From 5675c381ea51360b4968b78f23aefda73e3de90d Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 3 Dec 2021 15:19:48 -0800 Subject: [PATCH] scsi: ufs: Stop using the clock scaling lock in the error handler Instead of locking and unlocking the clock scaling lock, surround the command queueing code with an RCU reader lock and call synchronize_rcu(). This patch prepares for removal of the clock scaling lock. Link: https://lore.kernel.org/r/20211203231950.193369-16-bvanassche@acm.org Tested-by: Bean Huo Reviewed-by: Adrian Hunter Reviewed-by: Bean Huo Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/scsi/ufs/ufshcd.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index d434d76aa657..9f0a1f637030 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -2684,6 +2684,12 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) if (!down_read_trylock(&hba->clk_scaling_lock)) return SCSI_MLQUEUE_HOST_BUSY; + /* + * Allows the UFS error handler to wait for prior ufshcd_queuecommand() + * calls. + */ + rcu_read_lock(); + switch (hba->ufshcd_state) { case UFSHCD_STATE_OPERATIONAL: break; @@ -2762,7 +2768,10 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) } ufshcd_send_command(hba, tag); + out: + rcu_read_unlock(); + up_read(&hba->clk_scaling_lock); if (ufs_trigger_eh()) { @@ -5951,8 +5960,7 @@ static void ufshcd_err_handling_prepare(struct ufs_hba *hba) } ufshcd_scsi_block_requests(hba); /* Drain ufshcd_queuecommand() */ - down_write(&hba->clk_scaling_lock); - up_write(&hba->clk_scaling_lock); + synchronize_rcu(); cancel_work_sync(&hba->eeh_work); }