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authorAl Viro <viro@zeniv.linux.org.uk>2020-07-11 00:27:49 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2020-08-20 15:45:15 -0400
commitc693cc4676a055c4126e487b30b0a96ea7ec9936 (patch)
tree8f057e3923deeffd1405e40e7ab1c056fa204189 /arch/xtensa
parent99a2c96d52d312b11a943372964226fa134de3b1 (diff)
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 <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/xtensa')
-rw-r--r--arch/xtensa/include/asm/checksum.h30
1 files changed, 16 insertions, 14 deletions
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