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Commit 5b1c1bff authored by Karen Higgins's avatar Karen Higgins Committed by James Bottomley
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[SCSI] qla4xxx: Throttle active IOCBs to firmware limits 



Problem:
QLA4xxx firmware may assert if given more IOCBs than it can handle.

Solution:
The driver was updated to throttle the number of active IOCBs based
on the total number of IOCB buffers received from get_firmware_status
mbx_sts[2].

Signed-off-by: default avatarKaren Higgins <karen.higgins@qlogic.com>
Signed-off-by: default avatarVikas Chaudhary <vikas.chaudhary@qlogic.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent ff4108dc

drivers/scsi/qla4xxx/ql4_def.h

+2 −0
Original line number Diff line number Diff line
@@ -136,6 +136,7 @@ 
#define RESPONSE_QUEUE_DEPTH		64

#define QUEUE_SIZE			64

#define DMA_BUFFER_SIZE			512

#define IOCB_HIWAT_CUSHION		4



/*

 * Misc
@@ -540,6 +541,7 @@ struct scsi_qla_host { 
	uint32_t tot_ddbs;



	uint16_t iocb_cnt;

	uint16_t iocb_hiwat;



	/* SRB cache. */

#define SRB_MIN_REQ	128

drivers/scsi/qla4xxx/ql4_iocb.c

+1 −1
Original line number Diff line number Diff line
@@ -316,7 +316,7 @@ int qla4xxx_send_command_to_isp(struct scsi_qla_host *ha, struct srb * srb) 
		goto queuing_error;



	/* total iocbs active */

	if ((ha->iocb_cnt + req_cnt) >= REQUEST_QUEUE_DEPTH)

	if ((ha->iocb_cnt + req_cnt) >= ha->iocb_hiwat)

		goto queuing_error;



	/* Build command packet */

drivers/scsi/qla4xxx/ql4_mbx.c

+18 −2
Original line number Diff line number Diff line
@@ -697,8 +697,24 @@ int qla4xxx_get_firmware_status(struct scsi_qla_host * ha) 
		return QLA_ERROR;

	}



	ql4_printk(KERN_INFO, ha, "%ld firmware IOCBs available (%d).\n",

	    ha->host_no, mbox_sts[2]);

	/* High-water mark of IOCBs */

	ha->iocb_hiwat = mbox_sts[2];

	DEBUG2(ql4_printk(KERN_INFO, ha,

			  "%s: firmware IOCBs available = %d\n", __func__,

			  ha->iocb_hiwat));



	if (ha->iocb_hiwat > IOCB_HIWAT_CUSHION)

		ha->iocb_hiwat -= IOCB_HIWAT_CUSHION;



	/* Ideally, we should not enter this code, as the # of firmware

	 * IOCBs is hard-coded in the firmware. We set a default

	 * iocb_hiwat here just in case */

	if (ha->iocb_hiwat == 0) {

		ha->iocb_hiwat = REQUEST_QUEUE_DEPTH / 4;

		DEBUG2(ql4_printk(KERN_WARNING, ha,

				  "%s: Setting IOCB's to = %d\n", __func__,

				  ha->iocb_hiwat));

	}



	return QLA_SUCCESS;

}