linux/drivers/s390/scsi/zfcp_ext.h

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 22:07:57 +08:00
/* SPDX-License-Identifier: GPL-2.0 */
/*
* zfcp device driver
*
* External function declarations.
*
scsi: zfcp: fix rport unblock race with LUN recovery It is unavoidable that zfcp_scsi_queuecommand() has to finish requests with DID_IMM_RETRY (like fc_remote_port_chkready()) during the time window when zfcp detected an unavailable rport but fc_remote_port_delete(), which is asynchronous via zfcp_scsi_schedule_rport_block(), has not yet blocked the rport. However, for the case when the rport becomes available again, we should prevent unblocking the rport too early. In contrast to other FCP LLDDs, zfcp has to open each LUN with the FCP channel hardware before it can send I/O to a LUN. So if a port already has LUNs attached and we unblock the rport just after port recovery, recoveries of LUNs behind this port can still be pending which in turn force zfcp_scsi_queuecommand() to unnecessarily finish requests with DID_IMM_RETRY. This also opens a time window with unblocked rport (until the followup LUN reopen recovery has finished). If a scsi_cmnd timeout occurs during this time window fc_timed_out() cannot work as desired and such command would indeed time out and trigger scsi_eh. This prevents a clean and timely path failover. This should not happen if the path issue can be recovered on FC transport layer such as path issues involving RSCNs. Fix this by only calling zfcp_scsi_schedule_rport_register(), to asynchronously trigger fc_remote_port_add(), after all LUN recoveries as children of the rport have finished and no new recoveries of equal or higher order were triggered meanwhile. Finished intentionally includes any recovery result no matter if successful or failed (still unblock rport so other successful LUNs work). For simplicity, we check after each finished LUN recovery if there is another LUN recovery pending on the same port and then do nothing. We handle the special case of a successful recovery of a port without LUN children the same way without changing this case's semantics. For debugging we introduce 2 new trace records written if the rport unblock attempt was aborted due to still unfinished or freshly triggered recovery. The records are only written above the default trace level. Benjamin noticed the important special case of new recovery that can be triggered between having given up the erp_lock and before calling zfcp_erp_action_cleanup() within zfcp_erp_strategy(). We must avoid the following sequence: ERP thread rport_work other context ------------------------- -------------- -------------------------------- port is unblocked, rport still blocked, due to pending/running ERP action, so ((port->status & ...UNBLOCK) != 0) and (port->rport == NULL) unlock ERP zfcp_erp_action_cleanup() case ZFCP_ERP_ACTION_REOPEN_LUN: zfcp_erp_try_rport_unblock() ((status & ...UNBLOCK) != 0) [OLD!] zfcp_erp_port_reopen() lock ERP zfcp_erp_port_block() port->status clear ...UNBLOCK unlock ERP zfcp_scsi_schedule_rport_block() port->rport_task = RPORT_DEL queue_work(rport_work) zfcp_scsi_rport_work() (port->rport_task != RPORT_ADD) port->rport_task = RPORT_NONE zfcp_scsi_rport_block() if (!port->rport) return zfcp_scsi_schedule_rport_register() port->rport_task = RPORT_ADD queue_work(rport_work) zfcp_scsi_rport_work() (port->rport_task == RPORT_ADD) port->rport_task = RPORT_NONE zfcp_scsi_rport_register() (port->rport == NULL) rport = fc_remote_port_add() port->rport = rport; Now the rport was erroneously unblocked while the zfcp_port is blocked. This is another situation we want to avoid due to scsi_eh potential. This state would at least remain until the new recovery from the other context finished successfully, or potentially forever if it failed. In order to close this race, we take the erp_lock inside zfcp_erp_try_rport_unblock() when checking the status of zfcp_port or LUN. With that, the possible corresponding rport state sequences would be: (unblock[ERP thread],block[other context]) if the ERP thread gets