Re: [PATCH 1/2] mmc: atmel-mci: Switch to using managed resource in probe

[Ludovic Desroches]

Hi Pramod,

Thanks for taking care of device managed resources conversion. My only
concern is about using devm_request_irq. There are several discussions
about races which can occur when using it.

Keeping request_irq and free_irq the time it takes to solve this issue
is probably better.

Regards

Ludovic

On Sat, Sep 20, 2014 at 12:22:30PM +0530, Pramod Gurav wrote:
> This change uses managed resource APIs to allocate resources such as,
> clk, gpio, irq in order to simplify the driver unload or failure cases.
> Hence does away with release statements of the same resorces in error
> lables and remove function.
> 
> Cc: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
> Cc: Chris Ball <chris@xxxxxxxxxx>
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Cc: linux-mmc@xxxxxxxxxxxxxxx
> Signed-off-by: Pramod Gurav <pramod.gurav@xxxxxxxxxxxxxxx>
> ---
>  drivers/mmc/host/atmel-mci.c | 57 ++++++++++++++++----------------------------
>  1 file changed, 20 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> index bb585d9..21a222c 100644
> --- a/drivers/mmc/host/atmel-mci.c
> +++ b/drivers/mmc/host/atmel-mci.c
> @@ -17,6 +17,7 @@
>  #include <linux/gpio.h>
>  #include <linux/init.h>
>  #include <linux/interrupt.h>
> +#include <linux/io.h>
>  #include <linux/ioport.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> @@ -2195,7 +2196,8 @@ static int __init atmci_init_slot(struct atmel_mci *host,
>  	/* Assume card is present initially */
>  	set_bit(ATMCI_CARD_PRESENT, &slot->flags);
>  	if (gpio_is_valid(slot->detect_pin)) {
> -		if (gpio_request(slot->detect_pin, "mmc_detect")) {
> +		if (devm_gpio_request(&host->pdev->dev, slot->detect_pin,
> +				      "mmc_detect")) {
>  			dev_dbg(&mmc->class_dev, "no detect pin available\n");
>  			slot->detect_pin = -EBUSY;
>  		} else if (gpio_get_value(slot->detect_pin) ^
> @@ -2208,7 +2210,8 @@ static int __init atmci_init_slot(struct atmel_mci *host,
>  		mmc->caps |= MMC_CAP_NEEDS_POLL;
>  
>  	if (gpio_is_valid(slot->wp_pin)) {
> -		if (gpio_request(slot->wp_pin, "mmc_wp")) {
> +		if (devm_gpio_request(&host->pdev->dev, slot->wp_pin,
> +				      "mmc_wp")) {
>  			dev_dbg(&mmc->class_dev, "no WP pin available\n");
>  			slot->wp_pin = -EBUSY;
>  		}
> @@ -2224,7 +2227,8 @@ static int __init atmci_init_slot(struct atmel_mci *host,
>  		setup_timer(&slot->detect_timer, atmci_detect_change,
>  				(unsigned long)slot);
>  
> -		ret = request_irq(gpio_to_irq(slot->detect_pin),
> +		ret = devm_request_irq(&host->pdev->dev,
> +				gpio_to_irq(slot->detect_pin),
>  				atmci_detect_interrupt,
>  				IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
>  				"mmc-detect", slot);
> @@ -2232,7 +2236,6 @@ static int __init atmci_init_slot(struct atmel_mci *host,
>  			dev_dbg(&mmc->class_dev,
>  				"could not request IRQ %d for detect pin\n",
>  				gpio_to_irq(slot->detect_pin));
> -			gpio_free(slot->detect_pin);
>  			slot->detect_pin = -EBUSY;
>  		}
>  	}
> @@ -2252,15 +2255,8 @@ static void __exit atmci_cleanup_slot(struct atmel_mci_slot *slot,
>  
>  	mmc_remove_host(slot->mmc);
>  
> -	if (gpio_is_valid(slot->detect_pin)) {
> -		int pin = slot->detect_pin;
> -
> -		free_irq(gpio_to_irq(pin), slot);
> +	if (gpio_is_valid(slot->detect_pin))
>  		del_timer_sync(&slot->detect_timer);
> -		gpio_free(pin);
> -	}
> -	if (gpio_is_valid(slot->wp_pin))
> -		gpio_free(slot->wp_pin);
>  
>  	slot->host->slot[id] = NULL;
>  	mmc_free_host(slot->mmc);
> @@ -2395,7 +2391,7 @@ static int __init atmci_probe(struct platform_device *pdev)
>  	if (irq < 0)
>  		return irq;
>  
> -	host = kzalloc(sizeof(struct atmel_mci), GFP_KERNEL);
> +	host = devm_kzalloc(&pdev->dev, sizeof(*host), GFP_KERNEL);
>  	if (!host)
>  		return -ENOMEM;
>  
> @@ -2403,20 +2399,18 @@ static int __init atmci_probe(struct platform_device *pdev)
>  	spin_lock_init(&host->lock);
>  	INIT_LIST_HEAD(&host->queue);
>  
> -	host->mck = clk_get(&pdev->dev, "mci_clk");
> -	if (IS_ERR(host->mck)) {
> -		ret = PTR_ERR(host->mck);
> -		goto err_clk_get;
> -	}
> +	host->mck = devm_clk_get(&pdev->dev, "mci_clk");
> +	if (IS_ERR(host->mck))
> +		return PTR_ERR(host->mck);
>  
> -	ret = -ENOMEM;
> -	host->regs = ioremap(regs->start, resource_size(regs));
> +	host->regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
>  	if (!host->regs)
> -		goto err_ioremap;
> +		return -ENOMEM;
>  
>  	ret = clk_prepare_enable(host->mck);
>  	if (ret)
> -		goto err_request_irq;
> +		return ret;
> +
>  	atmci_writel(host, ATMCI_CR, ATMCI_CR_SWRST);
>  	host->bus_hz = clk_get_rate(host->mck);
>  	clk_disable_unprepare(host->mck);
> @@ -2425,9 +2419,10 @@ static int __init atmci_probe(struct platform_device *pdev)
>  
>  	tasklet_init(&host->tasklet, atmci_tasklet_func, (unsigned long)host);
>  
> -	ret = request_irq(irq, atmci_interrupt, 0, dev_name(&pdev->dev), host);
> +	ret = devm_request_irq(&pdev->dev, irq, atmci_interrupt, 0,
> +			       dev_name(&pdev->dev), host);
>  	if (ret)
> -		goto err_request_irq;
> +		return ret;
>  
>  	/* Get MCI capabilities and set operations according to it */
>  	atmci_get_cap(host);
> @@ -2498,13 +2493,7 @@ static int __init atmci_probe(struct platform_device *pdev)
>  err_init_slot:
>  	if (host->dma.chan)
>  		dma_release_channel(host->dma.chan);
> -	free_irq(irq, host);
> -err_request_irq:
> -	iounmap(host->regs);
> -err_ioremap:
> -	clk_put(host->mck);
> -err_clk_get:
> -	kfree(host);
> +
>  	return ret;
>  }
>  
> @@ -2531,12 +2520,6 @@ static int __exit atmci_remove(struct platform_device *pdev)
>  	if (host->dma.chan)
>  		dma_release_channel(host->dma.chan);
>  
> -	free_irq(platform_get_irq(pdev, 0), host);
> -	iounmap(host->regs);
> -
> -	clk_put(host->mck);
> -	kfree(host);
> -
>  	return 0;
>  }
>  
> -- 
> 1.8.3.2
> 
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