[PATCH V2 1/4] vmalloc: introduce vfree_atomic()

[Lai Jiangshan <laijs@cn.fujitsu.com>]

fdtable and sysipc use vfree() in RCU callback. this patch
introduce vfree_atomic() for them.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 307b885..195379a 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -60,6 +60,7 @@ extern void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot);
 extern void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask,
 				pgprot_t prot);
 extern void vfree(const void *addr);
+extern void vfree_atomic(void *addr);
 
 extern void *vmap(struct page **pages, unsigned int count,
 			unsigned long flags, pgprot_t prot);
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index ba6b0f5..39c164e 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -23,6 +23,7 @@
 #include <linux/rbtree.h>
 #include <linux/radix-tree.h>
 #include <linux/rcupdate.h>
+#include <linux/workqueue.h>
 
 #include <asm/atomic.h>
 #include <asm/uaccess.h>
@@ -1177,6 +1178,21 @@ void vfree(const void *addr)
 }
 EXPORT_SYMBOL(vfree);
 
+static void vfree_defer(struct work_struct *work)
+{
+	vfree(work);
+}
+
+void vfree_atomic(void *ptr)
+{
+	if (ptr) {
+		struct work_struct *work = ptr;
+		INIT_WORK(work, vfree_defer);
+		schedule_work(work);
+	}
+}
+EXPORT_SYMBOL_GPL(vfree_atomic);
+
 /**
  *	vunmap  -  release virtual mapping obtained by vmap()
  *	@addr:		memory base address