libceph: add ceph_kv{malloc,free}() and switch to them

Encapsulate kmalloc vs vmalloc memory allocation and freeing logic into
two helpers, ceph_kvmalloc() and ceph_kvfree(), and switch to them.

ceph_kvmalloc() kmalloc()'s a maximum of 8 pages, anything bigger is
vmalloc()'ed with __GFP_HIGHMEM set.  This changes the existing
behaviour:

- for buffers (ceph_buffer_new()), from trying to kmalloc() everything
  and using vmalloc() just as a fallback

- for messages (ceph_msg_new()), from going to vmalloc() for anything
  bigger than a page

- for messages (ceph_msg_new()), from disallowing vmalloc() to use high
  memory

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

3 files changed, 28 insertions, 27 deletions

diff --git a/net/ceph/buffer.c b/net/ceph/buffer.c
index bf3e6a13c215..621b5f65407f 100644
--- a/net/ceph/buffer.c
+++ b/net/ceph/buffer.c
@@ -6,6 +6,7 @@
 
 #include <linux/ceph/buffer.h>
 #include <linux/ceph/decode.h>
+#include <linux/ceph/libceph.h> /* for ceph_kv{malloc,free} */
 
 struct ceph_buffer *ceph_buffer_new(size_t len, gfp_t gfp)
 {
@@ -15,16 +16,10 @@ struct ceph_buffer *ceph_buffer_new(size_t len, gfp_t 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 | __GFP_HIGHMEM, PAGE_KERNEL);
-                if (!b->vec.iov_base) {
-                        kfree(b);
-                        return NULL;
-                }
-                b->is_vmalloc = true;
+        b->vec.iov_base = ceph_kvmalloc(len, gfp);
+        if (!b->vec.iov_base) {
+                kfree(b);
+                return NULL;
         }
 
         kref_init(&b->kref);
@@ -40,12 +35,7 @@ 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);
-        }
+        ceph_kvfree(b->vec.iov_base);
         kfree(b);
 }
 EXPORT_SYMBOL(ceph_buffer_release);
diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 43d8177a52e1..67d7721d237e 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/statfs.h>
 #include <linux/string.h>
+#include <linux/vmalloc.h>
 #include <linux/nsproxy.h>
 #include <net/net_namespace.h>
 
@@ -170,6 +171,25 @@ int ceph_compare_options(struct ceph_options *new_opt,
 }
 EXPORT_SYMBOL(ceph_compare_options);
 
+void *ceph_kvmalloc(size_t size, gfp_t flags)
+{
+        if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
+                void *ptr = kmalloc(size, flags | __GFP_NOWARN);
+                if (ptr)
+                        return ptr;
+        }
+
+        return __vmalloc(size, flags | __GFP_HIGHMEM, PAGE_KERNEL);
+}
+
+void ceph_kvfree(const void *ptr)
+{
+        if (is_vmalloc_addr(ptr))
+                vfree(ptr);
+        else
+                kfree(ptr);
+}
+
 
 static int parse_fsid(const char *str, struct ceph_fsid *fsid)
 {
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 252ad4e01cf8..2ed1304d22a7 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -3131,13 +3131,7 @@ struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags,
 
         /* front */
         if (front_len) {
-                if (front_len > PAGE_CACHE_SIZE) {
-                        m->front.iov_base = __vmalloc(front_len, flags,
-                                                      PAGE_KERNEL);
-                        m->front_is_vmalloc = true;
-                } else {
-                        m->front.iov_base = kmalloc(front_len, flags);
-                }
+                m->front.iov_base = ceph_kvmalloc(front_len, flags);
                 if (m->front.iov_base == NULL) {
                         dout("ceph_msg_new can't allocate %d bytes\n",
                              front_len);
@@ -3259,10 +3253,7 @@ static int ceph_con_in_msg_alloc(struct ceph_connection *con, int *skip)
 void ceph_msg_kfree(struct ceph_msg *m)
 {
         dout("msg_kfree %p\n", m);
-        if (m->front_is_vmalloc)
-                vfree(m->front.iov_base);
-        else
-                kfree(m->front.iov_base);
+        ceph_kvfree(m->front.iov_base);
         kmem_cache_free(ceph_msg_cache, m);
 }