UBI: support attaching by MTD character device name (f9b0080e) · Commits · 戴 / test

drivers/mtd/ubi/build.c

+55 −11

Original line number	Diff line number	Diff line
		@@ -37,6 +37,7 @@
		#include <linux/module.h>
		#include <linux/moduleparam.h>
		#include <linux/stringify.h>
		#include <linux/namei.h>
		#include <linux/stat.h>
		#include <linux/miscdevice.h>
		#include <linux/log2.h>
		@@ -50,7 +51,8 @@

		/**
		* struct mtd_dev_param - MTD device parameter description data structure.
		* @name: MTD device name or number string
		* @name: MTD character device node path, MTD device name, or MTD device number
		* string
		* @vid_hdr_offs: VID header offset
		*/
		struct mtd_dev_param {
		@@ -1116,13 +1118,50 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
		}

		/**
		* find_mtd_device - open an MTD device by its name or number.
		* @mtd_dev: name or number of the device
		* open_mtd_by_chdev - open an MTD device by its character device node path.
		* @mtd_dev: MTD character device node path
		*
		* This helper function opens an MTD device by its character node device path.
		* Returns MTD device description object in case of success and a negative
		* error code in case of failure.
		*/
		static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
		{
		int err, major, minor, mode;
		struct path path;

		/* Probably this is an MTD character device node path */
		err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
		if (err)
		return ERR_PTR(err);

		/* MTD device number is defined by the major / minor numbers */
		major = imajor(path.dentry->d_inode);
		minor = iminor(path.dentry->d_inode);
		mode = path.dentry->d_inode->i_mode;
		path_put(&path);
		if (major != MTD_CHAR_MAJOR \|\| !S_ISCHR(mode))
		return ERR_PTR(-EINVAL);

		if (minor & 1)
		/*
		* Just do not think the "/dev/mtdrX" devices support is need,
		* so do not support them to avoid doing extra work.
		*/
		return ERR_PTR(-EINVAL);

		return get_mtd_device(NULL, minor / 2);
		}

		/**
		* open_mtd_device - open MTD device by name, character device path, or number.
		* @mtd_dev: name, character device node path, or MTD device device number
		*
		* This function tries to open and MTD device described by @mtd_dev string,
		* which is first treated as an ASCII number, and if it is not true, it is
		* treated as MTD device name. Returns MTD device description object in case of
		* success and a negative error code in case of failure.
		* which is first treated as ASCII MTD device number, and if it is not true, it
		* is treated as MTD device name, and if that is also not true, it is treated
		* as MTD character device node path. Returns MTD device description object in
		* case of success and a negative error code in case of failure.
		*/
		static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
		{
		@@ -1137,6 +1176,9 @@ static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
		* MTD device name.
		*/
		mtd = get_mtd_device_nm(mtd_dev);
		if (IS_ERR(mtd) && PTR_ERR(mtd) == -ENODEV)
		/* Probably this is an MTD character device node path */
		mtd = open_mtd_by_chdev(mtd_dev);
		} else
		mtd = get_mtd_device(NULL, mtd_num);

		@@ -1352,13 +1394,15 @@ static int __init ubi_mtd_param_parse(const char val, struct kernel_param kp)

		module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 000);
		MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: "
		"mtd=<name\|num>[,<vid_hdr_offs>].\n"
		"mtd=<name\|num\|path>[,<vid_hdr_offs>].\n"
		"Multiple \"mtd\" parameters may be specified.\n"
		"MTD devices may be specified by their number or name.\n"
		"MTD devices may be specified by their number, name, or "
		"path to the MTD character device node.\n"
		"Optional \"vid_hdr_offs\" parameter specifies UBI VID "
		"header position and data starting position to be used "
		"by UBI.\n"
		"Example: mtd=content,1984 mtd=4 - attach MTD device"
		"header position to be used by UBI.\n"
		"Example 1: mtd=/dev/mtd0 - attach MTD device "
		"/dev/mtd0.\n"
		"Example 2: mtd=content,1984 mtd=4 - attach MTD device "
		"with name \"content\" using VID header offset 1984, and "
		"MTD device number 4 with default VID header offset.");

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