linux-kernel - [PATCH 30/44] kdbus: Cleanup kdbus_meta_proc

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Date:	Thu,  8 Oct 2015 14:31:59 +0300
From:	Sergei Zviagintsev <sergei@...v.net>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Daniel Mack <daniel@...que.org>,
	David Herrmann <dh.herrmann@...glemail.com>,
	Djalal Harouni <tixxdz@...ndz.org>
Cc:	linux-kernel@...r.kernel.org, Sergei Zviagintsev <sergei@...v.net>
Subject: [PATCH 30/44] kdbus: Cleanup kdbus_meta_proc_mask()

 - Simplify if-statements

   'proc < KDBUS_META_PROC_NORMAL' test only makes sense when we call
   kdbus_proc_permission(). Include it into 'prv_pid != req_pid' branch,
   remove redundant assignment of `proc' var and reduce its scope.

 - Drop redundant binary operation

   In 'proc < KDBUS_META_PROC_NORMAL' case we firstly do
   'wanted &= ~flags' and then 'wanted & flags' in the return statement,
   which is the same as 'wanted & 0'. Return 0 instead.

 - Cosmetic cleanup of the return statement.

Signed-off-by: Sergei Zviagintsev <sergei@...v.net>
---
 ipc/kdbus/metadata.c | 32 ++++++++++++--------------------
 1 file changed, 12 insertions(+), 20 deletions(-)

diff --git a/ipc/kdbus/metadata.c b/ipc/kdbus/metadata.c
index 61215a078359..b8d094d9fb56 100644
--- a/ipc/kdbus/metadata.c
+++ b/ipc/kdbus/metadata.c
@@ -1224,7 +1224,6 @@ static u64 kdbus_meta_proc_mask(struct pid *prv_pid,
 				u64 wanted)
 {
 	struct pid_namespace *prv_ns, *req_ns;
-	unsigned int proc;
 
 	prv_ns = ns_of_pid(prv_pid);
 	req_ns = ns_of_pid(req_pid);
@@ -1243,30 +1242,23 @@ static u64 kdbus_meta_proc_mask(struct pid *prv_pid,
 	 * provider and requestor are the same. If not, we perform rather
 	 * expensive /proc permission checks.
 	 */
-	if (prv_pid == req_pid)
-		proc = KDBUS_META_PROC_NORMAL;
-	else
-		proc = kdbus_proc_permission(req_ns, req_cred, prv_pid);
-
-	/* you need /proc access to read standard process attributes */
-	if (proc < KDBUS_META_PROC_NORMAL)
-		wanted &= ~(KDBUS_ATTACH_TID_COMM |
-			    KDBUS_ATTACH_PID_COMM |
-			    KDBUS_ATTACH_SECLABEL |
-			    KDBUS_ATTACH_CMDLINE |
-			    KDBUS_ATTACH_CGROUP |
-			    KDBUS_ATTACH_AUDIT |
-			    KDBUS_ATTACH_CAPS |
-			    KDBUS_ATTACH_EXE);
+	if (prv_pid != req_pid) {
+		unsigned int proc = kdbus_proc_permission(req_ns, req_cred,
+							  prv_pid);
+
+		/* you need /proc access to read standard process attributes */
+		if (proc < KDBUS_META_PROC_NORMAL)
+			return 0;
+	}
 
 	/* clear all non-/proc flags */
 	return wanted & (KDBUS_ATTACH_TID_COMM |
 			 KDBUS_ATTACH_PID_COMM |
 			 KDBUS_ATTACH_SECLABEL |
-			 KDBUS_ATTACH_CMDLINE |
-			 KDBUS_ATTACH_CGROUP |
-			 KDBUS_ATTACH_AUDIT |
-			 KDBUS_ATTACH_CAPS |
+			 KDBUS_ATTACH_CMDLINE  |
+			 KDBUS_ATTACH_CGROUP   |
+			 KDBUS_ATTACH_AUDIT    |
+			 KDBUS_ATTACH_CAPS     |
 			 KDBUS_ATTACH_EXE);
 }
 
-- 
1.8.3.1

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