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4da8c5f768
Case (1):
The only waiter on wka_port->completion_wq is zfcp_fc_wka_port_get()
trying to open a WKA port. As such it should only be woken up by WKA port
*open* responses, not by WKA port close responses.
Case (2):
A close WKA port response coming in just after having sent a new open WKA
port request and before blocking for the open response with wait_event()
in zfcp_fc_wka_port_get() erroneously renders the wait_event a NOP
because the close handler overwrites wka_port->status. Hence the
wait_event condition is erroneously true and it does not enter blocking
state.
With non-negligible probability, the following time space sequence happens
depending on timing without this fix:
user process ERP thread zfcp work queue tasklet system work queue
============ ========== =============== ======= =================
$ echo 1 > online
zfcp_ccw_set_online
zfcp_ccw_activate
zfcp_erp_adapter_reopen
msleep scan backoff zfcp_erp_strategy
| ...
| zfcp_erp_action_cleanup
| ...
| queue delayed scan_work
| queue ns_up_work
| ns_up_work:
| zfcp_fc_wka_port_get
| open wka request
| open response
| GSPN FC-GS
| RSPN FC-GS [NPIV-only]
| zfcp_fc_wka_port_put
| (--wka->refcount==0)
| sched delayed wka->work
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~~~Case (1)~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
zfcp_erp_wait
flush scan_work
| wka->work:
| wka->status=CLOSING
| close wka request
| scan_work:
| zfcp_fc_wka_port_get
| (wka->status==CLOSING)
| wka->status=OPENING
| open wka request
| wait_event
| | close response
| | wka->status=OFFLINE
| | wake_up /*WRONG*/
~~~Case (2)~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| wka->work:
| wka->status=CLOSING
| close wka request
zfcp_erp_wait
flush scan_work
| scan_work:
| zfcp_fc_wka_port_get
| (wka->status==CLOSING)
| wka->status=OPENING
| open wka request
| close response
| wka->status=OFFLINE
| wake_up /*WRONG&NOP*/
| wait_event /*NOP*/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| (wka->status!=ONLINE)
| return -EIO
| return early
open response
wka->status=ONLINE
wake_up /*NOP*/
So we erroneously end up with no automatic port scan. This is a big problem
when it happens during boot. The timing is influenced by v3.19 commit
18f87a67e6 ("zfcp: auto port scan resiliency").
Fix it by fully mutually excluding zfcp_fc_wka_port_get() and
zfcp_fc_wka_port_offline(). For that to work, we make the latter block
until we got the response for a close WKA port. In order not to penalize
the system workqueue, we move wka_port->work to our own adapter workqueue.
Note that before v2.6.30 commit 828bc1212a ("[SCSI] zfcp: Set WKA-port to
offline on adapter deactivation"), zfcp did block in
zfcp_fc_wka_port_offline() as well, but with a different condition.
While at it, make non-functional cleanups to improve code reading in
zfcp_fc_wka_port_get(). If we cannot send the WKA port open request, don't
rely on the subsequent wait_event condition to immediately let this case
pass without blocking. Also don't want to rely on the additional condition
handling the refcount to be skipped just to finally return with -EIO.
