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1184 lines
30 KiB
C
1184 lines
30 KiB
C
/*
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* Generic SCSI-3 ALUA SCSI Device Handler
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*
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* Copyright (C) 2007-2010 Hannes Reinecke, SUSE Linux Products GmbH.
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#include <linux/slab.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <asm/unaligned.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_proto.h>
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#include <scsi/scsi_dbg.h>
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#include <scsi/scsi_eh.h>
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#include <scsi/scsi_dh.h>
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#define ALUA_DH_NAME "alua"
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#define ALUA_DH_VER "2.0"
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#define TPGS_SUPPORT_NONE 0x00
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#define TPGS_SUPPORT_OPTIMIZED 0x01
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#define TPGS_SUPPORT_NONOPTIMIZED 0x02
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#define TPGS_SUPPORT_STANDBY 0x04
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#define TPGS_SUPPORT_UNAVAILABLE 0x08
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#define TPGS_SUPPORT_LBA_DEPENDENT 0x10
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#define TPGS_SUPPORT_OFFLINE 0x40
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#define TPGS_SUPPORT_TRANSITION 0x80
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#define RTPG_FMT_MASK 0x70
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#define RTPG_FMT_EXT_HDR 0x10
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#define TPGS_MODE_UNINITIALIZED -1
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#define TPGS_MODE_NONE 0x0
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#define TPGS_MODE_IMPLICIT 0x1
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#define TPGS_MODE_EXPLICIT 0x2
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#define ALUA_RTPG_SIZE 128
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#define ALUA_FAILOVER_TIMEOUT 60
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#define ALUA_FAILOVER_RETRIES 5
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#define ALUA_RTPG_DELAY_MSECS 5
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/* device handler flags */
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#define ALUA_OPTIMIZE_STPG 0x01
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#define ALUA_RTPG_EXT_HDR_UNSUPP 0x02
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#define ALUA_SYNC_STPG 0x04
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/* State machine flags */
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#define ALUA_PG_RUN_RTPG 0x10
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#define ALUA_PG_RUN_STPG 0x20
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#define ALUA_PG_RUNNING 0x40
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static uint optimize_stpg;
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module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR);
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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.");
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static LIST_HEAD(port_group_list);
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static DEFINE_SPINLOCK(port_group_lock);
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static struct workqueue_struct *kaluad_wq;
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static struct workqueue_struct *kaluad_sync_wq;
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struct alua_port_group {
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struct kref kref;
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struct rcu_head rcu;
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struct list_head node;
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struct list_head dh_list;
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unsigned char device_id_str[256];
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int device_id_len;
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int group_id;
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int tpgs;
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int state;
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int pref;
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unsigned flags; /* used for optimizing STPG */
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unsigned char transition_tmo;
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unsigned long expiry;
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unsigned long interval;
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struct delayed_work rtpg_work;
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spinlock_t lock;
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struct list_head rtpg_list;
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struct scsi_device *rtpg_sdev;
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};
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struct alua_dh_data {
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struct list_head node;
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struct alua_port_group *pg;
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int group_id;
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spinlock_t pg_lock;
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struct scsi_device *sdev;
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int init_error;
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struct mutex init_mutex;
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};
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struct alua_queue_data {
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struct list_head entry;
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activate_complete callback_fn;
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void *callback_data;
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};
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#define ALUA_POLICY_SWITCH_CURRENT 0
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#define ALUA_POLICY_SWITCH_ALL 1
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static void alua_rtpg_work(struct work_struct *work);
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static void alua_rtpg_queue(struct alua_port_group *pg,
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struct scsi_device *sdev,
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struct alua_queue_data *qdata, bool force);
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static void alua_check(struct scsi_device *sdev, bool force);
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static void release_port_group(struct kref *kref)
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{
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struct alua_port_group *pg;
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pg = container_of(kref, struct alua_port_group, kref);
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if (pg->rtpg_sdev)
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flush_delayed_work(&pg->rtpg_work);
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spin_lock(&port_group_lock);
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list_del(&pg->node);
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spin_unlock(&port_group_lock);
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kfree_rcu(pg, rcu);
