page cache: use xa_lock

Remove the address_space ->tree_lock and use the xa_lock newly added to
the radix_tree_root.  Rename the address_space ->page_tree to ->i_pages,
since we don't really care that it's a tree.

[willy@infradead.org: fix nds32, fs/dax.c]
  Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 30 insertions, 30 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index 4424fc0c33aa..9d6c7e595415 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -332,12 +332,12 @@ static int shmem_radix_tree_replace(struct address_space *mapping,
 
         VM_BUG_ON(!expected);
         VM_BUG_ON(!replacement);
-        item = __radix_tree_lookup(&mapping->page_tree, index, &node, &pslot);
+        item = __radix_tree_lookup(&mapping->i_pages, index, &node, &pslot);
         if (!item)
                 return -ENOENT;
         if (item != expected)
                 return -ENOENT;
-        __radix_tree_replace(&mapping->page_tree, node, pslot,
+        __radix_tree_replace(&mapping->i_pages, node, pslot,
                              replacement, NULL);
         return 0;
 }
@@ -355,7 +355,7 @@ static bool shmem_confirm_swap(struct address_space *mapping,
         void *item;
 
         rcu_read_lock();
-        item = radix_tree_lookup(&mapping->page_tree, index);
+        item = radix_tree_lookup(&mapping->i_pages, index);
         rcu_read_unlock();
         return item == swp_to_radix_entry(swap);
 }
@@ -590,14 +590,14 @@ static int shmem_add_to_page_cache(struct page *page,
         page->mapping = mapping;
         page->index = index;
 
-        spin_lock_irq(&mapping->tree_lock);
+        xa_lock_irq(&mapping->i_pages);
         if (PageTransHuge(page)) {
                 void __rcu **results;
                 pgoff_t idx;
                 int i;
 
                 error = 0;
-                if (radix_tree_gang_lookup_slot(&mapping->page_tree,
+                if (radix_tree_gang_lookup_slot(&mapping->i_pages,
                                         &results, &idx, index, 1) &&
                                 idx < index + HPAGE_PMD_NR) {
                         error = -EEXIST;
@@ -605,14 +605,14 @@ static int shmem_add_to_page_cache(struct page *page,
 
                 if (!error) {
                         for (i = 0; i < HPAGE_PMD_NR; i++) {
-                                error = radix_tree_insert(&mapping->page_tree,
+                                error = radix_tree_insert(&mapping->i_pages,
                                                 index + i, page + i);
                                 VM_BUG_ON(error);
                         }
                         count_vm_event(THP_FILE_ALLOC);
                 }
         } else if (!expected) {
-                error = radix_tree_insert(&mapping->page_tree, index, page);
+                error = radix_tree_insert(&mapping->i_pages, index, page);
         } else {
                 error = shmem_radix_tree_replace(mapping, index, expected,
                                                                  page);
@@ -624,10 +624,10 @@ static int shmem_add_to_page_cache(struct page *page,
                         __inc_node_page_state(page, NR_SHMEM_THPS);
                 __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr);
                 __mod_node_page_state(page_pgdat(page), NR_SHMEM, nr);
-                spin_unlock_irq(&mapping->tree_lock);
+                xa_unlock_irq(&mapping->i_pages);
         } else {
                 page->mapping = NULL;
-                spin_unlock_irq(&mapping->tree_lock);
+                xa_unlock_irq(&mapping->i_pages);
                 page_ref_sub(page, nr);
         }
         return error;
@@ -643,13 +643,13 @@ static void shmem_delete_from_page_cache(struct page *page, void *radswap)
 
         VM_BUG_ON_PAGE(PageCompound(page), page);
 
-        spin_lock_irq(&mapping->tree_lock);
+        xa_lock_irq(&mapping->i_pages);
         error = shmem_radix_tree_replace(mapping, page->index, page, radswap);
         page->mapping = NULL;
         mapping->nrpages--;
         __dec_node_page_state(page, NR_FILE_PAGES);
         __dec_node_page_state(page, NR_SHMEM);
-        spin_unlock_irq(&mapping->tree_lock);
+        xa_unlock_irq(&mapping->i_pages);
         put_page(page);
         BUG_ON(error);
 }
@@ -662,9 +662,9 @@ static int shmem_free_swap(struct address_space *mapping,
 {
         void *old;
 
-        spin_lock_irq(&mapping->tree_lock);
-        old = radix_tree_delete_item(&mapping->page_tree, index, radswap);
-        spin_unlock_irq(&mapping->tree_lock);
+        xa_lock_irq(&mapping->i_pages);
+        old = radix_tree_delete_item(&mapping->i_pages, index, radswap);
+        xa_unlock_irq(&mapping->i_pages);
         if (old != radswap)
                 return -ENOENT;
         free_swap_and_cache(radix_to_swp_entry(radswap));
@@ -675,7 +675,7 @@ static int shmem_free_swap(struct address_space *mapping,
  * Determine (in bytes) how many of the shmem object's pages mapped by the
  * given offsets are swapped out.
  *
- * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU,
+ * This is safe to call without i_mutex or the i_pages lock thanks to RCU,
  * as long as the inode doesn't go away and racy results are not a problem.
  */
 unsigned long shmem_partial_swap_usage(struct address_space *mapping,
@@ -688,7 +688,7 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping,
 
         rcu_read_lock();
 