erp_lock first and still sees ((port->status & ...UNBLOCK) != 0), (block[other context],NOP[ERP thread]) if the ERP thread gets erp_lock after the other context has already cleard ...UNBLOCK from port->status. Since checking fields of struct erp_action is unsafe because they could have been overwritten (re-used for new recovery) meanwhile, we only check status of zfcp_port and LUN since these are only changed under erp_lock elsewhere. Regarding the check of the proper status flags (port or port_forced are similar to the shown adapter recovery): [zfcp_erp_adapter_shutdown()] zfcp_erp_adapter_reopen() zfcp_erp_adapter_block() * clear UNBLOCK ---------------------------------------+ zfcp_scsi_schedule_rports_block() | write_lock_irqsave(&adapter->erp_lock, flags);-------+ | zfcp_erp_action_enqueue() | | zfcp_erp_setup_act() | | * set ERP_INUSE -----------------------------------|--|--+ write_unlock_irqrestore(&adapter->erp_lock, flags);--+ | | .context-switch. | | zfcp_erp_thread() | | zfcp_erp_strategy() | | write_lock_irqsave(&adapter->erp_lock, flags);------+ | | ... | | | zfcp_erp_strategy_check_target() | | | zfcp_erp_strategy_check_adapter() | | | zfcp_erp_adapter_unblock() | | | * set UNBLOCK -----------------------------------|--+ | zfcp_erp_action_dequeue() | | * clear ERP_INUSE ---------------------------------|-----+ ... | write_unlock_irqrestore(&adapter->erp_lock, flags);-+ Hence, we should check for both UNBLOCK and ERP_INUSE because they are interleaved. Also we need to explicitly check ERP_FAILED for the link down case which currently does not clear the UNBLOCK flag in zfcp_fsf_link_down_info_eval(). Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Fixes: 8830271c4819 ("[SCSI] zfcp: Dont fail SCSI commands when transitioning to blocked fc_rport") Fixes: a2fa0aede07c ("[SCSI] zfcp: Block FC transport rports early on errors") Fixes: 5f852be9e11d ("[SCSI] zfcp: Fix deadlock between zfcp ERP and SCSI") Fixes: 338151e06608 ("[SCSI] zfcp: make use of fc_remote_port_delete when target port is unavailable") Fixes: 3859f6a248cb ("[PATCH] zfcp: add rports to enable scsi_add_device to work again") Cc: <stable@vger.kernel.org> #2.6.32+ Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-12-10 00:16:33 +08:00
* Copyright IBM Corp. 2002, 2016
*/
#ifndef ZFCP_EXT_H
#define ZFCP_EXT_H
#include <linux/types.h>
#include <scsi/fc/fc_els.h>
#include "zfcp_def.h"
#include "zfcp_fc.h"
/* zfcp_aux.c */
extern struct zfcp_port *zfcp_get_port_by_wwpn(struct zfcp_adapter *, u64);
extern struct zfcp_adapter *zfcp_adapter_enqueue(struct ccw_device *);
extern struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *, u64, u32,
u32);
extern void zfcp_sg_free_table(struct scatterlist *, int);
extern int zfcp_sg_setup_table(struct scatterlist *, int);
extern void zfcp_adapter_release(struct kref *);
extern void zfcp_adapter_unregister(struct zfcp_adapter *);
/* zfcp_ccw.c */
extern struct ccw_driver zfcp_ccw_driver;
extern struct zfcp_adapter *zfcp_ccw_adapter_by_cdev(struct ccw_device *);
extern void zfcp_ccw_adapter_put(struct zfcp_adapter *);
/* zfcp_dbf.c */
extern int zfcp_dbf_adapter_register(struct zfcp_adapter *);
extern void zfcp_dbf_adapter_unregister(struct zfcp_adapter *);
extern void zfcp_dbf_rec_trig(char *, struct zfcp_adapter *,
struct zfcp_port *, struct scsi_device *, u8, u8);
extern void zfcp_dbf_rec_run(char *, struct zfcp_erp_action *);
scsi: zfcp: fix rport unblock race with LUN recovery It is unavoidable that zfcp_scsi_queuecommand() has to finish requests with DID_IMM_RETRY (like fc_remote_port_chkready()) during the time window when zfcp detected an unavailable rport but fc_remote_port_delete(), which is asynchronous via zfcp_scsi_schedule_rport_block(), has not yet blocked the rport. However, for the case when the rport becomes available again, we should prevent unblocking the rport too early. In contrast to other FCP LLDDs, zfcp has to open each LUN with the FCP channel hardware before it can send I/O to a LUN. So if a port already has LUNs attached and we unblock the rport just after port