[PATCH 2/4] virtio_blk: Less function calls in init_vq() after error detection

[SF Markus Elfring]

From: Markus Elfring <elfr...@users.sourceforge.net>
Date: Tue, 13 Sep 2016 13:20:44 +0200

The kfree() function was called in up to three cases
by the init_vq() function during error handling even if
the passed variable contained a null pointer.

* Split a condition check for memory allocation failures.

* Adjust jump targets according to the Linux coding style convention.

Signed-off-by: Markus Elfring <elfr...@users.sourceforge.net>
---
 drivers/block/virtio_blk.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 6553eb7..d28dbcf 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -395,11 +395,21 @@ static int init_vq(struct virtio_blk *vblk)
                return -ENOMEM;
 
        names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL);
+       if (!names) {
+               err = -ENOMEM;
+               goto free_vblk_vqs;
+       }
+
        callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL);
+       if (!callbacks) {
+               err = -ENOMEM;
+               goto free_names;
+       }
+
        vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL);
-       if (!names || !callbacks || !vqs) {
+       if (!vqs) {
                err = -ENOMEM;
-               goto out;
+               goto free_callbacks;
        }
 
        for (i = 0; i < num_vqs; i++) {
@@ -411,19 +421,21 @@ static int init_vq(struct virtio_blk *vblk)
        /* Discover virtqueues and write information to configuration.  */
        err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
        if (err)
-               goto out;
+               goto free_vqs;
 
        for (i = 0; i < num_vqs; i++) {
                spin_lock_init(&vblk->vqs[i].lock);
                vblk->vqs[i].vq = vqs[i];
        }
        vblk->num_vqs = num_vqs;
-
-out:
+ free_vqs:
        kfree(vqs);
+ free_callbacks:
        kfree(callbacks);
+ free_names:
        kfree(names);
        if (err)
+ free_vblk_vqs:
                kfree(vblk->vqs);
        return err;
 }
-- 
2.10.0