IB/srp: Implement SRP_CRED_REQ and SRP_AER_REQ
This patch adds support for SRP_CRED_REQ to avoid a lockup by targets that use that mechanism to return credits to the initiator. This prevents a lockup observed in the field where we would never add the credits from the SRP_CRED_REQ to our current count, and would therefore never send another command to the target. Minimal support for SRP_AER_REQ is also added, as these messages can also be used to convey additional credits to the initiator. Based upon extensive debugging and code by Bart Van Assche and a bug report by Chris Worley. Signed-off-by: David Dillow <dillowda@ornl.gov> Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
David Dillow
Roland Dreier
Родитель
dd5e6e38b2
Коммит
bb12588a38
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@ -83,6 +83,10 @@ static void srp_remove_one(struct ib_device *device);
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static void srp_recv_completion(struct ib_cq *cq, void *target_ptr);
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static void srp_send_completion(struct ib_cq *cq, void *target_ptr);
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static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event);
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static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target,
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enum srp_iu_type iu_type);
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static int __srp_post_send(struct srp_target_port *target,
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struct srp_iu *iu, int len);
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static struct scsi_transport_template *ib_srp_transport_template;
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@ -896,6 +900,71 @@ static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp)
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spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
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}
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static int srp_response_common(struct srp_target_port *target, s32 req_delta,
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void *rsp, int len)
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{
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struct ib_device *dev;
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unsigned long flags;
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struct srp_iu *iu;
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int err = 1;
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dev = target->srp_host->srp_dev->dev;
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spin_lock_irqsave(target->scsi_host->host_lock, flags);
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target->req_lim += req_delta;
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iu = __srp_get_tx_iu(target, SRP_IU_RSP);
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if (!iu) {
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shost_printk(KERN_ERR, target->scsi_host, PFX
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"no IU available to send response\n");
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goto out;
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}
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ib_dma_sync_single_for_cpu(dev, iu->dma, len, DMA_TO_DEVICE);
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memcpy(iu->buf, rsp, len);
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ib_dma_sync_single_for_device(dev, iu->dma, len, DMA_TO_DEVICE);
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err = __srp_post_send(target, iu, len);
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if (err)
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shost_printk(KERN_ERR, target->scsi_host, PFX
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"unable to post response: %d\n", err);
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out:
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spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
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return err;
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}
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static void srp_process_cred_req(struct srp_target_port *target,
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struct srp_cred_req *req)
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{
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struct srp_cred_rsp rsp = {
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.opcode = SRP_CRED_RSP,
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.tag = req->tag,
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};
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s32 delta = be32_to_cpu(req->req_lim_delta);
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if (srp_response_common(target, delta, &rsp, sizeof rsp))
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shost_printk(KERN_ERR, target->scsi_host, PFX
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"problems processing SRP_CRED_REQ\n");
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}
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static void srp_process_aer_req(struct srp_target_port *target,
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struct srp_aer_req *req)
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{
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struct srp_aer_rsp rsp = {
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.opcode = SRP_AER_RSP,
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.tag = req->tag,
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};
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s32 delta = be32_to_cpu(req->req_lim_delta);
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shost_printk(KERN_ERR, target->scsi_host, PFX
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"ignoring AER for LUN %llu\n", be64_to_cpu(req->lun));
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if (srp_response_common(target, delta, &rsp, sizeof rsp))
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shost_printk(KERN_ERR, target->scsi_host, PFX
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"problems processing SRP_AER_REQ\n");
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}
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static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc)
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{
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struct ib_device *dev;
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@ -923,6 +992,14 @@ static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc)
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srp_process_rsp(target, iu->buf);
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break;
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case SRP_CRED_REQ:
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srp_process_cred_req(target, iu->buf);
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break;
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case SRP_AER_REQ:
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srp_process_aer_req(target, iu->buf);
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break;
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case SRP_T_LOGOUT:
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/* XXX Handle target logout */
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shost_printk(KERN_WARNING, target->scsi_host,
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@ -985,23 +1062,36 @@ static void srp_send_completion(struct ib_cq *cq, void *target_ptr)
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* Must be called with target->scsi_host->host_lock held to protect
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* req_lim and tx_head. Lock cannot be dropped between call here and
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* call to __srp_post_send().