Link: https://lore.kernel.org/r/20220729162529.1620730-1-maier@linux.ibm.com
Fixes: 5ab944f97e ("[SCSI] zfcp: attach and release SAN nameserver port on demand")
Cc: <stable@vger.kernel.org> #v2.6.28+
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
318 lines
8.8 KiB
C
318 lines
8.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* zfcp device driver
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*
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* Fibre Channel related definitions and inline functions for the zfcp
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* device driver
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*
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* Copyright IBM Corp. 2009, 2017
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*/
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#ifndef ZFCP_FC_H
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#define ZFCP_FC_H
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#include <scsi/fc/fc_els.h>
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#include <scsi/fc/fc_fcp.h>
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#include <scsi/fc/fc_ns.h>
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#include <scsi/scsi_cmnd.h>
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#include <scsi/scsi_tcq.h>
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#include "zfcp_fsf.h"
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#define ZFCP_FC_CT_SIZE_PAGE (PAGE_SIZE - sizeof(struct fc_ct_hdr))
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#define ZFCP_FC_GPN_FT_ENT_PAGE (ZFCP_FC_CT_SIZE_PAGE \
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/ sizeof(struct fc_gpn_ft_resp))
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#define ZFCP_FC_GPN_FT_NUM_BUFS 4 /* memory pages */
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#define ZFCP_FC_GPN_FT_MAX_SIZE (ZFCP_FC_GPN_FT_NUM_BUFS * PAGE_SIZE \
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- sizeof(struct fc_ct_hdr))
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#define ZFCP_FC_GPN_FT_MAX_ENT (ZFCP_FC_GPN_FT_NUM_BUFS * \
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(ZFCP_FC_GPN_FT_ENT_PAGE + 1))
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#define ZFCP_FC_CTELS_TMO (2 * FC_DEF_R_A_TOV / 1000)
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/**
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* struct zfcp_fc_event - FC HBAAPI event for internal queueing from irq context
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* @code: Event code
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* @data: Event data
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* @list: list_head for zfcp_fc_events list
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*/
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struct zfcp_fc_event {
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enum fc_host_event_code code;
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u32 data;
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struct list_head list;
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};
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/**
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* struct zfcp_fc_events - Infrastructure for posting FC events from irq context
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* @list: List for queueing of events from irq context to workqueue
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* @list_lock: Lock for event list
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* @work: work_struct for forwarding events in workqueue
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*/
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struct zfcp_fc_events {
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struct list_head list;
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spinlock_t list_lock;
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struct work_struct work;
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};
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/**
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* struct zfcp_fc_gid_pn_req - container for ct header plus gid_pn request
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* @ct_hdr: FC GS common transport header
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* @gid_pn: GID_PN request
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*/
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struct zfcp_fc_gid_pn_req {
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struct fc_ct_hdr ct_hdr;
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struct fc_ns_gid_pn gid_pn;
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} __packed;
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/**
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* struct zfcp_fc_gid_pn_rsp - container for ct header plus gid_pn response
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* @ct_hdr: FC GS common transport header
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* @gid_pn: GID_PN response
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*/
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struct zfcp_fc_gid_pn_rsp {
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struct fc_ct_hdr ct_hdr;
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struct fc_gid_pn_resp gid_pn;
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} __packed;
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/**
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* struct zfcp_fc_gpn_ft - container for ct header plus gpn_ft request
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* @ct_hdr: FC GS common transport header
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* @gpn_ft: GPN_FT request
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*/
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struct zfcp_fc_gpn_ft_req {
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struct fc_ct_hdr ct_hdr;
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struct fc_ns_gid_ft gpn_ft;
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} __packed;
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/**
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* struct zfcp_fc_gspn_req - container for ct header plus GSPN_ID request
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* @ct_hdr: FC GS common transport header
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* @gspn: GSPN_ID request
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*/
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struct zfcp_fc_gspn_req {
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struct fc_ct_hdr ct_hdr;
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struct fc_gid_pn_resp gspn;
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} __packed;
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/**
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* struct zfcp_fc_gspn_rsp - container for ct header plus GSPN_ID response
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* @ct_hdr: FC GS common transport header
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* @gspn: GSPN_ID response
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* @name: The name string of the GSPN_ID response
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*/
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struct zfcp_fc_gspn_rsp {
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struct fc_ct_hdr ct_hdr;
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struct fc_gspn_resp gspn;
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char name[FC_SYMBOLIC_NAME_SIZE];
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} __packed;
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/**
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* struct zfcp_fc_rspn_req - container for ct header plus RSPN_ID request
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* @ct_hdr: FC GS common transport header
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* @rspn: RSPN_ID request
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* @name: The name string of the RSPN_ID request
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*/
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struct zfcp_fc_rspn_req {
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struct fc_ct_hdr ct_hdr;
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struct fc_ns_rspn rspn;
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char name[FC_SYMBOLIC_NAME_SIZE];
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} __packed;
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/**
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* struct zfcp_fc_req - Container for FC ELS and CT requests sent from zfcp
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* @ct_els: data required for issuing fsf command
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* @sg_req: scatterlist entry for request data, refers to embedded @u submember
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* @sg_rsp: scatterlist entry for response data, refers to embedded @u submember
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* @u: request and response specific data
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* @u.adisc: ADISC specific data
