[PATCH v4 01/12] libceph: introduce ceph_extract_encoded_string_kvmalloc

[Dongsheng Yang <dongsheng.yang@xxxxxxxxxxxx>]

When we are going to extract the encoded string, there
would be a large string encoded.

Especially in the journaling case, if we use the default
journal object size, 16M, there could be a 16M string
encoded in this object.

Signed-off-by: Dongsheng Yang <dongsheng.yang@xxxxxxxxxxxx>
---
 include/linux/ceph/decode.h | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/include/linux/ceph/decode.h b/include/linux/ceph/decode.h
index 450384f..555879f 100644
--- a/include/linux/ceph/decode.h
+++ b/include/linux/ceph/decode.h
@@ -104,8 +104,11 @@ static inline bool ceph_has_room(void **p, void *end, size_t n)
  *     beyond the "end" pointer provided (-ERANGE)
  *   - memory could not be allocated for the result (-ENOMEM)
  */
-static inline char *ceph_extract_encoded_string(void **p, void *end,
-						size_t *lenp, gfp_t gfp)
+typedef void * (mem_alloc_t)(size_t size, gfp_t flags);
+extern void *ceph_kvmalloc(size_t size, gfp_t flags);
+static inline char *extract_encoded_string(void **p, void *end,
+					   mem_alloc_t alloc_fn,
+					   size_t *lenp, gfp_t gfp)
 {
 	u32 len;
 	void *sp = *p;
@@ -115,7 +118,7 @@ static inline char *ceph_extract_encoded_string(void **p, void *end,
 	if (!ceph_has_room(&sp, end, len))
 		goto bad;
 
-	buf = kmalloc(len + 1, gfp);
+	buf = alloc_fn(len + 1, gfp);
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
@@ -133,6 +136,18 @@ static inline char *ceph_extract_encoded_string(void **p, void *end,
 	return ERR_PTR(-ERANGE);
 }
 
+static inline char *ceph_extract_encoded_string(void **p, void *end,
+						size_t *lenp, gfp_t gfp)
+{
+	return extract_encoded_string(p, end, kmalloc, lenp, gfp);
+}
+
+static inline char *ceph_extract_encoded_string_kvmalloc(void **p, void *end,
+							 size_t *lenp, gfp_t gfp)
+{
+	return extract_encoded_string(p, end, ceph_kvmalloc, lenp, gfp);
+}
+
 /*
  * skip helpers
  */
-- 
1.8.3.1