Commit c693cc46 authored by Al Viro's avatar Al Viro
Browse files

saner calling conventions for csum_and_copy_..._user() 



All callers of these primitives will
	* discard anything we might've copied in case of error
	* ignore the csum value in case of error
	* always pass 0xffffffff as the initial sum, so the
resulting csum value (in case of success, that is) will never be 0.

That suggest the following calling conventions:
	* don't pass err_ptr - just return 0 on error.
	* don't bother with zeroing destination, etc. in case of error
	* don't pass the initial sum - just use 0xffffffff.

This commit does the minimal conversion in the instances of csum_and_copy_...();
the changes of actual asm code behind them are done later in the series.
Note that this asm code is often shared with csum_partial_copy_nocheck();
the difference is that csum_partial_copy_nocheck() passes 0 for initial
sum while csum_and_copy_..._user() pass 0xffffffff.  Fortunately, we are
free to pass 0xffffffff in all cases and subsequent patches will use that
freedom without any special comments.

A part that could be split off: parisc and uml/i386 claimed to have
csum_and_copy_to_user() instances of their own, but those were identical
to the generic one, so we simply drop them.  Not sure if it's worth
a separate commit...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 99a2c96d

arch/alpha/include/asm/checksum.h

+1 −1
Original line number Diff line number Diff line
@@ -43,7 +43,7 @@ extern __wsum csum_partial(const void *buff, int len, __wsum sum); 
 */

#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER

#define _HAVE_ARCH_CSUM_AND_COPY

__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *errp);

__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len);



__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);

arch/alpha/lib/csum_partial_copy.c

+11 −14
Original line number Diff line number Diff line
@@ -325,30 +325,27 @@ csum_partial_cfu_unaligned(const unsigned long __user * src, 
}



__wsum

csum_and_copy_from_user(const void __user *src, void *dst, int len,

			       __wsum sum, int *errp)

csum_and_copy_from_user(const void __user *src, void *dst, int len)

{

	unsigned long checksum = (__force u32) sum;

	unsigned long checksum = ~0U;

	unsigned long soff = 7 & (unsigned long) src;

	unsigned long doff = 7 & (unsigned long) dst;

	int err = 0;



	if (len) {

		if (!access_ok(src, len)) {

			if (errp) *errp = -EFAULT;

			memset(dst, 0, len);

			return sum;

		}

		if (!access_ok(src, len))

			return 0;

		if (!doff) {

			if (!soff)

				checksum = csum_partial_cfu_aligned(

					(const unsigned long __user *) src,

					(unsigned long *) dst,

					len-8, checksum, errp);

					len-8, checksum, &err);

			else

				checksum = csum_partial_cfu_dest_aligned(

					(const unsigned long __user *) src,

					(unsigned long *) dst,

					soff, len-8, checksum, errp);

					soff, len-8, checksum, &err);

		} else {

			unsigned long partial_dest;

			ldq_u(partial_dest, dst);
@@ -357,15 +354,15 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len, 
					(const unsigned long __user *) src,

					(unsigned long *) dst,

					doff, len-8, checksum,

					partial_dest, errp);

					partial_dest, &err);

			else

				checksum = csum_partial_cfu_unaligned(

					(const unsigned long __user *) src,

					(unsigned long *) dst,

					soff, doff, len-8, checksum,

					partial_dest, errp);

					partial_dest, &err);

		}

		checksum = from64to16 (checksum);

		checksum = err ? 0 : from64to16 (checksum);

	}

	return (__force __wsum)checksum;

}
@@ -378,7 +375,7 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len) 
	mm_segment_t oldfs = get_fs();

	set_fs(KERNEL_DS);

	checksum = csum_and_copy_from_user((__force const void __user *)src,

						dst, len, 0, NULL);

						dst, len);

	set_fs(oldfs);

	return checksum;

}

arch/arm/include/asm/checksum.h

+6 −7
Original line number Diff line number Diff line
@@ -43,16 +43,15 @@ csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum s 
#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER

#define _HAVE_ARCH_CSUM_AND_COPY

static inline

__wsum csum_and_copy_from_user (const void __user *src, void *dst,

				      int len, __wsum sum, int *err_ptr)

__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)

{

	if (access_ok(src, len))

		return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);

	int err = 0;



	if (len)

		*err_ptr = -EFAULT;

	if (!access_ok(src, len))

		return 0;



	return sum;

	sum = csum_partial_copy_from_user(src, dst, len, ~0U, &err);

	return err ? 0 : sum;

}



/*

arch/m68k/include/asm/checksum.h

+1 −2
Original line number Diff line number Diff line
@@ -34,8 +34,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum); 
#define _HAVE_ARCH_CSUM_AND_COPY

extern __wsum csum_and_copy_from_user(const void __user *src,

						void *dst,

						int len, __wsum sum,

						int *csum_err);

						int len);



extern __wsum csum_partial_copy_nocheck(const void *src,

					      void *dst, int len);

arch/m68k/lib/checksum.c

+3 −5
Original line number Diff line number Diff line
@@ -129,8 +129,7 @@ EXPORT_SYMBOL(csum_partial); 
 */



__wsum

csum_and_copy_from_user(const void __user *src, void *dst,

			    int len, __wsum sum, int *csum_err)

csum_and_copy_from_user(const void __user *src, void *dst, int len)

{

	/*

	 * GCC doesn't like more than 10 operands for the asm
@@ -138,6 +137,7 @@ csum_and_copy_from_user(const void __user *src, void *dst, 
	 * code.

	 */

	unsigned long tmp1, tmp2;

	__wsum sum = ~0U;



	__asm__("movel %2,%4\n\t"

		"btst #1,%4\n\t"	/* Check alignment */
@@ -311,9 +311,7 @@ csum_and_copy_from_user(const void __user *src, void *dst, 
		: "0" (sum), "1" (len), "2" (src), "3" (dst)

	    );



	*csum_err = tmp2;



	return(sum);

	return tmp2 ? 0 : sum;

}



EXPORT_SYMBOL(csum_and_copy_from_user);