Hannes Reinecke wrote:
+
+static struct request *get_alua_req(struct scsi_device *sdev,
+ void *buffer, unsigned buflen, int rw)
+{
+ struct request *rq;
+ struct request_queue *q = sdev->request_queue;
+
+ rq = blk_get_request(q, rw, GFP_KERNEL);
+
+ if (!rq) {
+ sdev_printk(KERN_INFO, sdev,
+ "%s: blk_get_request failed\n", __FUNCTION__);
+ return NULL;
+ }
+
+ if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_KERNEL)) {
+ blk_put_request(rq);
+ sdev_printk(KERN_INFO, sdev,
+ "%s: blk_rq_map_kern failed\n", __FUNCTION__);
+ return NULL;
+ }
+
+ rq->cmd_type = REQ_TYPE_BLOCK_PC;
+ rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
+ rq->retries = ALUA_FAILOVER_RETRIES;
+ rq->timeout = ALUA_FAILOVER_TIMEOUT;
+
+ return rq;
+}
It looks like this can be called from alua_activate, and we cannot use
GFP_KERNEL in the same IO path something could get written to.
+/*
+ * submit_std_inquiry - Issue a standard INQUIRY command
+ * @sdev: sdev the command should be send to
+ */
+static int submit_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
+{
+ struct request *rq;
+ int err = SCSI_DH_RES_TEMP_UNAVAIL;
+
+ rq = get_alua_req(sdev, h->inq, ALUA_INQUIRY_SIZE, READ);
+ if (!rq)
+ goto done;
+
+ /* Prepare the command. */
+ rq->cmd[0] = INQUIRY;
+ rq->cmd[1] = 0;
+ rq->cmd[2] = 0;
+ rq->cmd[4] = ALUA_INQUIRY_SIZE;
+ rq->cmd_len = COMMAND_SIZE(INQUIRY);
+
+ rq->sense = h->sense;
+ memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
+ rq->sense_len = h->senselen = 0;
+
+ err = blk_execute_rq(rq->q, NULL, rq, 1);
+ if (err == -EIO) {
+ sdev_printk(KERN_INFO, sdev,
+ "%s: std inquiry failed with %x\n",
+ ALUA_DH_NAME, rq->errors);
+ h->senselen = rq->sense_len;
+ err = SCSI_DH_IO;
+ }
+ blk_put_request(rq);
+done:
+ return err;
+}
+
+/*
+ * submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command
+ * @sdev: sdev the command should be sent to
+ */
+static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
+{
+ struct request *rq;
+ int err = SCSI_DH_RES_TEMP_UNAVAIL;
+
+ rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
+ if (!rq)
+ goto done;
+
+ /* Prepare the command. */
+ rq->cmd[0] = INQUIRY;
+ rq->cmd[1] = 1;
+ rq->cmd[2] = 0x83;
+ rq->cmd[4] = h->bufflen;
+ rq->cmd_len = COMMAND_SIZE(INQUIRY);
+
+ rq->sense = h->sense;
+ memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
+ rq->sense_len = h->senselen = 0;
+
+ err = blk_execute_rq(rq->q, NULL, rq, 1);
+ if (err == -EIO) {
+ sdev_printk(KERN_INFO, sdev,
+ "%s: evpd inquiry failed with %x\n",
+ ALUA_DH_NAME, rq->errors);
+ h->senselen = rq->sense_len;
+ err = SCSI_DH_IO;
+ }
+ blk_put_request(rq);
+done:
+ return err;
+}
+
+/*
+ * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
+ * @sdev: sdev the command should be sent to
+ */
+static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
+{
+ struct request *rq;
+ int err = SCSI_DH_RES_TEMP_UNAVAIL;
+
+ rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
+ if (!rq)
+ goto done;
+
+ /* Prepare the command. */
+ rq->cmd[0] = MAINTENANCE_IN;
+ rq->cmd[1] = MI_REPORT_TARGET_PGS;
+ rq->cmd[6] = (h->bufflen >> 24) & 0xff;
+ rq->cmd[7] = (h->bufflen >> 16) & 0xff;
+ rq->cmd[8] = (h->bufflen >> 8) & 0xff;
+ rq->cmd[9] = h->bufflen & 0xff;
+ rq->cmd_len = COMMAND_SIZE(MAINTENANCE_IN);
+
+ rq->sense = h->sense;
+ memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
+ rq->sense_len = h->senselen = 0;
+
+ err = blk_execute_rq(rq->q, NULL, rq, 1);
+ if (err == -EIO) {
+ sdev_printk(KERN_INFO, sdev,
+ "%s: rtpg failed with %x\n",
+ ALUA_DH_NAME, rq->errors);
+ h->senselen = rq->sense_len;
+ err = SCSI_DH_IO;
+ }
+ blk_put_request(rq);
+done:
+ return err;
+}
+
+/*
+ * submit_stpg - Issue a SET TARGET GROUP STATES command
+ * @sdev: sdev the command should be sent to
+ *
+ * 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 unsigned submit_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
+{
+ struct request *rq;
+ int err = SCSI_DH_RES_TEMP_UNAVAIL;
+ int stpg_len = 8;
+
