From b3a9a0c36e1f7b9e2e6cf965c2bb973624f2b3b9 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Wed, 2 May 2018 06:46:33 -0700
Subject: [PATCH] dax: Introduce a ->copy_to_iter dax operation
Git-commit: b3a9a0c36e1f7b9e2e6cf965c2bb973624f2b3b9 (partial)
Patch-mainline: v4.18-rc1
References: FATE#326060 bsc#1098782
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: Dan Williams <dan.j.williams@intel.com>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
drivers/dax/super.c | 10 ++++++++++
drivers/md/dm-linear.c | 16 ++++++++++++++++
drivers/md/dm-log-writes.c | 15 +++++++++++++++
drivers/md/dm-stripe.c | 21 +++++++++++++++++++++
drivers/md/dm.c | 25 +++++++++++++++++++++++++
drivers/nvdimm/pmem.c | 7 +++++++
drivers/s390/block/dcssblk.c | 7 +++++++
fs/dax.c | 3 ++-
include/linux/dax.h | 5 +++++
include/linux/device-mapper.h | 5 +++--
10 files changed, 111 insertions(+), 3 deletions(-)
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -269,6 +269,16 @@ size_t dax_copy_from_iter(struct dax_dev
}
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)
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -185,9 +185,24 @@ static size_t linear_dax_copy_from_iter(st
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)
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -962,9 +962,23 @@ static size_t log_writes_dax_copy_from_ite
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)
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -354,9 +354,29 @@ static size_t stripe_dax_copy_from_iter(st
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)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1089,6 +1089,30 @@ static size_t dm_dax_copy_from_iter(stru
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.
@@ -2978,6 +2984,7 @@ static const struct block_device_operati
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,
};
/*
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -245,9 +245,16 @@ static size_t pmem_copy_from_iter(struct
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[] = {
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -50,9 +50,16 @@ static size_t dcssblk_dax_copy_from_iter
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 {
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -979,7 +979,8 @@ dax_iomap_actor(struct inode *inode, lof
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;
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -19,6 +19,9 @@ 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;
@@ -89,6 +92,8 @@ long dax_direct_access(struct dax_device
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,
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -133,7 +133,7 @@ typedef int (*dm_busy_fn) (struct dm_target
*/
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;