[PATCH v5 2/5] dax: relocate some dax functions

Ross Zwisler
2017-07-24T17:06:23Z

dax_load_hole() will soon need to call dax_insert_mapping_entry(), so it
needs to be moved lower in dax.c so the definition exists.

dax_wake_mapping_entry_waiter() will soon be removed from dax.h and be made
static to dax.c, so we need to move its definition above all its callers.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/dax.c | 138 +++++++++++++++++++++++++++++++--------------------------------
1 file changed, 69 insertions(+), 69 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 306c2b6..197067f 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -121,6 +121,31 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mo
}

/*
+ * We do not necessarily hold the mapping->tree_lock when we call this
+ * function so it is possible that 'entry' is no longer a valid item in the
+ * radix tree. This is okay because all we really need to do is to find the
+ * correct waitqueue where tasks might be waiting for that old 'entry' and
+ * wake them.
+ */
+void dax_wake_mapping_entry_waiter(struct address_space *mapping,
+ pgoff_t index, void *entry, bool wake_all)
+{
+ struct exceptional_entry_key key;
+ wait_queue_head_t *wq;
+
+ wq = dax_entry_waitqueue(mapping, index, entry, &key);
+
+ /*
+ * Checking for locked entry and prepare_to_wait_exclusive() happens
+ * under mapping->tree_lock, ditto for entry handling in our callers.
+ * So at this point all tasks that could have seen our entry locked
+ * must be in the waitqueue and the following check will see them.
+ */
+ if (waitqueue_active(wq))
+ __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key);
+}
+
+/*
* Check whether the given slot is locked. The function must be called with
* mapping->tree_lock held
*/
@@ -392,31 +417,6 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
return entry;
}

-/*
- * We do not necessarily hold the mapping->tree_lock when we call this
- * function so it is possible that 'entry' is no longer a valid item in the
- * radix tree. This is okay because all we really need to do is to find the
- * correct waitqueue where tasks might be waiting for that old 'entry' and
- * wake them.
- */
-void dax_wake_mapping_entry_waiter(struct address_space *mapping,
- pgoff_t index, void *entry, bool wake_all)
-{
- struct exceptional_entry_key key;
- wait_queue_head_t *wq;
-
- wq = dax_entry_waitqueue(mapping, index, entry, &key);
-
- /*
- * Checking for locked entry and prepare_to_wait_exclusive() happens
- * under mapping->tree_lock, ditto for entry handling in our callers.
- * So at this point all tasks that could have seen our entry locked
- * must be in the waitqueue and the following check will see them.
- */
- if (waitqueue_active(wq))
- __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key);
-}
-
static int __dax_invalidate_mapping_entry(struct address_space *mapping,
pgoff_t index, bool trunc)
{
@@ -468,50 +468,6 @@ int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
return __dax_invalidate_mapping_entry(mapping, index, false);
}

-/*
- * The user has performed a load from a hole in the file. Allocating
- * a new page in the file would cause excessive storage usage for
- * workloads with sparse files. We allocate a page cache page instead.
- * We'll kick it out of the page cache if it's ever written to,
- * otherwise it will simply fall out of the page cache under memory
- * pressure without ever having been dirtied.
- */
-static int dax_load_hole(struct address_space *mapping, void **entry,
- struct vm_fault *vmf)
-{
- struct inode *inode = mapping->host;
- struct page *page;
- int ret;
-
- /* Hole page already exists? Return it... */
- if (!radix_tree_exceptional_entry(*entry)) {
- page = *entry;
- goto finish_fault;
- }
-
- /* This will replace locked radix tree entry with a hole page */
- page = find_or_create_page(mapping, vmf->pgoff,
- vmf->gfp_mask | __GFP_ZERO);
- if (!page) {
- ret = VM_FAULT_OOM;
- goto out;
- }
-
-finish_fault:
- vmf->page = page;
- ret = finish_fault(vmf);
- vmf->page = NULL;
- *entry = page;
- if (!ret) {
- /* Grab reference for PTE that is now referencing the page */
- get_page(page);
- ret = VM_FAULT_NOPAGE;
- }
-out:
- trace_dax_load_hole(inode, vmf, ret);
- return ret;
-}
-
static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev,
sector_t sector, size_t size, struct page *to,
unsigned long vaddr)
@@ -938,6 +894,50 @@ int dax_pfn_mkwrite(struct vm_fault *vmf)
}
EXPORT_SYMBOL_GPL(dax_pfn_mkwrite);

+/*
+ * The user has performed a load from a hole in the file. Allocating
+ * a new page in the file would cause excessive storage usage for
+ * workloads with sparse files. We allocate a page cache page instead.
+ * We'll kick it out of the page cache if it's ever written to,
+ * otherwise it will simply fall out of the page cache under memory
+ * pressure without ever having been dirtied.
+ */
+static int dax_load_hole(struct address_space *mapping, void **entry,
+ struct vm_fault *vmf)
+{
+ struct inode *inode = mapping->host;
+ struct page *page;
+ int ret;
+
+ /* Hole page already exists? Return it... */
+ if (!radix_tree_exceptional_entry(*entry)) {
+ page = *entry;
+ goto finish_fault;
+ }
+
+ /* This will replace locked radix tree entry with a hole page */
+ page = find_or_create_page(mapping, vmf->pgoff,
+ vmf->gfp_mask | __GFP_ZERO);
+ if (!page) {
+ ret = VM_FAULT_OOM;
+ goto out;
+ }
+
+finish_fault:
+ vmf->page = page;
+ ret = finish_fault(vmf);
+ vmf->page = NULL;
+ *entry = page;
+ if (!ret) {
+ /* Grab reference for PTE that is now referencing the page */
+ get_page(page);
+ ret = VM_FAULT_NOPAGE;
+ }
+out:
+ trace_dax_load_hole(inode, vmf, ret);
+ return ret;
+}
+
static bool dax_range_is_aligned(struct block_device *bdev,
unsigned int offset, unsigned int length)
{
--
2.9.4