Date: Mon, 16 Aug 2010 21:58:03 +0200 (CEST) From: Stefan Richter Subject: firewire: sbp2: fix memory leak in sbp2_cancel_orbs or at send error When an ORB was canceled (Command ORB i.e. SCSI request timed out, or Management ORB timed out), or there was a send error in the initial transaction, we missed to drop one of the ORB's references and thus leaked memory. Background: In total, we hold 3 references to each Operation Request Block: - 1 during sbp2_scsi_queuecommand() or sbp2_send_management_orb() respectively, - 1 for the duration of the write transaction to the ORB_Pointer or Management_Agent register of the target, - 1 for as long as the ORB stays within the lu->orb_list, until the ORB is unlinked from the list and the orb->callback was executed. The latter one of these 3 references is finished - normally by sbp2_status_write() when the target wrote status for a pending ORB, - or by sbp2_cancel_orbs() in case of an ORB time-out, - or by complete_transaction() in case of a send error. Of them, the latter two lacked the kref_put. Add the missing kref_put()s. Add comments to the gets and puts of references for transaction callbacks and ORB callbacks so that it is easier to see what is supposed to happen. Signed-off-by: Stefan Richter --- drivers/firewire/sbp2.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) Index: b/drivers/firewire/sbp2.c =================================================================== --- a/drivers/firewire/sbp2.c +++ b/drivers/firewire/sbp2.c @@ -450,7 +450,7 @@ static void sbp2_status_write(struct fw_ if (&orb->link != &lu->orb_list) { orb->callback(orb, &status); - kref_put(&orb->kref, free_orb); + kref_put(&orb->kref, free_orb); /* orb callback reference */ } else { fw_error("status write for unknown orb\n"); } @@ -480,12 +480,14 @@ static void complete_transaction(struct if (orb->rcode != RCODE_COMPLETE) { list_del(&orb->link); spin_unlock_irqrestore(&card->lock, flags); + orb->callback(orb, NULL); + kref_put(&orb->kref, free_orb); /* orb callback reference */ } else { spin_unlock_irqrestore(&card->lock, flags); } - kref_put(&orb->kref, free_orb); + kref_put(&orb->kref, free_orb); /* transaction callback reference */ } static void sbp2_send_orb(struct sbp2_orb *orb, struct sbp2_logical_unit *lu, @@ -501,9 +503,8 @@ static void sbp2_send_orb(struct sbp2_or list_add_tail(&orb->link, &lu->orb_list); spin_unlock_irqrestore(&device->card->lock, flags); - /* Take a ref for the orb list and for the transaction callback. */ - kref_get(&orb->kref); - kref_get(&orb->kref); + kref_get(&orb->kref); /* transaction callback reference */ + kref_get(&orb->kref); /* orb callback reference */ fw_send_request(device->card, &orb->t, TCODE_WRITE_BLOCK_REQUEST, node_id, generation, device->max_speed, offset, @@ -530,6 +531,7 @@ static int sbp2_cancel_orbs(struct sbp2_ orb->rcode = RCODE_CANCELLED; orb->callback(orb, NULL); + kref_put(&orb->kref, free_orb); /* orb callback reference */ } return retval;