From f9eca022760079c0556cb311e3aa9091a3921a31 Mon Sep 17 00:00:00 2001 From: Steffen Maier Date: Thu, 8 Nov 2018 15:44:45 +0100 Subject: scsi: zfcp: drop duplicate fsf_command from zfcp_fsf_req which is also in QTCB header Status read buffers (SRBs, unsolicited notifications) never use a QTCB [zfcp_fsf_req_create()]. zfcp_fsf_req_send() already uses this to distinguish SRBs from other FSF request types. We can re-use this method in zfcp_fsf_req_complete(). Introduce a helper function to make the check for req->qtcb less magic. SRBs always are FSF_QTCB_UNSOLICITED_STATUS, so we can hard-code this for the two trace functions dealing with SRBs. All other FSF request types have a QTCB and we can get the fsf_command from there. zfcp_dbf_hba_fsf_response() and thus zfcp_dbf_hba_fsf_res() are only called for non-SRB requests so it's safe to dereference the QTCB [zfcp_fsf_req_complete() returns early on SRB, else calls zfcp_fsf_protstatus_eval() which calls zfcp_dbf_hba_fsf_response()]. In zfcp_scsi_forget_cmnd() we guard the QTCB dereference with a preceding NULL check and rely on boolean shortcut evaluation. As a side effect, this causes an alignment hole which we can close in a later patch after having cleaned up all fields of struct zfcp_fsf_req. Before: $ pahole -C zfcp_fsf_req drivers/s390/scsi/zfcp.ko ... u32 status; /* 136 4 */ u32 fsf_command; /* 140 4 */ struct fsf_qtcb * qtcb; /* 144 8 */ ... After: $ pahole -C zfcp_fsf_req drivers/s390/scsi/zfcp.ko ... u32 status; /* 136 4 */ /* XXX 4 bytes hole, try to pack */ struct fsf_qtcb * qtcb; /* 144 8 */ ... Signed-off-by: Steffen Maier Reviewed-by: Benjamin Block Signed-off-by: Martin K. Petersen --- drivers/s390/scsi/zfcp_dbf.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/s390/scsi/zfcp_dbf.h') diff --git a/drivers/s390/scsi/zfcp_dbf.h b/drivers/s390/scsi/zfcp_dbf.h index d116c07ed77a..b4438713d1cc 100644 --- a/drivers/s390/scsi/zfcp_dbf.h +++ b/drivers/s390/scsi/zfcp_dbf.h @@ -339,8 +339,8 @@ void zfcp_dbf_hba_fsf_response(struct zfcp_fsf_req *req) zfcp_dbf_hba_fsf_resp_suppress(req) ? 5 : 1, req); - } else if ((req->fsf_command == FSF_QTCB_OPEN_PORT_WITH_DID) || - (req->fsf_command == FSF_QTCB_OPEN_LUN)) { + } else if ((qtcb->header.fsf_command == FSF_QTCB_OPEN_PORT_WITH_DID) || + (qtcb->header.fsf_command == FSF_QTCB_OPEN_LUN)) { zfcp_dbf_hba_fsf_resp("fs_open", 4, req); } else if (qtcb->header.log_length) { -- cgit v1.2.3