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dax, dm: allow device-mapper to operate without dax support

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Change device-mapper's DAX dependency to require the presence of at
least one DAX_DRIVER. This allows device-mapper to be built without
bringing the DAX core along which is especially wasteful when there are
no DAX drivers, like BLK_DEV_PMEM, configured.

Cc: Alasdair Kergon <agk@redhat.com>
Reported-by: Bart Van Assche <Bart.VanAssche@wdc.com>
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2018-03-29 17:22:13 -07:00
parent 2080e88aec
commit 976431b02c
6 changed files with 93 additions and 56 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/md/Kconfig
View File

@ -201,7 +201,7 @@ config BLK_DEV_DM_BUILTIN
config BLK_DEV_DM
tristate "Device mapper support"
select BLK_DEV_DM_BUILTIN
select DAX
depends on DAX || DAX=n
---help---
Device-mapper is a low level volume manager. It works by allowing
people to specify mappings for ranges of logical sectors. Various

6
drivers/md/dm-linear.c
View File

@ -154,6 +154,7 @@ static int linear_iterate_devices(struct dm_target *ti,
return fn(ti, lc->dev, lc->start, ti->len, data);
}
#if IS_ENABLED(CONFIG_DAX_DRIVER)
static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
@ -184,6 +185,11 @@ static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
}
#else
#define linear_dax_direct_access NULL
#define linear_dax_copy_from_iter NULL
#endif
static struct target_type linear_target = {
.name = "linear",
.version = {1, 4, 0},

95
drivers/md/dm-log-writes.c
View File

@ -610,51 +610,6 @@ static int log_mark(struct log_writes_c *lc, char *data)
return 0;
}
static int log_dax(struct log_writes_c *lc, sector_t sector, size_t bytes,
struct iov_iter *i)
{
struct pending_block *block;
if (!bytes)
return 0;
block = kzalloc(sizeof(struct pending_block), GFP_KERNEL);
if (!block) {
DMERR("Error allocating dax pending block");
return -ENOMEM;
}
block->data = kzalloc(bytes, GFP_KERNEL);
if (!block->data) {
DMERR("Error allocating dax data space");
kfree(block);
return -ENOMEM;
}
/* write data provided via the iterator */
if (!copy_from_iter(block->data, bytes, i)) {
DMERR("Error copying dax data");
kfree(block->data);
kfree(block);
return -EIO;
}
/* rewind the iterator so that the block driver can use it */
iov_iter_revert(i, bytes);
block->datalen = bytes;
block->sector = bio_to_dev_sectors(lc, sector);
block->nr_sectors = ALIGN(bytes, lc->sectorsize) >> lc->sectorshift;
atomic_inc(&lc->pending_blocks);
spin_lock_irq(&lc->blocks_lock);
list_add_tail(&block->list, &lc->unflushed_blocks);
spin_unlock_irq(&lc->blocks_lock);
wake_up_process(lc->log_kthread);
return 0;
}
static void log_writes_dtr(struct dm_target *ti)
{
struct log_writes_c *lc = ti->private;
@ -920,6 +875,52 @@ static void log_writes_io_hints(struct dm_target *ti, struct queue_limits *limit
limits->io_min = limits->physical_block_size;
}
#if IS_ENABLED(CONFIG_DAX_DRIVER)
static int log_dax(struct log_writes_c *lc, sector_t sector, size_t bytes,
struct iov_iter *i)
{
struct pending_block *block;
if (!bytes)
return 0;
block = kzalloc(sizeof(struct pending_block), GFP_KERNEL);
if (!block) {
DMERR("Error allocating dax pending block");
return -ENOMEM;
}
block->data = kzalloc(bytes, GFP_KERNEL);
if (!block->data) {
DMERR("Error allocating dax data space");
kfree(block);
return -ENOMEM;
}
/* write data provided via the iterator */
if (!copy_from_iter(block->data, bytes, i)) {
DMERR("Error copying dax data");
kfree(block->data);
kfree(block);
return -EIO;
}
/* rewind the iterator so that the block driver can use it */
iov_iter_revert(i, bytes);
block->datalen = bytes;
block->sector = bio_to_dev_sectors(lc, sector);
block->nr_sectors = ALIGN(bytes, lc->sectorsize) >> lc->sectorshift;
atomic_inc(&lc->pending_blocks);
spin_lock_irq(&lc->blocks_lock);
list_add_tail(&block->list, &lc->unflushed_blocks);
spin_unlock_irq(&lc->blocks_lock);
wake_up_process(lc->log_kthread);
return 0;
}
static long log_writes_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
@ -956,6 +957,10 @@ static size_t log_writes_dax_copy_from_iter(struct dm_target *ti,
dax_copy:
return dax_copy_from_iter(lc->dev->dax_dev, pgoff, addr, bytes, i);
}
#else
#define log_writes_dax_direct_access NULL
#define log_writes_dax_copy_from_iter NULL
#endif
static struct target_type log_writes_target = {
.name = "log-writes",

