[PATCH 2/7] zsmalloc: prevent mappping in interrupt context

[Minchan Kim <minchan@kernel.org>]

From: Seth Jennings <sjenning@linux.vnet.ibm.com>

Because we use per-cpu mapping areas shared among the
pools/users, we can't allow mapping in interrupt context
because it can corrupt another users mappings.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 drivers/staging/zsmalloc/zsmalloc-main.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c
index 3c83c65..b86133f 100644
--- a/drivers/staging/zsmalloc/zsmalloc-main.c
+++ b/drivers/staging/zsmalloc/zsmalloc-main.c
@@ -75,6 +75,7 @@
 #include <linux/cpumask.h>
 #include <linux/cpu.h>
 #include <linux/vmalloc.h>
+#include <linux/hardirq.h>
 
 #include "zsmalloc.h"
 #include "zsmalloc_int.h"
@@ -761,6 +762,13 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
 
 	BUG_ON(!handle);
 
+	/*
+	 * Because we use per-cpu mapping areas shared among the
+	 * pools/users, we can't allow mapping in interrupt context
+	 * because it can corrupt another users mappings.
+	 */
+	BUG_ON(in_interrupt());
+
 	obj_handle_to_location(handle, &page, &obj_idx);
 	get_zspage_mapping(get_first_page(page), &class_idx, &fg);
 	class = &pool->size_class[class_idx];
-- 
1.7.9.5

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