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Release 4.7 drivers/scsi/device_handler/scsi_dh_alua.c

/*
 * Generic SCSI-3 ALUA SCSI Device Handler
 *
 * Copyright (C) 2007-2010 Hannes Reinecke, SUSE Linux Products GmbH.
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <asm/unaligned.h>
#include <scsi/scsi.h>
#include <scsi/scsi_proto.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dh.h>


#define ALUA_DH_NAME "alua"

#define ALUA_DH_VER "2.0"


#define TPGS_SUPPORT_NONE		0x00

#define TPGS_SUPPORT_OPTIMIZED		0x01

#define TPGS_SUPPORT_NONOPTIMIZED	0x02

#define TPGS_SUPPORT_STANDBY		0x04

#define TPGS_SUPPORT_UNAVAILABLE	0x08

#define TPGS_SUPPORT_LBA_DEPENDENT	0x10

#define TPGS_SUPPORT_OFFLINE		0x40

#define TPGS_SUPPORT_TRANSITION		0x80


#define RTPG_FMT_MASK			0x70

#define RTPG_FMT_EXT_HDR		0x10


#define TPGS_MODE_UNINITIALIZED		 -1

#define TPGS_MODE_NONE			0x0

#define TPGS_MODE_IMPLICIT		0x1

#define TPGS_MODE_EXPLICIT		0x2


#define ALUA_RTPG_SIZE			128

#define ALUA_FAILOVER_TIMEOUT		60

#define ALUA_FAILOVER_RETRIES		5

#define ALUA_RTPG_DELAY_MSECS		5

/* device handler flags */

#define ALUA_OPTIMIZE_STPG		0x01

#define ALUA_RTPG_EXT_HDR_UNSUPP	0x02

#define ALUA_SYNC_STPG			0x04
/* State machine flags */

#define ALUA_PG_RUN_RTPG		0x10

#define ALUA_PG_RUN_STPG		0x20

#define ALUA_PG_RUNNING			0x40


static uint optimize_stpg;
module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(optimize_stpg, "Allow use of a non-optimized path, rather than sending a STPG, when implicit TPGS is supported (0=No,1=Yes). Default is 0.");

static LIST_HEAD(port_group_list);
static DEFINE_SPINLOCK(port_group_lock);

static struct workqueue_struct *kaluad_wq;

static struct workqueue_struct *kaluad_sync_wq;


struct alua_port_group {
	
struct kref		kref;
	
struct rcu_head		rcu;
	
struct list_head	node;
	
struct list_head	dh_list;
	
unsigned char		device_id_str[256];
	
int			device_id_len;
	
int			group_id;
	
int			tpgs;
	
int			state;
	
int			pref;
	
unsigned		flags; /* used for optimizing STPG */
	
unsigned char		transition_tmo;
	
unsigned long		expiry;
	
unsigned long		interval;
	
struct delayed_work	rtpg_work;
	
spinlock_t		lock;
	
struct list_head	rtpg_list;
	
struct scsi_device	*rtpg_sdev;
};


struct alua_dh_data {
	
struct list_head	node;
	
struct alua_port_group	*pg;
	
int			group_id;
	
spinlock_t		pg_lock;
	
struct scsi_device	*sdev;
	
int			init_error;
	
struct mutex		init_mutex;
};


struct alua_queue_data {
	
struct list_head	entry;
	
activate_complete	callback_fn;
	
void			*callback_data;
};


#define ALUA_POLICY_SWITCH_CURRENT	0

#define ALUA_POLICY_SWITCH_ALL		1

static void alua_rtpg_work(struct work_struct *work);
static void alua_rtpg_queue(struct alua_port_group *pg,
			    struct scsi_device *sdev,
			    struct alua_queue_data *qdata, bool force);
static void alua_check(struct scsi_device *sdev, bool force);


static void release_port_group(struct kref *kref) { struct alua_port_group *pg; pg = container_of(kref, struct alua_port_group, kref); if (pg->rtpg_sdev) flush_delayed_work(&pg->rtpg_work); spin_lock(&port_group_lock); list_del(&pg->node); spin_unlock(&port_group_lock); kfree_rcu(pg, rcu); }

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/* * submit_rtpg - Issue a REPORT TARGET GROUP STATES command * @sdev: sdev the command should be sent to */
static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff, int bufflen, struct scsi_sense_hdr *sshdr, int flags) { u8 cdb[COMMAND_SIZE(MAINTENANCE_IN)]; int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER; /* Prepare the command. */ memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_IN)); cdb[0] = MAINTENANCE_IN; if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP)) cdb[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT; else cdb[1] = MI_REPORT_TARGET_PGS; put_unaligned_be32(bufflen, &cdb[6]); return scsi_execute_req_flags(sdev, cdb, DMA_FROM_DEVICE, buff, bufflen, sshdr, ALUA_FAILOVER_TIMEOUT * HZ, ALUA_FAILOVER_RETRIES, NULL, req_flags); }

