ceph: ref counted buffer
struct ceph_buffer is a simple ref-counted buffer. We transparently
choose between kmalloc for small buffers and vmalloc for large ones.
This is currently used only for allocating memory for xattr data.
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/buffer.c b/fs/ceph/buffer.c
new file mode 100644
index 0000000..cf9aacc
--- /dev/null
+++ b/fs/ceph/buffer.c
@@ -0,0 +1,34 @@
+
+#include "ceph_debug.h"
+#include "buffer.h"
+
+struct ceph_buffer *ceph_buffer_new(gfp_t gfp)
+{
+ struct ceph_buffer *b;
+
+ b = kmalloc(sizeof(*b), gfp);
+ if (!b)
+ return NULL;
+ atomic_set(&b->nref, 1);
+ b->vec.iov_base = NULL;
+ b->vec.iov_len = 0;
+ b->alloc_len = 0;
+ return b;
+}
+
+int ceph_buffer_alloc(struct ceph_buffer *b, int len, gfp_t gfp)
+{
+ b->vec.iov_base = kmalloc(len, gfp | __GFP_NOWARN);
+ if (b->vec.iov_base) {
+ b->is_vmalloc = false;
+ } else {
+ b->vec.iov_base = __vmalloc(len, gfp, PAGE_KERNEL);
+ b->is_vmalloc = true;
+ }
+ if (!b->vec.iov_base)
+ return -ENOMEM;
+ b->alloc_len = len;
+ b->vec.iov_len = len;
+ return 0;
+}
+