# HG changeset patch
# User yamahata@xxxxxxxxxxxxx
# Date 1185763112 -32400
# Node ID 9536c4366949dcd4a163d2129e18e319bf6d1ac2
# Parent  b0bf9ba32bfe341af07da97d57572659c920fd30
remove xencomm page size limit.
Currently xencomm has page size limit so that a domain with many memory
(e.g. 100GB~) can't be created.

Now that xencomm of xen side accepts struct xencomm_desc whose address array
crosses page boundary. Thus it isn't necessary to allocate single page
not to cross page boundary. We can allocate exact sized memory.
Note that struct xencomm_desc can't cross page boundary.
For that sake, this implementation depends on the slab allocator
implementation and sizeof(struct xencomm_desc) = 8 = sizeof (void*).
This is true on ia64, but may not be true on 32bit environment.
PATCHNAME: remove_xencomm_page_size_limit

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>

diff -r b0bf9ba32bfe -r 9536c4366949 arch/ia64/xen/xencomm.c
--- a/arch/ia64/xen/xencomm.c	Fri Jul 27 08:15:50 2007 -0600
+++ b/arch/ia64/xen/xencomm.c	Mon Jul 30 11:38:32 2007 +0900
@@ -158,16 +158,25 @@ xencomm_init_desc(struct xencomm_desc *d
 }
 
 static struct xencomm_desc *
-xencomm_alloc(gfp_t gfp_mask)
-{
-	struct xencomm_desc *desc;
-
-	desc = (struct xencomm_desc *)__get_free_page(gfp_mask);
+xencomm_alloc(gfp_t gfp_mask, void *buffer, unsigned long bytes)
+{
+	struct xencomm_desc *desc;
+	unsigned long buffer_ulong = (unsigned long)buffer;
+	unsigned long start = buffer_ulong & PAGE_MASK;
+	unsigned long end = (buffer_ulong + bytes) | ~PAGE_MASK;
+	unsigned long nr_addrs = (end - start + 1) >> PAGE_SHIFT;
+	unsigned long size = sizeof(*desc) +
+		sizeof(desc->address[0]) * nr_addrs;
+
+	/*
+	 * NOTE: kmalloc returns at least 64bit aligned value so that
+	 *       struct xencomm_desc doesn't cross page boundary.
+	 */
+	BUILD_BUG_ON(sizeof(*desc) > sizeof(void*));
+	desc = kmalloc(size, gfp_mask);
 	if (desc == NULL)
 		panic("%s: page allocation failed\n", __func__);
-
-	desc->nr_addrs = (PAGE_SIZE - sizeof(struct xencomm_desc)) /
-	                 sizeof(*desc->address);
+	desc->nr_addrs = nr_addrs;
 
 	return desc;
 }
@@ -176,7 +185,7 @@ xencomm_free(struct xencomm_handle *desc
 xencomm_free(struct xencomm_handle *desc)
 {
 	if (desc)
-		free_page((unsigned long)__va(desc));
+		kfree(__va(desc));
 }
 
 int
@@ -195,7 +204,7 @@ xencomm_create(void *buffer, unsigned lo
 		return 0;
 	}
 
-	desc = xencomm_alloc(gfp_mask);
+	desc = xencomm_alloc(gfp_mask, buffer, bytes);
 	if (!desc) {
 		printk("%s failure\n", "xencomm_alloc");
 		return -ENOMEM;