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 --- include/net/checksum.h | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) (limited to 'include') diff --git a/include/net/checksum.h b/include/net/checksum.h index 1029191986e3..0d05b9e8690b 100644 --- a/include/net/checksum.h +++ b/include/net/checksum.h @@ -24,26 +24,23 @@ #ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER static inline __wsum csum_and_copy_from_user (const void __user *src, void *dst, - int len, __wsum sum, int *err_ptr) + int len) { if (copy_from_user(dst, src, len)) - *err_ptr = -EFAULT; - return csum_partial(dst, len, sum); + return 0; + return csum_partial(dst, len, ~0U); } #endif #ifndef HAVE_CSUM_COPY_USER static __inline__ __wsum csum_and_copy_to_user -(const void *src, void __user *dst, int len, __wsum sum, int *err_ptr) +(const void *src, void __user *dst, int len) { - sum = csum_partial(src, len, sum); + __wsum sum = csum_partial(src, len, ~0U); if (copy_to_user(dst, src, len) == 0) return sum; - if (len) - *err_ptr = -EFAULT; - - return (__force __wsum)-1; /* invalid checksum */ + return 0; } #endif -- cgit v1.2.3