From: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> 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. [boaz] SQUASHME: pmem: Remove unused #include headers SQUASHME: pmem: Request from fdisk 4k alignment SQUASHME: pmem: Let each device manage private memory region SQUASHME: pmem: Support of multiple memory regions The API to pmem module a single string parameter named "map" of the form: map=mapS[,mapS...] where mapS=nn[KMG]$ss[KMG], or mapS=nn[KMG]@ss[KMG], nn=size, ss=offset Just like the Kernel command line map && memmap parameters, so anything you did at grub just copy/paste to here. The "@" form is exactly the same as the "$" form only that at bash prompt we need to escape the "$" with \$ so also support the '@' char for convenience. For each specified mapS there will be a device created. [This is the accumulated version of the driver developed by multiple programmers. To see the real history of these patches see: git://git.open-osd.org/pmem.git https://github.com/01org/prd This patch is based on: [673302b] pmem: KISS, remove register_blkdev ] TODO: Add Documentation/blockdev/pmem.txt Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> Signed-off-by: Boaz Harrosh <boaz@xxxxxxxxxxxxx> --- MAINTAINERS | 6 + drivers/block/Kconfig | 13 ++ drivers/block/Makefile | 1 + drivers/block/pmem.c | 385 +++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 405 insertions(+) create mode 100644 drivers/block/pmem.c diff --git a/MAINTAINERS b/MAINTAINERS index 5e7866a..2724ede 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7504,6 +7504,12 @@ S: Maintained F: Documentation/blockdev/ramdisk.txt F: drivers/block/brd.c +PERSISTENT MEMORY DRIVER +M: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> +L: linux-nvdimm@xxxxxxxxxxxx +S: Supported +F: drivers/block/pmem.c + RANDOM NUMBER DRIVER M: "Theodore Ts'o" <tytso@xxxxxxx> S: Maintained diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index 014a1cf..5da8cbf 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -403,6 +403,19 @@ config BLK_DEV_XIP 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 block devices. Memory for PMEM should be + reserved using the "memmap" kernel parameter. + + To compile this driver as a module, choose M here: the module will be + called pmem. + + Most normal users won't need this functionality, and can thus say N + here. + config CDROM_PKTCDVD tristate "Packet writing on CD/DVD media" depends on !UML diff --git a/drivers/block/Makefile b/drivers/block/Makefile index 02b688d..9cc6c18 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 0000000..0fcda58 --- /dev/null +++ b/drivers/block/pmem.c @@ -0,0 +1,385 @@ +/* + * Persistent Memory Driver + * Copyright (c) 2014, Intel Corporation. + * + * 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. + * + * This driver is heavily based on drivers/block/brd.c. + * Copyright (C) 2007 Nick Piggin + * Copyright (C) 2007 Novell Inc. + */ + +#include <linux/blkdev.h> +#include <linux/hdreg.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/slab.h> + +#define SECTOR_SHIFT 9 +#define PAGE_SECTORS_SHIFT (PAGE_SHIFT - SECTOR_SHIFT) +#define PAGE_SECTORS (1 << PAGE_SECTORS_SHIFT) + +struct pmem_device { + struct request_queue *pmem_queue; + struct gendisk *pmem_disk; + struct list_head pmem_list; + + /* One contiguous memory region per device */ + phys_addr_t phys_addr; + void *virt_addr; + size_t size; +}; + +/* + * direct translation from (pmem,sector) => void* + * We do not require that sector be page aligned. + * The return value will point to the beginning of the page containing the + * given sector, not to the sector itself. + */ +static void *pmem_lookup_pg_addr(struct pmem_device *pmem, sector_t sector) +{ + size_t page_offset = sector >> PAGE_SECTORS_SHIFT; + size_t offset = page_offset << PAGE_SHIFT; + + BUG_ON(offset >= pmem->size); + return pmem->virt_addr + offset; +} + +/* + * sector is not required to be page aligned. + * n is at most a single page, but could be less. + */ +static void copy_to_pmem(struct pmem_device *pmem, const void *src, + sector_t sector, size_t n) +{ + void *dst; + unsigned int offset = (sector & (PAGE_SECTORS - 1)) << SECTOR_SHIFT; + size_t copy; + + BUG_ON(n > PAGE_SIZE); + + copy = min_t(size_t, n, PAGE_SIZE - offset); + dst = pmem_lookup_pg_addr(pmem, sector); + memcpy(dst + offset, src, copy); + + if (copy < n) { + src += copy; + sector += copy >> SECTOR_SHIFT; + copy = n - copy; + dst = pmem_lookup_pg_addr(pmem, sector); + memcpy(dst, src, copy); + } +} + +/* + * sector is not required to be page aligned. + * n is at most a single page, but could be less. + */ +static void copy_from_pmem(void *dst, struct pmem_device *pmem, + sector_t sector, size_t n) +{ + void *src; + unsigned int offset = (sector & (PAGE_SECTORS - 1)) << SECTOR_SHIFT; + size_t copy; + + BUG_ON(n > PAGE_SIZE); + + copy = min_t(size_t, n, PAGE_SIZE - offset); + src = pmem_lookup_pg_addr(pmem, sector); + + memcpy(dst, src + offset, copy); + + if (copy < n) { + dst += copy; + sector += copy >> SECTOR_SHIFT; + copy = n - copy; + src = pmem_lookup_pg_addr(pmem, sector); + memcpy(dst, src, copy); + } +} + +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); + + if (rw == READ) { + copy_from_pmem(mem + off, pmem, sector, len); + flush_dcache_page(page); + } else { + /* + * FIXME: Need more involved flushing to ensure that writes to + * NVDIMMs are actually durable before returning. + */ + flush_dcache_page(page); + copy_to_pmem(pmem, mem + off, sector, 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; + + sector = bio->bi_iter.bi_sector; + if (bio_end_sector(bio) > get_capacity(bdev->bd_disk)) { + err = -EIO; + goto out; + } + + BUG_ON(bio->bi_rw & REQ_DISCARD); + + rw = bio_rw(bio); + if (rw == READA) + rw = READ; + + bio_for_each_segment(bvec, bio, iter) { + unsigned int len = bvec.bv_len; + + BUG_ON(len > PAGE_SIZE); + pmem_do_bvec(pmem, bvec.bv_page, len, + bvec.bv_offset, rw, sector); + sector += len >> SECTOR_SHIFT; + } + +out: + bio_endio(bio, err); +} + +static const struct block_device_operations pmem_fops = { + .owner = THIS_MODULE, +}; + +/* Kernel module stuff */ +static char *map; +module_param(map, charp, S_IRUGO); +MODULE_PARM_DESC(map, + "pmem device mapping: map=mapS[,mapS...] where:\n" + "mapS=nn[KMG]$ss[KMG] or mapS=nn[KMG]@ss[KMG], nn=size, ss=offset."); + +static LIST_HEAD(pmem_devices); +static int pmem_major; + +/* pmem->phys_addr and pmem->size need to be set. + * Will then set virt_addr if successful. + */ +int pmem_mapmem(struct pmem_device *pmem) +{ + struct resource *res_mem; + int err; + + res_mem = request_mem_region_exclusive(pmem->phys_addr, pmem->size, + "pmem"); + if (!