With the new addition of the multi-order radix tree support we can simplify
the DAX *sync PMD support a bit. Instead of manually checking to see if
our index is covered by a PMD entry we can rely on the new radix tree to
return the PMD entry if present.
Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
---
fs/dax.c | 31 +++++++++++--------------------
1 file changed, 11 insertions(+), 20 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 735a608..3f87fcc 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -40,6 +40,7 @@
#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)))
+#define RADIX_DAX_ORDER(pmd) (pmd ? PMD_SHIFT - PAGE_SHIFT : 0)
static long dax_map_atomic(struct block_device *bdev, struct blk_dax_ctl *dax)
{
@@ -360,13 +361,11 @@ static int copy_user_bh(struct page *to, struct inode *inode,
}
#define NO_SECTOR -1
-#define DAX_PMD_INDEX(page_index) (page_index & (PMD_MASK >> PAGE_CACHE_SHIFT))
static int dax_radix_entry(struct address_space *mapping, pgoff_t index,
sector_t sector, bool pmd_entry, bool dirty)
{
struct radix_tree_root *page_tree = &mapping->page_tree;
- pgoff_t pmd_index = DAX_PMD_INDEX(index);
int type, error = 0;
void *entry;
@@ -376,12 +375,6 @@ static int dax_radix_entry(struct address_space *mapping, pgoff_t index,
spin_lock_irq(&mapping->tree_lock);
- entry = radix_tree_lookup(page_tree, pmd_index);
- if (entry && RADIX_DAX_TYPE(entry) == RADIX_DAX_PMD) {
- index = pmd_index;
- goto dirty;
- }
-
entry = radix_tree_lookup(page_tree, index);
if (entry) {
type = RADIX_DAX_TYPE(entry);
@@ -418,7 +411,8 @@ static int dax_radix_entry(struct address_space *mapping, pgoff_t index,
goto unlock;
}
- error = radix_tree_insert(page_tree, index,
+ error = __radix_tree_insert(page_tree, index,
+ RADIX_DAX_ORDER(pmd_entry),
RADIX_DAX_ENTRY(sector, pmd_entry));
if (error)
goto unlock;
@@ -462,6 +456,13 @@ static int dax_writeback_one(struct block_device *bdev,
goto unlock;
}
+ /*
+ * Even if dax_writeback_mapping_range() was given a wbc->range_start
+ * in the middle of a PMD, the 'index' we are given will be aligned to
+ * the start index of the PMD, as will the sector we pull from
+ * 'entry'. This allows us to flush for PMD_SIZE and not have to
+ * worry about partial PMD writebacks.
+ */
dax.sector = RADIX_DAX_SECTOR(entry);
dax.size = (type == RADIX_DAX_PMD ? PMD_SIZE : PAGE_SIZE);
spin_unlock_irq(&mapping->tree_lock);
@@ -502,12 +503,11 @@ int dax_writeback_mapping_range(struct address_space *mapping,
struct block_device *bdev, struct writeback_control *wbc)
{
struct inode *inode = mapping->host;
- pgoff_t start_index, end_index, pmd_index;
+ pgoff_t start_index, end_index;
pgoff_t indices[PAGEVEC_SIZE];
struct pagevec pvec;
bool done = false;
int i, ret = 0;
- void *entry;
if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT))
return -EIO;
@@ -517,15 +517,6 @@ int dax_writeback_mapping_range(struct address_space *mapping,
start_index = wbc->range_start >> PAGE_CACHE_SHIFT;
end_index = wbc->range_end >> PAGE_CACHE_SHIFT;
- pmd_index = DAX_PMD_INDEX(start_index);
-
- rcu_read_lock();
- entry = radix_tree_lookup(&mapping->page_tree, pmd_index);
- rcu_read_unlock();
-
- /* see if the start of our range is covered by a PMD entry */
- if (entry && RADIX_DAX_TYPE(entry) == RADIX_DAX_PMD)
- start_index = pmd_index;
tag_pages_for_writeback(mapping, start_index, end_index);
--
2.5.5
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
