From: Sumant Patro Checks added in megasas_queue_command to know if FW is able to process commands within the timeout period. If number of retries is 2 or more, the driver stops sending cmd to FW. IO is resumed when pending cmd count reduces to 16 or 10 seconds has elapsed from the time cmds were last sent to FW. Signed-off-by: Sumant Patro Signed-off-by: Andrew Morton --- drivers/scsi/megaraid/megaraid_sas.c | 27 +++++++++++++++++++++++++ drivers/scsi/megaraid/megaraid_sas.h | 3 ++ 2 files changed, 30 insertions(+) diff -puN drivers/scsi/megaraid/megaraid_sas.c~scsi-megaraid_sas-throttle-io-if-fw-is-busy drivers/scsi/megaraid/megaraid_sas.c --- a/drivers/scsi/megaraid/megaraid_sas.c~scsi-megaraid_sas-throttle-io-if-fw-is-busy +++ a/drivers/scsi/megaraid/megaraid_sas.c @@ -839,6 +839,7 @@ megasas_queue_command(struct scsi_cmnd * u32 frame_count; struct megasas_cmd *cmd; struct megasas_instance *instance; + unsigned long sec; instance = (struct megasas_instance *) scmd->device->host->hostdata; @@ -856,6 +857,23 @@ megasas_queue_command(struct scsi_cmnd * goto out_done; } + /* Check if we can accept cmds */ + if (instance->is_busy) { + sec = (jiffies - instance->last_time) / HZ; + if (sec < 10) + return SCSI_MLQUEUE_HOST_BUSY; + else { + instance->is_busy = 0; + instance->last_time = 0; + } + } + + if (scmd->retries > 1) { + /* FW is busy */ + instance->is_busy = 1; + instance->last_time = jiffies; + } + cmd = megasas_get_cmd(instance); if (!cmd) return SCSI_MLQUEUE_HOST_BUSY; @@ -1200,6 +1218,7 @@ megasas_complete_cmd(struct megasas_inst { int exception = 0; struct megasas_header *hdr = &cmd->frame->hdr; + int outstanding; if (cmd->scmd) { cmd->scmd->SCp.ptr = (char *)0; @@ -1313,6 +1332,12 @@ megasas_complete_cmd(struct megasas_inst hdr->cmd); break; } + + if (instance->is_busy) { + outstanding = atomic_read(&instance->fw_outstanding); + if (outstanding < 17) + instance->is_busy = 0; + } } /** @@ -2384,6 +2409,8 @@ megasas_probe_one(struct pci_dev *pdev, instance->init_id = MEGASAS_DEFAULT_INIT_ID; megasas_dbg_lvl = 0; + instance->is_busy = 0; + instance->last_time = 0; /* * Initialize MFI Firmware diff -puN drivers/scsi/megaraid/megaraid_sas.h~scsi-megaraid_sas-throttle-io-if-fw-is-busy drivers/scsi/megaraid/megaraid_sas.h --- a/drivers/scsi/megaraid/megaraid_sas.h~scsi-megaraid_sas-throttle-io-if-fw-is-busy +++ a/drivers/scsi/megaraid/megaraid_sas.h @@ -1102,6 +1102,9 @@ struct megasas_instance { atomic_t fw_outstanding; u32 hw_crit_error; + u8 is_busy; + unsigned long last_time; + struct megasas_instance_template *instancet; struct tasklet_struct isr_tasklet; }; _