CacheFiles: Downgrade the requirements passed to the allocator

Downgrade the requirements passed to the allocator in the gfp flags parameter.
FS-Cache/CacheFiles can handle OOM conditions simply by aborting the attempt to
store an object or a page in the cache.

Signed-off-by: David Howells <dhowells@redhat.com>

6 files changed, 19 insertions, 15 deletions

diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index 67bef6d01484..9bff0f878cfd 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -41,12 +41,12 @@ static struct fscache_object *cachefiles_alloc_object(
 
         _enter("{%s},%p,", cache->cache.identifier, cookie);
 
-        lookup_data = kmalloc(sizeof(*lookup_data), GFP_KERNEL);
+        lookup_data = kmalloc(sizeof(*lookup_data), cachefiles_gfp);
         if (!lookup_data)
                 goto nomem_lookup_data;
 
         /* create a new object record and a temporary leaf image */
-        object = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL);
+        object = kmem_cache_alloc(cachefiles_object_jar, cachefiles_gfp);
         if (!object)
                 goto nomem_object;
 
@@ -63,7 +63,7 @@ static struct fscache_object *cachefiles_alloc_object(
          * - stick the length on the front and leave space on the back for the
          *   encoder
          */
-        buffer = kmalloc((2 + 512) + 3, GFP_KERNEL);
+        buffer = kmalloc((2 + 512) + 3, cachefiles_gfp);
         if (!buffer)
                 goto nomem_buffer;
 
@@ -219,7 +219,7 @@ static void cachefiles_update_object(struct fscache_object *_object)
                 return;
         }
 
-        auxdata = kmalloc(2 + 512 + 3, GFP_KERNEL);
+        auxdata = kmalloc(2 + 512 + 3, cachefiles_gfp);
         if (!auxdata) {
                 _leave(" [nomem]");
                 return;
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index bd6bc1bde2d7..49382519907a 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -23,6 +23,8 @@ extern unsigned cachefiles_debug;
 #define CACHEFILES_DEBUG_KLEAVE 2
 #define CACHEFILES_DEBUG_KDEBUG 4
 
+#define cachefiles_gfp (__GFP_WAIT | __GFP_NORETRY | __GFP_NOMEMALLOC)
+
 /*
  * node records
  */
diff --git a/fs/cachefiles/key.c b/fs/cachefiles/key.c
index 81b8b2b3a674..33b58c60f2d1 100644
--- a/fs/cachefiles/key.c
+++ b/fs/cachefiles/key.c
@@ -78,7 +78,7 @@ char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type)
 
         _debug("max: %d", max);
 
-        key = kmalloc(max, GFP_KERNEL);
+        key = kmalloc(max, cachefiles_gfp);
         if (!key)
                 return NULL;
 
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index 3367abdcdac4..9108b8ea505a 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -238,7 +238,7 @@ static int cachefiles_read_backing_file_one(struct cachefiles_object *object,
         _debug("read back %p{%lu,%d}",
                netpage, netpage->index, page_count(netpage));
 
-        monitor = kzalloc(sizeof(*monitor), GFP_KERNEL);
+        monitor = kzalloc(sizeof(*monitor), cachefiles_gfp);
         if (!monitor)
                 goto nomem;
 
@@ -257,13 +257,14 @@ static int cachefiles_read_backing_file_one(struct cachefiles_object *object,
                         goto backing_page_already_present;
 
                 if (!newpage) {
-                        newpage = page_cache_alloc_cold(bmapping);
+                        newpage = __page_cache_alloc(cachefiles_gfp |
+                                                     __GFP_COLD);
                         if (!newpage)
                                 goto nomem_monitor;
                 }
 
                 ret = add_to_page_cache(newpage, bmapping,
-                                        netpage->index, GFP_KERNEL);
+                                        netpage->index, cachefiles_gfp);
                 if (ret == 0)
                         goto installed_new_backing_page;
                 if (ret != -EEXIST)
@@ -481,7 +482,7 @@ static int cachefiles_read_backing_file(struct cachefiles_object *object,
                        netpage, netpage->index, page_count(netpage));
 
                 if (!monitor) {
-                        monitor = kzalloc(sizeof(*monitor), GFP_KERNEL);
+                        monitor = kzalloc(sizeof(*monitor), cachefiles_gfp);
                         if (!monitor)
                                 goto nomem;
 
@@ -496,13 +497,14 @@ static int cachefiles_read_backing_file(struct cachefiles_object *object,
                                 goto backing_page_already_present;
 
                         if (!newpage) {
-                                newpage = page_cache_alloc_cold(bmapping);
+                                newpage = __page_cache_alloc(cachefiles_gfp |
+                                                             __GFP_COLD);
                                 if (!newpage)
                                         goto nomem;
                         }
 
                         ret = add_to_page_cache(newpage, bmapping,
-                                                netpage->index, GFP_KERNEL);
+                                                netpage->index, cachefiles_gfp);
                         if (ret == 0)
                                 goto installed_new_backing_page;
                         if (ret != -EEXIST)
@@ -532,7 +534,7 @@ static int cachefiles_read_backing_file(struct cachefiles_object *object,
                 _debug("- monitor add");
 
                 ret = add_to_page_cache(netpage, op->mapping, netpage->index,
-                                        GFP_KERNEL);
+                                        cachefiles_gfp);
                 if (ret < 0) {
                         if (ret == -EEXIST) {
                                 page_cache_release(netpage);
@@ -608,7 +610,7 @@ static int cachefiles_read_backing_file(struct cachefiles_object *object,
                 _debug("- uptodate");
 
                 ret = add_to_page_cache(netpage, op->mapping, netpage->index,
-                                        GFP_KERNEL);
+                                        cachefiles_gfp);
                 if (ret < 0) {
                         if (ret == -EEXIST) {
                                 page_cache_release(netpage);
diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c
index e18b183b47e1..73b46288b54b 100644
--- a/fs/cachefiles/xattr.c
+++ b/fs/cachefiles/xattr.c
@@ -174,7 +174,7 @@ int cachefiles_check_object_xattr(struct cachefiles_object *object,
         ASSERT(dentry);
         ASSERT(dentry->d_inode);
 
-        auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL);
+        auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, cachefiles_gfp);
         if (!auxbuf) {
                 _leave(" = -ENOMEM");
                 return -ENOMEM;
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index d7c663cfc923..248a12e22532 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -759,7 +759,7 @@ int __fscache_write_page(struct fscache_cookie *cookie,
 
         fscache_stat(&fscache_n_stores);
 
-        op = kzalloc(sizeof(*op), GFP_NOIO);
+        op = kzalloc(sizeof(*op), GFP_NOIO | __GFP_NOMEMALLOC | __GFP_NORETRY);
         if (!op)
                 goto nomem;