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/xtensa/include/asm/checksum.h | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) (limited to 'arch/xtensa/include') diff --git a/arch/xtensa/include/asm/checksum.h b/arch/xtensa/include/asm/checksum.h index dc09448935bf..fe78fba7bd64 100644 --- a/arch/xtensa/include/asm/checksum.h +++ b/arch/xtensa/include/asm/checksum.h @@ -55,14 +55,16 @@ __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len) #define _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 (access_ok(src, len)) - return csum_partial_copy_generic((__force const void *)src, dst, - len, sum, err_ptr, NULL); - if (len) - *err_ptr = -EFAULT; - return sum; + int err = 0; + + if (!access_ok(src, len)) + return 0; + + sum = csum_partial_copy_generic((__force const void *)src, dst, + len, ~0U, &err, NULL); + return err ? 0 : sum; } /* @@ -243,15 +245,15 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr, */ #define 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) + void __user *dst, int len) { - if (access_ok(dst, len)) - return csum_partial_copy_generic(src,dst,len,sum,NULL,err_ptr); + int err = 0; + __wsum sum = ~0U; - if (len) - *err_ptr = -EFAULT; + if (!access_ok(dst, len)) + return 0; - return (__force __wsum)-1; /* invalid checksum */ + sum = csum_partial_copy_generic(src,dst,len,sum,NULL,&err); + return err ? 0 : sum; } #endif -- cgit v1.2.3