hwrng: core - Allocate memory during module init

In core rng_buffer and rng_fillbuf is allocated in hwrng_register only
once and it is freed during module exit. This patch moves allocating
rng_buffer and rng_fillbuf from hwrng_register to rng core's init. This
avoids checking whether rng_buffer and rng_fillbuf was allocated from
every hwrng_register call. Also moving them to module init makes it
explicit that it is freed in module exit.

Change in v2:
Fix memory leak when register_miscdev fails.

Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 9203f2d130c06fd8d4091bf36aeccfa1e538e371..482794526e8cd52418dc1c1e6e5b200943d3c4c8 100644 (file)
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -449,22 +449,6 @@ int hwrng_register(struct hwrng *rng)
                goto out;
 
        mutex_lock(&rng_mutex);
-
-       /* kmalloc makes this safe for virt_to_page() in virtio_rng.c */
-       err = -ENOMEM;
-       if (!rng_buffer) {
-               rng_buffer = kmalloc(rng_buffer_size(), GFP_KERNEL);
-               if (!rng_buffer)
-                       goto out_unlock;
-       }
-       if (!rng_fillbuf) {
-               rng_fillbuf = kmalloc(rng_buffer_size(), GFP_KERNEL);
-               if (!rng_fillbuf) {
-                       kfree(rng_buffer);
-                       goto out_unlock;
-               }
-       }
-
        /* Must not register two RNGs with the same name. */
        err = -EEXIST;
        list_for_each_entry(tmp, &rng_list, list) {
@@ -573,7 +557,26 @@ EXPORT_SYMBOL_GPL(devm_hwrng_unregister);
 
 static int __init hwrng_modinit(void)
 {
-       return register_miscdev();
+       int ret = -ENOMEM;
+
+       /* kmalloc makes this safe for virt_to_page() in virtio_rng.c */
+       rng_buffer = kmalloc(rng_buffer_size(), GFP_KERNEL);
+       if (!rng_buffer)
+               return -ENOMEM;
+
+       rng_fillbuf = kmalloc(rng_buffer_size(), GFP_KERNEL);
+       if (!rng_fillbuf) {
+               kfree(rng_buffer);
+               return -ENOMEM;
+       }
+
+       ret = register_miscdev();
+       if (ret) {
+               kfree(rng_fillbuf);
+               kfree(rng_buffer);
+       }
+
+       return ret;
 }
 
 static void __exit hwrng_modexit(void)