summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--fs/dax.c17
-rw-r--r--include/linux/dax.h3
2 files changed, 14 insertions, 6 deletions
diff --git a/fs/dax.c b/fs/dax.c
index 0433a2b5e484..351afd3cf8be 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -32,14 +32,19 @@
#include <linux/pfn_t.h>
#include <linux/sizes.h>
-#define RADIX_DAX_MASK 0xf
-#define RADIX_DAX_SHIFT 4
-#define RADIX_DAX_PTE (0x4 | RADIX_TREE_EXCEPTIONAL_ENTRY)
-#define RADIX_DAX_PMD (0x8 | RADIX_TREE_EXCEPTIONAL_ENTRY)
-#define RADIX_DAX_TYPE(entry) ((unsigned long)entry & RADIX_DAX_MASK)
+/*
+ * We use lowest available bit in exceptional entry for locking, other two
+ * bits to determine entry type. In total 3 special bits.
+ */
+#define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 3)
+#define RADIX_DAX_PTE (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
+#define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
+#define RADIX_DAX_TYPE_MASK (RADIX_DAX_PTE | RADIX_DAX_PMD)
+#define RADIX_DAX_TYPE(entry) ((unsigned long)entry & RADIX_DAX_TYPE_MASK)
#define RADIX_DAX_SECTOR(entry) (((unsigned long)entry >> RADIX_DAX_SHIFT))
#define RADIX_DAX_ENTRY(sector, pmd) ((void *)((unsigned long)sector << \
- RADIX_DAX_SHIFT | (pmd ? RADIX_DAX_PMD : RADIX_DAX_PTE)))
+ RADIX_DAX_SHIFT | (pmd ? RADIX_DAX_PMD : RADIX_DAX_PTE) | \
+ RADIX_TREE_EXCEPTIONAL_ENTRY))
static long dax_map_atomic(struct block_device *bdev, struct blk_dax_ctl *dax)
{
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 72dc81de3ddb..70600b63083f 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -5,6 +5,9 @@
#include <linux/mm.h>
#include <asm/pgtable.h>
+/* We use lowest available exceptional entry bit for locking */
+#define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
+
ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,
get_block_t, dio_iodone_t, int flags);
int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);