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: 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>
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 2c8ac36..edff083 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -201,7 +201,7 @@
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
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index d5f8eff..89443e0 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -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},
diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index 3362d86..7fcb421 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -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",
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index b5e8921..ac2e8ee 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -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:
*
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 6813680..ffc93ae 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -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);
