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>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 9d21fcd..28b6236 100644 (file)
--- 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;
 }