powerpc/perf: Avoid spurious PMU interrupts after idle

[mirror_ubuntu-zesty-kernel.git] / fs / dax.c

diff --git a/fs/dax.c b/fs/dax.c
index 3af2da5e64ce77fa8ae4b3f294c82882d350120f..917c66584810c510b112036364644af24cbbcfeb 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -369,6 +369,22 @@ restart:
                }
                spin_lock_irq(&mapping->tree_lock);
 
+               if (!entry) {
+                       /*
+                        * We needed to drop the page_tree lock while calling
+                        * radix_tree_preload() and we didn't have an entry to
+                        * lock.  See if another thread inserted an entry at
+                        * our index during this time.
+                        */
+                       entry = __radix_tree_lookup(&mapping->page_tree, index,
+                                       NULL, &slot);
+                       if (entry) {
+                               radix_tree_preload_end();
+                               spin_unlock_irq(&mapping->tree_lock);
+                               goto restart;
+                       }
+               }
+
                if (pmd_downgrade) {
                        radix_tree_delete(&mapping->page_tree, index);
                        mapping->nrexceptional--;
@@ -384,19 +400,12 @@ restart:
                if (err) {
                        spin_unlock_irq(&mapping->tree_lock);
                        /*
-                        * Someone already created the entry?  This is a
-                        * normal failure when inserting PMDs in a range
-                        * that already contains PTEs.  In that case we want
-                        * to return -EEXIST immediately.
-                        */
-                       if (err == -EEXIST && !(size_flag & RADIX_DAX_PMD))
-                               goto restart;
-                       /*
-                        * Our insertion of a DAX PMD entry failed, most
-                        * likely because it collided with a PTE sized entry
-                        * at a different index in the PMD range.  We haven't
-                        * inserted anything into the radix tree and have no
-                        * waiters to wake.
+                        * Our insertion of a DAX entry failed, most likely
+                        * because we were inserting a PMD entry and it
+                        * collided with a PTE sized entry at a different
+                        * index in the PMD range.  We haven't inserted
+                        * anything into the radix tree and have no waiters to
+                        * wake.
                         */
                        return ERR_PTR(err);
                }
@@ -493,35 +502,6 @@ int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index)
        return ret;
 }
 
-/*
- * Invalidate exceptional DAX entry if easily possible. This handles DAX
- * entries for invalidate_inode_pages() so we evict the entry only if we can
- * do so without blocking.
- */
-int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index)
-{
-       int ret = 0;
-       void *entry, **slot;
-       struct radix_tree_root *page_tree = &mapping->page_tree;
-
-       spin_lock_irq(&mapping->tree_lock);
-       entry = __radix_tree_lookup(page_tree, index, NULL, &slot);
-       if (!entry || !radix_tree_exceptional_entry(entry) ||
-           slot_locked(mapping, slot))
-               goto out;
-       if (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) ||
-           radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE))
-               goto out;
-       radix_tree_delete(page_tree, index);
-       mapping->nrexceptional--;
-       ret = 1;
-out:
-       spin_unlock_irq(&mapping->tree_lock);
-       if (ret)
-               dax_wake_mapping_entry_waiter(mapping, index, entry, true);
-       return ret;
-}
-
 /*
  * Invalidate exceptional DAX entry if it is clean.
  */
@@ -1020,7 +1000,7 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
         * into page tables. We have to tear down these mappings so that data
         * written by write(2) is visible in mmap.
         */
-       if ((iomap->flags & IOMAP_F_NEW) && inode->i_mapping->nrpages) {
+       if (iomap->flags & IOMAP_F_NEW) {
                invalidate_inode_pages2_range(inode->i_mapping,
                                              pos >> PAGE_SHIFT,
                                              (end - 1) >> PAGE_SHIFT);
@@ -1031,6 +1011,11 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
                struct blk_dax_ctl dax = { 0 };
                ssize_t map_len;
 
+               if (fatal_signal_pending(current)) {
+                       ret = -EINTR;
+                       break;
+               }
+
                dax.sector = dax_iomap_sector(iomap, pos);
                dax.size = (length + offset + PAGE_SIZE - 1) & PAGE_MASK;
                map_len = dax_map_atomic(iomap->bdev, &dax);