linux/drivers/s390
Steffen Maier 70369f8e15 zfcp: fix ELS/GS request&response length for hardware data router
In the hardware data router case, introduced with kernel 3.2
commit 86a9668a8d ("[SCSI] zfcp: support for hardware data router")
the ELS/GS request&response length needs to be initialized
as in the chained SBAL case.

Otherwise, the FCP channel rejects ELS requests with
FSF_REQUEST_SIZE_TOO_LARGE.

Such ELS requests can be issued by user space through BSG / HBA API,
or zfcp itself uses ADISC ELS for remote port link test on RSCN.
The latter can cause a short path outage due to
unnecessary remote target port recovery because the always
failing ADISC cannot detect extremely short path interruptions
beyond the local FCP channel.

Below example is decoded with zfcpdbf from s390-tools:

Timestamp      : ...
Area           : SAN
Subarea        : 00
Level          : 1
Exception      : -
CPU id         : ..
Caller         : zfcp_dbf_san_req+0408
Record id      : 1
Tag            : fssels1
Request id     : 0x<reqid>
Destination ID : 0x00<target d_id>
Payload info   : 52000000 00000000 <our wwpn       >           [ADISC]
                 <our wwnn       > 00<s_id> 00000000
                 00000000 00000000 00000000 00000000

Timestamp      : ...
Area           : HBA
Subarea        : 00
Level          : 1
Exception      : -
CPU id         : ..
Caller         : zfcp_dbf_hba_fsf_res+0740
Record id      : 1
Tag            : fs_ferr
Request id     : 0x<reqid>
Request status : 0x00000010
FSF cmnd       : 0x0000000b               [FSF_QTCB_SEND_ELS]
FSF sequence no: 0x...
FSF issued     : ...
FSF stat       : 0x00000061		  [FSF_REQUEST_SIZE_TOO_LARGE]
FSF stat qual  : 00000000 00000000 00000000 00000000
Prot stat      : 0x00000100
Prot stat qual : 00000000 00000000 00000000 00000000

Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Fixes: 86a9668a8d ("[SCSI] zfcp: support for hardware data router")
Cc: <stable@vger.kernel.org> # 3.2+
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-08-12 16:17:12 -04:00
..
block libnvdimm for 4.8 2016-07-28 17:38:16 -07:00
char - ARM: GICv3 ITS emulation and various fixes. Removal of the old 2016-08-02 16:11:27 -04:00
cio s390/cio: fix premature wakeup during chp configure 2016-07-31 05:27:57 -04:00
crypto s390/zcrypt: fix possible memory leak in ap_module_init() 2016-07-31 06:10:41 -04:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-07-06 10:35:22 -07:00
scsi zfcp: fix ELS/GS request&response length for hardware data router 2016-08-12 16:17:12 -04:00
virtio virtio/s390: size of SET_IND payload 2016-03-02 18:08:59 +02:00
Makefile virtio/s390: rename drivers/s390/kvm -> drivers/s390/virtio 2015-07-07 14:27:06 +03:00