Re: [PATCH v4 5/8] scsi: ufs: Fix ufshcd_hold() caused scheduling while atomic

[Asutosh Das (asd)]

On 1/22/2020 11:25 PM, Can Guo wrote:
> The async version of ufshcd_hold(async == true), which is only called
> in queuecommand path as for now, is expected to work in atomic context,
> thus it should not sleep or schedule out. When it runs into the condition
> that clocks are ON but link is still in hibern8 state, it should bail out
> without flushing the clock ungate work.
>
> Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
> Reviewed-by: Hongwu Su <hongwus@xxxxxxxxxxxxxx>
> ---

Reviewed-by: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>

>   drivers/scsi/ufs/ufshcd.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 4dfd705..c316a07 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1542,6 +1542,11 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
>   		 */
>   		if (ufshcd_can_hibern8_during_gating(hba) &&
>   		    ufshcd_is_link_hibern8(hba)) {
> +			if (async) {
> +				rc = -EAGAIN;
> +				hba->clk_gating.active_reqs--;
> +				break;
> +			}
>   			spin_unlock_irqrestore(hba->host->host_lock, flags);
>   			flush_work(&hba->clk_gating.ungate_work);
>   			spin_lock_irqsave(hba->host->host_lock, flags);


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