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authorSage Weil <sage@newdream.net>2009-10-06 11:31:07 -0700
committerSage Weil <sage@newdream.net>2009-10-06 11:31:07 -0700
commitc30dbb9cc7fc75ab1d0ee6fb084ba4684f7a665d (patch)
tree7e702615046c0c866bb0229c731f86916c526115 /fs/ceph/buffer.h
parentde57606c23afded22202825b3db8a5d61859f198 (diff)
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>
Diffstat (limited to 'fs/ceph/buffer.h')
-rw-r--r--fs/ceph/buffer.h55
1 files changed, 55 insertions, 0 deletions
diff --git a/fs/ceph/buffer.h b/fs/ceph/buffer.h
new file mode 100644
index 00000000000..16b1930acc4
--- /dev/null
+++ b/fs/ceph/buffer.h
@@ -0,0 +1,55 @@
+#ifndef __FS_CEPH_BUFFER_H
+#define __FS_CEPH_BUFFER_H
+
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/types.h>
+#include <linux/uio.h>
+
+/*
+ * a simple reference counted buffer.
+ *
+ * use kmalloc for small sizes (<= one page), vmalloc for larger
+ * sizes.
+ */
+struct ceph_buffer {
+ atomic_t nref;
+ struct kvec vec;
+ size_t alloc_len;
+ bool is_vmalloc;
+};
+
+struct ceph_buffer *ceph_buffer_new(gfp_t gfp);
+int ceph_buffer_alloc(struct ceph_buffer *b, int len, gfp_t gfp);
+
+static inline struct ceph_buffer *ceph_buffer_get(struct ceph_buffer *b)
+{
+ atomic_inc(&b->nref);
+ return b;
+}
+
+static inline void ceph_buffer_put(struct ceph_buffer *b)
+{
+ if (b && atomic_dec_and_test(&b->nref)) {
+ if (b->vec.iov_base) {
+ if (b->is_vmalloc)
+ vfree(b->vec.iov_base);
+ else
+ kfree(b->vec.iov_base);
+ }
+ kfree(b);
+ }
+}
+
+static inline struct ceph_buffer *ceph_buffer_new_alloc(int len, gfp_t gfp)
+{
+ struct ceph_buffer *b = ceph_buffer_new(gfp);
+
+ if (b && ceph_buffer_alloc(b, len, gfp) < 0) {
+ ceph_buffer_put(b);
+ b = NULL;
+ }
+ return b;
+}
+
+#endif