linux/drivers/nvdimm/pmem.c
Christoph Hellwig 7ac5360cd4 dax: remove the copy_from_iter and copy_to_iter methods
These methods indirect the actual DAX read/write path.  In the end pmem
uses magic flush and mc safe variants and fuse and dcssblk use plain ones
while device mapper picks redirects to the underlying device.

Add set_dax_nocache() and set_dax_nomc() APIs to control which copy
routines are used to remove indirect call from the read/write fast path
as well as a lot of boilerplate code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Vivek Goyal <vgoyal@redhat.com> [virtiofs]
Link: https://lore.kernel.org/r/20211215084508.435401-5-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-12-18 08:04:53 -08:00

686 lines
17 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Persistent Memory Driver
*
* Copyright (c) 2014-2015, Intel Corporation.
* Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
* Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
*/
#include <linux/blkdev.h>
#include <linux/pagemap.h>
#include <linux/hdreg.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/set_memory.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/mm.h>
#include <asm/cacheflush.h>
#include "pmem.h"
#include "btt.h"
#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 void hwpoison_clear(struct pmem_device *pmem,
phys_addr_t phys, unsigned int len)
{
unsigned long pfn_start, pfn_end, pfn;
/* only pmem in the linear map supports HWPoison */
if (is_vmalloc_addr(pmem->virt_addr))
return;
pfn_start = PHYS_PFN(phys);
pfn_end = pfn_start + PHYS_PFN(len);
for (pfn = pfn_start; pfn < pfn_end; pfn++) {
struct page *page = pfn_to_page(pfn);
/*
* Note, no need to hold a get_dev_pagemap() reference
* here since we're in the driver I/O path and
* outstanding I/O requests pin the dev_pagemap.
*/
if (test_and_clear_pmem_poison(page))
clear_mce_nospec(pfn);
}
}
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) {
hwpoison_clear(pmem, pmem->phys_addr + offset, cleared);
cleared /= 512;
dev_dbg(dev, "%#llx clear %ld sector%s\n",
(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)
{
unsigned int chunk;
void *mem;
while (len) {
mem = kmap_atomic(page);
chunk = min_t(unsigned int, len, PAGE_SIZE - off);
memcpy_flushcache(pmem_addr, mem + off, chunk);
kunmap_atomic(mem);
len -= chunk;
off = 0;
page++;
pmem_addr += chunk;
}
}
static blk_status_t read_pmem(struct page *page, unsigned int off,
void *pmem_addr, unsigned int len)
{
unsigned int chunk;
unsigned long rem;
void *mem;
while (len) {
mem = kmap_atomic(page);
chunk = min_t(unsigned int, len, PAGE_SIZE - off);
rem = copy_mc_to_kernel(mem + off, pmem_addr, chunk);
kunmap_atomic(mem);
if (rem)
return BLK_STS_IOERR;
len -= chunk;
off = 0;
page++;
pmem_addr += chunk;
}
return BLK_STS_OK;
}
static blk_status_t pmem_do_read(struct pmem_device *pmem,
struct page *page, unsigned int page_off,
sector_t sector, unsigned int len)
{
blk_status_t rc;
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)))
return BLK_STS_IOERR;
rc = read_pmem(page, page_off, pmem_addr, len);
flush_dcache_page(page);
return rc;
}
static blk_status_t pmem_do_write(struct pmem_device *pmem,
struct page *page, unsigned int page_off,
sector_t sector, unsigned int len)
{
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;
/*
* 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, page_off, len);
if (unlikely(bad_pmem)) {
rc = pmem_clear_poison(pmem, pmem_off, len);
write_pmem(pmem_addr, page, page_off, len);
}
return rc;
}
static void pmem_submit_bio(struct bio *bio)
{
int ret = 0;
blk_status_t rc = 0;
bool do_acct;
unsigned long start;
struct bio_vec bvec;
struct bvec_iter iter;
struct pmem_device *pmem = bio->bi_bdev->bd_disk->private_data;
struct nd_region *nd_region = to_region(pmem);
if (bio->bi_opf & REQ_PREFLUSH)
ret = nvdimm_flush(nd_region, bio);
do_acct = blk_queue_io_stat(bio->bi_bdev->bd_disk->queue);
if (do_acct)
start = bio_start_io_acct(bio);
bio_for_each_segment(bvec, bio, iter) {
if (op_is_write(bio_op(bio)))
rc = pmem_do_write(pmem, bvec.bv_page, bvec.bv_offset,
iter.bi_sector, bvec.bv_len);
else
rc = pmem_do_read(pmem, bvec.bv_page, bvec.bv_offset,
