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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/alpha
parent99a2c96d52d312b11a943372964226fa134de3b1 (diff)
downloadlinux-stericsson-c693cc4676a055c4126e487b30b0a96ea7ec9936.tar.gz
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/alpha')
-rw-r--r--arch/alpha/include/asm/checksum.h2
-rw-r--r--arch/alpha/lib/csum_partial_copy.c25
2 files changed, 12 insertions, 15 deletions
diff --git a/arch/alpha/include/asm/checksum.h b/arch/alpha/include/asm/checksum.h
index 84f9faea864a..99d631e146b2 100644
--- a/arch/alpha/include/asm/checksum.h
+++ b/arch/alpha/include/asm/checksum.h
@@ -43,7 +43,7 @@ extern __wsum csum_partial(const void *buff, int len, __wsum sum);
*/
#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
#define _HAVE_ARCH_CSUM_AND_COPY
-__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *errp);
+__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len);
__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);
diff --git a/arch/alpha/lib/csum_partial_copy.c b/arch/alpha/lib/csum_partial_copy.c
index f363dc89fcbe..3c0e89c39ddb 100644
--- a/arch/alpha/lib/csum_partial_copy.c
+++ b/arch/alpha/lib/csum_partial_copy.c
@@ -325,30 +325,27 @@ csum_partial_cfu_unaligned(const unsigned long __user * src,
}
__wsum
-csum_and_copy_from_user(const void __user *src, void *dst, int len,
- __wsum sum, int *errp)
+csum_and_copy_from_user(const void __user *src, void *dst, int len)
{
- unsigned long checksum = (__force u32) sum;
+ unsigned long checksum = ~0U;
unsigned long soff = 7 & (unsigned long) src;
unsigned long doff = 7 & (unsigned long) dst;
+ int err = 0;
if (len) {
- if (!access_ok(src, len)) {
- if (errp) *errp = -EFAULT;
- memset(dst, 0, len);
- return sum;
- }
+ if (!access_ok(src, len))
+ return 0;
if (!doff) {
if (!soff)
checksum = csum_partial_cfu_aligned(
(const unsigned long __user *) src,
(unsigned long *) dst,
- len-8, checksum, errp);
+ len-8, checksum, &err);
else
checksum = csum_partial_cfu_dest_aligned(
(const unsigned long __user *) src,
(unsigned long *) dst,
- soff, len-8, checksum, errp);
+ soff, len-8, checksum, &err);
} else {
unsigned long partial_dest;
ldq_u(partial_dest, dst);
@@ -357,15 +354,15 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len,
(const unsigned long __user *) src,
(unsigned long *) dst,
doff, len-8, checksum,
- partial_dest, errp);
+ partial_dest, &err);
else
checksum = csum_partial_cfu_unaligned(
(const unsigned long __user *) src,
(unsigned long *) dst,
soff, doff, len-8, checksum,
- partial_dest, errp);
+ partial_dest, &err);
}
- checksum = from64to16 (checksum);
+ checksum = err ? 0 : from64to16 (checksum);
}
return (__force __wsum)checksum;
}
@@ -378,7 +375,7 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len)
mm_segment_t oldfs = get_fs();
set_fs(KERNEL_DS);
checksum = csum_and_copy_from_user((__force const void __user *)src,
- dst, len, 0, NULL);
+ dst, len);
set_fs(oldfs);
return checksum;
}