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/* * submit_stpg - Issue a SET TARGET PORT GROUP command * * Currently we're only setting the current target port group state * to 'active/optimized' and let the array firmware figure out * the states of the remaining groups. */
static int submit_stpg(struct scsi_device *sdev, int group_id, struct scsi_sense_hdr *sshdr) { u8 cdb[COMMAND_SIZE(MAINTENANCE_OUT)]; unsigned char stpg_data[8]; int stpg_len = 8; int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER; /* Prepare the data buffer */ memset(stpg_data, 0, stpg_len); stpg_data[4] = SCSI_ACCESS_STATE_OPTIMAL; put_unaligned_be16(group_id, &stpg_data[6]); /* Prepare the command. */ memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_OUT)); cdb[0] = MAINTENANCE_OUT; cdb[1] = MO_SET_TARGET_PGS; put_unaligned_be32(stpg_len, &cdb[6]); return scsi_execute_req_flags(sdev, cdb, DMA_TO_DEVICE, stpg_data, stpg_len, sshdr, ALUA_FAILOVER_TIMEOUT * HZ, ALUA_FAILOVER_RETRIES, NULL, req_flags); }

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static struct alua_port_group *alua_find_get_pg(char *id_str, size_t id_size, int group_id) { struct alua_port_group *pg; if (!id_str || !id_size || !strlen(id_str)) return NULL; list_for_each_entry(pg, &port_group_list, node) { if (pg->group_id != group_id) continue; if (!pg->device_id_len || pg->device_id_len != id_size) continue; if (strncmp(pg->device_id_str, id_str, id_size)) continue; if (!kref_get_unless_zero(&pg->kref)) continue; return pg; } return NULL; }

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/* * alua_alloc_pg - Allocate a new port_group structure * @sdev: scsi device * @h: alua device_handler data * @group_id: port group id * * Allocate a new port_group structure for a given * device. */
static struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev, int group_id, int tpgs) { struct alua_port_group *pg, *tmp_pg; pg = kzalloc(sizeof(struct alua_port_group), GFP_KERNEL); if (!pg) return ERR_PTR(-ENOMEM); pg->device_id_len = scsi_vpd_lun_id(sdev, pg->device_id_str, sizeof(pg->device_id_str)); if (pg->device_id_len <= 0) { /* * TPGS supported but no device identification found. * Generate private device identification. */ sdev_printk(KERN_INFO, sdev, "%s: No device descriptors found\n", ALUA_DH_NAME); pg->device_id_str[0] = '\0'; pg->device_id_len = 0; } pg->group_id = group_id; pg->tpgs = tpgs; pg->state = SCSI_ACCESS_STATE_OPTIMAL; if (optimize_stpg) pg->flags |= ALUA_OPTIMIZE_STPG; kref_init(&pg->kref); INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work); INIT_LIST_HEAD(&pg->rtpg_list); INIT_LIST_HEAD(&pg->node); INIT_LIST_HEAD(&pg->dh_list); spin_lock_init(&pg->lock); spin_lock(&port_group_lock); tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len, group_id); if (tmp_pg) { spin_unlock(&port_group_lock); kfree(pg); return tmp_pg; } list_add(&pg->node, &port_group_list); spin_unlock(&port_group_lock); return pg; }

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/* * alua_check_tpgs - Evaluate TPGS setting * @sdev: device to be checked * * Examine the TPGS setting of the sdev to find out if ALUA * is supported. */
static int alua_check_tpgs(struct scsi_device *sdev) { int tpgs = TPGS_MODE_NONE; /* * ALUA support for non-disk devices is fraught with * difficulties, so disable it for now. */ if (sdev->type != TYPE_DISK) { sdev_printk(KERN_INFO, sdev, "%s: disable for non-disk devices\n", ALUA_DH_NAME); return tpgs; } tpgs = scsi_device_tpgs(sdev); switch (tpgs) { case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT: sdev_printk(KERN_INFO, sdev, "%s: supports implicit and explicit TPGS\n", ALUA_DH_NAME); break; case TPGS_MODE_EXPLICIT: sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n", ALUA_DH_NAME); break; case TPGS_MODE_IMPLICIT: sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n", ALUA_DH_NAME); break; case TPGS_MODE_NONE: sdev_printk(KERN_INFO, sdev, "%s: not supported\n", ALUA_DH_NAME); break; default: sdev_printk(KERN_INFO, sdev, "%s: unsupported TPGS setting %d\n", ALUA_DH_NAME, tpgs); tpgs = TPGS_MODE_NONE; break; } return tpgs; }