iter.bi_sector, bvec.bv_len);
if (rc) {
bio->bi_status = rc;
break;
}
}
if (do_acct)
bio_end_io_acct(bio, start);
if (bio->bi_opf & REQ_FUA)
ret = nvdimm_flush(nd_region, bio);
if (ret)
bio->bi_status = errno_to_blk_status(ret);
bio_endio(bio);
}
static int pmem_rw_page(struct block_device *bdev, sector_t sector,
struct page *page, unsigned int op)
{
struct pmem_device *pmem = bdev->bd_disk->private_data;
blk_status_t rc;
if (op_is_write(op))
rc = pmem_do_write(pmem, page, 0, sector, thp_size(page));
else
rc = pmem_do_read(pmem, page, 0, sector, thp_size(page));
/*
* 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, op_is_write(op), 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;
if (kaddr)
*kaddr = pmem->virt_addr + offset;
if (pfn)
*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,
.submit_bio = pmem_submit_bio,
.rw_page = pmem_rw_page,
};
static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
size_t nr_pages)
{
struct pmem_device *pmem = dax_get_private(dax_dev);
return blk_status_to_errno(pmem_do_write(pmem, ZERO_PAGE(0), 0,
PFN_PHYS(pgoff) >> SECTOR_SHIFT,
PAGE_SIZE));
}
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 const struct dax_operations pmem_dax_ops = {
.direct_access = pmem_dax_direct_access,
.zero_page_range = pmem_dax_zero_page_range,
};
static ssize_t write_cache_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct pmem_device *pmem = dev_to_disk(dev)->private_data;
return sprintf(buf, "%d\n", !!dax_write_cache_enabled(pmem->dax_dev));
}
static ssize_t write_cache_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct pmem_device *pmem = dev_to_disk(dev)->private_data;
bool write_cache;
int rc;
rc = strtobool(buf, &write_cache);
if (rc)
return rc;
dax_write_cache(pmem->dax_dev, write_cache);
return len;
}
static DEVICE_ATTR_RW(write_cache);
static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n)
{
#ifndef CONFIG_ARCH_HAS_PMEM_API
if (a == &dev_attr_write_cache.attr)
return 0;
#endif
return a->mode;
}
static struct attribute *dax_attributes[] = {
&dev_attr_write_cache.attr,
NULL,
};
static const struct attribute_group dax_attribute_group = {
.name = "dax",
.attrs = dax_attributes,
.is_visible = dax_visible,
};
static const struct attribute_group *pmem_attribute_groups[] = {
&dax_attribute_group,
NULL,
};
static void pmem_release_disk(void *__pmem)
{
struct pmem_device *pmem = __pmem;
dax_remove_host(pmem->disk);
kill_dax(pmem->dax_dev);
put_dax(pmem->dax_dev);
del_gendisk(pmem->disk);
blk_cleanup_disk(pmem->disk);
}
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);
int nid = dev_to_node(dev), fua;
struct resource *res = &nsio->res;
struct range bb_range;
struct nd_pfn *nd_pfn = NULL;
struct dax_device *dax_dev;
struct nd_pfn_sb *pfn_sb;
struct pmem_device *pmem;
struct request_queue *q;
struct gendisk *disk;
void *addr;
int rc;
pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
if (!pmem)
return -ENOMEM;
rc = devm_namespace_enable(dev, ndns, nd_info_block_reserve());
if (rc)
return rc;
/* while nsio_rw_bytes is active, parse a pfn info block if present */
if (is_nd_pfn(dev)) {
nd_pfn = to_nd_pfn(dev);
rc = nvdimm_setup_pfn(nd_pfn, &pmem->pgmap);
if (rc)
return rc;
}
/* we're attaching a block device, disable raw namespace access */
devm_namespace_disable(dev, ndns);
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;
}
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;
}
disk = blk_alloc_disk(nid);
if (!disk)
return -ENOMEM;
q = disk->queue;
pmem->disk = disk;
pmem->pgmap.owner = pmem;
pmem->pfn_flags = PFN_DEV;
if (is_nd_pfn(dev)) {
pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
addr = devm_memremap_pages(dev, &pmem->pgmap);
pfn_sb = nd_pfn->pfn_sb;
pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
pmem->pfn_pad = resource_size(res) -
range_len(&pmem->pgmap.range);
pmem->pfn_flags |= PFN_MAP;
bb_range = pmem->pgmap.range;
bb_range.start += pmem->data_offset;
} else if (pmem_should_map_pages(dev)) {
pmem->pgmap.range.start = res->start;
pmem->pgmap.range.end = res->end;
pmem->pgmap.nr_range = 1;
pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
addr = devm_memremap_pages(dev, &pmem->pgmap);
