Fix compile warnings: ignoring return value of 'xenbus_register_backend' ..

We neglect to check the return value of xenbus_register_backend
and take actions when that fails. This patch fixes that and adds
code to deal with those type of failures.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 13 insertions, 5 deletions

diff --git a/drivers/xen/blkback/blkback.c b/drivers/xen/blkback/blkback.c
index e9e3de119a73..a2ac7189cc0a 100644
--- a/drivers/xen/blkback/blkback.c
+++ b/drivers/xen/blkback/blkback.c
@@ -614,6 +614,7 @@ static void make_response(blkif_t *blkif, u64 id,
 static int __init blkif_init(void)
 {
         int i, mmap_pages;
+        int rc = 0;
 
         if (!xen_pv_domain())
                 return -ENODEV;
@@ -626,13 +627,17 @@ static int __init blkif_init(void)
                                         mmap_pages, GFP_KERNEL);
         pending_pages         = alloc_empty_pages_and_pagevec(mmap_pages);
 
-        if (!pending_reqs || !pending_grant_handles || !pending_pages)
+        if (!pending_reqs || !pending_grant_handles || !pending_pages) {
+                rc = -ENOMEM;
                 goto out_of_memory;
+        }
 
         for (i = 0; i < mmap_pages; i++)
                 pending_grant_handles[i] = BLKBACK_INVALID_HANDLE;
 
-        blkif_interface_init();
+        rc = blkif_interface_init();
+        if (rc)
+                goto failed_init;
 
         memset(pending_reqs, 0, sizeof(pending_reqs));
         INIT_LIST_HEAD(&pending_free);
@@ -640,16 +645,19 @@ static int __init blkif_init(void)
         for (i = 0; i < blkif_reqs; i++)
                 list_add_tail(&pending_reqs[i].free_list, &pending_free);
 
-        blkif_xenbus_init();
+        rc = blkif_xenbus_init();
+        if (rc)
+                goto failed_init;
 
         return 0;
 
  out_of_memory:
+        printk(KERN_ERR "%s: out of memory\n", __func__);
+ failed_init:
         kfree(pending_reqs);
         kfree(pending_grant_handles);
         free_empty_pages_and_pagevec(pending_pages, mmap_pages);
-        printk("%s: out of memory\n", __FUNCTION__);
-        return -ENOMEM;
+        return rc;
 }
 
 module_init(blkif_init);