drivers/message: move dereference after NULL test

PATCH In review [email protected] 1 participant 1 message May 24, 2010 SCSI

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2010-05-24 19:22 UTC #0 lore raw

PATCH 9/26 drivers/message: move dereference after NULL test

From: Julia Lawall <[email protected]>

If the NULL test on dev->i2o_dev or i2o_dev is needed, then the dereference should be after the NULL test.

A simplified version of the semantic match that detects this problem is as follows (http://coccinelle.lip6.fr/):

// <smpl>
@match exists@
expression x, E;
identifier fld;
@@

* x->fld
... when != \(x = E\|&x\)
* x == NULL
// </smpl>

Signed-off-by Julia Lawall <[email protected]>

Cc James Bottomley <[email protected]>

Cc Kashyap Desai <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

---

 drivers/message/i2o/i2o_block.c |    3 ++-
 drivers/message/i2o/i2o_scsi.c  |    3 +--
 2 files changed, 3 insertions(+), 3 deletions(-)

drivers/message/i2o/i2o_block.c renamed from drivers/message/i2o/i2o_block.c~drivers-message-move-dereference-after-null-test +2 -1

diff -puN drivers/message/i2o/i2o_block.c~drivers-message-move-dereference-after-null-test drivers/message/i2o/i2o_block.c
@@ -712,7 +712,7 @@ static int i2o_block_transfer(struct req
 {
 	struct i2o_block_device *dev = req->rq_disk->private_data;
 	struct i2o_controller *c;
-	u32 tid = dev->i2o_dev->lct_data.tid;
+	u32 tid;
 	struct i2o_message *msg;
 	u32 *mptr;
 	struct i2o_block_request *ireq = req->special;

@@ -728,6 +728,7 @@ static int i2o_block_transfer(struct req
 		goto exit;
 	}
 
+	tid = dev->i2o_dev->lct_data.tid;
 	c = dev->i2o_dev->iop;
 
 	msg = i2o_msg_get(c);

drivers/message/i2o/i2o_scsi.c renamed from drivers/message/i2o/i2o_scsi.c~drivers-message-move-dereference-after-null-test +1 -2

diff -puN drivers/message/i2o/i2o_scsi.c~drivers-message-move-dereference-after-null-test drivers/message/i2o/i2o_scsi.c
@@ -528,7 +528,6 @@ static int i2o_scsi_queuecommand(struct 
 	 *      Do the incoming paperwork
 	 */
 	i2o_dev = SCpnt->device->hostdata;
-	c = i2o_dev->iop;
 
 	SCpnt->scsi_done = done;

@@ -538,7 +537,7 @@ static int i2o_scsi_queuecommand(struct 
 		done(SCpnt);
 		goto exit;
 	}
-
+	c = i2o_dev->iop;
 	tid = i2o_dev->lct_data.tid;
 
 	osm_debug("qcmd: Tid = %03x\n", tid);