From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dolev Raviv Subject: [PATCH V2 5/5] scsi: ufs: Fix queue depth handling for best effort cases Date: Tue, 22 Jul 2014 17:23:50 +0300 Message-ID: <1406039030-14246-6-git-send-email-draviv@codeaurora.org> References: <1406039030-14246-1-git-send-email-draviv@codeaurora.org> Return-path: In-Reply-To: <1406039030-14246-1-git-send-email-draviv@codeaurora.org> Sender: linux-scsi-owner@vger.kernel.org To: James.Bottomley@HansenPartnership.com Cc: linux-scsi@vger.kernel.org, linux-scsi-owner@vger.kernel.org, sthumma@codeaurora.org, linux-arm-msm@vger.kernel.org, santoshsy@gmail.com, Dolev Raviv List-Id: linux-arm-msm@vger.kernel.org From: Sujit Reddy Thumma Some UFS devices may expose bLUQueueDepth field as zero indicating that the queue depth depends on the number of resources available for LUN at a particular instant to handle the outstanding transfer requests. Currently, when response for SCSI command is TASK_FULL the LLD decrements the queue depth but fails to increment when the resources are available. The scsi mid-layer handles the change in queue depth heuristically and offers simple interface with ->change_queue_depth. Signed-off-by: Sujit Reddy Thumma Signed-off-by: Dolev Raviv --- drivers/scsi/ufs/ufshcd.c | 97 ++++++++++++++++++++--------------------------- 1 file changed, 42 insertions(+), 55 deletions(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 7ea4b4d..ff57965 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -1992,27 +1992,55 @@ static int ufshcd_slave_alloc(struct scsi_device *sdev) /* allow SCSI layer to restart the device in case of errors */ sdev->allow_restart = 1; + lun_qdepth = ufshcd_read_sdev_qdepth(hba, sdev); - if (lun_qdepth == 0 || lun_qdepth > hba->nutrs) { - dev_info(hba->dev, "%s, lun %d queue depth is %d\n", __func__, - sdev->lun, lun_qdepth); + if (lun_qdepth <= 0) + /* eventually, we can figure out the real queue depth */ lun_qdepth = hba->nutrs; - } else if (lun_qdepth < 0) { - lun_qdepth = 1; - } + else + lun_qdepth = min_t(int, lun_qdepth, hba->nutrs); - /* - * Inform SCSI Midlayer that the LUN queue depth is same as the - * controller queue depth. If a LUN queue depth is less than the - * controller queue depth and if the LUN reports - * SAM_STAT_TASK_SET_FULL, the LUN queue depth will be adjusted - * with scsi_adjust_queue_depth. - */ + dev_dbg(hba->dev, "%s: activate tcq with queue depth %d\n", + __func__, lun_qdepth); scsi_activate_tcq(sdev, lun_qdepth); + return 0; } /** + * ufshcd_change_queue_depth - change queue depth + * @sdev: pointer to SCSI device + * @depth: required depth to set + * @reason: reason for changing the depth + * + * Change queue depth according to the reason and make sure + * the max. limits are not crossed. + */ +int ufshcd_change_queue_depth(struct scsi_device *sdev, int depth, int reason) +{ + struct ufs_hba *hba = shost_priv(sdev->host); + + if (depth > hba->nutrs) + depth = hba->nutrs; + + switch (reason) { + case SCSI_QDEPTH_DEFAULT: + case SCSI_QDEPTH_RAMP_UP: + if (!sdev->tagged_supported) + depth = 1; + scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth); + break; + case SCSI_QDEPTH_QFULL: + scsi_track_queue_full(sdev, depth); + break; + default: + return -EOPNOTSUPP; + } + + return depth; +} + +/** * ufshcd_slave_destroy - remove SCSI device configurations * @sdev: pointer to SCSI device */ @@ -2065,42 +2093,6 @@ static int ufshcd_task_req_compl(struct ufs_hba *hba, u32 index, u8 *resp) } /** - * ufshcd_adjust_lun_qdepth - Update LUN queue depth if device responds with - * SAM_STAT_TASK_SET_FULL SCSI command status. - * @cmd: pointer to SCSI command - */ -static void ufshcd_adjust_lun_qdepth(struct scsi_cmnd *cmd) -{ - struct ufs_hba *hba; - int i; - int lun_qdepth = 0; - - hba = shost_priv(cmd->device->host); - - /* - * LUN queue depth can be obtained by counting outstanding commands - * on the LUN. - */ - for (i = 0; i < hba->nutrs; i++) { - if (test_bit(i, &hba->outstanding_reqs)) { - - /* - * Check if the outstanding command belongs - * to the LUN which reported SAM_STAT_TASK_SET_FULL. - */ - if (cmd->device->lun == hba->lrb[i].lun) - lun_qdepth++; - } - } - - /* - * LUN queue depth will be total outstanding commands, except the - * command for which the LUN reported SAM_STAT_TASK_SET_FULL. - */ - scsi_adjust_queue_depth(cmd->device, MSG_SIMPLE_TAG, lun_qdepth - 1); -} - -/** * ufshcd_scsi_cmd_status - Update SCSI command result based on SCSI status * @lrb: pointer to local reference block of completed command * @scsi_status: SCSI command status @@ -2121,12 +2113,6 @@ ufshcd_scsi_cmd_status(struct ufshcd_lrb *lrbp, int scsi_status) scsi_status; break; case SAM_STAT_TASK_SET_FULL: - /* - * If a LUN reports SAM_STAT_TASK_SET_FULL, then the LUN queue - * depth needs to be adjusted to the exact number of - * outstanding commands the LUN can handle at any given time. - */ - ufshcd_adjust_lun_qdepth(lrbp->cmd); case SAM_STAT_BUSY: case SAM_STAT_TASK_ABORTED: ufshcd_copy_sense_data(lrbp); @@ -3157,6 +3143,7 @@ static struct scsi_host_template ufshcd_driver_template = { .queuecommand = ufshcd_queuecommand, .slave_alloc = ufshcd_slave_alloc, .slave_destroy = ufshcd_slave_destroy, + .change_queue_depth = ufshcd_change_queue_depth, .eh_abort_handler = ufshcd_abort, .eh_device_reset_handler = ufshcd_eh_device_reset_handler, .eh_host_reset_handler = ufshcd_eh_host_reset_handler, -- 1.8.5.2 -- QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation