patches.kzm9g/0047-mm-add-vm_area_add_early.patch

From faf323f0f552c0523cce81cf62b87a87b3eb0020 Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nicolas.pitre@linaro.org>
Date: Thu, 25 Aug 2011 00:24:21 -0400
Subject: mm: add vm_area_add_early()

The existing vm_area_register_early() allows for early vmalloc space
allocation.  However upcoming cleanups in the ARM architecture require
that some fixed locations in the vmalloc area be reserved also very early.

The name "vm_area_register_early" would have been a good name for the
reservation part without the allocation.  Since it is already in use with
different semantics, let's create vm_area_add_early() instead.

Both vm_area_register_early() and vm_area_add_early() can be used together
meaning that the former is now implemented using the later where it is
ensured that no conflicting areas are added, but no attempt is made to
make the allocation scheme in vm_area_register_early() more sophisticated.
After all, you must know what you're doing when using those functions.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
(cherry picked from commit be9b7335e70696bee731c152429b1737e42fe163)

Signed-off-by: Simon Horman <horms@verge.net.au>
---
 include/linux/vmalloc.h |    1 +
 mm/vmalloc.c            |   29 +++++++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 687fb11..4115d6a 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -131,6 +131,7 @@ extern long vwrite(char *buf, char *addr, unsigned long count);
  */
 extern rwlock_t vmlist_lock;
 extern struct vm_struct *vmlist;
+extern __init void vm_area_add_early(struct vm_struct *vm);
 extern __init void vm_area_register_early(struct vm_struct *vm, size_t align);
 
 #ifdef CONFIG_SMP
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 43b44db..fb0d354 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1132,6 +1132,32 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
 EXPORT_SYMBOL(vm_map_ram);
 
 /**
+ * vm_area_add_early - add vmap area early during boot
+ * @vm: vm_struct to add
+ *
+ * This function is used to add fixed kernel vm area to vmlist before
+ * vmalloc_init() is called.  @vm->addr, @vm->size, and @vm->flags
+ * should contain proper values and the other fields should be zero.
+ *
+ * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
+ */
+void __init vm_area_add_early(struct vm_struct *vm)
+{
+	struct vm_struct *tmp, **p;
+
+	BUG_ON(vmap_initialized);
+	for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
+		if (tmp->addr >= vm->addr) {
+			BUG_ON(tmp->addr < vm->addr + vm->size);
+			break;
+		} else
+			BUG_ON(tmp->addr + tmp->size > vm->addr);
+	}
+	vm->next = *p;
+	*p = vm;
+}
+
+/**
  * vm_area_register_early - register vmap area early during boot
  * @vm: vm_struct to register
  * @align: requested alignment
@@ -1153,8 +1179,7 @@ void __init vm_area_register_early(struct vm_struct *vm, size_t align)
 
 	vm->addr = (void *)addr;
 
-	vm->next = vmlist;
-	vmlist = vm;
+	vm_area_add_early(vm);
 }
 
 void __init vmalloc_init(void)
-- 
1.7.10.1.362.g242cab3