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mtd: block2mtd: add support for an optional custom MTD label

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This patch adds support for an optional MTD label for mtd2block emulated
MTD devices.  Useful when, e.g., testing device images using Qemu.

The following line in /etc/fstab can then be used to mount a file system
regardless if running on an embedded system, or emulated with block2mtd:

    mtd:Config  /mnt    jffs2   noatime,nodiratime      0    0

Kernel command line syntax in the emulated case:

    block2mtd.block2mtd=/dev/sda,,Config

Notice the ',,' it is the optional erase_size, which like before this
patch, defaults to PAGE_SIZE when omitted.  Hence the strlen() check.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211009060955.552636-3-troglobit@gmail.com
This commit is contained in:
Joachim Wiberg 2021-10-09 08:09:55 +02:00 committed by Miquel Raynal
parent a04e96537c
commit 7b09acdcb9
1 changed files with 17 additions and 7 deletions
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24
drivers/mtd/devices/block2mtd.c
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@ -32,7 +32,7 @@
#include <linux/major.h>
/* Maximum number of comma-separated items in the 'block2mtd=' parameter */
#define BLOCK2MTD_PARAM_MAX_COUNT 2
#define BLOCK2MTD_PARAM_MAX_COUNT 3
/* Info for the block device */
struct block2mtd_dev {
@ -217,7 +217,7 @@ static void block2mtd_free_device(struct block2mtd_dev *dev)
static struct block2mtd_dev *add_device(char *devname, int erase_size,
int timeout)
char *label, int timeout)
{
#ifndef MODULE
int i;
@ -281,7 +281,10 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size,
/* 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;
@ -308,7 +311,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size,
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;
@ -386,6 +389,7 @@ static int block2mtd_setup2(const char *val)
char *str = buf;
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;
@ -417,7 +421,8 @@ static int block2mtd_setup2(const char *val)
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");
@ -425,7 +430,12 @@ static int block2mtd_setup2(const char *val)
}
}
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;
}
@ -459,7 +469,7 @@ static int block2mtd_setup(const char *val, const struct kernel_param *kp)
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)
{