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Commit 976431b0 authored by Dan Williams's avatar Dan Williams
Browse files

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



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: default avatarBart Van Assche <Bart.VanAssche@wdc.com>
Reported-by: default avatarkbuild test robot <lkp@intel.com>
Reported-by: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 2080e88a

drivers/md/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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

drivers/md/dm-linear.c

+6 −0
Original line number Diff line number Diff line
@@ -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},

drivers/md/dm-log-writes.c

+50 −45
Original line number Diff line number Diff line
@@ -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",

drivers/md/dm-stripe.c

+6 −0
Original line number Diff line number Diff line
@@ -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:

 *

drivers/md/dm.c

+6 −4
Original line number Diff line number Diff line
@@ -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);



	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);