mm/dmapool.c: remove redundant NULL check for dev in dma_pool_create() (cc6b664a) · Commits · 戴 / test

"dev" cannot be NULL because it is already checked before calling dma_pool_create(). If dev ever was NULL, the code would oops in dev_to_node() after enabling CONFIG_NUMA. It is possible that some driver is using dev==NULL and has never been run on a NUMA machine. Such a driver is probably outdated, possibly buggy and will need some attention if it starts triggering NULL derefs. Signed-off-by:

Daeseok Youn <daeseok.youn@gmail.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/dmapool.c

+8 −16

Original line number	Diff line number	Diff line
		@@ -170,24 +170,16 @@ struct dma_pool dma_pool_create(const char name, struct device *dev,
		retval->boundary = boundary;
		retval->allocation = allocation;

		if (dev) {
		int ret;
		INIT_LIST_HEAD(&retval->pools);

		mutex_lock(&pools_lock);
		if (list_empty(&dev->dma_pools))
		ret = device_create_file(dev, &dev_attr_pools);
		else
		ret = 0;
		/* note: not currently insisting "name" be unique */
		if (!ret)
		list_add(&retval->pools, &dev->dma_pools);
		else {
		if (list_empty(&dev->dma_pools) &&
		device_create_file(dev, &dev_attr_pools)) {
		kfree(retval);
		retval = NULL;
		}
		mutex_unlock(&pools_lock);
		return NULL;
		} else
		INIT_LIST_HEAD(&retval->pools);
		list_add(&retval->pools, &dev->dma_pools);
		mutex_unlock(&pools_lock);

		return retval;
		}

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