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Commit b3a9a0c3 authored by Dan Williams's avatar Dan Williams
Browse files

dax: Introduce a ->copy_to_iter dax operation 



Similar to the ->copy_from_iter() operation, a platform may want to
deploy an architecture or device specific routine for handling reads
from a dax_device like /dev/pmemX. On x86 this routine will point to a
machine check safe version of copy_to_iter(). For now, add the plumbing
to device-mapper and the dax core.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 522239b4

drivers/dax/super.c

+10 −0
Original line number Diff line number Diff line
@@ -282,6 +282,16 @@ size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 
}

EXPORT_SYMBOL_GPL(dax_copy_from_iter);



size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,

		size_t bytes, struct iov_iter *i)

{

	if (!dax_alive(dax_dev))

		return 0;



	return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i);

}

EXPORT_SYMBOL_GPL(dax_copy_to_iter);



#ifdef CONFIG_ARCH_HAS_PMEM_API

void arch_wb_cache_pmem(void *addr, size_t size);

void dax_flush(struct dax_device *dax_dev, void *addr, size_t size)

drivers/md/dm-linear.c

+16 −0
Original line number Diff line number Diff line
@@ -185,9 +185,24 @@ 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);

}



static size_t linear_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff,

		void *addr, size_t bytes, struct iov_iter *i)

{

	struct linear_c *lc = ti->private;

	struct block_device *bdev = lc->dev->bdev;

	struct dax_device *dax_dev = lc->dev->dax_dev;

	sector_t dev_sector, sector = pgoff * PAGE_SECTORS;



	dev_sector = linear_map_sector(ti, sector);

	if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))

		return 0;

	return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i);

}



#else

#define linear_dax_direct_access NULL

#define linear_dax_copy_from_iter NULL

#define linear_dax_copy_to_iter NULL

#endif



static struct target_type linear_target = {
@@ -204,6 +219,7 @@ static struct target_type linear_target = { 
	.iterate_devices = linear_iterate_devices,

	.direct_access = linear_dax_direct_access,

	.dax_copy_from_iter = linear_dax_copy_from_iter,

	.dax_copy_to_iter = linear_dax_copy_to_iter,

};



int __init dm_linear_init(void)

drivers/md/dm-log-writes.c

+15 −0
Original line number Diff line number Diff line
@@ -962,9 +962,23 @@ 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);

}



static size_t log_writes_dax_copy_to_iter(struct dm_target *ti,

					  pgoff_t pgoff, void *addr, size_t bytes,

					  struct iov_iter *i)

{

	struct log_writes_c *lc = ti->private;

	sector_t sector = pgoff * PAGE_SECTORS;



	if (bdev_dax_pgoff(lc->dev->bdev, sector, ALIGN(bytes, PAGE_SIZE), &pgoff))

		return 0;

	return dax_copy_to_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

#define log_writes_dax_copy_to_iter NULL

#endif



static struct target_type log_writes_target = {
@@ -982,6 +996,7 @@ static struct target_type log_writes_target = { 
	.io_hints = log_writes_io_hints,

	.direct_access = log_writes_dax_direct_access,

	.dax_copy_from_iter = log_writes_dax_copy_from_iter,

	.dax_copy_to_iter = log_writes_dax_copy_to_iter,

};



static int __init dm_log_writes_init(void)

drivers/md/dm-stripe.c

+21 −0
Original line number Diff line number Diff line
@@ -354,9 +354,29 @@ 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);

}



static size_t stripe_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff,

		void *addr, size_t bytes, struct iov_iter *i)

{

	sector_t dev_sector, sector = pgoff * PAGE_SECTORS;

	struct stripe_c *sc = ti->private;

	struct dax_device *dax_dev;

	struct block_device *bdev;

	uint32_t stripe;



	stripe_map_sector(sc, sector, &stripe, &dev_sector);

	dev_sector += sc->stripe[stripe].physical_start;

	dax_dev = sc->stripe[stripe].dev->dax_dev;

	bdev = sc->stripe[stripe].dev->bdev;



	if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))

		return 0;

	return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i);

}



#else

#define stripe_dax_direct_access NULL

#define stripe_dax_copy_from_iter NULL

#define stripe_dax_copy_to_iter NULL

#endif



/*
@@ -478,6 +498,7 @@ static struct target_type stripe_target = { 
	.io_hints = stripe_io_hints,

	.direct_access = stripe_dax_direct_access,

	.dax_copy_from_iter = stripe_dax_copy_from_iter,

	.dax_copy_to_iter = stripe_dax_copy_to_iter,

};



int __init dm_stripe_init(void)

drivers/md/dm.c

+25 −0
Original line number Diff line number Diff line
@@ -1089,6 +1089,30 @@ static size_t dm_dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, 
	return ret;

}



static size_t dm_dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff,

		void *addr, size_t bytes, struct iov_iter *i)

{

	struct mapped_device *md = dax_get_private(dax_dev);

	sector_t sector = pgoff * PAGE_SECTORS;

	struct dm_target *ti;

	long ret = 0;

	int srcu_idx;



	ti = dm_dax_get_live_target(md, sector, &srcu_idx);



	if (!ti)

		goto out;

	if (!ti->type->dax_copy_to_iter) {

		ret = copy_to_iter(addr, bytes, i);

		goto out;

	}

	ret = ti->type->dax_copy_to_iter(ti, pgoff, addr, bytes, i);

 out:

	dm_put_live_table(md, srcu_idx);



	return ret;

}



/*

 * A target may call dm_accept_partial_bio only from the map routine.  It is

 * allowed for all bio types except REQ_PREFLUSH and REQ_OP_ZONE_RESET.
@@ -3134,6 +3158,7 @@ static const struct block_device_operations dm_blk_dops = { 
static const struct dax_operations dm_dax_ops = {

	.direct_access = dm_dax_direct_access,

	.copy_from_iter = dm_dax_copy_from_iter,

	.copy_to_iter = dm_dax_copy_to_iter,

};



/*