-        radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
+        radix_tree_for_each_slot(slot, &mapping->i_pages, &iter, start) {
                 if (iter.index >= end)
                         break;
 
@@ -717,7 +717,7 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping,
  * Determine (in bytes) how many of the shmem object's pages mapped by the
  * given vma is swapped out.
  *
- * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU,
+ * This is safe to call without i_mutex or the i_pages lock thanks to RCU,
  * as long as the inode doesn't go away and racy results are not a problem.
  */
 unsigned long shmem_swap_usage(struct vm_area_struct *vma)
@@ -1132,7 +1132,7 @@ static int shmem_unuse_inode(struct shmem_inode_info *info,
         int error = 0;
 
         radswap = swp_to_radix_entry(swap);
-        index = find_swap_entry(&mapping->page_tree, radswap);
+        index = find_swap_entry(&mapping->i_pages, radswap);
         if (index == -1)
                 return -EAGAIN; /* tell shmem_unuse we found nothing */
 
@@ -1448,7 +1448,7 @@ static struct page *shmem_alloc_hugepage(gfp_t gfp,
 
         hindex = round_down(index, HPAGE_PMD_NR);
         rcu_read_lock();
-        if (radix_tree_gang_lookup_slot(&mapping->page_tree, &results, &idx,
+        if (radix_tree_gang_lookup_slot(&mapping->i_pages, &results, &idx,
                                 hindex, 1) && idx < hindex + HPAGE_PMD_NR) {
                 rcu_read_unlock();
                 return NULL;
@@ -1561,14 +1561,14 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
          * Our caller will very soon move newpage out of swapcache, but it's
          * a nice clean interface for us to replace oldpage by newpage there.
          */
-        spin_lock_irq(&swap_mapping->tree_lock);
+        xa_lock_irq(&swap_mapping->i_pages);
         error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage,
                                                                    newpage);
         if (!error) {
                 __inc_node_page_state(newpage, NR_FILE_PAGES);
                 __dec_node_page_state(oldpage, NR_FILE_PAGES);
         }
-        spin_unlock_irq(&swap_mapping->tree_lock);
+        xa_unlock_irq(&swap_mapping->i_pages);
 
         if (unlikely(error)) {
                 /*
@@ -2634,7 +2634,7 @@ static void shmem_tag_pins(struct address_space *mapping)
         start = 0;
         rcu_read_lock();
 
-        radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
+        radix_tree_for_each_slot(slot, &mapping->i_pages, &iter, start) {
                 page = radix_tree_deref_slot(slot);
                 if (!page || radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page)) {
@@ -2642,10 +2642,10 @@ static void shmem_tag_pins(struct address_space *mapping)
                                 continue;
                         }
                 } else if (page_count(page) - page_mapcount(page) > 1) {
-                        spin_lock_irq(&mapping->tree_lock);
-                        radix_tree_tag_set(&mapping->page_tree, iter.index,
+                        xa_lock_irq(&mapping->i_pages);
+                        radix_tree_tag_set(&mapping->i_pages, iter.index,
                                            SHMEM_TAG_PINNED);
-                        spin_unlock_irq(&mapping->tree_lock);
+                        xa_unlock_irq(&mapping->i_pages);
                 }
 
                 if (need_resched()) {
@@ -2677,7 +2677,7 @@ static int shmem_wait_for_pins(struct address_space *mapping)
 
         error = 0;
         for (scan = 0; scan <= LAST_SCAN; scan++) {
-                if (!radix_tree_tagged(&mapping->page_tree, SHMEM_TAG_PINNED))
+                if (!radix_tree_tagged(&mapping->i_pages, SHMEM_TAG_PINNED))
                         break;
 
                 if (!scan)
@@ -2687,7 +2687,7 @@ static int shmem_wait_for_pins(struct address_space *mapping)
 
                 start = 0;
                 rcu_read_lock();
-                radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter,
+                radix_tree_for_each_tagged(slot, &mapping->i_pages, &iter,
                                            start, SHMEM_TAG_PINNED) {
 
                         page = radix_tree_deref_slot(slot);
@@ -2713,10 +2713,10 @@ static int shmem_wait_for_pins(struct address_space *mapping)
                                 error = -EBUSY;
                         }
 
-                        spin_lock_irq(&mapping->tree_lock);
-                        radix_tree_tag_clear(&mapping->page_tree,
+                        xa_lock_irq(&mapping->i_pages);
+                        radix_tree_tag_clear(&mapping->i_pages,
                                              iter.index, SHMEM_TAG_PINNED);
-                        spin_unlock_irq(&mapping->tree_lock);
+                        xa_unlock_irq(&mapping->i_pages);
 continue_resched:
                         if (need_resched()) {
                                 slot = radix_tree_iter_resume(slot, &iter);