From mboxrd@z Thu Jan 1 00:00:00 1970 From: nico@fluxnic.net (Nicolas Pitre) Date: Fri, 06 Aug 2010 12:53:47 -0400 (EDT) Subject: [PATCH v2 03/20] mmc: support embedded data field in mmc_host In-Reply-To: <20100806144605.GA21015@n2100.arm.linux.org.uk> References: <20100804114147.GB6852@n2100.arm.linux.org.uk> <20100806144605.GA21015@n2100.arm.linux.org.uk> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, 6 Aug 2010, Russell King - ARM Linux wrote: > On Fri, Aug 06, 2010 at 01:02:24PM +0300, Ohad Ben-Cohen wrote: > > We have Russell's suggestion which is nice and simple, but it has the > > 1 device limitation. > > You could make it generic by doing something like this: > > #define set_device_data(name, type, index, data) \ > ({ \ > extern void __set_device_data(const char *, int, void *, size_t); \ > BUILD_BUG_ON(!__same_type(type, *data)); \ > __set_device_data(name ":" #type, index, data, sizeof(type)); \ > }) > > #define get_device_data(name, type, index) ({ \ > extern void *__get_device_data(const char *, int); \ > type *__ptr = __get_device_data(name ":" #type, index); \ > __ptr; }) > > And now we have something that takes a string and index to use as a lookup > key in some kind of list - and it's typesafe (because the lookup key is > dependent on the stringified type.) > > But... at this point I feel that we're getting too complicated, and will > get shouted at to use something like DT which already solves this problem. DT is not generally available yet. A simple interim solution would still be worth it. Nicolas