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util: Fix assertion in iov_copy() upon zero 'bytes' and non-zero 'offset' 

In cases where iov_copy() is passed with zero 'bytes' argument and a
non-zero 'offset' argument, nothing gets copied - as expected.

However no copy iterations are performed, so 'offset' is left
unaltered, leading to the final assert(offset == 0) to fail.

Instead, change the loop condition to continue as long as 'offset || bytes',
similar to other iov_* functions.

This ensures 'offset' gets zeroed (even if no actual copy is made),
unless it is beyond end of source iov - which is asserted.

Signed-off-by: Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>
Message-Id: <1470130880-1050-1-git-send-email-shmulik.ladkani@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Shmulik Ladkani 2016-08-02 12:41:20 +03:00 committed by Paolo Bonzini
parent 0d4104e576
commit e911765cbb
1 changed files with 2 additions and 1 deletions
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3
util/iov.c
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@ -247,7 +247,8 @@ unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt,
{
size_t len;
unsigned int i, j;
for (i = 0, j = 0; i < iov_cnt && j < dst_iov_cnt && bytes; i++) {
for (i = 0, j = 0;
i < iov_cnt && j < dst_iov_cnt && (offset || bytes); i++) {
if (offset >= iov[i].iov_len) {
offset -= iov[i].iov_len;
continue;