From c693cc4676a055c4126e487b30b0a96ea7ec9936 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 11 Jul 2020 00:27:49 -0400 Subject: 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: Al Viro --- arch/m68k/include/asm/checksum.h | 3 +-- arch/m68k/lib/checksum.c | 8 +++----- 2 files changed, 4 insertions(+), 7 deletions(-) (limited to 'arch/m68k') diff --git a/arch/m68k/include/asm/checksum.h b/arch/m68k/include/asm/checksum.h index d5e74c64b6cd..692e7b6cc042 100644 --- a/arch/m68k/include/asm/checksum.h +++ b/arch/m68k/include/asm/checksum.h @@ -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); diff --git a/arch/m68k/lib/checksum.c b/arch/m68k/lib/checksum.c index 86ddd2ee187d..3aeca261f622 100644 --- a/arch/m68k/lib/checksum.c +++ b/arch/m68k/lib/checksum.c @@ -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); -- cgit v1.2.3