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}
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/*
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* submit_rtpg - Issue a REPORT TARGET GROUP STATES command
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* @sdev: sdev the command should be sent to
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*/
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static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff,
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int bufflen, struct scsi_sense_hdr *sshdr, int flags)
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{
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u8 cdb[COMMAND_SIZE(MAINTENANCE_IN)];
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int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
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REQ_FAILFAST_DRIVER;
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/* Prepare the command. */
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memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_IN));
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cdb[0] = MAINTENANCE_IN;
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if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP))
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cdb[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
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else
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cdb[1] = MI_REPORT_TARGET_PGS;
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put_unaligned_be32(bufflen, &cdb[6]);
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return scsi_execute_req_flags(sdev, cdb, DMA_FROM_DEVICE,
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buff, bufflen, sshdr,
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ALUA_FAILOVER_TIMEOUT * HZ,
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ALUA_FAILOVER_RETRIES, NULL, req_flags);
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}
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/*
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* submit_stpg - Issue a SET TARGET PORT GROUP command
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*
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* Currently we're only setting the current target port group state
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* to 'active/optimized' and let the array firmware figure out
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* the states of the remaining groups.
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*/
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static int submit_stpg(struct scsi_device *sdev, int group_id,
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struct scsi_sense_hdr *sshdr)
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{
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u8 cdb[COMMAND_SIZE(MAINTENANCE_OUT)];
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unsigned char stpg_data[8];
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int stpg_len = 8;
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int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
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REQ_FAILFAST_DRIVER;
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/* Prepare the data buffer */
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memset(stpg_data, 0, stpg_len);
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stpg_data[4] = SCSI_ACCESS_STATE_OPTIMAL;
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put_unaligned_be16(group_id, &stpg_data[6]);
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/* Prepare the command. */
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memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_OUT));
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cdb[0] = MAINTENANCE_OUT;
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cdb[1] = MO_SET_TARGET_PGS;
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put_unaligned_be32(stpg_len, &cdb[6]);
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return scsi_execute_req_flags(sdev, cdb, DMA_TO_DEVICE,
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stpg_data, stpg_len,
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sshdr, ALUA_FAILOVER_TIMEOUT * HZ,
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ALUA_FAILOVER_RETRIES, NULL, req_flags);
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}
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static struct alua_port_group *alua_find_get_pg(char *id_str, size_t id_size,
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int group_id)
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{
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struct alua_port_group *pg;
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if (!id_str || !id_size || !strlen(id_str))
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return NULL;
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list_for_each_entry(pg, &port_group_list, node) {
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if (pg->group_id != group_id)
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continue;
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if (!pg->device_id_len || pg->device_id_len != id_size)
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continue;
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if (strncmp(pg->device_id_str, id_str, id_size))
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continue;
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if (!kref_get_unless_zero(&pg->kref))
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continue;
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return pg;
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}
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return NULL;
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}
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/*
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* alua_alloc_pg - Allocate a new port_group structure
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* @sdev: scsi device
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* @h: alua device_handler data
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* @group_id: port group id
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*
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* Allocate a new port_group structure for a given
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* device.
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*/
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static struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev,
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int group_id, int tpgs)
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{
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struct alua_port_group *pg, *tmp_pg;
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pg = kzalloc(sizeof(struct alua_port_group), GFP_KERNEL);
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if (!pg)
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return ERR_PTR(-ENOMEM);
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pg->device_id_len = scsi_vpd_lun_id(sdev, pg->device_id_str,
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sizeof(pg->device_id_str));
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if (pg->device_id_len <= 0) {
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/*
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* TPGS supported but no device identification found.
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* Generate private device identification.
