[patch] x86, pat: freeing invalid memtype messages

[Dan Carpenter <error27@gmail.com>]

Commit 20413f27163 "x86, pat: Fix memory leak in free_memtype" added an
error message in free_memtype() if rbt_memtype_erase() returns NULL.  
The problem is that if CONFIG_X86_PAT is enabled, we use a different
implimentation of rbt_memtype_erase() that always returns NULL.

I've modified rbt_memtype_erase() to return an ERR_PTR() on errors and 
made free_memtype() check for that instead.

Addresses:  https://bugzilla.kernel.org/show_bug.cgi?id=16205

Signed-off-by: Dan Carpenter <error27@gmail.com>

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index acc15b2..81b7735 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -359,10 +359,10 @@ int free_memtype(u64 start, u64 end)
 	entry = rbt_memtype_erase(start, end);
 	spin_unlock(&memtype_lock);
 
-	if (!entry) {
+	if (IS_ERR(entry)) {
 		printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
 			current->comm, current->pid, start, end);
-		return -EINVAL;
+		return PTR_ERR(entry);
 	}
 
 	kfree(entry);
diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
index f537087..90e5cbe 100644
--- a/arch/x86/mm/pat_rbtree.c
+++ b/arch/x86/mm/pat_rbtree.c
@@ -236,8 +236,10 @@ struct memtype *rbt_memtype_erase(u64 start, u64 end)
 	struct memtype *data;
 
 	data = memtype_rb_exact_match(&memtype_rbroot, start, end);
-	if (!data)
+	if (!data) {
+		data = ERR_PTR(-EINVAL);
 		goto out;
+	}
 
 	rb_erase(&data->rb, &memtype_rbroot);
 out: