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

SF Markus Elfring
2016-09-13T12:13:03Z

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 <elfring@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