+ /* Prepare the data buffer */
+ memset(h->buff, 0, stpg_len);
+ h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f;
+ h->buff[6] = (h->group_id >> 8) & 0x0f;
+ h->buff[7] = h->group_id & 0x0f;
+
+ rq = get_alua_req(sdev, h->buff, stpg_len, WRITE);
+ if (!rq)
+ goto done;
+
+ /* Prepare the command. */
+ rq->cmd[0] = MAINTENANCE_OUT;
+ rq->cmd[1] = MO_SET_TARGET_PGS;
+ rq->cmd[6] = (stpg_len >> 24) & 0xff;
+ rq->cmd[7] = (stpg_len >> 16) & 0xff;
+ rq->cmd[8] = (stpg_len >> 8) & 0xff;
+ rq->cmd[9] = stpg_len & 0xff;
+ rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT);
+
+ rq->sense = h->sense;
+ memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
+ rq->sense_len = h->senselen = 0;
+
+ err = blk_execute_rq(rq->q, NULL, rq, 1);
+ if (err == -EIO) {
+ sdev_printk(KERN_INFO, sdev,
+ "%s: stpg failed with %x\n",
+ ALUA_DH_NAME, rq->errors);
+ h->senselen = rq->sense_len;
+ err = SCSI_DH_IO;
+ }
+ blk_put_request(rq);
+done:
+ return err;
+}
+
+/*
+ * alua_std_inquiry - Evaluate standard INQUIRY command
+ * @sdev: device to be checked
+ *
+ * Just extract the TPGS setting to find out if ALUA
+ * is supported.
+ */
+static int alua_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
+{
+ int err;
+
+ err = submit_std_inquiry(sdev, h);
+
You could remove the space so it looks like the other code.
+ if (err != SCSI_DH_OK)
+ return err;
+
+ /* Check TPGS setting */
+ h->tpgs = (h->inq[5] >> 4) & 0x3;
+ switch (h->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;
+ default:
+ h->tpgs = TPGS_MODE_NONE;
+ sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
+ ALUA_DH_NAME);
+ err = SCSI_DH_DEV_UNSUPP;
+ break;
+ }
+
+ return err;
+}
+
+/*
+ * alua_vpd_inquiry - 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_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
+{
+ int len;
+ unsigned err;
+ unsigned char *d;
+
+ retry:
+ err = submit_vpd_inquiry(sdev, h);
+
+ if (err != SCSI_DH_OK)
+ return err;
+
+ /* Check if vpd page exceeds initial buffer */
+ len = (h->buff[2] << 8) + h->buff[3] + 4;
+ if (len > h->bufflen) {
+ /* Resubmit with the correct length */
+ if (realloc_buffer(h, len)) {
+ sdev_printk(KERN_WARNING, sdev,
+ "%s: kmalloc buffer failed\n",
+ ALUA_DH_NAME);
+ /* Temporary failure, bypass */
+ return SCSI_DH_DEV_TEMP_BUSY;
+ }
+ goto retry;
+ }
+
+ /*
+ * Now look for the correct descriptor.
+ */
+ d = h->buff + 4;
+ while (d < h->buff + len) {
+ switch (d[1] & 0xf) {
+ case 0x4:
+ /* Relative target port */
+ h->rel_port = (d[6] << 8) + d[7];
+ break;
+ case 0x5:
+ /* Target port group */
+ h->group_id = (d[6] << 8) + d[7];
+ break;
+ default:
+ break;
+ }
+ d += d[3] + 4;
+ }
+
+ if (h->group_id == -1) {
+ /*
+ * 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);
+ h->state = TPGS_STATE_OPTIMIZED;
+ h->tpgs = TPGS_MODE_NONE;
+ err = SCSI_DH_DEV_UNSUPP;
+ } else {
+ sdev_printk(KERN_INFO, sdev,
+ "%s: port group %02x rel port %02x\n",
+ ALUA_DH_NAME, h->group_id, h->rel_port);
+ }
+
+ return err;
+}
+
+static char print_alua_state(int state)
+{
+ switch (state) {
+ case TPGS_STATE_OPTIMIZED:
+ return 'A';
+ case TPGS_STATE_NONOPTIMIZED:
+ return 'N';
+ case TPGS_STATE_STANDBY:
+ return 'S';
+ case TPGS_STATE_UNAVAILABLE:
+ return 'U';
+ case TPGS_STATE_OFFLINE:
+ return 'O';
+ case TPGS_STATE_TRANSITIONING:
+ return 'T';
+ default:
+ return 'X';
+ }
+}
+
+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
+ */
+ return NEEDS_RETRY;
+ if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b)
+ /*
+ * LUN Not Accessible -- Target port in standby state
+ */
+ return SUCCESS;
+ if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c)
+ /*
+ * LUN Not Accessible -- Target port in unavailable state
+ */
+ return SUCCESS;
+ if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12)
+ /*
+ * LUN Not Ready -- Offline
+ */
+ return SUCCESS;
+ break;
+ case UNIT_ATTENTION:
+ if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
+ /*
+ * Power On, Reset, or Bus Device Reset, just retry.
