Commit 6ac999ef authored by Jitendra Bhivare's avatar Jitendra Bhivare Committed by Martin K. Petersen
Browse files

be2iscsi: Fix soft lockup in mgmt_get_all_if_id path using bmbx 



We are taking mbox_lock spinlock which disables pre-emption before we
poll for mbox completion. Waiting there with spinlock held in excess of
20s will cause soft lockup.

Actual fix is to change mbox_lock to mutex. The changes are done in
phases. This is the first part.

1. Changed mgmt_get_all_if_id to use MCC where after posting lock is
released.

2. Changed be_mbox_db_ready_wait to busy wait for 12s max and removed
wait_event_timeout. Added error handling code for IO reads.
OPCODE_COMMON_QUERY_FIRMWARE_CONFIG mbox command takes 8s time when
unreachable boot targets configured.

Signed-off-by: default avatarJitendra Bhivare <jitendra.bhivare@avagotech.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 420eb6d7

drivers/scsi/be2iscsi/be_cmds.c

+29 −31
Original line number Diff line number Diff line
@@ -587,47 +587,42 @@ int be_mcc_notify_wait(struct beiscsi_hba *phba) 
 **/

static int be_mbox_db_ready_wait(struct be_ctrl_info *ctrl)

{

#define BEISCSI_MBX_RDY_BIT_TIMEOUT	4000	/* 4sec */

#define BEISCSI_MBX_RDY_BIT_TIMEOUT	12000	/* 12sec */

	void __iomem *db = ctrl->db + MPU_MAILBOX_DB_OFFSET;

	struct beiscsi_hba *phba = pci_get_drvdata(ctrl->pdev);

	unsigned long timeout;

	bool read_flag = false;

	int ret = 0, i;

	u32 ready;

	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(rdybit_check_q);



	/*

	 * This BMBX busy wait path is used during init only.

	 * For the commands executed during init, 5s should suffice.

	 */

	timeout = jiffies + msecs_to_jiffies(BEISCSI_MBX_RDY_BIT_TIMEOUT);

	do {

		if (beiscsi_error(phba))

			return -EIO;



	timeout = jiffies + (HZ * 110);

		ready = ioread32(db);

		if (ready == 0xffffffff)

			return -EIO;



		ready &= MPU_MAILBOX_DB_RDY_MASK;

		if (ready)

			return 0;



	do {

		for (i = 0; i < BEISCSI_MBX_RDY_BIT_TIMEOUT; i++) {

			ready = ioread32(db) & MPU_MAILBOX_DB_RDY_MASK;

			if (ready) {

				read_flag = true;

		if (time_after(jiffies, timeout))

			break;

			}

		mdelay(1);

		}



		if (!read_flag) {

			wait_event_timeout(rdybit_check_q,

					  (read_flag != true),

					   HZ * 5);

		}

	} while ((time_before(jiffies, timeout)) && !read_flag);

	} while (!ready);



	if (!read_flag) {

	beiscsi_log(phba, KERN_ERR,

			BEISCSI_LOG_CONFIG | BEISCSI_LOG_MBOX,

			"BC_%d : FW Timed Out\n");



	phba->fw_timeout = true;

	beiscsi_ue_detect(phba);

			ret = -EBUSY;

	}



	return ret;

	return -EBUSY;

}



/*
@@ -674,6 +669,9 @@ int be_mbox_notify(struct be_ctrl_info *ctrl) 
	if (status)

		return status;



	/* RDY is set; small delay before CQE read. */

	udelay(1);



	if (be_mcc_compl_is_new(compl)) {

		status = be_mcc_compl_process(ctrl, &mbox->compl);

		be_mcc_compl_use(compl);

drivers/scsi/be2iscsi/be_mgmt.c

+22 −10
Original line number Diff line number Diff line
@@ -809,27 +809,39 @@ int mgmt_open_connection(struct beiscsi_hba *phba, 
unsigned int mgmt_get_all_if_id(struct beiscsi_hba *phba)

{

	struct be_ctrl_info *ctrl = &phba->ctrl;

	struct be_mcc_wrb *wrb = wrb_from_mbox(&ctrl->mbox_mem);

	struct be_cmd_get_all_if_id_req *req = embedded_payload(wrb);

	struct be_cmd_get_all_if_id_req *pbe_allid = req;

	struct be_mcc_wrb *wrb;

	struct be_cmd_get_all_if_id_req *req;

	struct be_cmd_get_all_if_id_req *pbe_allid;

	unsigned int tag;

	int status = 0;



	memset(wrb, 0, sizeof(*wrb));



	spin_lock(&ctrl->mbox_lock);

	tag = alloc_mcc_tag(phba);

	if (!tag) {

		spin_unlock(&ctrl->mbox_lock);

		return -ENOMEM;

	}



	wrb = wrb_from_mccq(phba);

	req = embedded_payload(wrb);

	wrb->tag0 |= tag;



	be_wrb_hdr_prepare(wrb, sizeof(*req), true, 0);

	be_cmd_hdr_prepare(&req->hdr, CMD_SUBSYSTEM_ISCSI,

			   OPCODE_COMMON_ISCSI_NTWK_GET_ALL_IF_ID,

			   sizeof(*req));

	status = be_mbox_notify(ctrl);

	if (!status)

		phba->interface_handle = pbe_allid->if_hndl_list[0];

	else {

	be_mcc_notify(phba);

	spin_unlock(&ctrl->mbox_lock);



	status = beiscsi_mccq_compl(phba, tag, &wrb, NULL);

	if (status) {

		beiscsi_log(phba, KERN_WARNING, BEISCSI_LOG_CONFIG,

			    "BG_%d : Failed in mgmt_get_all_if_id\n");

		return -EBUSY;

	}

	spin_unlock(&ctrl->mbox_lock);



	pbe_allid = embedded_payload(wrb);

	phba->interface_handle = pbe_allid->if_hndl_list[0];



	return status;

}

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