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 <[email protected]> --- 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