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->virt_addr = ioremap_cache(pmem->phys_addr, pmem->size); + if (unlikely(!pmem->virt_addr)) { + err = -ENXIO; + goto out_release; + } + return 0; + +out_release: + release_mem_region(pmem->phys_addr, pmem->size); + return err; +} + +void pmem_unmapmem(struct pmem_device *pmem) +{ + if (unlikely(!pmem->virt_addr)) + return; + + iounmap(pmem->virt_addr); + release_mem_region(pmem->phys_addr, pmem->size); + pmem->virt_addr = NULL; +} + +static struct pmem_device *pmem_alloc(phys_addr_t phys_addr, size_t disk_size, + int i) +{ + struct pmem_device *pmem; + struct gendisk *disk; + int err; + + if (unlikely((phys_addr & ~PAGE_MASK) || (disk_size & ~PAGE_MASK))) { + pr_err("phys_addr=0x%llx disk_size=0x%zx must be 4k aligned\n", + phys_addr, disk_size); + err = -EINVAL; + goto out; + } + + pmem = kzalloc(sizeof(*pmem), GFP_KERNEL); + if (unlikely(!pmem)) { + err = -ENOMEM; + goto out; + } + + pmem->phys_addr = phys_addr; + pmem->size = disk_size; + + err = pmem_mapmem(pmem); + if (unlikely(err)) + goto out_free_dev; + + pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL); + if (unlikely(!pmem->pmem_queue)) { + err = -ENOMEM; + 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); + + /* This is so fdisk will align partitions on 4k, because of + * direct_access API needing 4k alignment, returning a PFN + */ + blk_queue_physical_block_size(pmem->pmem_queue, PAGE_SIZE); + pmem->pmem_queue->limits.io_min = 512; /* Don't use the accessor */ + + disk = alloc_disk(0); + if (unlikely(!disk)) { + err = -ENOMEM; + goto out_free_queue; + } + + disk->major = pmem_major; + disk->first_minor = 0; + 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", i); + set_capacity(disk, disk_size >> SECTOR_SHIFT); + pmem->pmem_disk = disk; + + return pmem; + +out_free_queue: + blk_cleanup_queue(pmem->pmem_queue); +out_unmap: + pmem_unmapmem(pmem); +out_free_dev: + kfree(pmem); +out: + return ERR_PTR(err); +} + +static void pmem_free(struct pmem_device *pmem) +{ + put_disk(pmem->pmem_disk); + blk_cleanup_queue(pmem->pmem_queue); + pmem_unmapmem(pmem); + kfree(pmem); +} + +static void pmem_del_one(struct pmem_device *pmem) +{ + list_del(&pmem->pmem_list); + del_gendisk(pmem->pmem_disk); + pmem_free(pmem); +} + +static int pmem_parse_map_one(char *map, phys_addr_t *start, size_t *size) +{ + char *p = map; + + *size = (size_t)memparse(p, &p); + if ((p == map) || ((*p != '$') && (*p != '@'))) + return -EINVAL; + + if (!*(++p)) + return -EINVAL; + + *start = (phys_addr_t)memparse(p, &p); + + return *p == '\0' ? 0 : -EINVAL; +} + +static int __init pmem_init(void) +{ + int result, i; + struct pmem_device *pmem, *next; + char *p, *pmem_map = map; + + if (!pmem_map) { + pr_err("pmem: must specify map=nn@ss parameter.\n"); + return -EINVAL; + } + + result = register_blkdev(0, "pmem"); + if (result < 0) + return -EIO; + else + pmem_major = result; + + i = 0; + while ((p = strsep(&pmem_map, ",")) != NULL) { + phys_addr_t phys_addr; + size_t disk_size; + + if (!*p) + continue; + result = pmem_parse_map_one(p, &phys_addr, &disk_size); + if (result) + goto out_free; + pmem = pmem_alloc(phys_addr, disk_size, i); + if (IS_ERR(pmem)) { + result = PTR_ERR(pmem); + goto out_free; + } + list_add_tail(&pmem->pmem_list, &pmem_devices); + ++i; + } + + list_for_each_entry(pmem, &pmem_devices, pmem_list) + add_disk(pmem->pmem_disk); + + pr_info("pmem: module loaded\n"); + return 0; + +out_free: + list_for_each_entry_safe(pmem, next, &pmem_devices, pmem_list) { + list_del(&pmem->pmem_list); + pmem_free(pmem); + } + unregister_blkdev(pmem_major, "pmem"); + + return result; +} + +static void __exit pmem_exit(void) +{ + struct pmem_device *pmem, *next; + + list_for_each_entry_safe(pmem, next, &pmem_devices, pmem_list) + pmem_del_one(pmem); + + unregister_blkdev(pmem_major, "pmem"); + pr_info("pmem: module unloaded\n"); +} + +MODULE_AUTHOR("Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>"); +MODULE_LICENSE("GPL"); +module_init(pmem_init); +module_exit(pmem_exit); -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
