linux-kernel - Re: [PATCH] mmc: dw_mmc: replace spin_lock_irqsave by spin

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Date:   Fri, 6 Nov 2020 12:26:00 +0900
From:   Jaehoon Chung <jh80.chung@...sung.com>
To:     Tian Tao <tiantao6@...ilicon.com>, ulf.hansson@...aro.org,
        p.zabel@...gutronix.de, linux-mmc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mmc: dw_mmc: replace spin_lock_irqsave by spin_lock in
 hard IRQ

Dear Tian,

On 11/6/20 10:56 AM, Tian Tao wrote:
> The code has been in a irq-disabled context since it is hard IRQ. There
> is no necessity to do it 
Even though I don't remember, there is a reason to use spin_lock_irqsave()..
I will check it. If there is no reason, i will reply.

Best Regards,
Jaehoon Chung

> 
> Signed-off-by: Tian Tao <tiantao6@...ilicon.com>
> ---
>  drivers/mmc/host/dw_mmc.c | 17 ++++++++---------
>  1 file changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 43c5795..a524443 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -2617,7 +2617,6 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
>  	struct dw_mci *host = dev_id;
>  	u32 pending;
>  	struct dw_mci_slot *slot = host->slot;
> -	unsigned long irqflags;
>  
>  	pending = mci_readl(host, MINTSTS); /* read-only mask reg */
>  
> @@ -2632,15 +2631,15 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
>  			 * Hold the lock; we know cmd11_timer can't be kicked
>  			 * off after the lock is released, so safe to delete.
>  			 */
> -			spin_lock_irqsave(&host->irq_lock, irqflags);
> +			spin_lock(&host->irq_lock);
>  			dw_mci_cmd_interrupt(host, pending);
> -			spin_unlock_irqrestore(&host->irq_lock, irqflags);
> +			spin_unlock(&host->irq_lock);
>  
>  			del_timer(&host->cmd11_timer);
>  		}
>  
>  		if (pending & DW_MCI_CMD_ERROR_FLAGS) {
> -			spin_lock_irqsave(&host->irq_lock, irqflags);
> +			spin_lock(&host->irq_lock);
>  
>  			del_timer(&host->cto_timer);
>  			mci_writel(host, RINTSTS, DW_MCI_CMD_ERROR_FLAGS);
> @@ -2648,7 +2647,7 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
>  			smp_wmb(); /* drain writebuffer */
>  			set_bit(EVENT_CMD_COMPLETE, &host->pending_events);
>  
> -			spin_unlock_irqrestore(&host->irq_lock, irqflags);
> +			spin_unlock(&host->irq_lock);
>  		}
>  
>  		if (pending & DW_MCI_DATA_ERROR_FLAGS) {
> @@ -2661,7 +2660,7 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
>  		}
>  
>  		if (pending & SDMMC_INT_DATA_OVER) {
> -			spin_lock_irqsave(&host->irq_lock, irqflags);
> +			spin_lock(&host->irq_lock);
>  
>  			del_timer(&host->dto_timer);
>  
> @@ -2676,7 +2675,7 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
>  			set_bit(EVENT_DATA_COMPLETE, &host->pending_events);
>  			tasklet_schedule(&host->tasklet);
>  
> -			spin_unlock_irqrestore(&host->irq_lock, irqflags);
> +			spin_unlock(&host->irq_lock);
>  		}
>  
>  		if (pending & SDMMC_INT_RXDR) {
> @@ -2692,12 +2691,12 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
>  		}
>  
>  		if (pending & SDMMC_INT_CMD_DONE) {
> -			spin_lock_irqsave(&host->irq_lock, irqflags);
> +			spin_lock(&host->irq_lock);
>  
>  			mci_writel(host, RINTSTS, SDMMC_INT_CMD_DONE);
>  			dw_mci_cmd_interrupt(host, pending);
>  
> -			spin_unlock_irqrestore(&host->irq_lock, irqflags);
> +			spin_unlock(&host->irq_lock);
>  		}
>  
>  		if (pending & SDMMC_INT_CD) {
>