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*/
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sdev_printk(KERN_INFO, sdev,
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"%s: No device descriptors found\n",
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ALUA_DH_NAME);
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pg->device_id_str[0] = '\0';
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pg->device_id_len = 0;
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}
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pg->group_id = group_id;
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pg->tpgs = tpgs;
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pg->state = SCSI_ACCESS_STATE_OPTIMAL;
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if (optimize_stpg)
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pg->flags |= ALUA_OPTIMIZE_STPG;
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kref_init(&pg->kref);
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INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work);
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INIT_LIST_HEAD(&pg->rtpg_list);
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INIT_LIST_HEAD(&pg->node);
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INIT_LIST_HEAD(&pg->dh_list);
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spin_lock_init(&pg->lock);
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spin_lock(&port_group_lock);
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tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
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group_id);
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if (tmp_pg) {
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spin_unlock(&port_group_lock);
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kfree(pg);
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return tmp_pg;
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}
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list_add(&pg->node, &port_group_list);
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spin_unlock(&port_group_lock);
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return pg;
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}
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/*
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* alua_check_tpgs - Evaluate TPGS setting
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* @sdev: device to be checked
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*
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* Examine the TPGS setting of the sdev to find out if ALUA
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* is supported.
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*/
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static int alua_check_tpgs(struct scsi_device *sdev)
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{
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int tpgs = TPGS_MODE_NONE;
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/*
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* ALUA support for non-disk devices is fraught with
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* difficulties, so disable it for now.
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*/
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if (sdev->type != TYPE_DISK) {
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sdev_printk(KERN_INFO, sdev,
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"%s: disable for non-disk devices\n",
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ALUA_DH_NAME);
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return tpgs;
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}
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tpgs = scsi_device_tpgs(sdev);
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switch (tpgs) {
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case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
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sdev_printk(KERN_INFO, sdev,
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"%s: supports implicit and explicit TPGS\n",
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ALUA_DH_NAME);
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break;
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case TPGS_MODE_EXPLICIT:
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sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
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ALUA_DH_NAME);
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break;
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case TPGS_MODE_IMPLICIT:
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sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
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ALUA_DH_NAME);
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break;
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case TPGS_MODE_NONE:
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sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
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ALUA_DH_NAME);
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break;
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default:
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sdev_printk(KERN_INFO, sdev,
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"%s: unsupported TPGS setting %d\n",
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ALUA_DH_NAME, tpgs);
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tpgs = TPGS_MODE_NONE;
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break;
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}
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return tpgs;
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}
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/*
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* alua_check_vpd - Evaluate INQUIRY vpd page 0x83
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* @sdev: device to be checked
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*
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* Extract the relative target port and the target port group
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* descriptor from the list of identificators.
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*/
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static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
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int tpgs)
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{
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int rel_port = -1, group_id;
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struct alua_port_group *pg, *old_pg = NULL;
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bool pg_updated = false;
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unsigned long flags;
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group_id = scsi_vpd_tpg_id(sdev, &rel_port);
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if (group_id < 0) {
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/*
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* Internal error; TPGS supported but required
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* VPD identification descriptors not present.
