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3c31b52f96
async_schedule() sd resume work to allow disks and other devices to
resume in parallel.
This moves the entirety of scsi_device resume to an async context to
ensure that scsi_device_resume() remains ordered with respect to the
completion of the start/stop command. For the duration of the resume,
new command submissions (that do not originate from the scsi-core) will
be deferred (BLKPREP_DEFER).
It adds a new ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain) as a container
of these operations. Like scsi_sd_probe_domain it is flushed at
sd_remove() time to ensure async ops do not continue past the
end-of-life of the sdev. The implementation explicitly refrains from
reusing scsi_sd_probe_domain directly for this purpose as it is flushed
at the end of dpm_resume(), potentially defeating some of the benefit.
Given sdevs are quiesced it is permissible for these resume operations
to bleed past the async_synchronize_full() calls made by the driver
core.
We defer the resolution of which pm callback to call until
scsi_dev_type_{suspend|resume} time and guarantee that the callback
parameter is never NULL. With this in place the type of resume
operation is encoded in the async function identifier.
There is a concern that async resume could trigger PSU overload. In the
enterprise, storage enclosures enforce staggered spin-up regardless of
what the kernel does making async scanning safe by default. Outside of
that context a user can disable asynchronous scanning via a kernel
command line or CONFIG_SCSI_SCAN_ASYNC. Honor that setting when
deciding whether to do resume asynchronously.
Inspired by Todd's analysis and initial proposal [2]:
https://01.org/suspendresume/blogs/tebrandt/2013/hard-disk-resume-optimization-simpler-approach
Cc: Len Brown <len.brown@intel.com>
Cc: Phillip Susi <psusi@ubuntu.com>
[alan: bug fix and clean up suggestion]
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Suggested-by: Todd Brandt <todd.e.brandt@linux.intel.com>
[djbw: kick all resume work to the async queue]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
184 lines
6.1 KiB
C
184 lines
6.1 KiB
C
#ifndef _SCSI_PRIV_H
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#define _SCSI_PRIV_H
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#include <linux/device.h>
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#include <linux/async.h>
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#include <scsi/scsi_device.h>
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struct request_queue;
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struct request;
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struct scsi_cmnd;
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struct scsi_device;
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struct scsi_target;
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struct scsi_host_template;
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struct Scsi_Host;
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struct scsi_nl_hdr;
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/*
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* Scsi Error Handler Flags
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*/
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#define SCSI_EH_CANCEL_CMD 0x0001 /* Cancel this cmd */
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#define SCSI_EH_ABORT_SCHEDULED 0x0002 /* Abort has been scheduled */
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#define SCSI_SENSE_VALID(scmd) \
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(((scmd)->sense_buffer[0] & 0x70) == 0x70)
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/* hosts.c */
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extern int scsi_init_hosts(void);
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extern void scsi_exit_hosts(void);
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/* scsi.c */
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extern int scsi_dispatch_cmd(struct scsi_cmnd *cmd);
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extern int scsi_setup_command_freelist(struct Scsi_Host *shost);
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extern void scsi_destroy_command_freelist(struct Scsi_Host *shost);
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#ifdef CONFIG_SCSI_LOGGING
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void scsi_log_send(struct scsi_cmnd *cmd);
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void scsi_log_completion(struct scsi_cmnd *cmd, int disposition);
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#else
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static inline void scsi_log_send(struct scsi_cmnd *cmd)
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{ };
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static inline void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
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{ };
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#endif
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/* scsi_devinfo.c */
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/* list of keys for the lists */
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enum {
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SCSI_DEVINFO_GLOBAL = 0,
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SCSI_DEVINFO_SPI,
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};
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extern int scsi_get_device_flags(struct scsi_device *sdev,
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const unsigned char *vendor,
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const unsigned char *model);
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extern int scsi_get_device_flags_keyed(struct scsi_device *sdev,
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const unsigned char *vendor,
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const unsigned char *model, int key);
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extern int scsi_dev_info_list_add_keyed(int compatible, char *vendor,
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char *model, char *strflags,
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int flags, int key);
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extern int scsi_dev_info_list_del_keyed(char *vendor, char *model, int key);
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extern int scsi_dev_info_add_list(int key, const char *name);
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extern int scsi_dev_info_remove_list(int key);
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extern int __init scsi_init_devinfo(void);
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extern void scsi_exit_devinfo(void);
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/* scsi_error.c */
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extern void scmd_eh_abort_handler(struct work_struct *work);
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extern enum blk_eh_timer_return scsi_times_out(struct request *req);
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extern int scsi_error_handler(void *host);
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extern int scsi_decide_disposition(struct scsi_cmnd *cmd);
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extern void scsi_eh_wakeup(struct Scsi_Host *shost);
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extern int scsi_eh_scmd_add(struct scsi_cmnd *, int);
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void scsi_eh_ready_devs(struct Scsi_Host *shost,
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struct list_head *work_q,
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struct list_head *done_q);
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int scsi_eh_get_sense(struct list_head *work_q,
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struct list_head *done_q);
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int scsi_noretry_cmd(struct scsi_cmnd *scmd);
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/* scsi_lib.c */
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extern int scsi_maybe_unblock_host(struct scsi_device *sdev);