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/* * alua_check_vpd - Evaluate INQUIRY vpd page 0x83 * @sdev: device to be checked * * Extract the relative target port and the target port group * descriptor from the list of identificators. */
static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, int tpgs) { int rel_port = -1, group_id; struct alua_port_group *pg, *old_pg = NULL; bool pg_updated = false; unsigned long flags; group_id = scsi_vpd_tpg_id(sdev, &rel_port); if (group_id < 0) { /* * Internal error; TPGS supported but required * VPD identification descriptors not present. * Disable ALUA support */ sdev_printk(KERN_INFO, sdev, "%s: No target port descriptors found\n", ALUA_DH_NAME); return SCSI_DH_DEV_UNSUPP; } pg = alua_alloc_pg(sdev, group_id, tpgs); if (IS_ERR(pg)) { if (PTR_ERR(pg) == -ENOMEM) return SCSI_DH_NOMEM; return SCSI_DH_DEV_UNSUPP; } if (pg->device_id_len) sdev_printk(KERN_INFO, sdev, "%s: device %s port group %x rel port %x\n", ALUA_DH_NAME, pg->device_id_str, group_id, rel_port); else sdev_printk(KERN_INFO, sdev, "%s: port group %x rel port %x\n", ALUA_DH_NAME, group_id, rel_port); /* Check for existing port group references */ spin_lock(&h->pg_lock); old_pg = h->pg; if (old_pg != pg) { /* port group has changed. Update to new port group */ if (h->pg) { spin_lock_irqsave(&old_pg->lock, flags); list_del_rcu(&h->node); spin_unlock_irqrestore(&old_pg->lock, flags); } rcu_assign_pointer(h->pg, pg); pg_updated = true; } spin_lock_irqsave(&pg->lock, flags); if (sdev->synchronous_alua) pg->flags |= ALUA_SYNC_STPG; if (pg_updated) list_add_rcu(&h->node, &pg->dh_list); spin_unlock_irqrestore(&pg->lock, flags); alua_rtpg_queue(h->pg, sdev, NULL, true); spin_unlock(&h->pg_lock); if (old_pg) kref_put(&old_pg->kref, release_port_group); return SCSI_DH_OK; }

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static char print_alua_state(unsigned char state) { switch (state) { case SCSI_ACCESS_STATE_OPTIMAL: return 'A'; case SCSI_ACCESS_STATE_ACTIVE: return 'N'; case SCSI_ACCESS_STATE_STANDBY: return 'S'; case SCSI_ACCESS_STATE_UNAVAILABLE: return 'U'; case SCSI_ACCESS_STATE_LBA: return 'L'; case SCSI_ACCESS_STATE_OFFLINE: return 'O'; case SCSI_ACCESS_STATE_TRANSITIONING: return 'T'; default: return 'X'; } }

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static int alua_check_sense(struct scsi_device *sdev, struct scsi_sense_hdr *sense_hdr) { switch (sense_hdr->sense_key) { case NOT_READY: if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) { /* * LUN Not Accessible - ALUA state transition */ alua_check(sdev, false); return NEEDS_RETRY; } break; case UNIT_ATTENTION: if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) { /* * Power On, Reset, or Bus Device Reset. * Might have obscured a state transition, * so schedule a recheck. */ alua_check(sdev, true); return ADD_TO_MLQUEUE; } if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04) /* * Device internal reset */ return ADD_TO_MLQUEUE; if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01) /* * Mode Parameters Changed */ return ADD_TO_MLQUEUE; if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) { /* * ALUA state changed */ alua_check(sdev, true); return ADD_TO_MLQUEUE; } if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) { /* * Implicit ALUA state transition failed */ alua_check(sdev, true); return ADD_TO_MLQUEUE; } if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03) /* * Inquiry data has changed */ return ADD_TO_MLQUEUE; if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e) /* * REPORTED_LUNS_DATA_HAS_CHANGED is reported * when switching controllers on targets like * Intel Multi-Flex. We can just retry. */ return ADD_TO_MLQUEUE; break; } return SCSI_RETURN_NOT_HANDLED; }

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/* * alua_tur - Send a TEST UNIT READY * @sdev: device to which the TEST UNIT READY command should be send * * Send a TEST UNIT READY to @sdev to figure out the device state * Returns SCSI_DH_RETRY if the sense code is NOT READY/ALUA TRANSITIONING, * SCSI_DH_OK if no error occurred, and SCSI_DH_IO otherwise. */
static int alua_tur(struct scsi_device *sdev) { struct scsi_sense_hdr sense_hdr; int retval; retval = scsi_test_unit_ready(sdev, ALUA_FAILOVER_TIMEOUT * HZ, ALUA_FAILOVER_RETRIES, &sense_hdr); if (sense_hdr.sense_key == NOT_READY && sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) return SCSI_DH_RETRY; else if (retval) return SCSI_DH_IO; else return SCSI_DH_OK; }

