diff mbox series

scsi: ufs: mediatek: avoid sched_clock() misuse

Message ID 20211018132022.2281589-1-arnd@kernel.org (mailing list archive)
State New, archived
Headers show
Series scsi: ufs: mediatek: avoid sched_clock() misuse | expand

Commit Message

Arnd Bergmann Oct. 18, 2021, 1:20 p.m. UTC 
From: Arnd Bergmann <arnd@arndb.de>

sched_clock() is not meant to be used in portable driver code,
and assuming a particular clock frequency is not how this is
meant to be used. It also causes a build failure because of
a missing header inclusion:

drivers/scsi/ufs/ufs-mediatek.c:321:12: error: implicit declaration of function 'sched_clock' [-Werror,-Wimplicit-function-declaration]
        timeout = sched_clock() + retry_ms * 1000000UL;

A better interface to use here ktime_get_mono_fast_ns(), which
works mostly like ktime_get() but is safe to use inside of a
suspend callback.

Fixes: 9561f58442e4 ("scsi: ufs: mediatek: Support vops pre suspend to disable auto-hibern8")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/scsi/ufs/ufs-mediatek.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Stanley Chu Oct. 20, 2021, 11:04 a.m. UTC | #1 
Hi Arnd,

On Mon, 2021-10-18 at 15:20 +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> sched_clock() is not meant to be used in portable driver code,
> and assuming a particular clock frequency is not how this is
> meant to be used. It also causes a build failure because of
> a missing header inclusion:
> 
> drivers/scsi/ufs/ufs-mediatek.c:321:12: error: implicit declaration
> of function 'sched_clock' [-Werror,-Wimplicit-function-declaration]
>         timeout = sched_clock() + retry_ms * 1000000UL;
> 
> A better interface to use here ktime_get_mono_fast_ns(), which
> works mostly like ktime_get() but is safe to use inside of a
> suspend callback.
> 
> Fixes: 9561f58442e4 ("scsi: ufs: mediatek: Support vops pre suspend
> to disable auto-hibern8")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/scsi/ufs/ufs-mediatek.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-
> mediatek.c
> index d1696db70ce8..a47241ed0a57 100644
> --- a/drivers/scsi/ufs/ufs-mediatek.c
> +++ b/drivers/scsi/ufs/ufs-mediatek.c
> @@ -318,15 +318,15 @@ static void ufs_mtk_wait_idle_state(struct
> ufs_hba *hba,
>  	u32 val, sm;
>  	bool wait_idle;
>  
> -	timeout = sched_clock() + retry_ms * 1000000UL;
> -
> +	/* cannot use plain ktime_get() in suspend */
> +	timeout = ktime_get_mono_fast_ns() + retry_ms * 1000000UL;

Thanks for this fix.

Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>

>  
>  	/* wait a specific time after check base */
>  	udelay(10);
>  	wait_idle = false;
>  
>  	do {
> -		time_checked = sched_clock();
> +		time_checked = ktime_get_mono_fast_ns();
>  		ufs_mtk_dbg_sel(hba);
>  		val = ufshcd_readl(hba, REG_UFS_PROBE);
>
Peter Wang (王信友) Oct. 21, 2021, 3:18 a.m. UTC | #2 
On Mon, 2021-10-18 at 15:20 +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> sched_clock() is not meant to be used in portable driver code,
> and assuming a particular clock frequency is not how this is
> meant to be used. It also causes a build failure because of
> a missing header inclusion:
> 
> drivers/scsi/ufs/ufs-mediatek.c:321:12: error: implicit declaration
> of function 'sched_clock' [-Werror,-Wimplicit-function-declaration]
>         timeout = sched_clock() + retry_ms * 1000000UL;
> 
> A better interface to use here ktime_get_mono_fast_ns(), which
> works mostly like ktime_get() but is safe to use inside of a
> suspend callback.
> 
> Fixes: 9561f58442e4 ("scsi: ufs: mediatek: Support vops pre suspend
> to disable auto-hibern8")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/scsi/ufs/ufs-mediatek.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-
> mediatek.c
> index d1696db70ce8..a47241ed0a57 100644
> --- a/drivers/scsi/ufs/ufs-mediatek.c
> +++ b/drivers/scsi/ufs/ufs-mediatek.c
> @@ -318,15 +318,15 @@ static void ufs_mtk_wait_idle_state(struct
> ufs_hba *hba,
>  	u32 val, sm;
>  	bool wait_idle;
>  
> -	timeout = sched_clock() + retry_ms * 1000000UL;
> -
> +	/* cannot use plain ktime_get() in suspend */
> +	timeout = ktime_get_mono_fast_ns() + retry_ms * 1000000UL;

Thanks for this patch.

>  
>  	/* wait a specific time after check base */
>  	udelay(10);
>  	wait_idle = false;
>  
>  	do {
> -		time_checked = sched_clock();
> +		time_checked = ktime_get_mono_fast_ns();
>  		ufs_mtk_dbg_sel(hba);
>  		val = ufshcd_readl(hba, REG_UFS_PROBE);
>
Martin K. Petersen Oct. 27, 2021, 4 a.m. UTC | #3 
On Mon, 18 Oct 2021 15:20:01 +0200, Arnd Bergmann wrote:

> From: Arnd Bergmann <arnd@arndb.de>
> 
> sched_clock() is not meant to be used in portable driver code,
> and assuming a particular clock frequency is not how this is
> meant to be used. It also causes a build failure because of
> a missing header inclusion:
> 
> [...]

Applied to 5.16/scsi-queue, thanks!

[1/1] scsi: ufs: mediatek: avoid sched_clock() misuse
      https://git.kernel.org/mkp/scsi/c/bb4a8dcb4e94
diff mbox series

Patch

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index d1696db70ce8..a47241ed0a57 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -318,15 +318,15 @@  static void ufs_mtk_wait_idle_state(struct ufs_hba *hba,
 	u32 val, sm;
 	bool wait_idle;
 
-	timeout = sched_clock() + retry_ms * 1000000UL;
-
+	/* cannot use plain ktime_get() in suspend */
+	timeout = ktime_get_mono_fast_ns() + retry_ms * 1000000UL;
 
 	/* wait a specific time after check base */
 	udelay(10);
 	wait_idle = false;
 
 	do {
-		time_checked = sched_clock();
+		time_checked = ktime_get_mono_fast_ns();
 		ufs_mtk_dbg_sel(hba);
 		val = ufshcd_readl(hba, REG_UFS_PROBE);