diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2020-07-11 00:27:49 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-08-20 15:45:15 -0400 |
| commit | c693cc4676a055c4126e487b30b0a96ea7ec9936 (patch) | |
| tree | 8f057e3923deeffd1405e40e7ab1c056fa204189 /lib/iov_iter.c | |
| parent | 99a2c96d52d312b11a943372964226fa134de3b1 (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 'lib/iov_iter.c')
| -rw-r--r-- | lib/iov_iter.c | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 437fbc14c972..ccb247faf79b 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1449,15 +1449,14 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, return 0; } iterate_and_advance(i, bytes, v, ({ - int err = 0; next = csum_and_copy_from_user(v.iov_base, (to += v.iov_len) - v.iov_len, - v.iov_len, ~0U, &err); - if (!err) { + v.iov_len); + if (next) { sum = csum_block_add(sum, next, off); off += v.iov_len; } - err ? v.iov_len : 0; + next ? 0 : v.iov_len; }), ({ char *p = kmap_atomic(v.bv_page); sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, @@ -1491,11 +1490,10 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, if (unlikely(i->count < bytes)) return false; iterate_all_kinds(i, bytes, v, ({ - int err = 0; next = csum_and_copy_from_user(v.iov_base, (to += v.iov_len) - v.iov_len, - v.iov_len, ~0U, &err); - if (err) + v.iov_len); + if (!next) return false; sum = csum_block_add(sum, next, off); off += v.iov_len; @@ -1537,15 +1535,14 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump, return 0; } iterate_and_advance(i, bytes, v, ({ - int err = 0; next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, v.iov_base, - v.iov_len, ~0U, &err); - if (!err) { + v.iov_len); + if (next) { sum = csum_block_add(sum, next, off); off += v.iov_len; } - err ? v.iov_len : 0; + next ? 0 : v.iov_len; }), ({ char *p = kmap_atomic(v.bv_page); sum = csum_and_memcpy(p + v.bv_offset, |