dax: relocate some dax functions

BugLink: http://bugs.launchpad.net/bugs/1704439
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.

Link: http://lkml.kernel.org/r/20170724170616.25810-3-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit e30331ff05f689f8f2faeb51664299c4d7841f15)
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

diff --git a/fs/dax.c b/fs/dax.c
index ab925dc6647ac764c5a2620a9ef21c53305f90dc..b8882b5ce6ede7882911d96322398cb58ba94730 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -120,6 +120,31 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mo
        return autoremove_wake_function(wait, mode, sync, NULL);
 }
 
+/*
+ * 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 @@ restart:
        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)
@@ -941,6 +897,50 @@ 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)
 {