6
drivers/md/dm-stripe.c
View File

@ -311,6 +311,7 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_REMAPPED;
}
#if IS_ENABLED(CONFIG_DAX_DRIVER)
static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
@ -351,6 +352,11 @@ static size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
}
#else
#define stripe_dax_direct_access NULL
#define stripe_dax_copy_from_iter NULL
#endif
/*
* Stripe status:
*

10
drivers/md/dm.c
View File

@ -1800,7 +1800,7 @@ static void cleanup_mapped_device(struct mapped_device *md)
static struct mapped_device *alloc_dev(int minor)
{
int r, numa_node_id = dm_get_numa_node();
struct dax_device *dax_dev;
struct dax_device *dax_dev = NULL;
struct mapped_device *md;
void *old_md;
@ -1866,9 +1866,11 @@ static struct mapped_device *alloc_dev(int minor)
md->disk->private_data = md;
sprintf(md->disk->disk_name, "dm-%d", minor);
dax_dev = alloc_dax(md, md->disk->disk_name, &dm_dax_ops);
if (!dax_dev)
goto bad;
if (IS_ENABLED(CONFIG_DAX_DRIVER)) {
dax_dev = alloc_dax(md, md->disk->disk_name, &dm_dax_ops);
if (!dax_dev)
goto bad;
}
md->dax_dev = dax_dev;
add_disk_no_queue_reg(md->disk);

30
include/linux/dax.h
View File

@ -26,16 +26,39 @@ extern struct attribute_group dax_attribute_group;
#if IS_ENABLED(CONFIG_DAX)
struct dax_device *dax_get_by_host(const char *host);
struct dax_device *alloc_dax(void *private, const char *host,
const struct dax_operations *ops);
void put_dax(struct dax_device *dax_dev);
void kill_dax(struct dax_device *dax_dev);
void dax_write_cache(struct dax_device *dax_dev, bool wc);
bool dax_write_cache_enabled(struct dax_device *dax_dev);
#else
static inline struct dax_device *dax_get_by_host(const char *host)
{
return NULL;
}
static inline struct dax_device *alloc_dax(void *private, const char *host,
const struct dax_operations *ops)
{
/*
* Callers should check IS_ENABLED(CONFIG_DAX) to know if this
* NULL is an error or expected.
*/
return NULL;
}
static inline void put_dax(struct dax_device *dax_dev)
{
}
static inline void kill_dax(struct dax_device *dax_dev)
{
}
static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
{
}
static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
{
return false;
}
#endif
struct writeback_control;
@ -89,18 +112,13 @@ static inline int dax_writeback_mapping_range(struct address_space *mapping,
int dax_read_lock(void);
void dax_read_unlock(int id);
struct dax_device *alloc_dax(void *private, const char *host,
const struct dax_operations *ops);
bool dax_alive(struct dax_device *dax_dev);
void kill_dax(struct dax_device *dax_dev);
void *dax_get_private(struct dax_device *dax_dev);
long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
void **kaddr, pfn_t *pfn);
size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
size_t bytes, struct iov_iter *i);
void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
void dax_write_cache(struct dax_device *dax_dev, bool wc);
bool dax_write_cache_enabled(struct dax_device *dax_dev);
ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops);