blob: 8dcc10b6db5b12c6994e2a6e1283be3eda73af29 [file] [log] [blame]
// 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/kstrtox.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 phys_addr_t pmem_to_phys(struct pmem_device *pmem, phys_addr_t offset)
{
return pmem->phys_addr + offset;
}
static sector_t to_sect(struct pmem_device *pmem, phys_addr_t offset)
{
return (offset - pmem->data_offset) >> SECTOR_SHIFT;
}
static phys_addr_t to_offset(struct pmem_device *pmem, sector_t sector)
{
return (sector << SECTOR_SHIFT) + pmem->data_offset;
}
static void pmem_mkpage_present(struct pmem_device *pmem, phys_addr_t offset,
unsigned int len)
{
phys_addr_t phys = pmem_to_phys(pmem, offset);
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 void pmem_clear_bb(struct pmem_device *pmem, sector_t sector, long blks)
{
if (blks == 0)
return;
badblocks_clear(&pmem->bb, sector, blks);
if (pmem->bb_state)
sysfs_notify_dirent(pmem->bb_state);
}
static long __pmem_clear_poison(struct pmem_device *pmem,
phys_addr_t offset, unsigned int len)
{
phys_addr_t phys = pmem_to_phys(pmem, offset);
long cleared = nvdimm_clear_poison(to_dev(pmem), phys, len);
if (cleared > 0) {
pmem_mkpage_present(pmem, offset, cleared);
arch_invalidate_pmem(pmem->virt_addr + offset, len);
}
return cleared;
}
static blk_status_t pmem_clear_poison(struct pmem_device *pmem,
phys_addr_t offset, unsigned int len)
{
long cleared = __pmem_clear_poison(pmem, offset, len);
if (cleared < 0)
return BLK_STS_IOERR;
pmem_clear_bb(pmem, to_sect(pmem, offset), cleared >> SECTOR_SHIFT);
if (cleared < len)
return BLK_STS_IOERR;
return BLK_STS_OK;
}
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 = to_offset(pmem, sector);
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)
{
phys_addr_t pmem_off = to_offset(pmem, sector);
void *pmem_addr = pmem->virt_addr + pmem_off;
if (unlikely(is_bad_pmem(&pmem->bb, sector, len))) {
blk_status_t rc = pmem_clear_poison(pmem, pmem_off, len);
if (rc != BLK_STS_OK)
return rc;
}
flush_dcache_page(page);
write_pmem(pmem_addr, page, page_off, len);
return BLK_STS_OK;
}
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);
}
/* 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, enum dax_access_mode mode, void **kaddr,
pfn_t *pfn)
{
resource_size_t offset = PFN_PHYS(pgoff) + pmem->data_offset;
sector_t sector = PFN_PHYS(pgoff) >> SECTOR_SHIFT;
unsigned int num = PFN_PHYS(nr_pages) >> SECTOR_SHIFT;
struct badblocks *bb = &pmem->bb;
sector_t first_bad;
int num_bad;
if (kaddr)
*kaddr = pmem->virt_addr + offset;
if (pfn)
*pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
if (bb->count &&
badblocks_check(bb, sector, num, &first_bad, &num_bad)) {
long actual_nr;
if (mode != DAX_RECOVERY_WRITE)
return -EHWPOISON;
/*
* Set the recovery stride is set to kernel page size because
* the underlying driver and firmware clear poison functions
* don't appear to handle large chunk(such as 2MiB) reliably.
*/
actual_nr = PHYS_PFN(
PAGE_ALIGN((first_bad - sector) << SECTOR_SHIFT));
dev_dbg(pmem->bb.dev, "start sector(%llu), nr_pages(%ld), first_bad(%llu), actual_nr(%ld)\n",
sector, nr_pages, first_bad, actual_nr);
if (actual_nr)
return actual_nr;
return 1;
}
/*
* If badblocks are present but not in the range, limit known good range
* to the requested range.
*/
if (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,
};
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, enum dax_access_mode mode,
void **kaddr, pfn_t *pfn)
{
struct pmem_device *pmem = dax_get_private(dax_dev);
return __pmem_direct_access(pmem, pgoff, nr_pages, mode, kaddr, pfn);
}
/*
* The recovery write thread started out as a normal pwrite thread and
* when the filesystem was told about potential media error in the
* range, filesystem turns the normal pwrite to a dax_recovery_write.
*
* The recovery write consists of clearing media poison, clearing page
* HWPoison bit, reenable page-wide read-write permission, flush the
* caches and finally write. A competing pread thread will be held
* off during the recovery process since data read back might not be
* valid, and this is achieved by clearing the badblock records after
* the recovery write is complete. Competing recovery write threads
* are already serialized by writer lock held by dax_iomap_rw().
*/
static size_t pmem_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
void *addr, size_t bytes, struct iov_iter *i)
{
struct pmem_device *pmem = dax_get_private(dax_dev);
size_t olen, len, off;
phys_addr_t pmem_off;
struct device *dev = pmem->bb.dev;
long cleared;
off = offset_in_page(addr);
len = PFN_PHYS(PFN_UP(off + bytes));
if (!is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) >> SECTOR_SHIFT, len))
return _copy_from_iter_flushcache(addr, bytes, i);
/*
* Not page-aligned range cannot be recovered. This should not
* happen unless something else went wrong.
*/
if (off || !PAGE_ALIGNED(bytes)) {
dev_dbg(dev, "Found poison, but addr(%p) or bytes(%#zx) not page aligned\n",
addr, bytes);
return 0;
}
pmem_off = PFN_PHYS(pgoff) + pmem->data_offset;
cleared = __pmem_clear_poison(pmem, pmem_off, len);
if (cleared > 0 && cleared < len) {
dev_dbg(dev, "poison cleared only %ld out of %zu bytes\n",
cleared, len);
return 0;
}
if (cleared < 0) {
dev_dbg(dev, "poison clear failed: %ld\n", cleared);
return 0;
}
olen = _copy_from_iter_flushcache(addr, bytes, i);
pmem_clear_bb(pmem, to_sect(pmem, pmem_off), cleared >> SECTOR_SHIFT);
return olen;
}
static const struct dax_operations pmem_dax_ops = {
.direct_access = pmem_dax_direct_access,
.zero_page_range = pmem_dax_zero_page_range,
.recovery_write = pmem_recovery_write,
};
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 = kstrtobool(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);
put_disk(pmem->disk);
}
static int pmem_pagemap_memory_failure(struct dev_pagemap *pgmap,
unsigned long pfn, unsigned long nr_pages, int mf_flags)
{
struct pmem_device *pmem =
container_of(pgmap, struct pmem_device, pgmap);
u64 offset = PFN_PHYS(pfn) - pmem->phys_addr - pmem->data_offset;
u64 len = nr_pages << PAGE_SHIFT;
return dax_holder_notify_failure(pmem->dax_dev, offset, len, mf_flags);
}
static const struct dev_pagemap_ops fsdax_pagemap_ops = {
.memory_failure = pmem_pagemap_memory_failure,
};
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 queue_limits lim = {
.logical_block_size = pmem_sector_size(ndns),
.physical_block_size = PAGE_SIZE,
.max_hw_sectors = UINT_MAX,
};
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(&lim, nid);
if (IS_ERR(disk))
return PTR_ERR(disk);
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;
pmem->pgmap.ops = &fsdax_pagemap_ops;
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;
pmem->pgmap.ops = &fsdax_pagemap_ops;
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_flag_set(QUEUE_FLAG_NONROT, q);
blk_queue_flag_set(QUEUE_FLAG_SYNCHRONOUS, 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:
put_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 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");