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/* * alua_rtpg - Evaluate REPORT TARGET GROUP STATES * @sdev: the device to be evaluated. * * Evaluate the Target Port Group State. * Returns SCSI_DH_DEV_OFFLINED if the path is * found to be unusable. */
static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg) { struct scsi_sense_hdr sense_hdr; struct alua_port_group *tmp_pg; int len, k, off, valid_states = 0, bufflen = ALUA_RTPG_SIZE; unsigned char *desc, *buff; unsigned err, retval; unsigned int tpg_desc_tbl_off; unsigned char orig_transition_tmo; unsigned long flags; if (!pg->expiry) { unsigned long transition_tmo = ALUA_FAILOVER_TIMEOUT * HZ; if (pg->transition_tmo) transition_tmo = pg->transition_tmo * HZ; pg->expiry = round_jiffies_up(jiffies + transition_tmo); } buff = kzalloc(bufflen, GFP_KERNEL); if (!buff) return SCSI_DH_DEV_TEMP_BUSY; retry: err = 0; retval = submit_rtpg(sdev, buff, bufflen, &sense_hdr, pg->flags); if (retval) { if (!scsi_sense_valid(&sense_hdr)) { sdev_printk(KERN_INFO, sdev, "%s: rtpg failed, result %d\n", ALUA_DH_NAME, retval); kfree(buff); if (driver_byte(retval) == DRIVER_ERROR) return SCSI_DH_DEV_TEMP_BUSY; return SCSI_DH_IO; } /* * submit_rtpg() has failed on existing arrays * when requesting extended header info, and * the array doesn't support extended headers, * even though it shouldn't according to T10. * The retry without rtpg_ext_hdr_req set * handles this. */ if (!(pg->flags & ALUA_RTPG_EXT_HDR_UNSUPP) && sense_hdr.sense_key == ILLEGAL_REQUEST && sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) { pg->flags |= ALUA_RTPG_EXT_HDR_UNSUPP; goto retry; } /* * Retry on ALUA state transition or if any * UNIT ATTENTION occurred. */ if (sense_hdr.sense_key == NOT_READY && sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) err = SCSI_DH_RETRY; else if (sense_hdr.sense_key == UNIT_ATTENTION) err = SCSI_DH_RETRY; if (err == SCSI_DH_RETRY && pg->expiry != 0 && time_before(jiffies, pg->expiry)) { sdev_printk(KERN_ERR, sdev, "%s: rtpg retry\n", ALUA_DH_NAME); scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr); return err; } sdev_printk(KERN_ERR, sdev, "%s: rtpg failed\n", ALUA_DH_NAME); scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr); kfree(buff); pg->expiry = 0; return SCSI_DH_IO; } len = get_unaligned_be32(&buff[0]) + 4; if (len > bufflen) { /* Resubmit with the correct length */ kfree(buff); bufflen = len; buff = kmalloc(bufflen, GFP_KERNEL); if (!buff) { sdev_printk(KERN_WARNING, sdev, "%s: kmalloc buffer failed\n",__func__); /* Temporary failure, bypass */ pg->expiry = 0; return SCSI_DH_DEV_TEMP_BUSY; } goto retry; } orig_transition_tmo = pg->transition_tmo; if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && buff[5] != 0) pg->transition_tmo = buff[5]; else pg->transition_tmo = ALUA_FAILOVER_TIMEOUT; if (orig_transition_tmo != pg->transition_tmo) { sdev_printk(KERN_INFO, sdev, "%s: transition timeout set to %d seconds\n", ALUA_DH_NAME, pg->transition_tmo); pg->expiry = jiffies + pg->transition_tmo * HZ; } if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR) tpg_desc_tbl_off = 8; else tpg_desc_tbl_off = 4; for (k = tpg_desc_tbl_off, desc = buff + tpg_desc_tbl_off; k < len; k += off, desc += off) { u16 group_id = get_unaligned_be16(&desc[2]); spin_lock_irqsave(&port_group_lock, flags); tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len, group_id); spin_unlock_irqrestore(&port_group_lock, flags); if (tmp_pg) { if (spin_trylock_irqsave(&tmp_pg->lock, flags)) { if ((tmp_pg == pg) || !(tmp_pg->flags & ALUA_PG_RUNNING)) { struct alua_dh_data *h; tmp_pg->state = desc[0] & 0x0f; tmp_pg->pref = desc[0] >> 7; rcu_read_lock(); list_for_each_entry_rcu(h, &tmp_pg->dh_list, node) { /* h->sdev should always be valid */ BUG_ON(!h->sdev); h->sdev->access_state = desc[0]; } rcu_read_unlock(); } if (tmp_pg == pg) valid_states = desc[1]; spin_unlock_irqrestore(&tmp_pg->lock, flags); } kref_put(&tmp_pg->kref, release_port_group); } off = 8 + (desc[7] * 4); } spin_lock_irqsave(&pg->lock, flags); sdev_printk(KERN_INFO, sdev, "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n", ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state), pg->pref ? "preferred" : "non-preferred", valid_states&TPGS_SUPPORT_TRANSITION?'T':'t', valid_states&TPGS_SUPPORT_OFFLINE?'O':'o', valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l', valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u', valid_states&TPGS_SUPPORT_STANDBY?'S':'s', valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n', valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a'); switch (pg->state) { case SCSI_ACCESS_STATE_TRANSITIONING: if (time_before(jiffies, pg->expiry)) { /* State transition, retry */ pg->interval = 2; err = SCSI_DH_RETRY; } else { struct alua_dh_data *h; /* Transitioning time exceeded, set port to standby */ err = SCSI_DH_IO; pg->state = SCSI_ACCESS_STATE_STANDBY; pg->expiry = 0; rcu_read_lock(); list_for_each_entry_rcu(h, &pg->dh_list, node) { BUG_ON(!h->sdev); h->sdev->access_state = (pg->state & SCSI_ACCESS_STATE_MASK); if (pg->pref) h->sdev->access_state |= SCSI_ACCESS_STATE_PREFERRED; } rcu_read_unlock(); } break; case SCSI_ACCESS_STATE_OFFLINE: /* Path unusable */ err = SCSI_DH_DEV_OFFLINED; pg->expiry = 0; break; default: /* Useable path if active */ err = SCSI_DH_OK; pg->expiry = 0; break; } spin_unlock_irqrestore(&pg->lock, flags); kfree(buff); return err; }

