hwrng: core - Allocate memory during module init (58b022ac) · Commits · 戴 / test

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>

drivers/char/hw_random/core.c

+20 −17

Original line number	Diff line number	Diff line
		@@ -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)

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