drivers/s390/scsi/zfcp_unit.c

   1 /*
   2  * zfcp device driver
   3  *
   4  * Tracking of manually configured LUNs and helper functions to
   5  * register the LUNs with the SCSI midlayer.
   6  *
   7  * Copyright IBM Corporation 2010
   8  */
   9
  10 #include "zfcp_def.h"
  11 #include "zfcp_ext.h"
  12
  13 /**
  14  * zfcp_unit_scsi_scan - Register LUN with SCSI midlayer
  15  * @unit: The zfcp LUN/unit to register
  16  *
  17  * When the SCSI midlayer is not allowed to automatically scan and
  18  * attach SCSI devices, zfcp has to register the single devices with
  19  * the SCSI midlayer.
  20  */
  21 void zfcp_unit_scsi_scan(struct zfcp_unit *unit)
  22 {
  23         struct fc_rport *rport = unit->port->rport;
  24         unsigned int lun;
  25
  26         lun = scsilun_to_int((struct scsi_lun *) &unit->fcp_lun);
  27
  28         if (rport && rport->port_state == FC_PORTSTATE_ONLINE)
  29                 scsi_scan_target(&rport->dev, 0, rport->scsi_target_id, lun, 1);
  30 }
  31
  32 static void zfcp_unit_scsi_scan_work(struct work_struct *work)
  33 {
  34         struct zfcp_unit *unit = container_of(work, struct zfcp_unit,
  35                                               scsi_work);
  36
  37         zfcp_unit_scsi_scan(unit);
  38         put_device(&unit->dev);
  39 }
  40
  41 /**
  42  * zfcp_unit_queue_scsi_scan - Register configured units on port
  43  * @port: The zfcp_port where to register units
  44  *
  45  * After opening a port, all units configured on this port have to be
  46  * registered with the SCSI midlayer. This function should be called
  47  * after calling fc_remote_port_add, so that the fc_rport is already
  48  * ONLINE and the call to scsi_scan_target runs the same way as the
  49  * call in the FC transport class.
  50  */
  51 void zfcp_unit_queue_scsi_scan(struct zfcp_port *port)
  52 {
  53         struct zfcp_unit *unit;
  54
  55         read_lock_irq(&port->unit_list_lock);
  56         list_for_each_entry(unit, &port->unit_list, list) {
  57                 get_device(&unit->dev);
  58                 if (scsi_queue_work(port->adapter->scsi_host,
  59                                     &unit->scsi_work) <= 0)
  60                         put_device(&unit->dev);
  61         }
  62         read_unlock_irq(&port->unit_list_lock);
  63 }
  64
  65 static struct zfcp_unit *_zfcp_unit_find(struct zfcp_port *port, u64 fcp_lun)
  66 {
  67         struct zfcp_unit *unit;
  68
  69         list_for_each_entry(unit, &port->unit_list, list)
  70                 if (unit->fcp_lun == fcp_lun) {
  71                         get_device(&unit->dev);
  72                         return unit;
  73                 }
  74
  75         return NULL;
  76 }
  77
  78 /**
  79  * zfcp_unit_find - Find and return zfcp_unit with specified FCP LUN
  80  * @port: zfcp_port where to look for the unit
  81  * @fcp_lun: 64 Bit FCP LUN used to identify the zfcp_unit
  82  *
  83  * If zfcp_unit is found, a reference is acquired that has to be
  84  * released later.
  85  *
  86  * Returns: Pointer to the zfcp_unit, or NULL if there is no zfcp_unit
  87  *          with the specified FCP LUN.
  88  */
  89 struct zfcp_unit *zfcp_unit_find(struct zfcp_port *port, u64 fcp_lun)
  90 {
  91         struct zfcp_unit *unit;
  92
  93         read_lock_irq(&port->unit_list_lock);
  94         unit = _zfcp_unit_find(port, fcp_lun);
  95         read_unlock_irq(&port->unit_list_lock);
  96         return unit;
  97 }
  98
  99 /**
 100  * zfcp_unit_release - Drop reference to zfcp_port and free memory of zfcp_unit.
 101  * @dev: pointer to device in zfcp_unit
 102  */
 103 static void zfcp_unit_release(struct device *dev)
 104 {
 105         struct zfcp_unit *unit = container_of(dev, struct zfcp_unit, dev);
 106
 107         put_device(&unit->port->dev);
 108         kfree(unit);
 109 }
 110
 111 /**
 112  * zfcp_unit_enqueue - enqueue unit to unit list of a port.
 113  * @port: pointer to port where unit is added
 114  * @fcp_lun: FCP LUN of unit to be enqueued
 115  * Returns: 0 success
 116  *
 117  * Sets up some unit internal structures and creates sysfs entry.
