[patch] aio: make aio_ring_info->nr_pages an unsigned int

["Chen, Kenneth W" <kenneth.w.chen@intel.com>]

The number of io_event in AIO event queue allowed currently is no more
than 2^32-1, because the syscall defines:

	asmlinkage long sys_io_setup(unsigned nr_events, aio_context_t __user *ctxp)

We internally allocate a ring buffer for nr_events and keeps tracks of
page descriptors for each of these ring buffer pages.  Since page size
is significantly larger than AIO event size (4096 versus 32), I don't
think it is ever possible to overflow nr_pages in 32-bit quantity.

This patch changes nr_pages to unsigned int. on 64-bit arch, changing
it to unsigned int also allows better packing of aio_ring_info structure.


Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>

--- ./include/linux/aio.h.orig	2006-12-24 22:31:55.000000000 -0800
+++ ./include/linux/aio.h	2006-12-24 22:41:28.000000000 -0800
@@ -165,7 +165,7 @@ struct aio_ring_info {
 
 	struct page		**ring_pages;
 	spinlock_t		ring_lock;
-	long			nr_pages;
+	unsigned		nr_pages;
 
 	unsigned		nr, tail;