From: Vasiliy Ulyanov <v.ulyanov@samsung.com>
Date: Wed, 4 Jun 2014 08:16:33 +0000 (+0400)
Subject: [IMPROVE] Add orig_ret_addr restore condition
X-Git-Tag: submit/tizen/20151123.110932~102
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=refs%2Fchanges%2F54%2F33654%2F2;p=kernel%2Fswap-modules.git

[IMPROVE] Add orig_ret_addr restore condition

In some situations there is no need to restore the original return
address because all the related actions are performed inside the handler
(e.g. preload implementation)

Change-Id: I4d917cdd7201039002d56e7780a7c5701327c16d
Signed-off-by: Vasiliy Ulyanov <v.ulyanov@samsung.com>
---

diff --git a/uprobe/swap_uprobes.c b/uprobe/swap_uprobes.c
index 6f9237f..08d33f2 100644
--- a/uprobe/swap_uprobes.c
+++ b/uprobe/swap_uprobes.c
@@ -740,7 +740,10 @@ int trampoline_uprobe_handler(struct kprobe *p, struct pt_regs *regs)
 	}
 
 	spin_unlock_irqrestore(&uretprobe_lock, flags);
-	arch_set_orig_ret_addr(orig_ret_addr, regs);
+	/* orig_ret_addr is NULL when there is no need to restore anything
+	 * (all the magic is performed inside handler) */
+	if (likely(orig_ret_addr))
+		arch_set_orig_ret_addr(orig_ret_addr, regs);
 
 	return 1;
 }