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Commit 28488fc2 authored by Artem Bityutskiy's avatar Artem Bityutskiy Committed by Artem Bityutskiy
Browse files

UBIFS: introduce debugfs helpers 



Separate out pieces of code from the debugfs file read/write functions and
create separate 'interpret_user_input()'/'provide_user_output()' helpers. These
helpers will be needed in one of the following patches, so this is just a
preparational change.

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 7dae997d

fs/ubifs/debug.c

+56 −20
Original line number Diff line number Diff line
@@ -2820,13 +2820,39 @@ static int dfs_file_open(struct inode *inode, struct file *file) 
	return nonseekable_open(inode, file);

}



/**

 * provide_user_output - provide output to the user reading a debugfs file.

 * @val: boolean value for the answer

 * @u: the buffer to store the answer at

 * @count: size of the buffer

 * @ppos: position in the @u output buffer

 *

 * This is a simple helper function which stores @val boolean value in the user

 * buffer when the user reads one of UBIFS debugfs files. Returns amount of

 * bytes written to @u in case of success and a negative error code in case of

 * failure.

 */

static int provide_user_output(int val, char __user *u, size_t count,

			       loff_t *ppos)

{

	char buf[3];



	if (val)

		buf[0] = '1';

	else

		buf[0] = '0';

	buf[1] = '\n';

	buf[2] = 0x00;



	return simple_read_from_buffer(u, count, ppos, buf, 2);

}



static ssize_t dfs_file_read(struct file *file, char __user *u, size_t count,

			     loff_t *ppos)

{

	struct dentry *dent = file->f_path.dentry;

	struct ubifs_info *c = file->private_data;

	struct ubifs_debug_info *d = c->dbg;

	char buf[3];

	int val;



	if (dent == d->dfs_chk_gen)
@@ -2844,14 +2870,33 @@ static ssize_t dfs_file_read(struct file *file, char __user *u, size_t count, 
	else

		return -EINVAL;



	if (val)

		buf[0] = '1';

	else

		buf[0] = '0';

	buf[1] = '\n';

	buf[2] = 0x00;

	return provide_user_output(val, u, count, ppos);

}



	return simple_read_from_buffer(u, count, ppos, buf, 2);

/**

 * interpret_user_input - interpret user debugfs file input.

 * @u: user-provided buffer with the input

 * @count: buffer size

 *

 * This is a helper function which interpret user input to a boolean UBIFS

 * debugfs file. Returns %0 or %1 in case of success and a negative error code

 * in case of failure.

 */

static int interpret_user_input(const char __user *u, size_t count)

{

	size_t buf_size;

	char buf[8];



	buf_size = min_t(size_t, count, (sizeof(buf) - 1));

	if (copy_from_user(buf, u, buf_size))

		return -EFAULT;



	if (buf[0] == '1')

		return 1;

	else if (buf[0] == '0')

		return 0;



	return -EINVAL;

}



static ssize_t dfs_file_write(struct file *file, const char __user *u,
@@ -2860,8 +2905,6 @@ static ssize_t dfs_file_write(struct file *file, const char __user *u, 
	struct ubifs_info *c = file->private_data;

	struct ubifs_debug_info *d = c->dbg;

	struct dentry *dent = file->f_path.dentry;

	size_t buf_size;

	char buf[8];

	int val;



	/*
@@ -2891,16 +2934,9 @@ static ssize_t dfs_file_write(struct file *file, const char __user *u, 
		return count;

	}



	buf_size = min_t(size_t, count, (sizeof(buf) - 1));

	if (copy_from_user(buf, u, buf_size))

		return -EFAULT;



	if (buf[0] == '1')

		val = 1;

	else if (buf[0] == '0')

		val = 0;

	else

		return -EINVAL;

	val = interpret_user_input(u, count);

	if (val < 0)

		return val;



	if (dent == d->dfs_chk_gen)

		d->chk_gen = val;