Messages in this thread | | | Date | Mon, 3 Oct 2005 13:49:51 +0100 | From | Russell King <> | Subject | Re: [PATCH] release_resource() check for NULL resource |
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On Mon, Oct 03, 2005 at 03:43:50PM +0300, Pekka Enberg wrote: > Usually yes but it makes releasing partial initialization much simpler > because you can reuse the normal release counterpart. For example, > > static int driver_init(void) > { > dev->resource1 = request_region(...); > if (!dev->resource1) > goto failed; > > dev->resource2 = request_region(...); > if (!dev->resource2) > goto failed; > > return 0; > > failed: > driver_release(dev); > return -1; > } > > static void driver_release(struct device * dev) > { > release_resource(dev->resource1); > release_resource(dev->resource2); > kfree(dev); > } > > Many drivers have the release function copy-pasted to init with lots > of goto labels exactly because release_region, iounmap, and friends > aren't NULL safe.
And the above is buggy. request_region() allocates memory. release_resource() unregisters the resource but does _not_ free the allocated memory.
On the other hand, release_region() is the counter-part of request_region() and should be used to release resources created by request_region().
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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