Messages in this thread | | | Date | Thu, 7 Apr 2005 12:43:02 +0100 | From | Christoph Hellwig <> | Subject | Re: [RFC] Add support for semaphore-like structure with support for asynchronous I/O |
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On Tue, Apr 05, 2005 at 11:46:41AM -0400, Benjamin LaHaise wrote: > On Mon, Apr 04, 2005 at 01:56:35PM -0400, Trond Myklebust wrote: > > IOW: the current semaphore implementations really all need to die, and > > be replaced by a single generic version to which it is actually > > practical to add new functionality. > > I can see that goal, but I don't think introducing iosems is the right > way to acheive it. Instead (and I'll start tackling this), how about > factoring out the existing semaphore implementations to use a common > lib/semaphore.c, much like lib/rwsem.c? The iosems can be used as a > basis for the implementation, but we can avoid having to do a giant > s/semaphore/iosem/g over the kernel tree.
Note that iosem is also a total misowner, it's not a counting semaphore but a sleeping mutex with some special features.
Now if someone wants my two cent on how to resolve the two gazillion different implementations mess:
- switch all current semaphore users that don't need counting semaphores over to use a mutex_t type. For now it can map to struct semaphore. - rip out all existing complicated struct semaphore implementations and replace it with a portable C implementation. There's not a lot of users anyway. Add a mutex_t implementation that allows sensible assembly hooks for architectures instead of reimplementing all of it - add more features to mutex_t where nessecary
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