Commit b3a9a0c3 authored by Dan Williams's avatar Dan Williams

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
......@@ -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)
......
......@@ -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)
......
......@@ -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)
......
......@@ -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)
......
......@@ -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,
};
/*
......
......@@ -264,9 +264,16 @@ static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
return copy_from_iter_flushcache(addr, bytes, i);
}
static size_t pmem_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff,
void *addr, size_t bytes, struct iov_iter *i)
{
return copy_to_iter(addr, bytes, i);
}
static const struct dax_operations pmem_dax_ops = {
.direct_access = pmem_dax_direct_access,
.copy_from_iter = pmem_copy_from_iter,
.copy_to_iter = pmem_copy_to_iter,
};
static const struct attribute_group *pmem_attribute_groups[] = {
......
......@@ -51,9 +51,16 @@ static size_t dcssblk_dax_copy_from_iter(struct dax_device *dax_dev,
return copy_from_iter(addr, bytes, i);
}
static size_t dcssblk_dax_copy_to_iter(struct dax_device *dax_dev,
pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
{
return copy_to_iter(addr, bytes, i);
}
static const struct dax_operations dcssblk_dax_ops = {
.direct_access = dcssblk_dax_direct_access,
.copy_from_iter = dcssblk_dax_copy_from_iter,
.copy_to_iter = dcssblk_dax_copy_to_iter,
};
struct dcssblk_dev_info {
......
......@@ -1057,7 +1057,8 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
map_len = dax_copy_from_iter(dax_dev, pgoff, kaddr,
map_len, iter);
else
map_len = copy_to_iter(kaddr, map_len, iter);
map_len = dax_copy_to_iter(dax_dev, pgoff, kaddr,
map_len, iter);
if (map_len <= 0) {
ret = map_len ? map_len : -EFAULT;
break;
......
......@@ -20,6 +20,9 @@ struct dax_operations {
/* copy_from_iter: required operation for fs-dax direct-i/o */
size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
struct iov_iter *);
/* copy_to_iter: required operation for fs-dax direct-i/o */
size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t,
struct iov_iter *);
};
extern struct attribute_group dax_attribute_group;
......@@ -118,6 +121,8 @@ 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);
size_t dax_copy_to_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);
ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
......
......@@ -133,7 +133,7 @@ typedef int (*dm_busy_fn) (struct dm_target *ti);
*/
typedef long (*dm_dax_direct_access_fn) (struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn);
typedef size_t (*dm_dax_copy_from_iter_fn)(struct dm_target *ti, pgoff_t pgoff,
typedef size_t (*dm_dax_copy_iter_fn)(struct dm_target *ti, pgoff_t pgoff,
void *addr, size_t bytes, struct iov_iter *i);
#define PAGE_SECTORS (PAGE_SIZE / 512)
......@@ -184,7 +184,8 @@ struct target_type {
dm_iterate_devices_fn iterate_devices;
dm_io_hints_fn io_hints;
dm_dax_direct_access_fn direct_access;
dm_dax_copy_from_iter_fn dax_copy_from_iter;
dm_dax_copy_iter_fn dax_copy_from_iter;
dm_dax_copy_iter_fn dax_copy_to_iter;
/* For internal device-mapper use. */
struct list_head list;
......
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