From 801e0ced1891a2b8cad1a435c45234a719b3b6bf Mon Sep 17 00:00:00 2001 From: Christof Schmitt Date: Tue, 8 May 2007 11:15:48 +0200 Subject: [SCSI] zfcp: Locking for req_no and req_seq_no There is a possible race condition while generating the unique request ids and sequence numbers. Both might be read at the same time and have the same value. Fix this by serializing the access through the queue lock of the adapter: First call zfcp_fsf_req_sbal_get that acquires the lock, then read and increment the unique ids. Signed-off-by: Christof Schmitt Signed-off-by: Swen Schillig Signed-off-by: James Bottomley --- drivers/s390/scsi/zfcp_fsf.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) (limited to 'drivers/s390') diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c index f120b16c77d..07094c3dc34 100644 --- a/drivers/s390/scsi/zfcp_fsf.c +++ b/drivers/s390/scsi/zfcp_fsf.c @@ -4645,23 +4645,22 @@ zfcp_fsf_req_create(struct zfcp_adapter *adapter, u32 fsf_cmd, int req_flags, fsf_req->adapter = adapter; fsf_req->fsf_command = fsf_cmd; INIT_LIST_HEAD(&fsf_req->list); - - /* this is serialized (we are holding req_queue-lock of adapter */ - if (adapter->req_no == 0) - adapter->req_no++; - fsf_req->req_id = adapter->req_no++; - init_timer(&fsf_req->timer); - zfcp_fsf_req_qtcb_init(fsf_req); /* initialize waitqueue which may be used to wait on this request completion */ init_waitqueue_head(&fsf_req->completion_wq); ret = zfcp_fsf_req_sbal_get(adapter, req_flags, lock_flags); - if(ret < 0) { + if (ret < 0) goto failed_sbals; - } + + /* this is serialized (we are holding req_queue-lock of adapter) */ + if (adapter->req_no == 0) + adapter->req_no++; + fsf_req->req_id = adapter->req_no++; + + zfcp_fsf_req_qtcb_init(fsf_req); /* * We hold queue_lock here. Check if QDIOUP is set and let request fail -- cgit v1.2.3