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>

1 files changed, 6 insertions, 16 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);