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virtio-rng: fixes for device registration/unregistration

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There are several fixes in this patch (mostly because it's hard
splitting them up):

 - Revert the name field in struct hwrng back to 'const'. Also, don't
do an extra kmalloc for the name - just wasteful.
 - Deal with allocation failures properly.
 - Use IDA to allocate device number instead of brute forcing one.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Sasha Levin 2014-05-16 11:42:43 +09:30 committed by Rusty Russell
parent e5d23a8cc3
commit a17597d3b4
2 changed files with 24 additions and 19 deletions
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39
drivers/char/hw_random/virtio-rng.c
View File

@ -25,6 +25,7 @@
#include <linux/virtio_rng.h>
#include <linux/module.h>
static DEFINE_IDA(rng_index_ida);
struct virtrng_info {
struct virtio_device *vdev;
@ -33,6 +34,8 @@ struct virtrng_info {
unsigned int data_avail;
struct completion have_data;
bool busy;
char name[25];
int index;
};
static void random_recv_done(struct virtqueue *vq)
@ -92,41 +95,45 @@ static void virtio_cleanup(struct hwrng *rng)
static int probe_common(struct virtio_device *vdev)
{
int err, i;
int err, index;
struct virtrng_info *vi = NULL;
vi = kzalloc(sizeof(struct virtrng_info), GFP_KERNEL);
vi->hwrng.name = kmalloc(40, GFP_KERNEL);
if (!vi)
return -ENOMEM;
vi->index = index = ida_simple_get(&rng_index_ida, 0, 0, GFP_KERNEL);
if (index < 0) {
kfree(vi);
return index;
}
sprintf(vi->name, "virtio_rng.%d", index);
init_completion(&vi->have_data);
vi->hwrng.read = virtio_read;
vi->hwrng.cleanup = virtio_cleanup;
vi->hwrng.priv = (unsigned long)vi;
vi->hwrng = (struct hwrng) {
.read = virtio_read,
.cleanup = virtio_cleanup,
.priv = (unsigned long)vi,
.name = vi->name,
};
vdev->priv = vi;
/* We expect a single virtqueue. */
vi->vq = virtio_find_single_vq(vdev, random_recv_done, "input");
if (IS_ERR(vi->vq)) {
err = PTR_ERR(vi->vq);
kfree(vi->hwrng.name);
vi->vq = NULL;
kfree(vi);
vi = NULL;
ida_simple_remove(&rng_index_ida, index);
return err;
}
i = 0;
do {
sprintf(vi->hwrng.name, "virtio_rng.%d", i++);
err = hwrng_register(&vi->hwrng);
} while (err == -EEXIST);
if (err) {
vdev->config->del_vqs(vdev);
kfree(vi->hwrng.name);
vi->vq = NULL;
kfree(vi);
vi = NULL;
ida_simple_remove(&rng_index_ida, index);
return err;
}
@ -140,10 +147,8 @@ static void remove_common(struct virtio_device *vdev)
vi->busy = false;
hwrng_unregister(&vi->hwrng);
vdev->config->del_vqs(vdev);
kfree(vi->hwrng.name);
vi->vq = NULL;
ida_simple_remove(&rng_index_ida, vi->index);
kfree(vi);
vi = NULL;
}
static int virtrng_probe(struct virtio_device *vdev)

2
include/linux/hw_random.h
View File

@ -31,7 +31,7 @@
* @priv: Private data, for use by the RNG driver.
*/
struct hwrng {
char *name;
const char *name;
int (*init)(struct hwrng *rng);
void (*cleanup)(struct hwrng *rng);
int (*data_present)(struct hwrng *rng, int wait);