diff options
author | Al Viro <viro@zeniv.linux.org.uk> | 2020-07-11 07:27:49 +0300 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-08-20 22:45:15 +0300 |
commit | c693cc4676a055c4126e487b30b0a96ea7ec9936 (patch) | |
tree | 8f057e3923deeffd1405e40e7ab1c056fa204189 /arch/arm/include/asm | |
parent | 99a2c96d52d312b11a943372964226fa134de3b1 (diff) | |
download | linux-c693cc4676a055c4126e487b30b0a96ea7ec9936.tar.xz |
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/arm/include/asm')
-rw-r--r-- | arch/arm/include/asm/checksum.h | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/arch/arm/include/asm/checksum.h b/arch/arm/include/asm/checksum.h index 7612b2bd4e9b..1601c132b064 100644 --- a/arch/arm/include/asm/checksum.h +++ b/arch/arm/include/asm/checksum.h @@ -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; } /* |