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bart van asschebart van assche10.10%14.17%
Total1003100.00%24100.00%

/* * alua_stpg - Issue a SET TARGET PORT GROUP command * * Issue a SET TARGET PORT GROUP command and evaluate the * response. Returns SCSI_DH_RETRY per default to trigger * a re-evaluation of the target group state or SCSI_DH_OK * if no further action needs to be taken. */
static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg) { int retval; struct scsi_sense_hdr sense_hdr; if (!(pg->tpgs & TPGS_MODE_EXPLICIT)) { /* Only implicit ALUA supported, retry */ return SCSI_DH_RETRY; } switch (pg->state) { case SCSI_ACCESS_STATE_OPTIMAL: return SCSI_DH_OK; case SCSI_ACCESS_STATE_ACTIVE: if ((pg->flags & ALUA_OPTIMIZE_STPG) && !pg->pref && (pg->tpgs & TPGS_MODE_IMPLICIT)) return SCSI_DH_OK; break; case SCSI_ACCESS_STATE_STANDBY: case SCSI_ACCESS_STATE_UNAVAILABLE: break; case SCSI_ACCESS_STATE_OFFLINE: return SCSI_DH_IO; case SCSI_ACCESS_STATE_TRANSITIONING: break; default: sdev_printk(KERN_INFO, sdev, "%s: stpg failed, unhandled TPGS state %d", ALUA_DH_NAME, pg->state); return SCSI_DH_NOSYS; } retval = submit_stpg(sdev, pg->group_id, &sense_hdr); if (retval) { if (!scsi_sense_valid(&sense_hdr)) { sdev_printk(KERN_INFO, sdev, "%s: stpg failed, result %d", ALUA_DH_NAME, retval); if (driver_byte(retval) == DRIVER_ERROR) return SCSI_DH_DEV_TEMP_BUSY; } else { sdev_printk(KERN_INFO, sdev, "%s: stpg failed\n", ALUA_DH_NAME); scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr); } } /* Retry RTPG */ return SCSI_DH_RETRY; }