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* @u.adisc.req: ADISC request
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* @u.adisc.rsp: ADISC response
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* @u.gid_pn: GID_PN specific data
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* @u.gid_pn.req: GID_PN request
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* @u.gid_pn.rsp: GID_PN response
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* @u.gpn_ft: GPN_FT specific data
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* @u.gpn_ft.sg_rsp2: GPN_FT response, not embedded here, allocated elsewhere
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* @u.gpn_ft.req: GPN_FT request
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* @u.gspn: GSPN specific data
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* @u.gspn.req: GSPN request
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* @u.gspn.rsp: GSPN response
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* @u.rspn: RSPN specific data
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* @u.rspn.req: RSPN request
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* @u.rspn.rsp: RSPN response
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*/
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struct zfcp_fc_req {
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struct zfcp_fsf_ct_els ct_els;
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struct scatterlist sg_req;
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struct scatterlist sg_rsp;
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union {
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struct {
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struct fc_els_adisc req;
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struct fc_els_adisc rsp;
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} adisc;
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struct {
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struct zfcp_fc_gid_pn_req req;
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struct zfcp_fc_gid_pn_rsp rsp;
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} gid_pn;
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struct {
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struct scatterlist sg_rsp2[ZFCP_FC_GPN_FT_NUM_BUFS - 1];
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struct zfcp_fc_gpn_ft_req req;
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} gpn_ft;
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struct {
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struct zfcp_fc_gspn_req req;
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struct zfcp_fc_gspn_rsp rsp;
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} gspn;
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struct {
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struct zfcp_fc_rspn_req req;
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struct fc_ct_hdr rsp;
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} rspn;
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} u;
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};
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/**
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* enum zfcp_fc_wka_status - FC WKA port status in zfcp
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* @ZFCP_FC_WKA_PORT_OFFLINE: Port is closed and not in use
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* @ZFCP_FC_WKA_PORT_CLOSING: The FSF "close port" request is pending
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* @ZFCP_FC_WKA_PORT_OPENING: The FSF "open port" request is pending
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* @ZFCP_FC_WKA_PORT_ONLINE: The port is open and the port handle is valid
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*/
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enum zfcp_fc_wka_status {
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ZFCP_FC_WKA_PORT_OFFLINE,
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ZFCP_FC_WKA_PORT_CLOSING,
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ZFCP_FC_WKA_PORT_OPENING,
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ZFCP_FC_WKA_PORT_ONLINE,
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};
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/**
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* struct zfcp_fc_wka_port - representation of well-known-address (WKA) FC port
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* @adapter: Pointer to adapter structure this WKA port belongs to
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* @opened: Wait for completion of open command
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* @closed: Wait for completion of close command
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* @status: Current status of WKA port
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* @refcount: Reference count to keep port open as long as it is in use
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* @d_id: FC destination id or well-known-address
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* @handle: FSF handle for the open WKA port
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* @mutex: Mutex used during opening/closing state changes
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* @work: For delaying the closing of the WKA port
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*/
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struct zfcp_fc_wka_port {
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struct zfcp_adapter *adapter;
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wait_queue_head_t opened;
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wait_queue_head_t closed;
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enum zfcp_fc_wka_status status;
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atomic_t refcount;
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u32 d_id;
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u32 handle;
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struct mutex mutex;
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struct delayed_work work;
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};
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/**
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* struct zfcp_fc_wka_ports - Data structures for FC generic services
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* @ms: FC Management service
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* @ts: FC time service
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* @ds: FC directory service
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* @as: FC alias service
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*/
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struct zfcp_fc_wka_ports {
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struct zfcp_fc_wka_port ms;
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struct zfcp_fc_wka_port ts;
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struct zfcp_fc_wka_port ds;
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struct zfcp_fc_wka_port as;
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};
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/**
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* zfcp_fc_scsi_to_fcp - setup FCP command with data from scsi_cmnd
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* @fcp: fcp_cmnd to setup
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* @scsi: scsi_cmnd where to get LUN, task attributes/flags and CDB
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*/
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static inline
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void zfcp_fc_scsi_to_fcp(struct fcp_cmnd *fcp, struct scsi_cmnd *scsi)
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{
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u32 datalen;
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int_to_scsilun(scsi->device->lun, (struct scsi_lun *) &fcp->fc_lun);
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fcp->fc_pri_ta = FCP_PTA_SIMPLE;
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if (scsi->sc_data_direction == DMA_FROM_DEVICE)
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fcp->fc_flags |= FCP_CFL_RDDATA;
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if (scsi->sc_data_direction == DMA_TO_DEVICE)
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fcp->fc_flags |= FCP_CFL_WRDATA;
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memcpy(fcp->fc_cdb, scsi->cmnd, scsi->cmd_len);
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datalen = scsi_bufflen(scsi);
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fcp->fc_dl = cpu_to_be32(datalen);
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if (scsi_get_prot_type(scsi) == SCSI_PROT_DIF_TYPE1) {
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datalen += datalen / scsi->device->sector_size * 8;
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fcp->fc_dl = cpu_to_be32(datalen);
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}
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}
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/**
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* zfcp_fc_fcp_tm() - Setup FCP command as task management command.
