mm: move handling of COW faults into DAX code

[sfrench/cifs-2.6.git] / fs / dax.c

diff --git a/fs/dax.c b/fs/dax.c
index f1dfae64b11af0fa0f1708155334a3da783c6859..e83aa4077df4fc63e479c377be469b404f77edc5 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -240,6 +240,23 @@ static void *get_unlocked_mapping_entry(struct address_space *mapping,
        }
 }
 
+static void dax_unlock_mapping_entry(struct address_space *mapping,
+                                    pgoff_t index)
+{
+       void *entry, **slot;
+
+       spin_lock_irq(&mapping->tree_lock);
+       entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, &slot);
+       if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry) ||
+                        !slot_locked(mapping, slot))) {
+               spin_unlock_irq(&mapping->tree_lock);
+               return;
+       }
+       unlock_slot(mapping, slot);
+       spin_unlock_irq(&mapping->tree_lock);
+       dax_wake_mapping_entry_waiter(mapping, index, entry, false);
+}
+
 static void put_locked_mapping_entry(struct address_space *mapping,
                                     pgoff_t index, void *entry)
 {
@@ -433,22 +450,6 @@ void dax_wake_mapping_entry_waiter(struct address_space *mapping,
                __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key);
 }
 
-void dax_unlock_mapping_entry(struct address_space *mapping, pgoff_t index)
-{
-       void *entry, **slot;
-
-       spin_lock_irq(&mapping->tree_lock);
-       entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, &slot);
-       if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry) ||
-                        !slot_locked(mapping, slot))) {
-               spin_unlock_irq(&mapping->tree_lock);
-               return;
-       }
-       unlock_slot(mapping, slot);
-       spin_unlock_irq(&mapping->tree_lock);
-       dax_wake_mapping_entry_waiter(mapping, index, entry, false);
-}
-
 /*
  * Delete exceptional DAX entry at @index from @mapping. Wait for radix tree
  * entry to get unlocked before deleting it.
@@ -500,10 +501,8 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
        /* 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) {
-               put_locked_mapping_entry(mapping, vmf->pgoff, entry);
+       if (!page)
                return VM_FAULT_OOM;
-       }
        vmf->page = page;
        return VM_FAULT_LOCKED;
 }
@@ -954,7 +953,7 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
        struct iomap iomap = { 0 };
        unsigned flags = IOMAP_FAULT;
        int error, major = 0;
-       int locked_status = 0;
+       int vmf_ret = 0;
        void *entry;
 
        /*
@@ -1007,13 +1006,11 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 
                if (error)
                        goto finish_iomap;
-               if (!radix_tree_exceptional_entry(entry)) {
-                       vmf->page = entry;
-                       locked_status = VM_FAULT_LOCKED;
-               } else {
-                       vmf->entry = entry;
-                       locked_status = VM_FAULT_DAX_LOCKED;
-               }
+
+               __SetPageUptodate(vmf->cow_page);
+               vmf_ret = finish_fault(vmf);
+               if (!vmf_ret)
+                       vmf_ret = VM_FAULT_DONE_COW;
                goto finish_iomap;
        }
 
@@ -1030,7 +1027,7 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
        case IOMAP_UNWRITTEN:
        case IOMAP_HOLE:
                if (!(vmf->flags & FAULT_FLAG_WRITE)) {
-                       locked_status = dax_load_hole(mapping, entry, vmf);
+                       vmf_ret = dax_load_hole(mapping, entry, vmf);
                        break;
                }
                /*FALLTHRU*/
@@ -1042,7 +1039,7 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 
  finish_iomap:
        if (ops->iomap_end) {
-               if (error) {
+               if (error || (vmf_ret & VM_FAULT_ERROR)) {
                        /* keep previous error */
                        ops->iomap_end(inode, pos, PAGE_SIZE, 0, flags,
                                        &iomap);
@@ -1052,7 +1049,7 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
                }
        }
  unlock_entry:
-       if (!locked_status || error)
+       if (vmf_ret != VM_FAULT_LOCKED || error)
                put_locked_mapping_entry(mapping, vmf->pgoff, entry);
  out:
        if (error == -ENOMEM)
@@ -1060,9 +1057,9 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
        /* -EBUSY is fine, somebody else faulted on the same PTE */
        if (error < 0 && error != -EBUSY)
                return VM_FAULT_SIGBUS | major;
-       if (locked_status) {
+       if (vmf_ret) {
                WARN_ON_ONCE(error); /* -EBUSY from ops->iomap_end? */
-               return locked_status;
+               return vmf_ret;
        }
        return VM_FAULT_NOPAGE | major;
 }