xen/blkback: fix memory leaks

In read_per_ring_refs(), after 'req' and related memory regions are
allocated, xen_blkif_map() is invoked to map the shared frame, irq, and
etc. However, if this mapping process fails, no cleanup is performed,
leading to memory leaks. To fix this issue, invoke the cleanup before
returning the error.

Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 3ac6a5d18071729a7747a72835223f02234e240f..b90dbcd99c03e9c4e1ae0bc5f22180b80c5903e1 100644 (file)
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -965,6 +965,7 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
                }
        }
 
+       err = -ENOMEM;
        for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) {
                req = kzalloc(sizeof(*req), GFP_KERNEL);
                if (!req)
@@ -987,7 +988,7 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
        err = xen_blkif_map(ring, ring_ref, nr_grefs, evtchn);
        if (err) {
                xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", evtchn);
-               return err;
+               goto fail;
        }
 
        return 0;
@@ -1007,8 +1008,7 @@ fail:
                }
                kfree(req);
        }
-       return -ENOMEM;
-
+       return err;
 }
 
 static int connect_ring(struct backend_info *be)