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Commit 32ef0e3e authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: serial2002: fix different address space sparse warnings 



The struct file_operations (*read) and (*write) operations expect the
buffer to be a __user space pointer.

Currently the (*write) operations in this driver cause this warning:
warning: incorrect type in argument 2 (different address spaces)
  expected char const [noderef] <asn:1>*<noident>
  got unsigned char [usertype] *buf

And the (*read) operations cause this warning:
warning: incorrect type in argument 2 (different address spaces)
  expected char [noderef] <asn:1>*<noident>
  got unsigned char *<noident>

Use __force to cast the buffer to a __user pointer to suppress the
warnings.

Consolidate the (*read) calls into a helper function, __tty_readb().

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4445d254

drivers/staging/comedi/drivers/serial2002.c

+14 −11
Original line number Diff line number Diff line
@@ -82,17 +82,26 @@ static long tty_ioctl(struct file *f, unsigned op, unsigned long param) 


static int tty_write(struct file *f, unsigned char *buf, int count)

{

	const char __user *p = (__force const char __user *)buf;

	int result;

	mm_segment_t oldfs;



	oldfs = get_fs();

	set_fs(KERNEL_DS);

	f->f_pos = 0;

	result = f->f_op->write(f, buf, count, &f->f_pos);

	result = f->f_op->write(f, p, count, &f->f_pos);

	set_fs(oldfs);

	return result;

}



static int __tty_readb(struct file *f, unsigned char *buf)

{

	char __user *p = (__force char __user *)buf;



	f->f_pos = 0;

	return f->f_op->read(f, p, 1, &f->f_pos);

}



#if 0

/*

 * On 2.6.26.3 this occaisonally gave me page faults, worked around by
@@ -113,6 +122,7 @@ static int tty_available(struct file *f) 


static int tty_read(struct file *f, int timeout)

{

	unsigned char ch;

	int result;



	result = -1;
@@ -147,25 +157,18 @@ static int tty_read(struct file *f, int timeout) 
						   elapsed) * HZ) / 10000);

			}

			poll_freewait(&table);

			{

				unsigned char ch;



				f->f_pos = 0;

				if (f->f_op->read(f, &ch, 1, &f->f_pos) == 1)

			if (__tty_readb(f, &ch) == 1)

				result = ch;

			}

		} else {

			/* Device does not support poll, busy wait */

			int retries = 0;

			while (1) {

				unsigned char ch;



				retries++;

				if (retries >= timeout)

					break;



				f->f_pos = 0;

				if (f->f_op->read(f, &ch, 1, &f->f_pos) == 1) {

				if (__tty_readb(f, &ch) == 1) {

					result = ch;

					break;

				}