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Message-ID: <20150224080512.GE24441@norris-Latitude-E6410>
Date: Tue, 24 Feb 2015 00:05:12 -0800
From: Brian Norris <computersforpeace@...il.com>
To: Rodrigo Freire <rfreire@...hat.com>
Cc: linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
Jörn Engel <joern@...fs.org>,
Felix Fietkau <nbd@...nwrt.org>, dwmw2@...radead.org,
Herton Krzesinski <hkrzesin@...hat.com>
Subject: Re: [PATCH v3 2/3] mtd: block2mtd: Adds a mtd name and a block
device timeout option
On Sun, Nov 09, 2014 at 07:22:27AM -0500, Rodrigo Freire wrote:
> From: Felix Fietkau <nbd@...nwrt.org>
>
> mtd: block2mtd: Adds a mtd name and a block device timeout option
>
> This patch adds support to a block2mtd MTD name and allows to specify
> a block device timeout when adding a block2mtd MTD drive.
> Usage: block2mtd=<dev>[,<erasesize>[,<name>[,<timeout>]]]
Hmm, are all 4 required in this order? What if I want to set the timeout
without the erasesize or name? I suppose it's not a requirement for this
patch, but it's probably not hard to handle that as a future
enhancement. e.g. block2mtd=<dev[,[<erasesize>][,[<name>][,<timeout>]]]
so I could do
block2mtd=/dev/mmcblk0p2,,,4
to set the timeout to 4 seconds.
> The devices will be identified the following way:
> [root@...ver01 ~]# cat /proc/mtd
> dev: size erasesize name
> mtd0: a0000000 00010000 "rootfs"
> mtd1: 265080000 00010000 "anothername"
> mtd2: acd00000 00010000 "/dev/mmcblk0p2"
> Notice that the device mtd2 was added without specifying a name.
>
> Signed-off-by: Felix Fietkau <nbd@...nwrt.org>
> Signed-off-by: Rodrigo Freire <rfreire@...hat.com>
> Signed-off-by: Herton Krzesinski <herton@...hat.com>
> ---
> V3: Separated on a single patch
> --- a/drivers/mtd/devices/block2mtd.c 2014-11-07 17:16:11.711479312 -0200
> +++ b/drivers/mtd/devices/block2mtd.c 2014-11-07 17:15:14.255464054 -0200
> @@ -25,6 +25,7 @@
> #include <linux/list.h>
> #include <linux/init.h>
> #include <linux/mtd/mtd.h>
> +#include <linux/mtd/partitions.h>
> #include <linux/mutex.h>
> #include <linux/mount.h>
> #include <linux/slab.h>
> @@ -218,7 +219,7 @@ static void block2mtd_free_device(struct
>
>
> static struct block2mtd_dev *add_device(char *devname, int erase_size,
> - int timeout)
> + const char *mtdname, int timeout)
> {
> #ifndef MODULE
> int i;
> @@ -226,6 +227,7 @@ static struct block2mtd_dev *add_device(
> const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
> struct block_device *bdev = ERR_PTR(-ENODEV);
> struct block2mtd_dev *dev;
> + struct mtd_partition *part;
> char *name;
>
> if (!devname)
> @@ -282,7 +284,9 @@ static struct block2mtd_dev *add_device(
>
> /* Setup the MTD structure */
> /* make the name contain the block device in */
> - name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
> + if (!mtdname)
> + mtdname = devname;
> + name = kstrdup(mtdname, GFP_KERNEL);
> if (!name)
> goto err_destroy_mutex;
>
> @@ -301,7 +305,11 @@ static struct block2mtd_dev *add_device(
> dev->mtd.priv = dev;
> dev->mtd.owner = THIS_MODULE;
>
> - if (mtd_device_register(&dev->mtd, NULL, 0)) {
> + part = kzalloc(sizeof(struct mtd_partition), GFP_KERNEL);
sizeof(*part)
> + part->name = name;
> + part->offset = 0;
> + part->size = dev->mtd.size;
> + if (mtd_device_register(&dev->mtd, part, 1)) {
> /* Device didn't get added, so free the entry */
> goto err_destroy_mutex;
> }
> @@ -309,8 +317,7 @@ static struct block2mtd_dev *add_device(
> 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: "),
> - dev->mtd.erasesize >> 10, dev->mtd.erasesize);
> + mtdname, dev->mtd.erasesize >> 10, dev->mtd.erasesize);
> return dev;
>
> err_destroy_mutex:
> @@ -383,7 +390,7 @@ static int block2mtd_setup2(const char *
> /* 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[4];
> char *name;
> size_t erase_size = PAGE_SIZE;
> unsigned long timeout = MTD_DEFAULT_TIMEOUT;
> @@ -397,7 +404,7 @@ static int block2mtd_setup2(const char *
> strcpy(str, val);
> kill_final_newline(str);
>
> - for (i = 0; i < 2; i++)
> + for (i = 0; i < 4; i++)
Maybe use ARRAY_SIZE(token)?
> token[i] = strsep(&str, ",");
>
> if (str) {
> @@ -424,7 +431,13 @@ static int block2mtd_setup2(const char *
> }
> }
>
> - add_device(name, erase_size, timeout);
> + if (token[2] && (strlen(token[2]) + 1 > 80))
> + pr_err("mtd device name too long");
Hmm, so it's too long, but you continue? Shouldn't we return here?
> +
> +
> + if (token[3] && kstrtoul(token[3], 0, &timeout))
> + pr_err("invalid timeout");
Again, shouldn't we return here? It's best not to just ignore invalid
input.
> + add_device(name, erase_size, token[2], timeout);
>
> return 0;
> }
> @@ -458,7 +471,7 @@ static int block2mtd_setup(const char *v
>
>
> 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>[,<name>[,<timeout>]]]\"");
>
> static int __init block2mtd_init(void)
> {
Brian
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