tmpfs: open a window in shmem_unuse_inode

[linux-2.6-omap-h63xx.git] / mm / shmem.c

diff --git a/mm/shmem.c b/mm/shmem.c
index 2e03d6031c244dbc213514bfb95cb862d4583975..a0126c4371054edf7120aaea97fd4d2785e4fdbf 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -838,10 +838,8 @@ static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, s
        if (size > SHMEM_NR_DIRECT)
                size = SHMEM_NR_DIRECT;
        offset = shmem_find_swp(entry, ptr, ptr+size);
-       if (offset >= 0) {
-               shmem_swp_balance_unmap();
+       if (offset >= 0)
                goto found;
-       }
        if (!info->i_indirect)
                goto lost2;
 
@@ -879,11 +877,11 @@ static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, s
                        if (size > ENTRIES_PER_PAGE)
                                size = ENTRIES_PER_PAGE;
                        offset = shmem_find_swp(entry, ptr, ptr+size);
+                       shmem_swp_unmap(ptr);
                        if (offset >= 0) {
                                shmem_dir_unmap(dir);
                                goto found;
                        }
-                       shmem_swp_unmap(ptr);
                }
        }
 lost1:
@@ -893,10 +891,25 @@ lost2:
        return 0;
 found:
        idx += offset;
-       inode = &info->vfs_inode;
-       error = add_to_page_cache(page, inode->i_mapping, idx, GFP_ATOMIC);
+       inode = igrab(&info->vfs_inode);
+       spin_unlock(&info->lock);
+
+       /* move head to start search for next from here */
+       list_move_tail(&shmem_swaplist, &info->swaplist);
+       mutex_unlock(&shmem_swaplist_mutex);
+
+       error = 1;
+       if (!inode)
+               goto out;
+
+       spin_lock(&info->lock);
+       ptr = shmem_swp_entry(info, idx, NULL);
+       if (ptr && ptr->val == entry.val)
+               error = add_to_page_cache(page, inode->i_mapping,
+                                               idx, GFP_ATOMIC);
        if (error == -EEXIST) {
                struct page *filepage = find_get_page(inode->i_mapping, idx);
+               error = 1;
                if (filepage) {
                        /*
                         * There might be a more uptodate page coming down
@@ -911,16 +924,18 @@ found:
                delete_from_swap_cache(page);
                set_page_dirty(page);
                info->flags |= SHMEM_PAGEIN;
-               shmem_swp_set(info, ptr + offset, 0);
+               shmem_swp_set(info, ptr, 0);
+               swap_free(entry);
+               error = 1;      /* not an error, but entry was found */
        }
-       shmem_swp_unmap(ptr);
+       if (ptr)
+               shmem_swp_unmap(ptr);
        spin_unlock(&info->lock);
-       /*
-        * Decrement swap count even when the entry is left behind:
-        * try_to_unuse will skip over mms, then reincrement count.
-        */
-       swap_free(entry);
-       return 1;
+out:
+       unlock_page(page);
+       page_cache_release(page);
+       iput(inode);            /* allows for NULL */
+       return error;
 }
 
 /*
@@ -935,18 +950,16 @@ int shmem_unuse(swp_entry_t entry, struct page *page)
        mutex_lock(&shmem_swaplist_mutex);
        list_for_each_safe(p, next, &shmem_swaplist) {
                info = list_entry(p, struct shmem_inode_info, swaplist);
-               if (!info->swapped)
+               if (info->swapped)
+                       found = shmem_unuse_inode(info, entry, page);
+               else
                        list_del_init(&info->swaplist);
-               else if (shmem_unuse_inode(info, entry, page)) {
-                       /* move head to start search for next from here */
-                       list_move_tail(&shmem_swaplist, &info->swaplist);
-                       found = 1;
-                       break;
-               }
                cond_resched();
+               if (found)
+                       goto out;
        }
        mutex_unlock(&shmem_swaplist_mutex);
-       return found;
+out:   return found;   /* 0 or 1 or -ENOMEM */
 }
 
 /*