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authorDan Williams <dan.j.williams@intel.com>2018-03-30 03:22:13 +0300
committerDan Williams <dan.j.williams@intel.com>2018-04-03 15:41:19 +0300
commit976431b02c2ef92ae3f8b6a7d699fc554025e118 (patch)
treee05121a5ccc869096a1732847f92e4b485106336 /drivers/md/dm-log-writes.c
parent2080e88aecd78773eacbe7d6b9d59968000ba55a (diff)
downloadlinux-976431b02c2ef92ae3f8b6a7d699fc554025e118.tar.xz
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>
Diffstat (limited to 'drivers/md/dm-log-writes.c')
-rw-r--r--drivers/md/dm-log-writes.c95
1 files changed, 50 insertions, 45 deletions
diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index 3362d866793b..7fcb4216973f 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",