recovery, recoveries of LUNs behind this port can still be pending which in turn force zfcp_scsi_queuecommand() to unnecessarily finish requests with DID_IMM_RETRY. This also opens a time window with unblocked rport (until the followup LUN reopen recovery has finished). If a scsi_cmnd timeout occurs during this time window fc_timed_out() cannot work as desired and such command would indeed time out and trigger scsi_eh. This prevents a clean and timely path failover. This should not happen if the path issue can be recovered on FC transport layer such as path issues involving RSCNs. Fix this by only calling zfcp_scsi_schedule_rport_register(), to asynchronously trigger fc_remote_port_add(), after all LUN recoveries as children of the rport have finished and no new recoveries of equal or higher order were triggered meanwhile. Finished intentionally includes any recovery result no matter if successful or failed (still unblock rport so other successful LUNs work). For simplicity, we check after each finished LUN recovery if there is another LUN recovery pending on the same port and then do nothing. We handle the special case of a successful recovery of a port without LUN children the same way without changing this case's semantics. For debugging we introduce 2 new trace records written if the rport unblock attempt was aborted due to still unfinished or freshly triggered recovery. The records are only written above the default trace level. Benjamin noticed the important special case of new recovery that can be triggered between having given up the erp_lock and before calling zfcp_erp_action_cleanup() within zfcp_erp_strategy(). We must avoid the following sequence: ERP thread rport_work other context ------------------------- -------------- -------------------------------- port is unblocked, rport still blocked, due to pending/running ERP action, so ((port->status & ...UNBLOCK) != 0) and (port->rport == NULL) unlock ERP zfcp_erp_action_cleanup() case ZFCP_ERP_ACTION_REOPEN_LUN: zfcp_erp_try_rport_unblock() ((status & ...UNBLOCK) != 0) [OLD!] zfcp_erp_port_reopen() lock ERP zfcp_erp_port_block() port->status clear ...UNBLOCK unlock ERP zfcp_scsi_schedule_rport_block() port->rport_task = RPORT_DEL queue_work(rport_work) zfcp_scsi_rport_work() (port->rport_task != RPORT_ADD) port->rport_task = RPORT_NONE zfcp_scsi_rport_block() if (!port->rport) return zfcp_scsi_schedule_rport_register() port->rport_task = RPORT_ADD queue_work(rport_work) zfcp_scsi_rport_work() (port->rport_task == RPORT_ADD) port->rport_task = RPORT_NONE zfcp_scsi_rport_register() (port->rport == NULL) rport = fc_remote_port_add() port->rport = rport; Now the rport was erroneously unblocked while the zfcp_port is blocked. This is another situation we want to avoid due to scsi_eh potential. This state would at least remain until the new recovery from the other context finished successfully, or potentially forever if it failed. In order to close this race, we take the erp_lock inside zfcp_erp_try_rport_unblock() when checking the status of zfcp_port or LUN. With that, the possible corresponding rport state sequences would be: (unblock[ERP thread],block[other context]) if the ERP thread gets erp_lock first and still sees ((port->status & ...UNBLOCK) != 0), (block[other context],NOP[ERP thread]) if the ERP thread gets erp_lock after the other context has already cleard ...UNBLOCK from port->status. Since checking fields of struct erp_action is unsafe because they could have been overwritten (re-used for new recovery) meanwhile, we only check status of zfcp_port and LUN since these are only changed under erp_lock elsewhere. Regarding the check of the proper status flags (port or port_forced are similar to the shown adapter recovery): [zfcp_erp_adapter_shutdown()] zfcp_erp_adapter_reopen() zfcp_erp_adapter_block() * clear UNBLOCK ---------------------------------------+ zfcp_scsi_schedule_rports_block() | write_lock_irqsave(&adapter->erp_lock, flags);-------+ | zfcp_erp_action_enqueue() | | zfcp_erp_setup_act() | | * set ERP_INUSE -----------------------------------|--|--+ write_unlock_irqrestore(&adapter->erp_lock, flags);--+ | | .context-switch. | | zfcp_erp_thread() | | zfcp_erp_strategy() | | write_lock_irqsave(&adapter->erp_lock, flags);------+ | | ... | | | zfcp_erp_strategy_check_target() | | | zfcp_erp_strategy_check_adapter() | | | zfcp_erp_adapter_unblock() | | | * set UNBLOCK -----------------------------------|--+ | zfcp_erp_action_dequeue() | | * clear ERP_INUSE ---------------------------------|-----+ ... | write_unlock_irqrestore(&adapter->erp_lock, flags);-+ Hence, we should check for both UNBLOCK and ERP_INUSE because they are interleaved. Also we need to explicitly check ERP_FAILED for the link down case which currently does not clear the UNBLOCK flag in zfcp_fsf_link_down_info_eval(). Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Fixes: 8830271c4819 ("[SCSI] zfcp: Dont fail SCSI commands when transitioning to blocked fc_rport") Fixes: a2fa0aede07c ("[SCSI] zfcp: Block FC transport rports early on errors") Fixes: 5f852be9e11d ("[SCSI] zfcp: Fix deadlock between zfcp ERP and SCSI") Fixes: 338151e06608 ("[SCSI] zfcp: make use of fc_remote_port_delete when target port is unavailable") Fixes: 3859f6a248cb ("[PATCH] zfcp: add rports to enable scsi_add_device to work again") Cc: <stable@vger.kernel.org> #2.6.32+ Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-12-10 00:16:33 +08:00
extern void zfcp_dbf_rec_run_lvl(int level, char *tag,
struct zfcp_erp_action *erp);
extern void zfcp_dbf_rec_run_wka(char *, struct zfcp_fc_wka_port *, u64);
extern void zfcp_dbf_hba_fsf_uss(char *, struct zfcp_fsf_req *);
extern void zfcp_dbf_hba_fsf_res(char *, int, struct zfcp_fsf_req *);
extern void zfcp_dbf_hba_bit_err(char *, struct zfcp_fsf_req *);
extern void zfcp_dbf_hba_def_err(struct zfcp_adapter *, u64, u16, void **);
[SCSI] zfcp: Do not wakeup while suspended If the mapping of FCP device bus ID and corresponding subchannel is modified while the Linux image is suspended, the resume of FCP devices can fail. During resume, zfcp gets callbacks from cio regarding the modified subchannels but they can be arbitrarily mixed with the restore/resume callback. Since the cio callbacks would trigger adapter recovery, zfcp could wakeup before the resume callback. Therefore, ignore the cio callbacks regarding subchannels while being suspended. We can safely do so, since zfcp does not deal itself with subchannels. For problem determination purposes, we still trace the ignored callback events. The following kernel messages could be seen on resume: kernel: <WWPN>: parent <FCP device bus ID> should not be sleeping As part of adapter reopen recovery, zfcp performs auto port scanning which can erroneously try to register new remote ports with scsi_transport_fc and the device core code complains about the parent (adapter) still sleeping. kernel: zfcp.3dff9c: <FCP device bus ID>:\ Setting up the QDIO connection to the FCP adapter failed <last kernel message repeated 3 more times> kernel: zfcp.574d43: <FCP device bus ID>:\ ERP cannot recover an error on the FCP device In such cases, the adapter gave up recovery and remained blocked along with its child objects: remote ports and LUNs/scsi devices. Even the adapter shutdown as part of giving up recovery failed because the ccw device state remained disconnected. Later, the corresponding remote ports ran into dev_loss_tmo. As a result, the LUNs were erroneously not available again after resume. Even a manually triggered adapter recovery (e.g. sysfs attribute failed, or device offline/online via sysfs) could not recover the adapter due to the remaining disconnected state of the corresponding ccw device. Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> #2.6.32+ Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-04 21:23:32 +08:00
extern void zfcp_dbf_hba_basic(char *, struct zfcp_adapter *);
extern void zfcp_dbf_san_req(char *, struct zfcp_fsf_req *, u32);
extern void zfcp_dbf_san_res(char *, struct zfcp_fsf_req *);
extern void zfcp_dbf_san_in_els(char *, struct zfcp_fsf_req *);
extern void zfcp_dbf_scsi(char *, int, struct scsi_cmnd *,
struct zfcp_fsf_req *);
/* zfcp_erp.c */
extern void zfcp_erp_set_adapter_status(struct zfcp_adapter *, u32);
extern void zfcp_erp_clear_adapter_status(struct zfcp_adapter *, u32);
extern void zfcp_erp_adapter_reopen(struct zfcp_adapter *, int, char *);
extern void zfcp_erp_adapter_shutdown(struct zfcp_adapter *, int, char *);
extern void zfcp_erp_set_port_status(struct zfcp_port *, u32);
extern void zfcp_erp_clear_port_status(struct zfcp_port *, u32);
extern int zfcp_erp_port_reopen(struct zfcp_port *, int, char *);
extern void zfcp_erp_port_shutdown(struct zfcp_port *, int, char *);
extern void zfcp_erp_port_forced_reopen(struct zfcp_port *, int, char *);
extern void zfcp_erp_set_lun_status(struct scsi_device *, u32);
extern void zfcp_erp_clear_lun_status(struct scsi_device *, u32);
extern void zfcp_erp_lun_reopen(struct scsi_device *, int, char *);
extern void zfcp_erp_lun_shutdown(struct scsi_device *, int, char *);
extern void zfcp_erp_lun_shutdown_wait(struct scsi_device *, char *);
extern int zfcp_erp_thread_setup(struct zfcp_adapter *);
extern void zfcp_erp_thread_kill(struct zfcp_adapter *);
extern void zfcp_erp_wait(struct zfcp_adapter *);
extern void zfcp_erp_notify(struct zfcp_erp_action *, unsigned long);
extern void zfcp_erp_timeout_handler(struct timer_list *t);
/* zfcp_fc.c */
extern struct kmem_cache *zfcp_fc_req_cache;
extern void zfcp_fc_enqueue_event(struct zfcp_adapter *,
enum fc_host_event_code event_code, u32);
extern void zfcp_fc_post_event(struct work_struct *);
extern void zfcp_fc_scan_ports(struct work_struct *);
extern void zfcp_fc_incoming_els(struct zfcp_fsf_req *);
extern void zfcp_fc_port_did_lookup(struct work_struct *);
extern void zfcp_fc_trigger_did_lookup(struct zfcp_port *);
extern void zfcp_fc_plogi_evaluate(struct zfcp_port *, struct fc_els_flogi *);
extern void zfcp_fc_test_link(struct zfcp_port *);
extern void zfcp_fc_link_test_work(struct work_struct *);
extern void zfcp_fc_wka_ports_force_offline(struct zfcp_fc_wka_ports *);
extern int zfcp_fc_gs_setup(struct zfcp_adapter *);
extern void zfcp_fc_gs_destroy(struct zfcp_adapter *);
extern int zfcp_fc_exec_bsg_job(struct bsg_job *);
extern int zfcp_fc_timeout_bsg_job(struct bsg_job *);
extern void zfcp_fc_sym_name_update(struct work_struct *);
zfcp: auto port scan resiliency This patch improves the Fibre Channel port scan behaviour of the zfcp lldd. Without it the zfcp device driver may churn up the storage area network by excessive scanning and scan bursts, particularly in big virtual server environments, potentially resulting in interference of virtual servers and reduced availability of storage connectivity. The two main issues as to the zfcp device drivers automatic port scan in virtual server environments are frequency and simultaneity. On the one hand, there is no point in allowing lots of ports scans in a row. It makes sense, though, to make sure that a scan is conducted eventually if there has been any indication for potential SAN changes. On the other hand, lots of virtual servers receiving the same indication for a SAN change had better not attempt to conduct a scan instantly, that is, at the same time. Hence this patch has a two-fold approach for better port scanning: the introduction of a rate limit to amend frequency issues, and the introduction of a short random backoff to amend simultaneity issues. Both approaches boil down to deferred port scans, with delays comprising parts for both approaches. The new port scan behaviour is summarised best by: NEW: NEW: no_auto_port_rescan random rate flush backoff limit =wait adapter resume/thaw yes yes no yes* adapter online (user) no yes no yes* port rescan (user) no no no yes adapter recovery (user) yes yes yes no adapter recovery (other) yes yes yes no incoming ELS yes yes yes no incoming ELS lost yes yes yes no Implementation is straight-forward by converting an existing worker to a delayed worker. But care is needed whenever that worker is going to be flushed (in order to make sure work has been completed), since a flush operation cancels the timer set up for deferred execution (see * above). There is a small race window whenever a port scan work starts running up to the point in time of storing the time stamp for that port scan. The impact is negligible. Closing that gap isn't trivial, though, and would the destroy the beauty of a simple work-to-delayed-work conversion. Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-13 21:59:48 +08:00
