[PATCH] linux: add in labels for block2mtd

[Daniel Golle]

On Tue, Nov 29, 2022 at 10:23:48AM -0500, Peter Naulls wrote:
> 
> This backports the upstream label feature in block2mtd to the 5.10.x kernel
> in 22.03:
> 
> https://github.com/torvalds/linux/blob/master/drivers/mtd/devices/block2mtd.c

Where are we using block2mtd and why?

I'm not against backporting this, but I don't understand why it is
needed or where we are even using block2mtd.


> --- a/drivers/mtd/devices/block2mtd.c	2022-11-29 07:35:32.382695321 -0500
> +++ b/drivers/mtd/devices/block2mtd.c	2022-11-29 08:04:27.406754981 -0500
> @@ -31,6 +31,9 @@
>  #include <linux/slab.h>
>  #include <linux/major.h>
>  
> +/* Maximum number of comma-separated items in the 'block2mtd=' parameter */
> +#define BLOCK2MTD_PARAM_MAX_COUNT 3
> +
>  /* Info for the block device */
>  struct block2mtd_dev {
>  	struct list_head list;
> @@ -214,7 +217,7 @@
>  
>  
>  static struct block2mtd_dev *add_device(char *devname, int erase_size,
> -		int timeout)
> +		char *label, int timeout)
>  {
>  #ifndef MODULE
>  	int i;
> @@ -278,7 +281,10 @@
>  
>  	/* Setup the MTD structure */
>  	/* make the name contain the block device in */
> -	name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
> +	if (!label)
> +		name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
> +	else
> +		name = kstrdup(label, GFP_KERNEL);
>  	if (!name)
>  		goto err_destroy_mutex;
>  
> @@ -305,7 +311,7 @@
>  	list_add(&dev->list, &blkmtd_device_list);
>  	pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",
>  		dev->mtd.index,
> -		dev->mtd.name + strlen("block2mtd: "),
> +		label ? label : dev->mtd.name + strlen("block2mtd: "),
>  		dev->mtd.erasesize >> 10, dev->mtd.erasesize);
>  	return dev;
>  
> @@ -381,8 +387,9 @@
>  	/* 80 for device, 12 for erase size, 80 for name, 8 for timeout */
>  	char buf[80 + 12 + 80 + 8];
>  	char *str = buf;
> -	char *token[2];
> +	char *token[BLOCK2MTD_PARAM_MAX_COUNT];
>  	char *name;
> +	char *label = NULL;
>  	size_t erase_size = PAGE_SIZE;
>  	unsigned long timeout = MTD_DEFAULT_TIMEOUT;
>  	int i, ret;
> @@ -395,7 +402,7 @@
>  	strcpy(str, val);
>  	kill_final_newline(str);
>  
> -	for (i = 0; i < 2; i++)
> +	for (i = 0; i < BLOCK2MTD_PARAM_MAX_COUNT; i++)
>  		token[i] = strsep(&str, ",");
>  
>  	if (str) {
> @@ -414,7 +421,8 @@
>  		return 0;
>  	}
>  
> -	if (token[1]) {
> +	/* Optional argument when custom label is used */
> +	if (token[1] && strlen(token[1])) {
>  		ret = parse_num(&erase_size, token[1]);
>  		if (ret) {
>  			pr_err("illegal erase size\n");
> @@ -422,7 +430,12 @@
>  		}
>  	}
>  
> -	add_device(name, erase_size, timeout);
> +	if (token[2]) {
> +		label = token[2];
> +		pr_info("Using custom MTD label '%s' for dev %s\n", label, name);
> +	}
> +
> +	add_device(name, erase_size, label, timeout);
>  
>  	return 0;
>  }
> @@ -448,7 +461,7 @@
>  	   the device (even kmalloc() fails). Deter that work to
>  	   block2mtd_setup2(). */
>  
> -	strlcpy(block2mtd_paramline, val, sizeof(block2mtd_paramline));
> +	strscpy(block2mtd_paramline, val, sizeof(block2mtd_paramline));
>  
>  	return 0;
>  #endif
> @@ -456,7 +469,7 @@
>  
>  
>  module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200);
> -MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,<erasesize>]\"");
> +MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,[<erasesize>][,<label>]]\"");
>  
>  static int __init block2mtd_init(void)
>  {

> _______________________________________________
> openwrt-devel mailing list
> openwrt-devel at lists.openwrt.org
> https://lists.openwrt.org/mailman/listinfo/openwrt-devel