 118  */
 119 int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
 120 {
 121         struct zfcp_unit *unit;
 122
 123         unit = zfcp_unit_find(port, fcp_lun);
 124         if (unit) {
 125                 put_device(&unit->dev);
 126                 return -EEXIST;
 127         }
 128
 129         unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
 130         if (!unit)
 131                 return -ENOMEM;
 132
 133         unit->port = port;
 134         unit->fcp_lun = fcp_lun;
 135         unit->dev.parent = &port->dev;
 136         unit->dev.release = zfcp_unit_release;
 137         INIT_WORK(&unit->scsi_work, zfcp_unit_scsi_scan_work);
 138
 139         if (dev_set_name(&unit->dev, "0x%016llx",
 140                          (unsigned long long) fcp_lun)) {
 141                 kfree(unit);
 142                 return -ENOMEM;
 143         }
 144
 145         get_device(&port->dev);
 146
 147         if (device_register(&unit->dev)) {
 148                 put_device(&unit->dev);
 149                 return -ENOMEM;
 150         }
 151
 152         if (sysfs_create_group(&unit->dev.kobj, &zfcp_sysfs_unit_attrs)) {
 153                 device_unregister(&unit->dev);
 154                 return -EINVAL;
 155         }
 156
 157         write_lock_irq(&port->unit_list_lock);
 158         list_add_tail(&unit->list, &port->unit_list);
 159         write_unlock_irq(&port->unit_list_lock);
 160
 161         zfcp_unit_scsi_scan(unit);
 162
 163         return 0;
 164 }
 165
 166 /**
 167  * zfcp_unit_sdev - Return SCSI device for zfcp_unit
 168  * @unit: The zfcp_unit where to get the SCSI device for
 169  *
 170  * Returns: scsi_device pointer on success, NULL if there is no SCSI
 171  *          device for this zfcp_unit
 172  *
 173  * On success, the caller also holds a reference to the SCSI device
 174  * that must be released with scsi_device_put.
 175  */
 176 struct scsi_device *zfcp_unit_sdev(struct zfcp_unit *unit)
 177 {
 178         struct Scsi_Host *shost;
 179         struct zfcp_port *port;
 180         unsigned int lun;
 181
 182         lun = scsilun_to_int((struct scsi_lun *) &unit->fcp_lun);
 183         port = unit->port;
 184         shost = port->adapter->scsi_host;
 185         return scsi_device_lookup(shost, 0, port->starget_id, lun);
 186 }
 187
 188 /**
 189  * zfcp_unit_sdev_status - Return zfcp LUN status for SCSI device
 190  * @unit: The unit to lookup the SCSI device for
 191  *
 192  * Returns the zfcp LUN status field of the SCSI device if the SCSI device
 193  * for the zfcp_unit exists, 0 otherwise.
 194  */
 195 unsigned int zfcp_unit_sdev_status(struct zfcp_unit *unit)
 196 {
 197         unsigned int status = 0;
 198         struct scsi_device *sdev;
 199         struct zfcp_scsi_dev *zfcp_sdev;
 200
 201         sdev = zfcp_unit_sdev(unit);
 202         if (sdev) {
 203                 zfcp_sdev = sdev_to_zfcp(sdev);
 204                 status = atomic_read(&zfcp_sdev->status);
 205                 scsi_device_put(sdev);
 206         }
 207
 208         return status;
 209 }
 210
 211 /**
 212  * zfcp_unit_remove - Remove entry from list of configured units
 213  * @port: The port where to remove the unit from the configuration
 214  * @fcp_lun: The 64 bit LUN of the unit to remove
 215  *
 216  * Returns: -EINVAL if a unit with the specified LUN does not exist,
 217  *          0 on success.
 218  */
 219 int zfcp_unit_remove(struct zfcp_port *port, u64 fcp_lun)
 220 {
 221         struct zfcp_unit *unit;
 222         struct scsi_device *sdev;
 223
 224         write_lock_irq(&port->unit_list_lock);
 225         unit = _zfcp_unit_find(port, fcp_lun);
 226         if (unit)
 227                 list_del(&unit->list);
 228         write_unlock_irq(&port->unit_list_lock);
 229
 230         if (!unit)
 231                 return -EINVAL;
 232
 233         sdev = zfcp_unit_sdev(unit);
 234         if (sdev) {
 235                 scsi_remove_device(sdev);
 236                 scsi_device_put(sdev);
 237         }
 238
 239         put_device(&unit->dev);
 240
 241         zfcp_device_unregister(&unit->dev, &zfcp_sysfs_unit_attrs);
 242
 243         return 0;
 244 }