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hannes reineckehannes reinecke204100.00%5100.00%
Total204100.00%5100.00%


static void alua_rtpg_work(struct work_struct *work) { struct alua_port_group *pg = container_of(work, struct alua_port_group, rtpg_work.work); struct scsi_device *sdev; LIST_HEAD(qdata_list); int err = SCSI_DH_OK; struct alua_queue_data *qdata, *tmp; unsigned long flags; struct workqueue_struct *alua_wq = kaluad_wq; spin_lock_irqsave(&pg->lock, flags); sdev = pg->rtpg_sdev; if (!sdev) { WARN_ON(pg->flags & ALUA_PG_RUN_RTPG); WARN_ON(pg->flags & ALUA_PG_RUN_STPG); spin_unlock_irqrestore(&pg->lock, flags); return; } if (pg->flags & ALUA_SYNC_STPG) alua_wq = kaluad_sync_wq; pg->flags |= ALUA_PG_RUNNING; if (pg->flags & ALUA_PG_RUN_RTPG) { int state = pg->state; pg->flags &= ~ALUA_PG_RUN_RTPG; spin_unlock_irqrestore(&pg->lock, flags); if (state == SCSI_ACCESS_STATE_TRANSITIONING) { if (alua_tur(sdev) == SCSI_DH_RETRY) { spin_lock_irqsave(&pg->lock, flags); pg->flags &= ~ALUA_PG_RUNNING; pg->flags |= ALUA_PG_RUN_RTPG; spin_unlock_irqrestore(&pg->lock, flags); queue_delayed_work(alua_wq, &pg->rtpg_work, pg->interval * HZ); return; } /* Send RTPG on failure or if TUR indicates SUCCESS */ } err = alua_rtpg(sdev, pg); spin_lock_irqsave(&pg->lock, flags); if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) { pg->flags &= ~ALUA_PG_RUNNING; pg->flags |= ALUA_PG_RUN_RTPG; spin_unlock_irqrestore(&pg->lock, flags); queue_delayed_work(alua_wq, &pg->rtpg_work, pg->interval * HZ); return; } if (err != SCSI_DH_OK) pg->flags &= ~ALUA_PG_RUN_STPG; } if (pg->flags & ALUA_PG_RUN_STPG) { pg->flags &= ~ALUA_PG_RUN_STPG; spin_unlock_irqrestore(&pg->lock, flags); err = alua_stpg(sdev, pg); spin_lock_irqsave(&pg->lock, flags); if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) { pg->flags |= ALUA_PG_RUN_RTPG; pg->interval = 0; pg->flags &= ~ALUA_PG_RUNNING; spin_unlock_irqrestore(&pg->lock, flags); queue_delayed_work(alua_wq, &pg->rtpg_work, pg->interval * HZ); return; } } list_splice_init(&pg->rtpg_list, &qdata_list); pg->rtpg_sdev = NULL; spin_unlock_irqrestore(&pg->lock, flags); list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) { list_del(&qdata->entry); if (qdata->callback_fn) qdata->callback_fn(qdata->callback_data, err); kfree(qdata); } spin_lock_irqsave(&pg->lock, flags); pg->flags &= ~ALUA_PG_RUNNING; spin_unlock_irqrestore(&pg->lock, flags); scsi_device_put(sdev); kref_put(&pg->kref, release_port_group); }

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hannes reineckehannes reinecke51795.92%880.00%
babu mogerbabu moger213.90%110.00%
sean stewartsean stewart10.19%110.00%
Total539100.00%10100.00%


static void alua_rtpg_queue(struct alua_port_group *pg, struct scsi_device *sdev, struct alua_queue_data *qdata, bool force) { int start_queue = 0; unsigned long flags; struct workqueue_struct *alua_wq = kaluad_wq; if (!pg) return; spin_lock_irqsave(&pg->lock, flags); if (qdata) { list_add_tail(&qdata->entry, &pg->rtpg_list); pg->flags |= ALUA_PG_RUN_STPG; force = true; } if (pg->rtpg_sdev == NULL) { pg->interval = 0; pg->flags |= ALUA_PG_RUN_RTPG; kref_get(&pg->kref); pg->rtpg_sdev = sdev; scsi_device_get(sdev); start_queue = 1; } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) { pg->flags |= ALUA_PG_RUN_RTPG; /* Do not queue if the worker is already running */ if (!(pg->flags & ALUA_PG_RUNNING)) { kref_get(&pg->kref); start_queue = 1; } } if (pg->flags & ALUA_SYNC_STPG) alua_wq = kaluad_sync_wq; spin_unlock_irqrestore(&pg->lock, flags); if (start_queue && !queue_delayed_work(alua_wq, &pg->rtpg_work, msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS))) { scsi_device_put(sdev); kref_put(&pg->kref, release_port_group); } }

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hannes reineckehannes reinecke237100.00%3100.00%
Total237100.00%3100.00%

/* * alua_initialize - Initialize ALUA state * @sdev: the device to be initialized * * For the prep_fn to work correctly we have * to initialize the ALUA state for the device. */
static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h) { int err = SCSI_DH_DEV_UNSUPP, tpgs; mutex_lock(&h->init_mutex); tpgs = alua_check_tpgs(sdev); if (tpgs != TPGS_MODE_NONE) err = alua_check_vpd(sdev, h, tpgs); h->init_error = err; mutex_unlock(&h->init_mutex); return err; }

