[POWERPC] spufs: Add infrastructure needed for gang scheduling

Add the concept of a gang to spufs as a new type of object.
So far, this has no impact whatsover on scheduling, but makes
it possible to add that later.

A new type of object in spufs is now a spu_gang. It is created
with the spu_create system call with the flags argument set
to SPU_CREATE_GANG (0x2). Inside of a spu_gang, it
is then possible to create spu_context objects, which until
now was only possible at the root of spufs.

There is a new member in struct spu_context pointing to
the spu_gang it belongs to, if any. The spu_gang maintains
a list of spu_context structures that are its children.
This information can then be used in the scheduler in the
future.

There is still a bug that needs to be resolved in this
basic infrastructure regarding the order in which objects
are removed. When the spu_gang file descriptor is closed
before the spu_context descriptors, we leak the dentry
and inode for the gang. Any ideas how to cleanly solve
this are appreciated.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/asm-powerpc/spu.h b/include/asm-powerpc/spu.h
index 87cc21e21946..83b6dae48efc 100644
--- a/include/asm-powerpc/spu.h
+++ b/include/asm-powerpc/spu.h
@@ -181,7 +181,10 @@ extern struct spufs_calls {
  * Flags for sys_spu_create.
  */
 #define SPU_CREATE_EVENTS_ENABLED       0x0001
-#define SPU_CREATE_FLAG_ALL             0x0001 /* mask of all valid flags */
+#define SPU_CREATE_GANG                 0x0002
+
+#define SPU_CREATE_FLAG_ALL             0x0003 /* mask of all valid flags */
+
 
 #ifdef CONFIG_SPU_FS_MODULE
 int register_spu_syscalls(struct spufs_calls *calls);