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extern void scsi_device_unbusy(struct scsi_device *sdev);
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extern void scsi_queue_insert(struct scsi_cmnd *cmd, int reason);
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extern void scsi_next_command(struct scsi_cmnd *cmd);
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extern void scsi_io_completion(struct scsi_cmnd *, unsigned int);
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extern void scsi_run_host_queues(struct Scsi_Host *shost);
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extern struct request_queue *scsi_alloc_queue(struct scsi_device *sdev);
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extern int scsi_init_queue(void);
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extern void scsi_exit_queue(void);
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struct request_queue;
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struct request;
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extern struct kmem_cache *scsi_sdb_cache;
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/* scsi_proc.c */
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#ifdef CONFIG_SCSI_PROC_FS
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extern void scsi_proc_hostdir_add(struct scsi_host_template *);
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extern void scsi_proc_hostdir_rm(struct scsi_host_template *);
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extern void scsi_proc_host_add(struct Scsi_Host *);
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extern void scsi_proc_host_rm(struct Scsi_Host *);
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extern int scsi_init_procfs(void);
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extern void scsi_exit_procfs(void);
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#else
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# define scsi_proc_hostdir_add(sht) do { } while (0)
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# define scsi_proc_hostdir_rm(sht) do { } while (0)
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# define scsi_proc_host_add(shost) do { } while (0)
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# define scsi_proc_host_rm(shost) do { } while (0)
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# define scsi_init_procfs() (0)
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# define scsi_exit_procfs() do { } while (0)
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#endif /* CONFIG_PROC_FS */
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/* scsi_scan.c */
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extern char scsi_scan_type[];
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extern int scsi_complete_async_scans(void);
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extern int scsi_scan_host_selected(struct Scsi_Host *, unsigned int,
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unsigned int, unsigned int, int);
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extern void scsi_forget_host(struct Scsi_Host *);
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extern void scsi_rescan_device(struct device *);
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/* scsi_sysctl.c */
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#ifdef CONFIG_SYSCTL
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extern int scsi_init_sysctl(void);
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extern void scsi_exit_sysctl(void);
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#else
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# define scsi_init_sysctl() (0)
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# define scsi_exit_sysctl() do { } while (0)
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#endif /* CONFIG_SYSCTL */
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/* scsi_sysfs.c */
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extern int scsi_sysfs_add_sdev(struct scsi_device *);
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extern int scsi_sysfs_add_host(struct Scsi_Host *);
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extern int scsi_sysfs_register(void);
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extern void scsi_sysfs_unregister(void);
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extern void scsi_sysfs_device_initialize(struct scsi_device *);
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extern int scsi_sysfs_target_initialize(struct scsi_device *);
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extern struct scsi_transport_template blank_transport_template;
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extern void __scsi_remove_device(struct scsi_device *);
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extern struct bus_type scsi_bus_type;
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extern const struct attribute_group *scsi_sysfs_shost_attr_groups[];
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/* scsi_netlink.c */
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#ifdef CONFIG_SCSI_NETLINK
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extern void scsi_netlink_init(void);
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extern void scsi_netlink_exit(void);
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extern struct sock *scsi_nl_sock;
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#else
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static inline void scsi_netlink_init(void) {}
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static inline void scsi_netlink_exit(void) {}
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#endif
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/* scsi_pm.c */
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#ifdef CONFIG_PM
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extern const struct dev_pm_ops scsi_bus_pm_ops;
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#endif
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#ifdef CONFIG_PM_RUNTIME
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extern void scsi_autopm_get_target(struct scsi_target *);
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extern void scsi_autopm_put_target(struct scsi_target *);
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extern int scsi_autopm_get_host(struct Scsi_Host *);
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extern void scsi_autopm_put_host(struct Scsi_Host *);
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#else
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static inline void scsi_autopm_get_target(struct scsi_target *t) {}
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static inline void scsi_autopm_put_target(struct scsi_target *t) {}
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static inline int scsi_autopm_get_host(struct Scsi_Host *h) { return 0; }
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static inline void scsi_autopm_put_host(struct Scsi_Host *h) {}
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#endif /* CONFIG_PM_RUNTIME */
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extern struct async_domain scsi_sd_pm_domain;
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extern struct async_domain scsi_sd_probe_domain;
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/*
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* internal scsi timeout functions: for use by mid-layer and transport
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* classes.
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*/
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#define SCSI_DEVICE_BLOCK_MAX_TIMEOUT 600 /* units in seconds */
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extern int scsi_internal_device_block(struct scsi_device *sdev);
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extern int scsi_internal_device_unblock(struct scsi_device *sdev,
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enum scsi_device_state new_state);
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#endif /* _SCSI_PRIV_H */
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