rbd: don't leak rbd_req on synchronous requests

When rbd_do_request() is called it allocates and populates an
rbd_req structure to hold information about the osd request to be
sent.  This is done for the benefit of the callback function (in
particular, rbd_req_cb()), which uses this in processing when
the request completes.

Synchronous requests provide no callback function, in which case
rbd_do_request() waits for the request to complete before returning.
This case is not handling the needed free of the rbd_req structure
like it should, so it is getting leaked.

Note however that the synchronous case has no need for the rbd_req
structure at all.  So rather than simply freeing this structure for
synchronous requests, just don't allocate it to begin with.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 24 insertions, 24 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 9d21fcd7e188..28b62367ff93 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1113,20 +1113,11 @@ static int rbd_do_request(struct request *rq,
                           struct ceph_osd_request **linger_req,
                           u64 *ver)
 {
+        struct ceph_osd_client *osdc;
         struct ceph_osd_request *osd_req;
-        int ret;
+        struct rbd_request *rbd_req = NULL;
         struct timespec mtime = CURRENT_TIME;
-        struct rbd_request *rbd_req;
-        struct ceph_osd_client *osdc;
-
-        rbd_req = kzalloc(sizeof(*rbd_req), GFP_NOIO);
-        if (!rbd_req)
-                return -ENOMEM;
-
-        if (coll) {
-                rbd_req->coll = coll;
-                rbd_req->coll_index = coll_index;
-        }
+        int ret;
 
         dout("rbd_do_request object_name=%s ofs=%llu len=%llu coll=%p[%d]\n",
                 object_name, (unsigned long long) ofs,
@@ -1134,10 +1125,8 @@ static int rbd_do_request(struct request *rq,
 
         osdc = &rbd_dev->rbd_client->client->osdc;
         osd_req = ceph_osdc_alloc_request(osdc, snapc, 1, false, GFP_NOIO);
-        if (!osd_req) {
-                ret = -ENOMEM;
-                goto done_pages;
-        }
+        if (!osd_req)
+                return -ENOMEM;
 
         osd_req->r_flags = flags;
         osd_req->r_pages = pages;
@@ -1145,13 +1134,22 @@ static int rbd_do_request(struct request *rq,
                 osd_req->r_bio = bio;
                 bio_get(osd_req->r_bio);
         }
-        osd_req->r_callback = rbd_cb;
 
-        rbd_req->rq = rq;
-        rbd_req->bio = bio;
-        rbd_req->pages = pages;
-        rbd_req->len = len;
+        if (rbd_cb) {
+                ret = -ENOMEM;
+                rbd_req = kmalloc(sizeof(*rbd_req), GFP_NOIO);
+                if (!rbd_req)
+                        goto done_osd_req;
+
+                rbd_req->rq = rq;
+                rbd_req->bio = bio;
+                rbd_req->pages = pages;
+                rbd_req->len = len;
+                rbd_req->coll = coll;
+                rbd_req->coll_index = coll ? coll_index : 0;
+        }
 
+        osd_req->r_callback = rbd_cb;
         osd_req->r_priv = rbd_req;
 
         strncpy(osd_req->r_oid, object_name, sizeof(osd_req->r_oid));
@@ -1193,10 +1191,12 @@ static int rbd_do_request(struct request *rq,
         return ret;
 
 done_err:
-        bio_chain_put(rbd_req->bio);
-        ceph_osdc_put_request(osd_req);
-done_pages:
+        if (bio)
+                bio_chain_put(osd_req->r_bio);
         kfree(rbd_req);
+done_osd_req:
+        ceph_osdc_put_request(osd_req);
+
         return ret;
 }