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hannes reineckehannes reinecke72100.00%1100.00%
Total72100.00%1100.00%

/* * alua_set_params - set/unset the optimize flag * @sdev: device on the path to be activated * params - parameters in the following format * "no_of_params\0param1\0param2\0param3\0...\0" * For example, to set the flag pass the following parameters * from multipath.conf * hardware_handler "2 alua 1" */
static int alua_set_params(struct scsi_device *sdev, const char *params) { struct alua_dh_data *h = sdev->handler_data; struct alua_port_group __rcu *pg = NULL; unsigned int optimize = 0, argc; const char *p = params; int result = SCSI_DH_OK; unsigned long flags; if ((sscanf(params, "%u", &argc) != 1) || (argc != 1)) return -EINVAL; while (*p++) ; if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1)) return -EINVAL; rcu_read_lock(); pg = rcu_dereference(h->pg); if (!pg) { rcu_read_unlock(); return -ENXIO; } spin_lock_irqsave(&pg->lock, flags); if (optimize) pg->flags |= ALUA_OPTIMIZE_STPG; else pg->flags &= ~ALUA_OPTIMIZE_STPG; spin_unlock_irqrestore(&pg->lock, flags); rcu_read_unlock(); return result; }

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hannes reineckehannes reinecke18498.92%150.00%
babu mogerbabu moger21.08%150.00%
Total186100.00%2100.00%

/* * alua_activate - activate a path * @sdev: device on the path to be activated * * We're currently switching the port group to be activated only and * let the array figure out the rest. * There may be other arrays which require us to switch all port groups * based on a certain policy. But until we actually encounter them it * should be okay. */
static int alua_activate(struct scsi_device *sdev, activate_complete fn, void *data) { struct alua_dh_data *h = sdev->handler_data; int err = SCSI_DH_OK; struct alua_queue_data *qdata; struct alua_port_group __rcu *pg; qdata = kzalloc(sizeof(*qdata), GFP_KERNEL); if (!qdata) { err = SCSI_DH_RES_TEMP_UNAVAIL; goto out; } qdata->callback_fn = fn; qdata->callback_data = data; mutex_lock(&h->init_mutex); rcu_read_lock(); pg = rcu_dereference(h->pg); if (!pg || !kref_get_unless_zero(&pg->kref)) { rcu_read_unlock(); kfree(qdata); err = h->init_error; mutex_unlock(&h->init_mutex); goto out; } fn = NULL; rcu_read_unlock(); mutex_unlock(&h->init_mutex); alua_rtpg_queue(pg, sdev, qdata, true); kref_put(&pg->kref, release_port_group); out: if (fn) fn(data, err); return 0; }

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hannes reineckehannes reinecke16986.67%654.55%
chandra seetharamanchandra seetharaman2010.26%218.18%
sean stewartsean stewart31.54%19.09%
christoph hellwigchristoph hellwig21.03%19.09%
babu mogerbabu moger10.51%19.09%
Total195100.00%11100.00%

/* * alua_check - check path status * @sdev: device on the path to be checked * * Check the device status */
static void alua_check(struct scsi_device *sdev, bool force) { struct alua_dh_data *h = sdev->handler_data; struct alua_port_group *pg; rcu_read_lock(); pg = rcu_dereference(h->pg); if (!pg || !kref_get_unless_zero(&pg->kref)) { rcu_read_unlock(); return; } rcu_read_unlock(); alua_rtpg_queue(pg, sdev, NULL, force); kref_put(&pg->kref, release_port_group); }

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hannes reineckehannes reinecke84100.00%1100.00%
Total84100.00%1100.00%

/* * alua_prep_fn - request callback * * Fail I/O to all paths not in state * active/optimized or active/non-optimized. */
static int alua_prep_fn(struct scsi_device *sdev, struct request *req) { struct alua_dh_data *h = sdev->handler_data; struct alua_port_group __rcu *pg; unsigned char state = SCSI_ACCESS_STATE_OPTIMAL; int ret = BLKPREP_OK; rcu_read_lock(); pg = rcu_dereference(h->pg); if (pg) state = pg->state; rcu_read_unlock(); if (state == SCSI_ACCESS_STATE_TRANSITIONING) ret = BLKPREP_DEFER; else if (state != SCSI_ACCESS_STATE_OPTIMAL && state != SCSI_ACCESS_STATE_ACTIVE && state != SCSI_ACCESS_STATE_LBA) { ret = BLKPREP_KILL; req->cmd_flags |= REQ_QUIET; } return ret; }

