scsi: ufs: core: Don't perform UFS clkscaling during host async scan

When preparing for UFS clock scaling, the UFS driver will quiesce all
sdevs queues in the UFS SCSI host tagset list and then unquiesce them in
ufshcd_clock_scaling_unprepare(). If the UFS SCSI host async scan is in
progress at this time, some LUs may be added to the tagset list between
UFS clkscale prepare and unprepare. This can cause two issues:

1. During clock scaling, there may be I/O requests issued through new
added queues that have not been quiesced, leading to task abort issue.

2. These new added queues that have not been quiesced will be unquiesced
as well when UFS clkscale is unprepared, resulting in warning prints.

Therefore, use the mutex lock scan_mutex in
ufshcd_clock_scaling_prepare() and ufshcd_clock_scaling_unprepare() to
protect it.

Co-developed-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Ziqi Chen <quic_ziqichen@quicinc.com>
Link: https://lore.kernel.org/r/20250522081233.2358565-1-quic_ziqichen@quicinc.com
Suggested-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index d7ff24b48de3ffeffcc860efef8e47d1f88ff80e..a7513f256057b78771d2b8ac69d085d36a4aac2b 100644 (file)
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -1397,6 +1397,7 @@ static int ufshcd_clock_scaling_prepare(struct ufs_hba *hba, u64 timeout_us)
         * make sure that there are no outstanding requests when
         * clock scaling is in progress
         */
+       mutex_lock(&hba->host->scan_mutex);
        blk_mq_quiesce_tagset(&hba->host->tag_set);
        mutex_lock(&hba->wb_mutex);
        down_write(&hba->clk_scaling_lock);
@@ -1407,6 +1408,7 @@ static int ufshcd_clock_scaling_prepare(struct ufs_hba *hba, u64 timeout_us)
                up_write(&hba->clk_scaling_lock);
                mutex_unlock(&hba->wb_mutex);
                blk_mq_unquiesce_tagset(&hba->host->tag_set);
+               mutex_unlock(&hba->host->scan_mutex);
                goto out;
        }
 
@@ -1428,6 +1430,7 @@ static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba, int err)
        mutex_unlock(&hba->wb_mutex);
 
        blk_mq_unquiesce_tagset(&hba->host->tag_set);
+       mutex_unlock(&hba->host->scan_mutex);
        ufshcd_release(hba);
 }