extern unsigned int zfcp_fc_port_scan_backoff(void);
extern void zfcp_fc_conditional_port_scan(struct zfcp_adapter *);
extern void zfcp_fc_inverse_conditional_port_scan(struct zfcp_adapter *);
/* zfcp_fsf.c */
extern struct kmem_cache *zfcp_fsf_qtcb_cache;
extern int zfcp_fsf_open_port(struct zfcp_erp_action *);
extern int zfcp_fsf_open_wka_port(struct zfcp_fc_wka_port *);
extern int zfcp_fsf_close_wka_port(struct zfcp_fc_wka_port *);
extern int zfcp_fsf_close_port(struct zfcp_erp_action *);
extern int zfcp_fsf_close_physical_port(struct zfcp_erp_action *);
extern int zfcp_fsf_open_lun(struct zfcp_erp_action *);
extern int zfcp_fsf_close_lun(struct zfcp_erp_action *);
extern int zfcp_fsf_exchange_config_data(struct zfcp_erp_action *);
extern int zfcp_fsf_exchange_config_data_sync(struct zfcp_qdio *,
struct fsf_qtcb_bottom_config *);
extern int zfcp_fsf_exchange_port_data(struct zfcp_erp_action *);
extern int zfcp_fsf_exchange_port_data_sync(struct zfcp_qdio *,
struct fsf_qtcb_bottom_port *);
extern void zfcp_fsf_req_dismiss_all(struct zfcp_adapter *);
extern int zfcp_fsf_status_read(struct zfcp_qdio *);
extern int zfcp_status_read_refill(struct zfcp_adapter *adapter);
extern int zfcp_fsf_send_ct(struct zfcp_fc_wka_port *, struct zfcp_fsf_ct_els *,
mempool_t *, unsigned int);
extern int zfcp_fsf_send_els(struct zfcp_adapter *, u32,
struct zfcp_fsf_ct_els *, unsigned int);
extern int zfcp_fsf_fcp_cmnd(struct scsi_cmnd *);
extern void zfcp_fsf_req_free(struct zfcp_fsf_req *);
extern struct zfcp_fsf_req *zfcp_fsf_fcp_task_mgmt(struct scsi_cmnd *, u8);
extern struct zfcp_fsf_req *zfcp_fsf_abort_fcp_cmnd(struct scsi_cmnd *);
extern void zfcp_fsf_reqid_check(struct zfcp_qdio *, int);
/* zfcp_qdio.c */
extern int zfcp_qdio_setup(struct zfcp_adapter *);
extern void zfcp_qdio_destroy(struct zfcp_qdio *);
extern int zfcp_qdio_sbal_get(struct zfcp_qdio *);
extern int zfcp_qdio_send(struct zfcp_qdio *, struct zfcp_qdio_req *);
extern int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *, struct zfcp_qdio_req *,
struct scatterlist *);
extern int zfcp_qdio_open(struct zfcp_qdio *);
extern void zfcp_qdio_close(struct zfcp_qdio *);
extern void zfcp_qdio_siosl(struct zfcp_adapter *);
/* zfcp_scsi.c */
extern struct scsi_transport_template *zfcp_scsi_transport_template;
extern int zfcp_scsi_adapter_register(struct zfcp_adapter *);
extern void zfcp_scsi_adapter_unregister(struct zfcp_adapter *);
extern struct fc_function_template zfcp_transport_functions;
extern void zfcp_scsi_rport_work(struct work_struct *);
extern void zfcp_scsi_schedule_rport_register(struct zfcp_port *);
extern void zfcp_scsi_schedule_rport_block(struct zfcp_port *);
extern void zfcp_scsi_schedule_rports_block(struct zfcp_adapter *);
extern void zfcp_scsi_set_prot(struct zfcp_adapter *);
extern void zfcp_scsi_dif_sense_error(struct scsi_cmnd *, int);
/* zfcp_sysfs.c */
extern const struct attribute_group *zfcp_unit_attr_groups[];
extern struct attribute_group zfcp_sysfs_adapter_attrs;
extern const struct attribute_group *zfcp_port_attr_groups[];
extern struct mutex zfcp_sysfs_port_units_mutex;
extern struct device_attribute *zfcp_sysfs_sdev_attrs[];
extern struct device_attribute *zfcp_sysfs_shost_attrs[];
/* zfcp_unit.c */
extern int zfcp_unit_add(struct zfcp_port *, u64);
extern int zfcp_unit_remove(struct zfcp_port *, u64);
extern struct zfcp_unit *zfcp_unit_find(struct zfcp_port *, u64);
extern struct scsi_device *zfcp_unit_sdev(struct zfcp_unit *unit);
extern void zfcp_unit_scsi_scan(struct zfcp_unit *);
extern void zfcp_unit_queue_scsi_scan(struct zfcp_port *);
extern unsigned int zfcp_unit_sdev_status(struct zfcp_unit *);
#endif /* ZFCP_EXT_H */