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* Disable ALUA support
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*/
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sdev_printk(KERN_INFO, sdev,
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"%s: No target port descriptors found\n",
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ALUA_DH_NAME);
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return SCSI_DH_DEV_UNSUPP;
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}
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pg = alua_alloc_pg(sdev, group_id, tpgs);
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if (IS_ERR(pg)) {
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if (PTR_ERR(pg) == -ENOMEM)
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return SCSI_DH_NOMEM;
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return SCSI_DH_DEV_UNSUPP;
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}
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if (pg->device_id_len)
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sdev_printk(KERN_INFO, sdev,
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"%s: device %s port group %x rel port %x\n",
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ALUA_DH_NAME, pg->device_id_str,
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group_id, rel_port);
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else
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sdev_printk(KERN_INFO, sdev,
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"%s: port group %x rel port %x\n",
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ALUA_DH_NAME, group_id, rel_port);
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/* Check for existing port group references */
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spin_lock(&h->pg_lock);
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old_pg = h->pg;
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if (old_pg != pg) {
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/* port group has changed. Update to new port group */
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if (h->pg) {
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spin_lock_irqsave(&old_pg->lock, flags);
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list_del_rcu(&h->node);
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spin_unlock_irqrestore(&old_pg->lock, flags);
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}
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rcu_assign_pointer(h->pg, pg);
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pg_updated = true;
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}
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spin_lock_irqsave(&pg->lock, flags);
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if (sdev->synchronous_alua)
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pg->flags |= ALUA_SYNC_STPG;
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if (pg_updated)
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list_add_rcu(&h->node, &pg->dh_list);
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spin_unlock_irqrestore(&pg->lock, flags);
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alua_rtpg_queue(h->pg, sdev, NULL, true);
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spin_unlock(&h->pg_lock);
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if (old_pg)
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kref_put(&old_pg->kref, release_port_group);
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return SCSI_DH_OK;
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}
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static char print_alua_state(unsigned char state)
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{
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switch (state) {
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case SCSI_ACCESS_STATE_OPTIMAL:
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return 'A';
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case SCSI_ACCESS_STATE_ACTIVE:
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return 'N';
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case SCSI_ACCESS_STATE_STANDBY:
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return 'S';
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case SCSI_ACCESS_STATE_UNAVAILABLE:
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return 'U';
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case SCSI_ACCESS_STATE_LBA:
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return 'L';
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case SCSI_ACCESS_STATE_OFFLINE:
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return 'O';
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case SCSI_ACCESS_STATE_TRANSITIONING:
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return 'T';
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default:
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return 'X';
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}
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}
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static int alua_check_sense(struct scsi_device *sdev,
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struct scsi_sense_hdr *sense_hdr)
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{
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switch (sense_hdr->sense_key) {
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case NOT_READY:
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if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) {
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/*
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* LUN Not Accessible - ALUA state transition
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*/
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alua_check(sdev, false);
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return NEEDS_RETRY;
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}
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break;
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case UNIT_ATTENTION:
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if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) {
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/*
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* Power On, Reset, or Bus Device Reset.
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* Might have obscured a state transition,
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* so schedule a recheck.
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*/
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alua_check(sdev, true);
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return ADD_TO_MLQUEUE;
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}
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if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04)
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/*
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* Device internal reset
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*/
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return ADD_TO_MLQUEUE;
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if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
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/*
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* Mode Parameters Changed
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*/
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return ADD_TO_MLQUEUE;
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if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
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/*
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* ALUA state changed
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*/
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alua_check(sdev, true);
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return ADD_TO_MLQUEUE;
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}
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if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
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/*
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* Implicit ALUA state transition failed
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*/
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alua_check(sdev, true);
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return ADD_TO_MLQUEUE;
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}
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if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03)
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/*
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* Inquiry data has changed
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*/
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return ADD_TO_MLQUEUE;
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if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e)
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/*
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* REPORTED_LUNS_DATA_HAS_CHANGED is reported
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* when switching controllers on targets like
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* Intel Multi-Flex. We can just retry.
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*/
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return ADD_TO_MLQUEUE;
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break;
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}
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return SCSI_RETURN_NOT_HANDLED;
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}
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/*
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* alua_tur - Send a TEST UNIT READY
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* @sdev: device to which the TEST UNIT READY command should be send
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|
*
|
|
* 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;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
}
|
|
|
|
static void alua_rescan(struct scsi_device *sdev)
|
|
{
|
|
struct alua_dh_data *h = sdev->handler_data;
|
|
|
|
alua_initialize(sdev, h);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
static void __exit alua_exit(void)
|
|
{
|
|
scsi_unregister_device_handler(&alua_dh);
|
|
destroy_workqueue(kaluad_sync_wq);
|
|
destroy_workqueue(kaluad_wq);
|
|
}
|
|
|
|
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);
|