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);