diff options
| author | Ross Zwisler <ross.zwisler@linux.intel.com> | 2015-04-01 09:12:19 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-04-01 17:03:56 +0200 |
| commit | 9e853f2313e5eb163cb1ea461b23c2332cf6438a (patch) | |
| tree | 1cc98a03ff9582111fdd8032237c406d67f976fa /drivers/block | |
| parent | ec776ef6bbe1734c29cd6bd05219cd93b2731bd4 (diff) | |
drivers/block/pmem: Add a driver for persistent memory
PMEM is a new driver that presents a reserved range of memory as
a block device. This is useful for developing with NV-DIMMs,
and can be used with volatile memory as a development platform.
This patch contains the initial driver from Ross Zwisler, with
various changes: converted it to use a platform_device for
discovery, fixed partition support and merged various patches
from Boaz Harrosh.
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-nvdimm@ml01.01.org
Link: http://lkml.kernel.org/r/1427872339-6688-3-git-send-email-hch@lst.de
[ Minor cleanups. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/block/Makefile | 1 | ||||
| -rw-r--r-- | drivers/block/pmem.c | 263 |
3 files changed, 275 insertions, 0 deletions
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index 1b8094d4d7af..eb1fed5bd516 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -404,6 +404,17 @@ config BLK_DEV_RAM_DAX and will prevent RAM block device backing store memory from being allocated from highmem (only a problem for highmem systems). +config BLK_DEV_PMEM + tristate "Persistent memory block device support" + help + Saying Y here will allow you to use a contiguous range of reserved + memory as one or more persistent block devices. + + To compile this driver as a module, choose M here: the module will be + called 'pmem'. + + If unsure, say N. + config CDROM_PKTCDVD tristate "Packet writing on CD/DVD media" depends on !UML diff --git a/drivers/block/Makefile b/drivers/block/Makefile index 02b688d1438d..9cc6c18a1c7e 100644 --- a/drivers/block/Makefile +++ b/drivers/block/Makefile @@ -14,6 +14,7 @@ obj-$(CONFIG_PS3_VRAM) += ps3vram.o obj-$(CONFIG_ATARI_FLOPPY) += ataflop.o obj-$(CONFIG_AMIGA_Z2RAM) += z2ram.o obj-$(CONFIG_BLK_DEV_RAM) += brd.o +obj-$(CONFIG_BLK_DEV_PMEM) += pmem.o obj-$(CONFIG_BLK_DEV_LOOP) += loop.o obj-$(CONFIG_BLK_CPQ_DA) += cpqarray.o obj-$(CONFIG_BLK_CPQ_CISS_DA) += cciss.o diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c new file mode 100644 index 000000000000..988f3846dc3e --- /dev/null +++ b/drivers/block/pmem.c @@ -0,0 +1,263 @@ +/* + * Persistent Memory Driver + * + * Copyright (c) 2014, Intel Corporation. + * Copyright (c) 2015, Christoph Hellwig <hch@lst.de>. + * Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>. + * + * 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/slab.h> + +#define PMEM_MINORS 16 + +struct pmem_device { + struct request_queue *pmem_queue; + struct gendisk *pmem_disk; + + /* One contiguous memory region per device */ + phys_addr_t phys_addr; + void *virt_addr; + size_t size; +}; + +static int pmem_major; +static atomic_t pmem_index; + +static void pmem_do_bvec(struct pmem_device *pmem, struct page *page, + unsigned int len, unsigned int off, int rw, + sector_t sector) +{ + void *mem = kmap_atomic(page); + size_t pmem_off = sector << 9; + + if (rw == READ) { + memcpy(mem + off, pmem->virt_addr + pmem_off, len); + flush_dcache_page(page); + } else { + flush_dcache_page(page); + memcpy(pmem->virt_addr + pmem_off, mem + off, len); + } + + kunmap_atomic(mem); +} + +static void pmem_make_request(struct request_queue *q, struct bio *bio) +{ + struct block_device *bdev = bio->bi_bdev; + struct pmem_device *pmem = bdev->bd_disk->private_data; + int rw; + struct bio_vec bvec; + sector_t sector; + struct bvec_iter iter; + int err = 0; + + if (bio_end_sector(bio) > get_capacity(bdev->bd_disk)) { + err = -EIO; + goto out; + } + + BUG_ON(bio->bi_rw & REQ_DISCARD); + + rw = bio_data_dir(bio); + sector = bio->bi_iter.bi_sector; + bio_for_each_segment(bvec, bio, iter) { + pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, bvec.bv_offset, + rw, sector); + sector += bvec.bv_len >> 9; + } + +out: + bio_endio(bio, err); +} + +static int pmem_rw_page(struct block_device *bdev, sector_t sector, + struct page *page, int rw) +{ + struct pmem_device *pmem = bdev->bd_disk->private_data; + + pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector); + page_endio(page, rw & WRITE, 0); + + return 0; +} + +static long pmem_direct_access(struct block_device *bdev, sector_t sector, + void **kaddr, unsigned long *pfn, long size) +{ + struct pmem_device *pmem = bdev->bd_disk->private_data; + size_t offset = sector << 9; + + if (!pmem) + return -ENODEV; + + *kaddr = pmem->virt_addr + offset; + *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT; + + return pmem->size - offset; +} + +static const struct block_device_operations pmem_fops = { + .owner = THIS_MODULE, + .rw_page = pmem_rw_page, + .direct_access = pmem_direct_access, +}; + +static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res) +{ + struct pmem_device *pmem; + struct gendisk *disk; + int idx, err; + + err = -ENOMEM; + pmem = kzalloc(sizeof(*pmem), GFP_KERNEL); + if (!pmem) + goto out; + + pmem->phys_addr = res->start; + pmem->size = resource_size(res); + + err = -EINVAL; + if (!request_mem_region(pmem->phys_addr, pmem->size, "pmem")) { + dev_warn(dev, "could not reserve region [0x%llx:0x%zx]\n", + pmem->phys_addr, pmem->size); + goto out_free_dev; + } + + /* + * Map the memory as non-cachable, as we can't write back the contents + * of the CPU caches in case of a crash. + */ + err = -ENOMEM; + pmem->virt_addr = ioremap_nocache(pmem->phys_addr, pmem->size); + if (!pmem->virt_addr) + goto out_release_region; + + pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL); + if (!pmem->pmem_queue) + goto out_unmap; + + blk_queue_make_request(pmem->pmem_queue, pmem_make_request); + blk_queue_max_hw_sectors(pmem->pmem_queue, 1024); + blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY); + + disk = alloc_disk(PMEM_MINORS); + if (!disk) + goto out_free_queue; + + idx = atomic_inc_return(&pmem_index) - 1; + + disk->major = pmem_major; + disk->first_minor = PMEM_MINORS * idx; + disk->fops = &pmem_fops; + disk->private_data = pmem; + disk->queue = pmem->pmem_queue; + disk->flags = GENHD_FL_EXT_DEVT; + sprintf(disk->disk_name, "pmem%d", idx); + disk->driverfs_dev = dev; + set_capacity(disk, pmem->size >> 9); + pmem->pmem_disk = disk; + + add_disk(disk); + + return pmem; + +out_free_queue: + blk_cleanup_queue(pmem->pmem_queue); +out_unmap: + iounmap(pmem->virt_addr); +out_release_region: + release_mem_region(pmem->phys_addr, pmem->size); +out_free_dev: + kfree(pmem); +out: + return ERR_PTR(err); +} + +static void pmem_free(struct pmem_device *pmem) +{ + del_gendisk(pmem->pmem_disk); + put_disk(pmem->pmem_disk); + blk_cleanup_queue(pmem->pmem_queue); + iounmap(pmem->virt_addr); + release_mem_region(pmem->phys_addr, pmem->size); + kfree(pmem); +} + +static int pmem_probe(struct platform_device *pdev) +{ + struct pmem_device *pmem; + struct resource *res; + + if (WARN_ON(pdev->num_resources > 1)) + return -ENXIO; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENXIO; + + pmem = pmem_alloc(&pdev->dev, res); + if (IS_ERR(pmem)) + return PTR_ERR(pmem); + + platform_set_drvdata(pdev, pmem); + + return 0; +} + +static int pmem_remove(struct platform_device *pdev) +{ + struct pmem_device *pmem = platform_get_drvdata(pdev); + + pmem_free(pmem); + return 0; +} + +static struct platform_driver pmem_driver = { + .probe = pmem_probe, + .remove = pmem_remove, + .driver = { + .owner = THIS_MODULE, + .name = "pmem", + }, +}; + +static int __init pmem_init(void) +{ + int error; + + pmem_major = register_blkdev(0, "pmem"); + if (pmem_major < 0) + return pmem_major; + + error = platform_driver_register(&pmem_driver); + if (error) + unregister_blkdev(pmem_major, "pmem"); + return error; +} +module_init(pmem_init); + +static void pmem_exit(void) +{ + platform_driver_unregister(&pmem_driver); + unregister_blkdev(pmem_major, "pmem"); +} +module_exit(pmem_exit); + +MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>"); +MODULE_LICENSE("GPL v2"); |