+ */
+ return NEEDS_RETRY;
+ if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
+ /*
+ * ALUA state changed
+ */
+ return NEEDS_RETRY;
+ }
+ if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
+ /*
+ * Implicit ALUA state transition failed
+ */
+ return NEEDS_RETRY;
+ }
+ break;
+ }
+
+ return SCSI_RETURN_NOT_HANDLED;
+}
+
+/*
+ * alua_stpg - Evaluate SET TARGET GROUP STATES
+ * @sdev: the device to be evaluated
+ * @state: the new target group state
+ *
+ * Send a SET TARGET GROUP STATES command to the device.
+ * We only have to test here if we should resubmit the command;
+ * any other error is assumed as a failure.
+ */
+static int alua_stpg(struct scsi_device *sdev, int state,
+ struct alua_dh_data *h)
+{
+ struct scsi_sense_hdr sense_hdr;
+ unsigned err;
+ int retry = ALUA_FAILOVER_RETRIES;
+
+ retry:
+ err = submit_stpg(sdev, h);
+ if (err == SCSI_DH_IO && h->senselen > 0) {
+ err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
+ &sense_hdr);
+ if (!err)
+ return SCSI_DH_IO;
+ err = alua_check_sense(sdev, &sense_hdr);
+ if (retry > 0 && err == NEEDS_RETRY) {
+ retry--;
+ goto retry;
+ }
+ sdev_printk(KERN_INFO, sdev,
+ "%s: stpg sense code: %02x/%02x/%02x\n",
+ ALUA_DH_NAME, sense_hdr.sense_key,
+ sense_hdr.asc, sense_hdr.ascq);
+ err = SCSI_DH_IO;
+ }
+ if (err == SCSI_DH_OK) {
+ h->state = state;
+ sdev_printk(KERN_INFO, sdev,
+ "%s: port group %02x switched to state %c\n",
+ ALUA_DH_NAME, h->group_id,
+ print_alua_state(h->state) );
+ }
+ return err;
+}
+
+/*
+ * 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 unuseable.
+ */
+static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
+{
+ struct scsi_sense_hdr sense_hdr;
+ int len, k, off, valid_states = 0;
+ char *ucp;
+ unsigned err;
+
+ retry:
+ err = submit_rtpg(sdev, h);
+
+ if (err == SCSI_DH_IO && h->senselen > 0) {
+ err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
+ &sense_hdr);
+ if (!err)
+ return SCSI_DH_IO;
+
+ err = alua_check_sense(sdev, &sense_hdr);
+ if (err == NEEDS_RETRY)
+ goto retry;
+ sdev_printk(KERN_INFO, sdev,
+ "%s: rtpg sense code %02x/%02x/%02x\n",
+ ALUA_DH_NAME, sense_hdr.sense_key,
+ sense_hdr.asc, sense_hdr.ascq);
+ err = SCSI_DH_IO;
+ }
+ if (err != SCSI_DH_OK)
+ return err;
+
+ len = (h->buff[0] << 24) + (h->buff[1] << 16) +
+ (h->buff[2] << 8) + h->buff[3] + 4;
+
+ if (len > h->bufflen) {
+ /* Resubmit with the correct length */
+ if (realloc_buffer(h, len)) {
+ sdev_printk(KERN_WARNING, sdev,
+ "%s: kmalloc buffer failed\n",__FUNCTION__);
+ /* Temporary failure, bypass */
+ return SCSI_DH_DEV_TEMP_BUSY;
+ }
+ goto retry;
+ }
+
+ for (k = 4, ucp = h->buff + 4; k < len; k += off, ucp += off) {
+ if (h->group_id == (ucp[2] << 8) + ucp[3]) {
+ h->state = ucp[0] & 0x0f;
+ valid_states = ucp[1];
+ }
+ off = 8 + (ucp[7] * 4);
+ }
+
+ sdev_printk(KERN_INFO, sdev,
+ "%s: port group %02x state %c supports %c%c%c%c%c%c\n",
+ ALUA_DH_NAME, h->group_id, print_alua_state(h->state),
+ valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
+ valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
+ 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');
+
+ if (h->tpgs & TPGS_MODE_EXPLICIT) {
+ switch (h->state) {
+ case TPGS_STATE_TRANSITIONING:
