parent)); + + return 0; +} +EXPORT_SYMBOL_GPL(nd_pmem_remove); + +void nd_pmem_shutdown(struct device *dev) +{ + nvdimm_flush(to_nd_region(dev->parent)); +} +EXPORT_SYMBOL_GPL(nd_pmem_shutdown); + +void pmem_freeze_queue(void *q) +{ + blk_freeze_queue_start(q); +} +EXPORT_SYMBOL_GPL(pmem_freeze_queue); + +void pmem_release_disk(void *__pmem) +{ + struct pmem_device *pmem = __pmem; + + kill_dax(pmem->dax_dev); + put_dax(pmem->dax_dev); + del_gendisk(pmem->disk); + put_disk(pmem->disk); +} +EXPORT_SYMBOL_GPL(pmem_release_disk); + +MODULE_LICENSE("GPL v2"); diff --git a/drivers/nvdimm/pmem_dma.c b/drivers/nvdimm/pmem_dma.c new file mode 100644 index 0000000..3a5e4f6 --- /dev/null +++ b/drivers/nvdimm/pmem_dma.c @@ -0,0 +1,606 @@ +/* + * Persistent Memory Block Multi-Queue Driver + * - This driver is largely adapted from Ross's pmem block driver. + * Copyright (c) 2014-2017, Intel Corporation. + * Copyright (c) 2015, Christoph Hellwig . + * Copyright (c) 2015, Boaz Harrosh . + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "pmem.h" +#include "pfn.h" +#include "nd.h" + +#define QUEUE_DEPTH 128 +#define SG_ALLOCATED 128 + +static int use_dma = 1; + +struct pmem_cmd { + struct request *rq; + struct dma_chan *chan; + int sg_nents; + struct scatterlist sg[]; +}; + +static void pmem_release_queue(void *data) +{ + struct pmem_device *pmem = data; + + blk_cleanup_queue(pmem->q); + blk_mq_free_tag_set(&pmem->tag_set); +} + +static void nd_pmem_dma_callback(void *data, + const struct dmaengine_result *res) +{ + struct pmem_cmd *cmd = data; + struct request *req = cmd->rq; + struct request_queue *q = req->q; + struct pmem_device *pmem = q->queuedata; + struct nd_region *nd_region = to_region(pmem); + struct device *dev = to_dev(pmem); + blk_status_t blk_status = BLK_STS_OK; + + if (res) { + switch (res->result) { + case DMA_TRANS_READ_FAILED: + case DMA_TRANS_WRITE_FAILED: + case DMA_TRANS_ABORTED: + dev_dbg(dev, "bio failed\n"); + blk_status = BLK_STS_IOERR; + break; + case DMA_TRANS_NOERROR: + default: + break; + } + } + + if (req_op(req) == REQ_OP_WRITE && req->cmd_flags & REQ_FUA) + nvdimm_flush(nd_region); + + blk_mq_end_request(cmd->rq, blk_status); +} + +static int pmem_check_bad_pmem(struct pmem_cmd *cmd, bool is_write) +{ + struct request *req = cmd->rq; + struct request_queue *q = req->q; + struct pmem_device *pmem = q->queuedata; + struct bio_vec bvec; + struct req_iterator iter; + + rq_for_each_segment(bvec, req, iter) { + sector_t sector = iter.iter.bi_sector; + unsigned int len = bvec.bv_len; + unsigned int off = bvec.bv_offset; + + if (unlikely(is_bad_pmem(&pmem->bb, sector, len))) { + if (is_write) { + struct page *page = bvec.bv_page; + phys_addr_t pmem_off = sector * 512 + + pmem->data_offset; + void *pmem_addr = pmem->virt_addr + pmem_off; + + /* + * Note that we write the data both before and after + * clearing poison. The write before clear poison + * handles situations where the latest written data is + * preserved and the clear poison operation simply marks + * the address range as valid without changing the data. + * In this case application software can assume that an + * interrupted write will either