[PATCH] kevent_user: use struct kevent_mring for the page ring

[Christoph Hellwig <hch@infradead.org>]

Currently struct kevent_user.print is an array of unsigned long, but it's used
as an array of pointers to struct kevent_mring everyewhere in the code.

Switch it to use the real type and cast the return value from __get_free_page /
argument to free_page.


 include/linux/kevent.h      |    2 +-
 kernel/kevent/kevent_user.c |   31 +++++++++++--------------------
  2 files changed, 12 insertions(+), 21 deletions(-)

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/include/linux/kevent.h
===================================================================
--- linux-2.6.orig/include/linux/kevent.h	2006-08-22 12:10:24.000000000 +0200
+++ linux-2.6/include/linux/kevent.h	2006-08-22 13:30:48.000000000 +0200
@@ -105,7 +105,7 @@
 	
 	unsigned int		pages_in_use;
 	/* Array of pages forming mapped ring buffer */
-	unsigned long		*pring;
+	struct kevent_mring	**pring;
 
 #ifdef CONFIG_KEVENT_USER_STAT
 	unsigned long		im_num;
Index: linux-2.6/kernel/kevent/kevent_user.c
===================================================================
--- linux-2.6.orig/kernel/kevent/kevent_user.c	2006-08-22 13:28:06.000000000 +0200
+++ linux-2.6/kernel/kevent/kevent_user.c	2006-08-22 13:43:46.000000000 +0200
@@ -69,30 +69,21 @@
 
 static inline void kevent_user_ring_set(struct kevent_user *u, unsigned int num)
 {
-	struct kevent_mring *ring;
-
-	ring = (struct kevent_mring *)u->pring[0];
-	ring->index = num;
+	u->pring[0]->index = num;
 }
 
 static inline void kevent_user_ring_inc(struct kevent_user *u)
 {
-	struct kevent_mring *ring;
-
-	ring = (struct kevent_mring *)u->pring[0];
-	ring->index++;
+	u->pring[0]->index++;
 }
 
 static int kevent_user_ring_grow(struct kevent_user *u)
 {
-	struct kevent_mring *ring;
 	unsigned int idx;
 
-	ring = (struct kevent_mring *)u->pring[0];
-
-	idx = (ring->index + 1) / KEVENTS_ON_PAGE;
+	idx = (u->pring[0]->index + 1) / KEVENTS_ON_PAGE;
 	if (idx >= u->pages_in_use) {
-		u->pring[idx] = __get_free_page(GFP_KERNEL);
+		u->pring[idx] = (void *)__get_free_page(GFP_KERNEL);
 		if (!u->pring[idx])
 			return -ENOMEM;
 		u->pages_in_use++;
@@ -108,12 +99,12 @@
 	unsigned int pidx, off;
 	struct kevent_mring *ring, *copy_ring;
 
-	ring = (struct kevent_mring *)k->user->pring[0];
-	
+	ring = k->user->pring[0];
+
 	pidx = ring->index/KEVENTS_ON_PAGE;
 	off = ring->index%KEVENTS_ON_PAGE;
 
-	copy_ring = (struct kevent_mring *)k->user->pring[pidx];
+	copy_ring = k->user->pring[pidx];
 
 	copy_ring->event[off].id.raw[0] = k->event.id.raw[0];
 	copy_ring->event[off].id.raw[1] = k->event.id.raw[1];
@@ -134,11 +125,11 @@
 
 	pnum = ALIGN(KEVENT_MAX_EVENTS*sizeof(struct mukevent) + sizeof(unsigned int), PAGE_SIZE)/PAGE_SIZE;
 
-	u->pring = kmalloc(pnum * sizeof(unsigned long), GFP_KERNEL);
+	u->pring = kmalloc(pnum * sizeof(struct kevent_mring *), GFP_KERNEL);
 	if (!u->pring)
 		return -ENOMEM;
 
-	u->pring[0] = __get_free_page(GFP_KERNEL);
+	u->pring[0] = (struct kevent_mring *)__get_free_page(GFP_KERNEL);
 	if (!u->pring[0])
 		goto err_out_free;
 
@@ -158,7 +149,7 @@
 	int i;
 	
 	for (i = 0; i < u->pages_in_use; ++i)
-		free_page(u->pring[i]);
+		free_page((unsigned long)u->pring[i]);
 
 	kfree(u->pring);
 }
@@ -254,7 +245,7 @@
 	vma->vm_flags |= VM_RESERVED;
 	vma->vm_file = file;
 
-	if (vm_insert_page(vma, start, virt_to_page((void *)u->pring[0])))
+	if (vm_insert_page(vma, start, virt_to_page(u->pring[0])))
 		return -EFAULT;
 
 	return 0;