linux-stable/drivers/s390/scsi
Steffen Maier f9eca02276 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 <maier@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-11-15 15:01:17 -05:00
..
Makefile s390: add a few more SPDX identifiers 2017-12-05 07:51:09 +01:00
zfcp_aux.c scsi: zfcp: move SG table helper from aux to fc and make them static 2018-11-15 15:01:17 -05:00
zfcp_ccw.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
zfcp_dbf.c scsi: zfcp: drop duplicate fsf_command from zfcp_fsf_req which is also in QTCB header 2018-11-15 15:01:17 -05:00
zfcp_dbf.h scsi: zfcp: drop duplicate fsf_command from zfcp_fsf_req which is also in QTCB header 2018-11-15 15:01:17 -05:00
zfcp_def.h scsi: zfcp: drop duplicate fsf_command from zfcp_fsf_req which is also in QTCB header 2018-11-15 15:01:17 -05:00
zfcp_erp.c scsi: zfcp: support SCSI_ADAPTER_RESET via scsi_host sysfs attribute host_reset 2018-05-18 11:28:15 -04:00
zfcp_ext.h SCSI misc on 20180610 2018-06-10 13:01:12 -07:00
zfcp_fc.c scsi: zfcp: move SG table helper from aux to fc and make them static 2018-11-15 15:01:17 -05:00
zfcp_fc.h scsi: zfcp: split FCP_CMND IU setup between SCSI I/O and TMF again 2018-05-18 11:22:11 -04:00
zfcp_fsf.c scsi: zfcp: drop duplicate fsf_command from zfcp_fsf_req which is also in QTCB header 2018-11-15 15:01:17 -05:00
zfcp_fsf.h scsi: zfcp: enhance comments on fc_link_speed and supported_speed 2018-05-18 11:28:17 -04:00
zfcp_qdio.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
zfcp_qdio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
zfcp_reqlist.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
zfcp_scsi.c scsi: zfcp: drop duplicate fsf_command from zfcp_fsf_req which is also in QTCB header 2018-11-15 15:01:17 -05:00
zfcp_sysfs.c scsi: zfcp: support SCSI_ADAPTER_RESET via scsi_host sysfs attribute host_reset 2018-05-18 11:28:15 -04:00
zfcp_unit.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00