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hannes reineckehannes reinecke10598.13%583.33%
christoph hellwigchristoph hellwig21.87%116.67%
Total107100.00%6100.00%


static void alua_rescan(struct scsi_device *sdev) { struct alua_dh_data *h = sdev->handler_data; alua_initialize(sdev, h); }

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hannes reineckehannes reinecke27100.00%1100.00%
Total27100.00%1100.00%

/* * alua_bus_attach - Attach device handler * @sdev: device to be attached to */
static int alua_bus_attach(struct scsi_device *sdev) { struct alua_dh_data *h; int err, ret = -EINVAL; h = kzalloc(sizeof(*h) , GFP_KERNEL); if (!h) return -ENOMEM; spin_lock_init(&h->pg_lock); rcu_assign_pointer(h->pg, NULL); h->init_error = SCSI_DH_OK; h->sdev = sdev; INIT_LIST_HEAD(&h->node); mutex_init(&h->init_mutex); err = alua_initialize(sdev, h); if (err == SCSI_DH_NOMEM) ret = -ENOMEM; if (err != SCSI_DH_OK && err != SCSI_DH_DEV_OFFLINED) goto failed; sdev->handler_data = h; return 0; failed: kfree(h); return ret; }

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hannes reineckehannes reinecke12486.71%444.44%
christoph hellwigchristoph hellwig96.29%222.22%
chandra seetharamanchandra seetharaman42.80%111.11%
martin georgemartin george42.80%111.11%
babu mogerbabu moger21.40%111.11%
Total143100.00%9100.00%

/* * alua_bus_detach - Detach device handler * @sdev: device to be detached from */
static void alua_bus_detach(struct scsi_device *sdev) { struct alua_dh_data *h = sdev->handler_data; struct alua_port_group *pg; spin_lock(&h->pg_lock); pg = h->pg; rcu_assign_pointer(h->pg, NULL); h->sdev = NULL; spin_unlock(&h->pg_lock); if (pg) { spin_lock_irq(&pg->lock); list_del_rcu(&h->node); spin_unlock_irq(&pg->lock); kref_put(&pg->kref, release_port_group); } sdev->handler_data = NULL; kfree(h); }

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hannes reineckehannes reinecke10088.50%457.14%
christoph hellwigchristoph hellwig119.73%228.57%
bart van asschebart van assche21.77%114.29%
Total113100.00%7100.00%

static struct scsi_device_handler alua_dh = { .name = ALUA_DH_NAME, .module = THIS_MODULE, .attach = alua_bus_attach, .detach = alua_bus_detach, .prep_fn = alua_prep_fn, .check_sense = alua_check_sense, .activate = alua_activate, .rescan = alua_rescan, .set_params = alua_set_params, };
static int __init alua_init(void) { int r; kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0); if (!kaluad_wq) { /* Temporary failure, bypass */ return SCSI_DH_DEV_TEMP_BUSY; } kaluad_sync_wq = create_workqueue("kaluad_sync"); if (!kaluad_sync_wq) { destroy_workqueue(kaluad_wq); return SCSI_DH_DEV_TEMP_BUSY; } r = scsi_register_device_handler(&alua_dh); if (r != 0) { printk(KERN_ERR "%s: Failed to register scsi device handler", ALUA_DH_NAME); destroy_workqueue(kaluad_sync_wq); destroy_workqueue(kaluad_wq); } return r; }

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hannes reineckehannes reinecke93100.00%3100.00%
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static void __exit alua_exit(void) { scsi_unregister_device_handler(&alua_dh); destroy_workqueue(kaluad_sync_wq); destroy_workqueue(kaluad_wq); }

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hannes reineckehannes reinecke25100.00%3100.00%
Total25100.00%3100.00%

module_init(alua_init); module_exit(alua_exit); MODULE_DESCRIPTION("DM Multipath ALUA support"); MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>"); MODULE_LICENSE("GPL"); MODULE_VERSION(ALUA_DH_VER);

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hannes reineckehannes reinecke452891.05%3757.81%
rob eversrob evers1713.44%23.12%
babu mogerbabu moger891.79%69.38%
christoph hellwigchristoph hellwig711.43%34.69%
chandra seetharamanchandra seetharaman490.99%23.12%
sean stewartsean stewart220.44%34.69%
ilgu hongilgu hong180.36%11.56%
dan carpenterdan carpenter60.12%23.12%
bart van asschebart van assche50.10%34.69%
martin georgemartin george40.08%11.56%
tejun heotejun heo30.06%11.56%
paul gortmakerpaul gortmaker30.06%11.56%
mike andersonmike anderson30.06%11.56%
harvey harrisonharvey harrison10.02%11.56%
Total4973100.00%64100.00%
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