linux-kernel - Re: [PATCH v1] mtd: plat-ram: use release_mem_region instead of release

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Message-ID: <20170815191301.56c3ab9d@bbrezillon>
Date:   Tue, 15 Aug 2017 19:13:01 +0200
From:   Boris Brezillon <boris.brezillon@...e-electrons.com>
To:     Anton Vasilyev <vasilyev@...ras.ru>
Cc:     David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Richard Weinberger <richard@....at>,
        Cyrille Pitchen <cyrille.pitchen@...ev4u.fr>,
        linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        ldv-project@...uxtesting.org
Subject: Re: [PATCH v1] mtd: plat-ram: use release_mem_region instead of
 release_resource

Le Tue, 15 Aug 2017 15:21:34 +0300,
Anton Vasilyev <vasilyev@...ras.ru> a écrit :

> Use api pair of request_mem_region and release_mem_region
> instead of release_resource.
> 
> Found by Linux Driver Verification project (linuxtesting.

Missing ')'.

> 
> Signed-off-by: Anton Vasilyev <vasilyev@...ras.ru>
> ---
> v1: Fix commit based on Boris Brezillon review
> ---
>  drivers/mtd/maps/plat-ram.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/maps/plat-ram.c b/drivers/mtd/maps/plat-ram.c
> index 5157289..90bc87f 100644
> --- a/drivers/mtd/maps/plat-ram.c
> +++ b/drivers/mtd/maps/plat-ram.c
> @@ -100,8 +100,8 @@ static int platram_remove(struct platform_device *pdev)
>  	/* release resources */
>  
>  	if (info->area) {
> -		release_resource(info->area);
> -		kfree(info->area);
> +		release_mem_region(info->area->start,
> +				resource_size(info->area));
>  	}
>  
>  	if (info->map.virt != NULL)

Sorry to realize that only know but it seems a lot of boilerplate code
can be removed if we use devm_ioremap_resource(). I'd prefer the
following solution to the change you're proposing here.

--->8---
diff --git a/drivers/mtd/maps/plat-ram.c b/drivers/mtd/maps/plat-ram.c
index 51572895c02c..6d9a4d6f9839 100644
--- a/drivers/mtd/maps/plat-ram.c
+++ b/drivers/mtd/maps/plat-ram.c
@@ -43,7 +43,6 @@ struct platram_info {
 	struct device		*dev;
 	struct mtd_info		*mtd;
 	struct map_info		 map;
-	struct resource		*area;
 	struct platdata_mtd_ram	*pdata;
 };
 
@@ -97,16 +96,6 @@ static int platram_remove(struct platform_device *pdev)
 
 	platram_setrw(info, PLATRAM_RO);
 
-	/* release resources */
-
-	if (info->area) {
-		release_resource(info->area);
-		kfree(info->area);
-	}
-
-	if (info->map.virt != NULL)
-		iounmap(info->map.virt);
-
 	kfree(info);
 
 	return 0;
@@ -147,12 +136,11 @@ static int platram_probe(struct platform_device *pdev)
 	info->pdata = pdata;
 
 	/* get the resource for the memory mapping */
-
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-
-	if (res == NULL) {
-		dev_err(&pdev->dev, "no memory resource specified\n");
-		err = -ENOENT;
+	info->map.virt = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(info->map.virt)) {
+		err = PTR_ERR(info->map.virt);
+		dev_err(&pdev->dev, "failed to ioremap() region\n");
 		goto exit_free;
 	}
 
@@ -167,26 +155,8 @@ static int platram_probe(struct platform_device *pdev)
 			(char *)pdata->mapname : (char *)pdev->name;
 	info->map.bankwidth = pdata->bankwidth;
 
-	/* register our usage of the memory area */
-
-	info->area = request_mem_region(res->start, info->map.size, pdev->name);
-	if (info->area == NULL) {
-		dev_err(&pdev->dev, "failed to request memory region\n");
-		err = -EIO;
-		goto exit_free;
-	}
-
-	/* remap the memory area */
-
-	info->map.virt = ioremap(res->start, info->map.size);
 	dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
 
-	if (info->map.virt == NULL) {
-		dev_err(&pdev->dev, "failed to ioremap() region\n");
-		err = -EIO;
-		goto exit_free;
-	}
-
 	simple_map_init(&info->map);
 
 	dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");