Re: 2.6.10-rc1-mm5

[Andrew Morton <akpm@osdl.org>]

"Martin J. Bligh" <mbligh@aracnet.com> wrote:
>
>  That works. But something broke shmem:
> 
>  ipc/shm.c:171: error: `shmem_set_policy' undeclared here (not in a function)
>  ipc/shm.c:171: error: initializer element is not constant
>  ipc/shm.c:171: error: (near initialization for `shm_vm_ops.set_policy')
>  ipc/shm.c:172: error: `shmem_get_policy' undeclared here (not in a function)
>  ipc/shm.c:172: error: initializer element is not constant
>  ipc/shm.c:172: error: (near initialization for `shm_vm_ops.get_policy')

OK, I tracked this down to another secret dhowells diff.

 config SHMEM
-       default y
-       bool "Use full shmem filesystem" if EMBEDDED && MMU
+       bool "Use full shmem filesystem"
+       default y if EMBEDDED
+       depends on MMU

This change permits CONFIG_SHMEM=n on !CONFIG_MMU, even if !EMBEDDED.  Or
something.  I'm not really sure what it's trying to do, nor am I clear on
what semantics we wanted to have for CONFIG_SHMEM on CONFIG_MMU machines.

I think the semantics we want are: you always get shmem, unless you
selected EMBEDDED.  So perhaps we want:

config SHMEM
	bool "Use full shmem filesystem" if EMBEDDED
	depends on MMU
	default y if MMU