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css_schedule_reprobe() function calls the evaluation for CSS_EVAL_UNREG which is specific to the idset of unregistered subchannels. This evaluation was introduced because, previously, if the underlying device become not-accessible, the subchannel was unregistered. But, in the recent changes in cio,with the commit '2297791c92d0 s390/cio: dont unregister subchannel from child-drivers', we no longer unregister the subchannels just because of a non-operational device. This allows to have subchannels without any operational device connected on it. So, a css_schedule_reprobe function on unregistered subchannel does not have any effect. Change this functionality to evaluate the subchannels which does not have a working path to the device. This could be due the erroneous device or due to the erraneous path. Evaluate based on the values of OPM and PAM&POM. Here we introduced a new idset function,to keep I/O subchannels in the idset when the last seen status indicates that the device has no working path. A device has no working path if all available paths have been tried without success.A failed I/O attempt on a path is indicated as a 0 bit value in the POM mask. By looking at the POM mask bit values of available paths (1 in PAM) that Linux is supposed to use (1 in vary mask OPM), we can identify a non-working device as a device where the bit-wise and of the PAM, POM and OPM mask return 0. css_schedule_reprobe() is being used by dasd-driver and chsc-cio component. dasd driver, when it detects a change in the pathgroup, invokes the re-evaluation of the subchannel. And chsc-cio component upon a CRW event, (resource accessibility event). In both the cases, it makes much better sense to re-evalute the subchannel with no-valid path. Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com> Reported-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com> Tested-by: Eric Farman <farman@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
158 lines
4.6 KiB
C
158 lines
4.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _CSS_H
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#define _CSS_H
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#include <linux/mutex.h>
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#include <linux/wait.h>
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#include <linux/workqueue.h>
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#include <linux/device.h>
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#include <linux/types.h>
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#include <asm/cio.h>
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#include <asm/chpid.h>
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#include <asm/schid.h>
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#include "cio.h"
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/*
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* path grouping stuff
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*/
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#define SPID_FUNC_SINGLE_PATH 0x00
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#define SPID_FUNC_MULTI_PATH 0x80
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#define SPID_FUNC_ESTABLISH 0x00
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#define SPID_FUNC_RESIGN 0x40
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#define SPID_FUNC_DISBAND 0x20
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#define SNID_STATE1_RESET 0
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#define SNID_STATE1_UNGROUPED 2
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#define SNID_STATE1_GROUPED 3
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#define SNID_STATE2_NOT_RESVD 0
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#define SNID_STATE2_RESVD_ELSE 2
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#define SNID_STATE2_RESVD_SELF 3
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#define SNID_STATE3_MULTI_PATH 1
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#define SNID_STATE3_SINGLE_PATH 0
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/*
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* Conditions used to specify which subchannels need evaluation
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*/
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enum css_eval_cond {
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CSS_EVAL_NO_PATH, /* Subchannels with no operational paths */
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CSS_EVAL_NOT_ONLINE /* sch without an online-device */
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};
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struct path_state {
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__u8 state1 : 2; /* path state value 1 */
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__u8 state2 : 2; /* path state value 2 */
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__u8 state3 : 1; /* path state value 3 */
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__u8 resvd : 3; /* reserved */
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} __attribute__ ((packed));
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struct extended_cssid {
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u8 version;
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u8 cssid;
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} __attribute__ ((packed));
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struct pgid {
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union {
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__u8 fc; /* SPID function code */
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struct path_state ps; /* SNID path state */
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} __attribute__ ((packed)) inf;
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union {
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__u32 cpu_addr : 16; /* CPU address */
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struct extended_cssid ext_cssid;
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} __attribute__ ((packed)) pgid_high;
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__u32 cpu_id : 24; /* CPU identification */
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__u32 cpu_model : 16; /* CPU model */
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__u32 tod_high; /* high word TOD clock */
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} __attribute__ ((packed));
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struct subchannel;
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struct chp_link;
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/**
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* struct css_driver - device driver for subchannels
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* @subchannel_type: subchannel type supported by this driver
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* @drv: embedded device driver structure
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* @irq: called on interrupts
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* @chp_event: called for events affecting a channel path
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* @sch_event: called for events affecting the subchannel
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* @probe: function called on probe
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* @remove: function called on remove
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* @shutdown: called at device shutdown
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* @settle: wait for asynchronous work to finish
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*/
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struct css_driver {
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struct css_device_id *subchannel_type;
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struct device_driver drv;
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void (*irq)(struct subchannel *);
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int (*chp_event)(struct subchannel *, struct chp_link *, int);
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int (*sch_event)(struct subchannel *, int);
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int (*probe)(struct subchannel *);
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void (*remove)(struct subchannel *);
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void (*shutdown)(struct subchannel *);
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int (*settle)(void);
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};
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#define to_cssdriver(n) container_of(n, struct css_driver, drv)
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extern int css_driver_register(struct css_driver *);
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extern void css_driver_unregister(struct css_driver *);
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extern void css_sch_device_unregister(struct subchannel *);
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extern int css_register_subchannel(struct subchannel *);
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extern struct subchannel *css_alloc_subchannel(struct subchannel_id,
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struct schib *schib);
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extern struct subchannel *get_subchannel_by_schid(struct subchannel_id);
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extern int css_init_done;
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extern int max_ssid;
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int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
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int (*fn_unknown)(struct subchannel_id,
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void *), void *data);
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extern int for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *);
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void css_update_ssd_info(struct subchannel *sch);
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struct channel_subsystem {
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u8 cssid;
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u8 iid;
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bool id_valid; /* cssid,iid */
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struct channel_path *chps[__MAX_CHPID + 1];
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struct device device;
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struct pgid global_pgid;
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struct mutex mutex;
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/* channel measurement related */
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int cm_enabled;
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void *cub_addr1;
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void *cub_addr2;
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/* for orphaned ccw devices */
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struct subchannel *pseudo_subchannel;
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};
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#define to_css(dev) container_of(dev, struct channel_subsystem, device)
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extern struct channel_subsystem *channel_subsystems[];
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/* Dummy helper which needs to change once we support more than one css. */
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static inline struct channel_subsystem *css_by_id(u8 cssid)
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{
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return channel_subsystems[0];
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}
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/* Dummy iterator which needs to change once we support more than one css. */
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#define for_each_css(css) \
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for ((css) = channel_subsystems[0]; (css); (css) = NULL)
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/* Helper functions to build lists for the slow path. */
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void css_schedule_eval(struct subchannel_id schid);
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void css_schedule_eval_all(void);
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void css_schedule_eval_cond(enum css_eval_cond, unsigned long delay);
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int css_complete_work(void);
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int sch_is_pseudo_sch(struct subchannel *);
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struct schib;
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int css_sch_is_valid(struct schib *);
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extern struct workqueue_struct *cio_work_q;
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void css_wait_for_slow_path(void);
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void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo);
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#endif
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