+ /* State transition, retry */
+ goto retry;
+ break;
+ case TPGS_STATE_OFFLINE:
+ /* Path is offline, fail */
+ err = SCSI_DH_DEV_OFFLINED;
+ break;
+ default:
+ break;
+ }
+ } else {
+ /* Only Implicit ALUA support */
+ if (h->state == TPGS_STATE_OPTIMIZED ||
+ h->state == TPGS_STATE_NONOPTIMIZED ||
+ h->state == TPGS_STATE_STANDBY)
+ /* Useable path if active */
+ err = SCSI_DH_OK;
+ else
+ /* Path unuseable for unavailable/offline */
+ err = SCSI_DH_DEV_OFFLINED;
+ }
+ return err;
+}
+
+/*
+ * 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;
+
+ err = alua_std_inquiry(sdev, h);
+ if (err != SCSI_DH_OK)
+ goto out;
+
+ err = alua_vpd_inquiry(sdev, h);
+ if (err != SCSI_DH_OK)
+ goto out;
+
+ err = alua_rtpg(sdev, h);
+ if (err != SCSI_DH_OK)
+ goto out;
+
+out:
+ return err;
+}
+
+/*
+ * 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)
+{
+ struct alua_dh_data *h = get_alua_data(sdev);
+ int err = SCSI_DH_OK;
+
+ if (h->group_id != -1) {
+ err = alua_rtpg(sdev, h);
+ if (err != SCSI_DH_OK)
+ goto out;
+ }
+
+ if (h->tpgs == TPGS_MODE_EXPLICIT && h->state != TPGS_STATE_OPTIMIZED)
+ err = alua_stpg(sdev, TPGS_STATE_OPTIMIZED, h);
+
+out:
+ return err;
+}
+
+/*
+ * 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 = get_alua_data(sdev);
+ int ret = BLKPREP_OK;
+
+ if (h->state != TPGS_STATE_OPTIMIZED &&
+ h->state != TPGS_STATE_NONOPTIMIZED) {
+ ret = BLKPREP_KILL;
+ req->cmd_flags |= REQ_QUIET;
+ }
+ return ret;
+
+}
+
+const struct scsi_dh_devlist alua_dev_list[] = {
+ {"HP", "MSA VOLUME" },
+ {"HP", "HSV101" },
+ {"HP", "HSV111" },
+ {"HP", "HSV200" },
+ {"HP", "HSV210" },
+ {"HP", "HSV300" },
+ {"IBM", "2107900" },
+ {"IBM", "2145" },
+ {"Pillar", "Axiom" },
+ {NULL, NULL}
+};
+
+static int alua_bus_attach(struct scsi_device *sdev);
+static void alua_bus_detach(struct scsi_device *sdev);
+
+static struct scsi_device_handler alua_dh = {
+ .name = ALUA_DH_NAME,
+ .module = THIS_MODULE,
+ .devlist = alua_dev_list,
+ .attach = alua_bus_attach,
+ .detach = alua_bus_detach,
+ .prep_fn = alua_prep_fn,
+ .check_sense = alua_check_sense,
+ .activate = alua_activate,
+};
+
+/*
+ * alua_bus_attach - Attach device handler
+ * @sdev: device to be attached to
+ */
+static int alua_bus_attach(struct scsi_device *sdev)
+{
+ struct scsi_dh_data *scsi_dh_data;
+ struct alua_dh_data *h;
+ unsigned long flags;
+ int err = SCSI_DH_OK;
+
+ scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
+ + sizeof(*h) , GFP_KERNEL);
+ if (!scsi_dh_data) {
+ sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
+ ALUA_DH_NAME);
+ return -ENOMEM;
+ }
+
+ scsi_dh_data->scsi_dh = &alua_dh;
+ h = (struct alua_dh_data *) scsi_dh_data->buf;
+ h->tpgs = TPGS_MODE_UNINITIALIZED;
+ h->state = TPGS_STATE_OPTIMIZED;
+ h->group_id = -1;
+ h->rel_port = -1;
+ h->buff = h->inq;
+ h->bufflen = ALUA_INQUIRY_SIZE;
+
+ err = alua_initialize(sdev, h);
+ if (err != SCSI_DH_OK)
+ goto failed;
+
+ spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
+ sdev->scsi_dh_data = scsi_dh_data;
+ spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+
+ try_module_get(THIS_MODULE);
Do we need to handle the case where this fails?
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