s390/mem_detect: do not update output parameters on failure

Function __get_mem_detect_block() resets start and end
output parameters in case of invalid mem_detect array
index is provided. That violates the rule of sparing
the output on fail path and leads e.g to a below anomaly:

	for_each_mem_detect_block(i, &start, &end)
		continue;

One would expect start and end contain addresses of the
last memory block (if available), but in fact the two
will be reset to zeroes. That is not how an iterator is
expected to work.

Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Alexander Gordeev 2023-01-25 19:16:10 +01:00 committed by Heiko Carstens
parent 0c6924c262
commit cbc29f107e

View File

@ -40,11 +40,8 @@ void add_mem_detect_block(u64 start, u64 end);
static inline int __get_mem_detect_block(u32 n, unsigned long *start, static inline int __get_mem_detect_block(u32 n, unsigned long *start,
unsigned long *end) unsigned long *end)
{ {
if (n >= mem_detect.count) { if (n >= mem_detect.count)
*start = 0;
*end = 0;
return -1; return -1;
}
if (n < MEM_INLINED_ENTRIES) { if (n < MEM_INLINED_ENTRIES) {
*start = (unsigned long)mem_detect.entries[n].start; *start = (unsigned long)mem_detect.entries[n].start;