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[SCSI] qla4xxx: Throttle active IOCBs to firmware limits

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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: Karen Higgins <karen.higgins@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Karen Higgins 2013-01-20 23:51:00 -05:00 committed by James Bottomley
parent ff4108dce9
commit 5b1c1bff07
3 changed files with 21 additions and 3 deletions
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2
drivers/scsi/qla4xxx/ql4_def.h
View File

@ -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

2
drivers/scsi/qla4xxx/ql4_iocb.c
View File

@ -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 */

20
drivers/scsi/qla4xxx/ql4_mbx.c
View File

@ -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;
}