pmem->pfn_flags |= PFN_MAP;
bb_range = pmem->pgmap.range;
} else {
addr = devm_memremap(dev, pmem->phys_addr,
pmem->size, ARCH_MEMREMAP_PMEM);
bb_range.start = res->start;
bb_range.end = res->end;
}
if (IS_ERR(addr)) {
rc = PTR_ERR(addr);
goto out;
}
pmem->virt_addr = addr;
blk_queue_write_cache(q, true, fua);
blk_queue_physical_block_size(q, PAGE_SIZE);
blk_queue_logical_block_size(q, pmem_sector_size(ndns));
blk_queue_max_hw_sectors(q, UINT_MAX);
blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
if (pmem->pfn_flags & PFN_MAP)
blk_queue_flag_set(QUEUE_FLAG_DAX, q);
disk->fops = &pmem_fops;
disk->private_data = pmem;
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, &bb_range);
disk->bb = &pmem->bb;
dax_dev = alloc_dax(pmem, &pmem_dax_ops);
if (IS_ERR(dax_dev)) {
rc = PTR_ERR(dax_dev);
goto out;
}
set_dax_nocache(dax_dev);
set_dax_nomc(dax_dev);
if (is_nvdimm_sync(nd_region))
set_dax_synchronous(dax_dev);
rc = dax_add_host(dax_dev, disk);
if (rc)
goto out_cleanup_dax;
dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
pmem->dax_dev = dax_dev;
rc = device_add_disk(dev, disk, pmem_attribute_groups);
if (rc)
goto out_remove_host;
if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
return -ENOMEM;
nvdimm_check_and_set_ro(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;
out_remove_host:
dax_remove_host(pmem->disk);
out_cleanup_dax:
kill_dax(pmem->dax_dev);
put_dax(pmem->dax_dev);
out:
blk_cleanup_disk(pmem->disk);
return rc;
}
static int nd_pmem_probe(struct device *dev)
{
int ret;
struct nd_namespace_common *ndns;
ndns = nvdimm_namespace_common_probe(dev);
if (IS_ERR(ndns))
return PTR_ERR(ndns);
if (is_nd_btt(dev))
return nvdimm_namespace_attach_btt(ndns);
if (is_nd_pfn(dev))
return pmem_attach_disk(dev, ndns);
ret = devm_namespace_enable(dev, ndns, nd_info_block_reserve());
if (ret)
return ret;
ret = nd_btt_probe(dev, ndns);
if (ret == 0)
return -ENXIO;
/*
* We have two failure conditions here, there is no
* info reserver block or we found a valid info reserve block
* but failed to initialize the pfn superblock.
*
* For the first case consider namespace as a raw pmem namespace
* and attach a disk.
*
* For the latter, consider this a success and advance the namespace
* seed.
*/
ret = nd_pfn_probe(dev, ndns);
if (ret == 0)
return -ENXIO;
else if (ret == -EOPNOTSUPP)
return ret;
ret = nd_dax_probe(dev, ndns);
if (ret == 0)
return -ENXIO;
else if (ret == -EOPNOTSUPP)
return ret;
/* probe complete, attach handles namespace enabling */
devm_namespace_disable(dev, ndns);
return pmem_attach_disk(dev, ndns);
}
static void 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 nd_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), NULL);
}
static void nd_pmem_shutdown(struct device *dev)
{
nvdimm_flush(to_nd_region(dev->parent), NULL);
}
static void pmem_revalidate_poison(struct device *dev)
{
struct nd_region *nd_region;
resource_size_t offset = 0, end_trunc = 0;
struct nd_namespace_common *ndns;
struct nd_namespace_io *nsio;
struct badblocks *bb;
struct range range;
struct kernfs_node *bb_state;
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);
}
range.start = nsio->res.start + offset;
range.end = nsio->res.end - end_trunc;
nvdimm_badblocks_populate(nd_region, bb, &range);
if (bb_state)
sysfs_notify_dirent(bb_state);
}
static void pmem_revalidate_region(struct device *dev)
{
struct pmem_device *pmem;
if (is_nd_btt(dev)) {
struct nd_btt *nd_btt = to_nd_btt(dev);
struct btt *btt = nd_btt->btt;
nvdimm_check_and_set_ro(btt->btt_disk);
return;
}
pmem = dev_get_drvdata(dev);
nvdimm_check_and_set_ro(pmem->disk);
}
static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
{
switch (event) {
case NVDIMM_REVALIDATE_POISON:
pmem_revalidate_poison(dev);
break;
case NVDIMM_REVALIDATE_REGION:
pmem_revalidate_region(dev);
break;
default:
dev_WARN_ONCE(dev, 1, "notify: unknown event: %d\n", event);
break;
}
}
MODULE_ALIAS("pmem");
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
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,
};
module_nd_driver(nd_pmem_driver);
MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
MODULE_LICENSE("GPL v2");