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* @fcp: Pointer to FCP_CMND IU to set up.
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* @dev: Pointer to SCSI_device where to send the task management command.
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* @tm_flags: Task management flags to setup tm command.
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*/
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static inline
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void zfcp_fc_fcp_tm(struct fcp_cmnd *fcp, struct scsi_device *dev, u8 tm_flags)
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{
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int_to_scsilun(dev->lun, (struct scsi_lun *) &fcp->fc_lun);
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fcp->fc_tm_flags = tm_flags;
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}
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/**
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* zfcp_fc_evap_fcp_rsp - evaluate FCP RSP IU and update scsi_cmnd accordingly
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* @fcp_rsp: FCP RSP IU to evaluate
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* @scsi: SCSI command where to update status and sense buffer
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*/
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static inline
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void zfcp_fc_eval_fcp_rsp(struct fcp_resp_with_ext *fcp_rsp,
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struct scsi_cmnd *scsi)
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{
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struct fcp_resp_rsp_info *rsp_info;
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char *sense;
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u32 sense_len, resid;
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u8 rsp_flags;
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scsi->result |= fcp_rsp->resp.fr_status;
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rsp_flags = fcp_rsp->resp.fr_flags;
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if (unlikely(rsp_flags & FCP_RSP_LEN_VAL)) {
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rsp_info = (struct fcp_resp_rsp_info *) &fcp_rsp[1];
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if (rsp_info->rsp_code == FCP_TMF_CMPL)
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set_host_byte(scsi, DID_OK);
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else {
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set_host_byte(scsi, DID_ERROR);
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return;
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}
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}
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if (unlikely(rsp_flags & FCP_SNS_LEN_VAL)) {
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sense = (char *) &fcp_rsp[1];
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if (rsp_flags & FCP_RSP_LEN_VAL)
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sense += be32_to_cpu(fcp_rsp->ext.fr_rsp_len);
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sense_len = min_t(u32, be32_to_cpu(fcp_rsp->ext.fr_sns_len),
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SCSI_SENSE_BUFFERSIZE);
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memcpy(scsi->sense_buffer, sense, sense_len);
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}
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if (unlikely(rsp_flags & FCP_RESID_UNDER)) {
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resid = be32_to_cpu(fcp_rsp->ext.fr_resid);
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scsi_set_resid(scsi, resid);
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if (scsi_bufflen(scsi) - resid < scsi->underflow &&
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!(rsp_flags & FCP_SNS_LEN_VAL) &&
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fcp_rsp->resp.fr_status == SAM_STAT_GOOD)
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set_host_byte(scsi, DID_ERROR);
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} else if (unlikely(rsp_flags & FCP_RESID_OVER)) {
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/* FCP_DL was not sufficient for SCSI data length */
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if (fcp_rsp->resp.fr_status == SAM_STAT_GOOD)
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set_host_byte(scsi, DID_ERROR);
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}
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}
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#endif
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