[PATCH AUTOSEL 5.4 11/37] scsi: ufs: Verify UIC locking requirements at runtime

[Sasha Levin]

From: Bart Van Assche <bvanassche@xxxxxxx>

[ Upstream commit 35c7d874f5993db04ce3aa310ae088f14b801eda ]

Instead of documenting the locking requirements of the UIC code as
comments, use lockdep_assert_held() such that lockdep verifies the lockdep
requirements at runtime if lockdep is enabled.

Link: https://lore.kernel.org/r/20210722033439.26550-8-bvanassche@xxxxxxx
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
Cc: Can Guo <cang@xxxxxxxxxxxxxx>
Cc: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
Reviewed-by: Avri Altman <avri.altman@xxxxxxx>
Reviewed-by: Bean Huo <beanhuo@xxxxxxxxxx>
Reviewed-by: Daejun Park <daejun7.park@xxxxxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/scsi/ufs/ufshcd.c | 16 +++++++++-------
 drivers/scsi/ufs/ufshcd.h |  2 +-
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 0429ba5d7d23..f8d0fe6cb09d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1986,15 +1986,15 @@ static inline u8 ufshcd_get_upmcrs(struct ufs_hba *hba)
 }
 
 /**
- * ufshcd_dispatch_uic_cmd - Dispatch UIC commands to unipro layers
+ * ufshcd_dispatch_uic_cmd - Dispatch an UIC command to the Unipro layer
  * @hba: per adapter instance
  * @uic_cmd: UIC command
- *
- * Mutex must be held.
  */
 static inline void
 ufshcd_dispatch_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 {
+	lockdep_assert_held(&hba->uic_cmd_mutex);
+
 	WARN_ON(hba->active_uic_cmd);
 
 	hba->active_uic_cmd = uic_cmd;
@@ -2010,11 +2010,10 @@ ufshcd_dispatch_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 }
 
 /**
- * ufshcd_wait_for_uic_cmd - Wait complectioin of UIC command
+ * ufshcd_wait_for_uic_cmd - Wait for completion of an UIC command
  * @hba: per adapter instance
  * @uic_cmd: UIC command
  *
- * Must be called with mutex held.
  * Returns 0 only if success.
  */
 static int
@@ -2023,6 +2022,8 @@ ufshcd_wait_for_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	int ret;
 	unsigned long flags;
 
+	lockdep_assert_held(&hba->uic_cmd_mutex);
+
 	if (wait_for_completion_timeout(&uic_cmd->done,
 					msecs_to_jiffies(UIC_CMD_TIMEOUT)))
 		ret = uic_cmd->argument2 & MASK_UIC_COMMAND_RESULT;
@@ -2042,14 +2043,15 @@ ufshcd_wait_for_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
  * @uic_cmd: UIC command
  * @completion: initialize the completion only if this is set to true
  *
- * Identical to ufshcd_send_uic_cmd() expect mutex. Must be called
- * with mutex held and host_lock locked.
  * Returns 0 only if success.
  */
 static int
 __ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd,
 		      bool completion)
 {
+	lockdep_assert_held(&hba->uic_cmd_mutex);
+	lockdep_assert_held(hba->host->host_lock);
+
 	if (!ufshcd_ready_for_uic_cmd(hba)) {
 		dev_err(hba->dev,
 			"Controller not ready to accept UIC commands\n");
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 92ef6e6a3e51..803a2a37875b 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -493,7 +493,7 @@ struct ufs_stats {
  * @priv: pointer to variant specific private data
  * @irq: Irq number of the controller
  * @active_uic_cmd: handle of active UIC command
- * @uic_cmd_mutex: mutex for uic command
+ * @uic_cmd_mutex: mutex for UIC command
  * @tmf_tag_set: TMF tag set.
  * @tmf_queue: Used to allocate TMF tags.
  * @pwr_done: completion for power mode change
-- 
2.30.2