Adding a DMA supported blk-mq driver for pmem. This provides signficant CPU
utilization reduction. By default the pmem driver will be using blk-mq with
DMA through the dmaengine API. DMA can be turned off with use_dma=0 kernel
parameter. Additional kernel parameters are provided:
queue_depth: The queue depth for blk-mq. Typically in relation to what the
DMA engine can provide per queue/channel. This needs to take
into account of num_sg as well for some DMA engines. i.e.
num_sg * queue_depth < total descriptors available per queue or
channel.
q_per_node: Hardware queues per node. Typically the number of channels the
DMA engine can provide per socket.
num_sg: Number of scatterlist we can handle per I/O request.
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
Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
drivers/nvdimm/Kconfig | 23 +
drivers/nvdimm/Makefile | 3
drivers/nvdimm/pmem.h | 3
drivers/nvdimm/pmem_mq.c | 853 ++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 882 insertions(+)
create mode 100644 drivers/nvdimm/pmem_mq.c
diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
index 5bdd499..c88c2bb 100644
--- a/drivers/nvdimm/Kconfig
+++ b/drivers/nvdimm/Kconfig
@@ -36,6 +36,29 @@ config BLK_DEV_PMEM
Say Y if you want to use an NVDIMM
+config BLK_DEV_PMEM_MQ
+ tristate "PMEM: Persistent memory block device multi-queue support"
+ depends on m
+ default LIBNVDIMM
+ select DAX
+ select ND_BTT if BTT
+ select ND_PFN if NVDIMM_PFN
+ select DMA_ENGINE
+ help
+ Memory ranges for PMEM are described by either an NFIT
+ (NVDIMM Firmware Interface Table, see CONFIG_NFIT_ACPI), a
+ non-standard OEM-specific E820 memory type (type-12, see
+ CONFIG_X86_PMEM_LEGACY), or it is manually specified by the
+ 'memmap=nn[KMG]!ss[KMG]' kernel command line (see
+ Documentation/admin-guide/kernel-parameters.rst). This driver
+ converts these persistent memory ranges into block devices that are
+ capable of DAX (direct-access) file system mappings. See
+ Documentation/nvdimm/nvdimm.txt for more details. This driver
+ utilizes block layer multi-queue in order to support using DMA
+ engines to help offload the data copying.
+
+ 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..8bfd107 100644
--- a/drivers/nvdimm/Makefile
+++ b/drivers/nvdimm/Makefile
@@ -1,11 +1,14 @@
obj-$(CONFIG_LIBNVDIMM) += libnvdimm.o
obj-$(CONFIG_BLK_DEV_PMEM) += nd_pmem.o
+obj-$(CONFIG_BLK_DEV_PMEM_MQ) += nd_pmem_mq.o
obj-$(CONFIG_ND_BTT) += nd_btt.o
obj-$(CONFIG_ND_BLK) += nd_blk.o
obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o
nd_pmem-y := pmem.o
+nd_pmem_mq-y := pmem_mq.o
+
nd_btt-y := btt.o
nd_blk-y := blk.o
diff --git a/drivers/nvdimm/pmem.h b/drivers/nvdimm/pmem.h
index 5434321..bbbe982 100644
--- a/drivers/nvdimm/pmem.h
+++ b/drivers/nvdimm/pmem.h
@@ -4,6 +4,7 @@
#include <linux/types.h>
#include <linux/pfn_t.h>
#include <linux/fs.h>
+#include <linux/blk-mq.h>
#ifdef CONFIG_ARCH_HAS_PMEM_API
#define ARCH_MEMREMAP_PMEM MEMREMAP_WB
@@ -35,6 +36,8 @@ 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;
};
long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
diff --git a/drivers/nvdimm/pmem_mq.c b/drivers/nvdimm/pmem_mq.c
new file mode 100644
index 0000000..db2fc2a
--- /dev/null
+++ b/drivers/nvdimm/pmem_mq.c
@@ -0,0 +1,853 @@
+/*
+ * 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 <hch@xxxxxx>.
+ * Copyright (c) 2015, Boaz Harrosh <boaz@xxxxxxxxxxxxx>.
+ *
+ * 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 <asm/cacheflush.h>
+#include <linux/blkdev.h>
+#include <linux/hdreg.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/badblocks.h>
+#include <linux/memremap.h>
+#include <linux/vmalloc.h>
+#include <linux/blk-mq.h>
+#include <linux/pfn_t.h>
+#include <linux/slab.h>
+#include <linux/uio.h>
+#include <linux/dax.h>
+#include <linux/nd.h>
+#include <linux/blk-mq.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/nodemask.h>
+#include "pmem.h"
+#include "pfn.h"
+#include "nd.h"
+
+static int use_dma = 1;
+module_param(use_dma, int, 0444);
+MODULE_PARM_DESC(use_dma, "Turn on/off DMA usage");
+
+static int queue_depth = 128;
+module_param(queue_depth, int, 0444);
+MODULE_PARM_DESC(queue_depth, "I/O Queue Depth for multi queue mode");
+
+/* typically maps to number of DMA channels/devices per socket */
+static int q_per_node = 8;
+module_param(q_per_node, int, 0444);
+MODULE_PARM_DESC(q_per_node, "Hardware queues per node");
+
+static int num_sg = 128;
+module_param(num_sg, int, 0444);
+MODULE_PARM_DESC(num_sg, "Number of scatterlist entries per request");
+
+struct pmem_cmd {
+ struct request *rq;
+ struct dma_chan *chan;
+ int sg_nents;
+ struct scatterlist sg[];
+};
+
+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 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,
+ .flush = pmem_dax_flush,
+};
+
+static const struct attribute_group *pmem_attribute_groups[] = {
+ &dax_attribute_group,
+ NULL,
+};
+
+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 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 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 > num_sg);
+
+ 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 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");
+ }
+ }
+
+ pmem->tag_set.ops = &pmem_mq_ops;
+ pmem->tag_set.nr_hw_queues = num_possible_nodes() * q_per_node;
+ pmem->tag_set.queue_depth = queue_depth;
+ pmem->tag_set.numa_node = dev_to_node(dev);
+ pmem->tag_set.cmd_size = sizeof(struct pmem_cmd) +
+ sizeof(struct scatterlist) * num_sg;
+ 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, num_sg * xfercap / 512);
+ blk_queue_max_segments(pmem->q, num_sg);
+ }
+ 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 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);
+}
+
+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_AUTHOR("Dave Jiang <dave.jiang@xxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
--
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