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Date: Tue, 2 Mar 2010 16:46:36 -0800
From: Sage Weil <sage@...dream.net>
To: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Sage Weil <sage@...dream.net>
Subject: [PATCH 05/26] 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@...dream.net>
---
fs/ceph/buffer.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ceph/buffer.h | 39 +++++++++++++++++++++++++++
2 files changed, 117 insertions(+), 0 deletions(-)
create mode 100644 fs/ceph/buffer.c
create mode 100644 fs/ceph/buffer.h
diff --git a/fs/ceph/buffer.c b/fs/ceph/buffer.c
new file mode 100644
index 0000000..b98086c
--- /dev/null
+++ b/fs/ceph/buffer.c
@@ -0,0 +1,78 @@
+
+#include "ceph_debug.h"
+#include "buffer.h"
+#include "decode.h"
+
+struct ceph_buffer *ceph_buffer_new(size_t len, gfp_t gfp)
+{
+ struct ceph_buffer *b;
+
+ b = kmalloc(sizeof(*b), gfp);
+ if (!b)
+ return NULL;
+
+ 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);
+ if (!b->vec.iov_base) {
+ kfree(b);
+ return NULL;
+ }
+ b->is_vmalloc = true;
+ }
+
+ kref_init(&b->kref);
+ b->alloc_len = len;
+ b->vec.iov_len = len;
+ dout("buffer_new %p\n", b);
+ return b;
+}
+
+void ceph_buffer_release(struct kref *kref)
+{
+ struct ceph_buffer *b = container_of(kref, struct ceph_buffer, kref);
+
+ dout("buffer_release %p\n", b);
+ if (b->vec.iov_base) {
+ if (b->is_vmalloc)
+ vfree(b->vec.iov_base);
+ else
+ kfree(b->vec.iov_base);
+ }
+ kfree(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;
+}
+
+int ceph_decode_buffer(struct ceph_buffer **b, void **p, void *end)
+{
+ size_t len;
+
+ ceph_decode_need(p, end, sizeof(u32), bad);
+ len = ceph_decode_32(p);
+ dout("decode_buffer len %d\n", (int)len);
+ ceph_decode_need(p, end, len, bad);
+ *b = ceph_buffer_new(len, GFP_NOFS);
+ if (!*b)
+ return -ENOMEM;
+ ceph_decode_copy(p, (*b)->vec.iov_base, len);
+ return 0;
+bad:
+ return -EINVAL;
+}
diff --git a/fs/ceph/buffer.h b/fs/ceph/buffer.h
new file mode 100644
index 0000000..58d1901
--- /dev/null
+++ b/fs/ceph/buffer.h
@@ -0,0 +1,39 @@
+#ifndef __FS_CEPH_BUFFER_H
+#define __FS_CEPH_BUFFER_H
+
+#include <linux/kref.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 {
+ struct kref kref;
+ struct kvec vec;
+ size_t alloc_len;
+ bool is_vmalloc;
+};
+
+extern struct ceph_buffer *ceph_buffer_new(size_t len, gfp_t gfp);
+extern void ceph_buffer_release(struct kref *kref);
+
+static inline struct ceph_buffer *ceph_buffer_get(struct ceph_buffer *b)
+{
+ kref_get(&b->kref);
+ return b;
+}
+
+static inline void ceph_buffer_put(struct ceph_buffer *b)
+{
+ kref_put(&b->kref, ceph_buffer_release);
+}
+
+extern int ceph_decode_buffer(struct ceph_buffer **b, void **p, void *end);
+
+#endif
--
1.7.0
--
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