Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753465Ab3H0I7Q (ORCPT ); Tue, 27 Aug 2013 04:59:16 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:47682 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753352Ab3H0I7N (ORCPT ); Tue, 27 Aug 2013 04:59:13 -0400 Message-ID: <521C6A5C.4050202@codeaurora.org> Date: Tue, 27 Aug 2013 14:29:08 +0530 From: Subhash Jadavani User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Dolev Raviv CC: linux-scsi@vger.kernel.org, linux-arm-msm@vger.kernel.org, open list Subject: Re: [PATCH] scsi: ufs: read door bell register after clearing interrupt aggregation References: <1377427016-28469-1-git-send-email-draviv@codeaurora.org> <521C6155.9080207@codeaurora.org> In-Reply-To: <521C6155.9080207@codeaurora.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6118 Lines: 152 On 8/27/2013 1:50 PM, Subhash Jadavani wrote: > > > Looks good to me. > Reviewed-by: Subhash Jadavani > > On 8/25/2013 4:06 PM, Dolev Raviv wrote: >> In interrupt context, after reading and comparing the UTRLDBR to >> hba->outstanding_request and before resetting the interrupt aggregation, >> there might be completion of another transfer request (TR). Such TRs >> might >> get stuck, pending, until the next interrupt is generated. >> >> The fix reads the UTRLDBR after resetting the interrupt aggregation and >> handles completed TRs. >> >> Signed-off-by: Dolev Raviv >> >> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c >> index 4dca9b4..30c84d8 100644 >> --- a/drivers/scsi/ufs/ufshcd.c >> +++ b/drivers/scsi/ufs/ufshcd.c >> @@ -1915,6 +1915,13 @@ static void ufshcd_uic_cmd_compl(struct >> ufs_hba *hba) >> /** >> * ufshcd_transfer_req_compl - handle SCSI and query command >> completion >> * @hba: per adapter instance >> + * >> + * Resetting interrupt aggregation counters first and reading the >> DOOR_BELL >> + * afterward , allows us to handle all the completed requests. >> + * In order to prevent other interrupts starvation the DB is read once >> + * after reset. The down side of this solution is the possibility of >> false >> + * interrupt if device completes another request after resetting >> aggregation >> + * and before reading the DB. >> */ >> static void ufshcd_transfer_req_compl(struct ufs_hba *hba) >> { >> @@ -1924,47 +1931,36 @@ static void ufshcd_transfer_req_compl(struct >> ufs_hba *hba) >> u32 tr_doorbell; >> int result; >> int index; >> - bool int_aggr_reset = false; >> + >> + /* Reset interrupt aggregation counters */ >> + ufshcd_config_int_aggr(hba, INT_AGGR_RESET); You may have to rebase your change on top of "[PATCH v3 2/6] scsi: ufs: fix the setting interrupt aggregation counter" patch. Once you do that, you will be calling ufshcd_reset_intr_aggr() (instead of ufshscd_config_int_aggr()) to reset the interrupt aggregation counters. >> tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL); >> completed_reqs = tr_doorbell ^ hba->outstanding_reqs; >> - for (index = 0; index < hba->nutrs; index++) { >> - if (test_bit(index, &completed_reqs)) { >> - lrbp = &hba->lrb[index]; >> - cmd = lrbp->cmd; >> - /* >> - * Don't skip resetting interrupt aggregation counters >> - * if a regular command is present. >> - */ >> - int_aggr_reset |= !lrbp->intr_cmd; >> - >> - if (cmd) { >> - result = ufshcd_transfer_rsp_status(hba, lrbp); >> - scsi_dma_unmap(cmd); >> - cmd->result = result; >> - /* Mark completed command as NULL in LRB */ >> - lrbp->cmd = NULL; >> - clear_bit_unlock(index, &hba->lrb_in_use); >> - /* Do not touch lrbp after scsi done */ >> - cmd->scsi_done(cmd); >> - } else if (lrbp->command_type == >> - UTP_CMD_TYPE_DEV_MANAGE) { >> - if (hba->dev_cmd.complete) >> - complete(hba->dev_cmd.complete); >> - } >> - } /* end of if */ >> - } /* end of for */ >> + for_each_set_bit(index, &completed_reqs, hba->nutrs) { >> + lrbp = &hba->lrb[index]; >> + cmd = lrbp->cmd; >> + if (cmd) { >> + result = ufshcd_transfer_rsp_status(hba, lrbp); >> + scsi_dma_unmap(cmd); >> + cmd->result = result; >> + /* Mark completed command as NULL in LRB */ >> + lrbp->cmd = NULL; >> + clear_bit_unlock(index, &hba->lrb_in_use); >> + /* Do not touch lrbp after scsi done */ >> + cmd->scsi_done(cmd); >> + } else if (lrbp->command_type == UTP_CMD_TYPE_DEV_MANAGE) { >> + if (hba->dev_cmd.complete) >> + complete(hba->dev_cmd.complete); >> + } >> + } /* end of for_each_set_bit */ >> /* clear corresponding bits of completed commands */ >> hba->outstanding_reqs ^= completed_reqs; >> /* we might have free'd some tags above */ >> wake_up(&hba->dev_cmd.tag_wq); >> - >> - /* Reset interrupt aggregation counters */ >> - if (int_aggr_reset) >> - ufshcd_config_int_aggr(hba, INT_AGGR_RESET); >> } >> /** >> @@ -2569,6 +2565,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) >> int poll_cnt; >> u8 resp = 0xF; >> struct ufshcd_lrb *lrbp; >> + u32 reg; >> host = cmd->device->host; >> hba = shost_priv(host); >> @@ -2578,6 +2575,13 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) >> if (!(test_bit(tag, &hba->outstanding_reqs))) >> goto out; >> + reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL); >> + if (!(reg & (1 << tag))) { >> + dev_err(hba->dev, >> + "%s: cmd was completed, but without a notifying intr, tag = >> %d", >> + __func__, tag); >> + } >> + >> lrbp = &hba->lrb[tag]; >> for (poll_cnt = 100; poll_cnt; poll_cnt--) { >> err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag, >> @@ -2586,8 +2590,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) >> /* cmd pending in the device */ >> break; >> } else if (!err && resp == UPIU_TASK_MANAGEMENT_FUNC_COMPL) { >> - u32 reg; >> - >> /* >> * cmd not pending in the device, check if it is >> * in transition. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/