return the new good + * data or an error. + * + * However, if pmem_clear_poison() leaves the data in an + * indeterminate state we need to perform the write + * after clear poison. + */ + flush_dcache_page(page); + write_pmem(pmem_addr, page, off, len); + pmem_clear_poison(pmem, pmem_off, len); + write_pmem(pmem_addr, page, off, len); + } else + return -EIO; + } + } + + return 0; +} + +static blk_status_t pmem_handle_cmd_dma(struct pmem_cmd *cmd, bool is_write) +{ + struct request *req = cmd->rq; + struct request_queue *q = req->q; + struct pmem_device *pmem = q->queuedata; + struct device *dev = to_dev(pmem); + phys_addr_t pmem_off = blk_rq_pos(req) * 512 + pmem->data_offset; + void *pmem_addr = pmem->virt_addr + pmem_off; + size_t len; + struct dma_device *dma = cmd->chan->device; + struct dmaengine_unmap_data *unmap; + dma_cookie_t cookie; + struct dma_async_tx_descriptor *txd; + struct page *page; + unsigned int off; + int rc; + blk_status_t blk_status = BLK_STS_OK; + enum dma_data_direction dir; + dma_addr_t dma_addr; + + rc = pmem_check_bad_pmem(cmd, is_write); + if (rc < 0) { + blk_status = BLK_STS_IOERR; + goto err; + } + + unmap = dmaengine_get_unmap_data(dma->dev, 2, GFP_NOWAIT); + if (!unmap) { + dev_dbg(dev, "failed to get dma unmap data\n"); + blk_status = BLK_STS_IOERR; + goto err; + } + + /* + * If reading from pmem, writing to scatterlist, + * and if writing to pmem, reading from scatterlist. + */ + dir = is_write ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + cmd->sg_nents = blk_rq_map_sg(req->q, req, cmd->sg); + if (cmd->sg_nents < 1) { + blk_status = BLK_STS_IOERR; + goto err; + } + + WARN_ON_ONCE(cmd->sg_nents > SG_ALLOCATED); + + rc = dma_map_sg(dma->dev, cmd->sg, cmd->sg_nents, dir); + if (rc < 1) { + dev_dbg(dma->dev, "DMA scatterlist mapping error\n"); + blk_status = BLK_STS_IOERR; + goto err; + } + + unmap->unmap_sg.sg = cmd->sg; + unmap->sg_nents = cmd->sg_nents; + if (is_write) + unmap->from_sg = 1; + else + unmap->to_sg = 1; + + len = blk_rq_payload_bytes(req); + page = virt_to_page(pmem_addr); + off = offset_in_page(pmem_addr); + dir = is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE; + dma_addr = dma_map_page(dma->dev, page, off, len, dir); + if (dma_mapping_error(dma->dev, unmap->addr[0])) { + dev_dbg(dma->dev, "DMA buffer mapping error\n"); + blk_status = BLK_STS_IOERR; + goto err_unmap_sg; + } + + unmap->unmap_sg.buf_phys = dma_addr; + unmap->len = len; + if (is_write) + unmap->to_cnt = 1; + else + unmap->from_cnt = 1; + + txd = dmaengine_prep_dma_memcpy_sg(cmd->chan, + cmd->sg, cmd->sg_nents, dma_addr, + !is_write, DMA_PREP_INTERRUPT); + if (!txd) { + dev_dbg(dma->dev, "dma prep failed\n"); + blk_status = BLK_STS_IOERR; + goto err_unmap_buffer; + } + + txd->callback_result = nd_pmem_dma_callback; + txd->callback_param = cmd; + dma_set_unmap(txd, unmap); + cookie = dmaengine_submit(txd); + if (dma_submit_error(cookie)) { + dev_dbg(dma->dev, "dma submit error\n"); + blk_status = BLK_STS_IOERR; + goto err_set_unmap; + } + + dmaengine_unmap_put(unmap); + dma_async_issue_pending(cmd->chan); + return BLK_STS_OK; + +err_set_unmap: + dmaengine_unmap_put(unmap); +err_unmap_buffer: + dma_unmap_page(dev, dma_addr, len, dir); +err_unmap_sg: + if (dir == DMA_TO_DEVICE) + dir = DMA_FROM_DEVICE; + else + dir = DMA_TO_DEVICE; + dma_unmap_sg(dev, cmd->sg, cmd->sg_nents, dir); + dmaengine_unmap_put(unmap); +err: + blk_mq_end_request(cmd->rq, blk_status); + return blk_status; +} + +static blk_status_t pmem_handle_cmd(struct pmem_cmd *cmd, bool is_write) +{ + struct request *req = cmd->rq; + struct request_queue *q = req->q; + struct pmem_device *pmem = q->queuedata; + struct nd_region *nd_region = to_region(pmem); + struct bio_vec bvec; + struct req_iterator iter; + blk_status_t blk_status = BLK_STS_OK; + + rq_for_each_segment(bvec, req, iter) { + blk_status = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, + bvec.bv_offset, is_write, + iter.iter.bi_sector); + if (blk_status != BLK_STS_OK) + break; + } + + if (is_write && req->cmd_flags & REQ_FUA) + nvdimm_flush(nd_region); + + blk_mq_end_request(cmd->rq, blk_status); + + return blk_status; +} + +typedef blk_status_t (*pmem_do_io)(struct pmem_cmd *cmd, bool is_write); + +static blk_status_t pmem_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + struct pmem_cmd *cmd = blk_mq_rq_to_pdu(bd->rq); + struct request *req = cmd->rq = bd->rq; + struct request_queue *q = req->q; + struct pmem_device *pmem = q->queuedata; + struct nd_region *nd_region = to_region(pmem); + blk_status_t blk_status = BLK_STS_OK; + pmem_do_io do_io; + + blk_mq_start_request(req); + + if (use_dma) + cmd->chan = dma_find_channel(DMA_MEMCPY_SG); + + if (cmd->chan) + do_io = pmem_handle_cmd_dma; + else + do_io = pmem_handle_cmd; + + switch (req_op(req)) { + case REQ_FLUSH: + nvdimm_flush(nd_region); + blk_mq_end_request(cmd->rq, BLK_STS_OK); + break; + case REQ_OP_READ: + blk_status = do_io(cmd, false); + break; + case REQ_OP_WRITE: + blk_status = do_io(cmd, true); + break; + default: + blk_status = BLK_STS_NOTSUPP; + break; + } + + if (blk_status != BLK_STS_OK) + blk_mq_end_request(cmd->rq, blk_status); + + return blk_status; +} + +static const struct blk_mq_ops pmem_mq_ops = { + .queue_rq = pmem_queue_rq, +}; + +static const struct attribute_group *pmem_attribute_groups[] = { + &dax_attribute_group, + NULL, +}; + +static const struct block_device_operations pmem_fops = { + .owner = THIS_MODULE, + .rw_page = pmem_rw_page, + .revalidate_disk = nvdimm_revalidate_disk, +}; + +static const struct dax_operations pmem_dax_ops = { + .direct_access = pmem_dax_direct_access, + .copy_from_iter = pmem_copy_from_iter, + .flush = pmem_dax_flush, +}; + +static bool pmem_dma_filter_fn(struct dma_chan *chan, void *node) +{ + return dev_to_node(&chan->dev->device) == (int)(unsigned long)node; +} + +static int pmem_attach_disk(struct device *dev, + struct nd_namespace_common *ndns) +{ + struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev); + struct nd_region *nd_region = to_nd_region(dev->parent); + struct vmem_altmap __altmap, *altmap = NULL; + int nid = dev_to_node(dev), fua, wbc; + struct resource *res = &nsio->res; + struct nd_pfn *nd_pfn = NULL; + struct dax_device *dax_dev; + struct nd_pfn_sb *pfn_sb; + struct pmem_device *pmem; + struct resource pfn_res; + struct device *gendev; + struct gendisk *disk; + void *addr; + int rc; + struct dma_chan *chan = NULL; + + /* while nsio_rw_bytes is active, parse a pfn info block if present */ + if (is_nd_pfn(dev)) { + nd_pfn = to_nd_pfn(dev); + altmap = nvdimm_setup_pfn(nd_pfn, &pfn_res, &__altmap); + if (IS_ERR(altmap)) + return PTR_ERR(altmap); + } + + /* we're attaching a block device, disable raw namespace access */ + devm_nsio_disable(dev, nsio); + + pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL); + if (!pmem) + return -ENOMEM; + + dev_set_drvdata(dev, pmem); + pmem->phys_addr = res->start; + pmem->size = resource_size(res); + fua = nvdimm_has_flush(nd_region); + if (!IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) || fua < 0) { + dev_warn(dev, "unable to guarantee persistence of writes\n"); + fua = 0; + } + wbc = nvdimm_has_cache(nd_region); + + if (!devm_request_mem_region(dev, res->start, resource_size(res), + dev_name(&ndns->dev))) { + dev_warn(dev, "could not reserve region %pR\n", res); + return -EBUSY; + } + + if (use_dma) { + chan = dma_find_channel(DMA_MEMCPY_SG); + if (!chan) { + use_dma = 0; + dev_warn(dev, "Forced back to CPU, no DMA\n"); + } else { + } + } + + pmem->tag_set.ops = &pmem_mq_ops; + if (use_dma) { + dma_cap_mask_t dma_mask; + int node = 0, count; + + dma_cap_zero(dma_mask); + dma_cap_set(DMA_MEMCPY_SG, dma_mask); + count = dma_get_channel_count(&dma_mask, pmem_dma_filter_fn, + (void *)(unsigned long)node); + if (count) + pmem->tag_set.nr_hw_queues = count; + else { + use_dma = 0; + pmem->tag_set.nr_hw_queues = num_online_cpus(); + } + } else + pmem->tag_set.nr_hw_queues = num_online_cpus(); + + dev_dbg(dev, "%d HW queues allocated\n", pmem->tag_set.nr_hw_queues); + + pmem->tag_set.queue_depth = QUEUE_DEPTH; + pmem->tag_set.numa_node = dev_to_node(dev); + + if (use_dma) { + pmem->tag_set.cmd_size = sizeof(struct pmem_cmd) + + sizeof(struct scatterlist) * SG_ALLOCATED; + } else + pmem->tag_set.cmd_size = sizeof(struct pmem_cmd); + + pmem->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; + pmem->tag_set.driver_data = pmem; + + rc = blk_mq_alloc_tag_set(&pmem->tag_set); + if (rc < 0) + return rc; + + pmem->q = blk_mq_init_queue(&pmem->tag_set); + if (IS_ERR(pmem->q)) { + blk_mq_free_tag_set(&pmem->tag_set); + return -ENOMEM; + } + + if (devm_add_action_or_reset(dev, pmem_release_queue, pmem)) { + pmem_release_queue(pmem); + return -ENOMEM; + } + + pmem->pfn_flags = PFN_DEV; + if (is_nd_pfn(dev)) { + addr = devm_memremap_pages(dev, &pfn_res, + &pmem->q->q_usage_counter, altmap); + pfn_sb = nd_pfn->pfn_sb; + pmem->data_offset = le64_to_cpu(pfn_sb->dataoff); + pmem->pfn_pad = resource_size(res) - resource_size(&pfn_res); + pmem->pfn_flags |= PFN_MAP; + res = &pfn_res; /* for badblocks populate */ + res->start += pmem->data_offset; + } else if (pmem_should_map_pages(dev)) { + addr = devm_memremap_pages(dev, &nsio->res, + &pmem->q->q_usage_counter, NULL); + pmem->pfn_flags |= PFN_MAP; + } else + addr = devm_memremap(dev, pmem->phys_addr, + pmem->size, ARCH_MEMREMAP_PMEM); + + /* + * At release time the queue must be frozen before + * devm_memremap_pages is unwound + */ + if (devm_add_action_or_reset(dev, pmem_freeze_queue, pmem->q)) + return -ENOMEM; + + if (IS_ERR(addr)) + return PTR_ERR(addr); + pmem->virt_addr = addr; + + blk_queue_write_cache(pmem->q, wbc, fua); + blk_queue_physical_block_size(pmem->q, PAGE_SIZE); + blk_queue_logical_block_size(pmem->q, pmem_sector_size(ndns)); + if (use_dma) { + u64 xfercap = dma_get_desc_xfercap(chan); + + /* set it to some sane size if DMA driver didn't export */ + if (xfercap == 0) + xfercap = SZ_1M; + + dev_dbg(dev, "xfercap: %#llx\n", xfercap); + /* max xfer size is per_descriptor_cap * num_of_sg */ + blk_queue_max_hw_sectors(pmem->q, + SG_ALLOCATED * xfercap / 512); + blk_queue_max_segments(pmem->q, SG_ALLOCATED); + } + blk_queue_max_hw_sectors(pmem->q, UINT_MAX); + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->q); + queue_flag_set_unlocked(QUEUE_FLAG_DAX, pmem->q); + pmem->q->queuedata = pmem; + + disk = alloc_disk_node(0, nid); + if (!disk) + return -ENOMEM; + pmem->disk = disk; + + disk->fops = &pmem_fops; + disk->queue = pmem->q; + disk->flags = GENHD_FL_EXT_DEVT; + nvdimm_namespace_disk_name(ndns, disk->disk_name); + set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset) + / 512); + if (devm_init_badblocks(dev, &pmem->bb)) + return -ENOMEM; + nvdimm_badblocks_populate(nd_region, &pmem->bb, res); + disk->bb = &pmem->bb; + + dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops); + if (!dax_dev) { + put_disk(disk); + return -ENOMEM; + } + dax_write_cache(dax_dev, wbc); + pmem->dax_dev = dax_dev; + + gendev = disk_to_dev(disk); + gendev->groups = pmem_attribute_groups; + + device_add_disk(dev, disk); + if (devm_add_action_or_reset(dev, pmem_release_disk, pmem)) + return -ENOMEM; + + revalidate_disk(disk); + + pmem->bb_state = sysfs_get_dirent(disk_to_dev(disk)->kobj.sd, + "badblocks"); + if (!pmem->bb_state) + dev_warn(dev, "'badblocks' notification disabled\n"); + + return 0; +} + +static int nd_pmem_probe(struct device *dev) +{ + struct nd_namespace_common *ndns; + + ndns = nvdimm_namespace_common_probe(dev); + if (IS_ERR(ndns)) + return PTR_ERR(ndns); + + if (devm_nsio_enable(dev, to_nd_namespace_io(&ndns->dev))) + return -ENXIO; + + if (is_nd_btt(dev)) + return nvdimm_namespace_attach_btt(ndns); + + if (is_nd_pfn(dev)) + return pmem_attach_disk(dev, ndns); + + /* if we find a valid info-block we'll come back as that personality */ + if (nd_btt_probe(dev, ndns) == 0 || nd_pfn_probe(dev, ndns) == 0 + || nd_dax_probe(dev, ndns) == 0) + return -ENXIO; + + /* ...otherwise we're just a raw pmem device */ + return pmem_attach_disk(dev, ndns); +} + +static struct nd_device_driver nd_pmem_driver = { + .probe = nd_pmem_probe, + .remove = nd_pmem_remove, + .notify = nd_pmem_notify, + .shutdown = nd_pmem_shutdown, + .drv = { + .name = "nd_pmem", + }, + .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM, +}; + +static int __init pmem_init(void) +{ + if (use_dma) + dmaengine_get(); + + return nd_driver_register(&nd_pmem_driver); +} +module_init(pmem_init); + +static void pmem_exit(void) +{ + if (use_dma) + dmaengine_put(); + + driver_unregister(&nd_pmem_driver.drv); +} +module_exit(pmem_exit); + +MODULE_SOFTDEP("pre: dmaengine"); +MODULE_LICENSE("GPL v2");