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*
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* Note:
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* An upper limit for the number of allocated information units for each
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* request type is:
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* - SRP_IU_CMD: SRP_CMD_SQ_SIZE, since the SCSI mid-layer never queues
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* more than Scsi_Host.can_queue requests.
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* - SRP_IU_TSK_MGMT: SRP_TSK_MGMT_SQ_SIZE.
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* - SRP_IU_RSP: 1, since a conforming SRP target never sends more than
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* one unanswered SRP request to an initiator.
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*/
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static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target,
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enum srp_request_type req_type)
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enum srp_iu_type iu_type)
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{
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s32 rsv = (req_type == SRP_REQ_TASK_MGMT) ? 0 : SRP_TSK_MGMT_SQ_SIZE;
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s32 rsv = (iu_type == SRP_IU_TSK_MGMT) ? 0 : SRP_TSK_MGMT_SQ_SIZE;
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struct srp_iu *iu;
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srp_send_completion(target->send_cq, target);
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if (target->tx_head - target->tx_tail >= SRP_SQ_SIZE)
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return NULL;
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if (target->req_lim <= rsv) {
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/* Initiator responses to target requests do not consume credits */
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if (target->req_lim <= rsv && iu_type != SRP_IU_RSP) {
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++target->zero_req_lim;
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return NULL;
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}
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return target->tx_ring[target->tx_head & SRP_SQ_MASK];
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iu = target->tx_ring[target->tx_head & SRP_SQ_MASK];
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iu->type = iu_type;
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return iu;
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}
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/*
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@ -1030,7 +1120,8 @@ static int __srp_post_send(struct srp_target_port *target,
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if (!ret) {
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++target->tx_head;
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--target->req_lim;
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if (iu->type != SRP_IU_RSP)
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--target->req_lim;
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}
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return ret;
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@ -1056,7 +1147,7 @@ static int srp_queuecommand(struct scsi_cmnd *scmnd,
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return 0;
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}
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iu = __srp_get_tx_iu(target, SRP_REQ_NORMAL);
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iu = __srp_get_tx_iu(target, SRP_IU_CMD);
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if (!iu)
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goto err;
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@ -1363,7 +1454,7 @@ static int srp_send_tsk_mgmt(struct srp_target_port *target,
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init_completion(&req->done);
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iu = __srp_get_tx_iu(target, SRP_REQ_TASK_MGMT);
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iu = __srp_get_tx_iu(target, SRP_IU_TSK_MGMT);
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if (!iu)
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goto out;
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@ -82,9 +82,10 @@ enum srp_target_state {
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SRP_TARGET_REMOVED
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};
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enum srp_request_type {
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SRP_REQ_NORMAL,
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SRP_REQ_TASK_MGMT,
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enum srp_iu_type {
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SRP_IU_CMD,
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SRP_IU_TSK_MGMT,
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SRP_IU_RSP,
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};
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struct srp_device {
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@ -171,6 +172,7 @@ struct srp_iu {
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void *buf;
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size_t size;
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enum dma_data_direction direction;
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enum srp_iu_type type;
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};
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#endif /* IB_SRP_H */
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@ -239,4 +239,42 @@ struct srp_rsp {
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u8 data[0];
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} __attribute__((packed));
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struct srp_cred_req {
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u8 opcode;
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u8 sol_not;
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u8 reserved[2];
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__be32 req_lim_delta;
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u64 tag;
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};
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struct srp_cred_rsp {
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u8 opcode;
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u8 reserved[7];
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u64 tag;
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};
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/*
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* The SRP spec defines the fixed portion of the AER_REQ structure to be
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* 36 bytes, so it needs to be packed to avoid having it padded to 40 bytes
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* on 64-bit architectures.
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*/
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struct srp_aer_req {
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u8 opcode;
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u8 sol_not;
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u8 reserved[2];
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__be32 req_lim_delta;
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u64 tag;
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u32 reserved2;
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__be64 lun;
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__be32 sense_data_len;
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u32 reserved3;
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u8 sense_data[0];
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} __attribute__((packed));
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struct srp_aer_rsp {
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u8 opcode;
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u8 reserved[7];
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u64 tag;
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};
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#endif /* SCSI_SRP_H */
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