mem: fix potential underflow on mem size calculation

If total memory is already bigger than max memory, an underflow
will occur on subtraction. Fix it by simply stopping whenever
we already have amount of memory that is bigger than maximum.

Fixes: 66cc45e293ed ("mem: replace memseg with memseg lists")
Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>

diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
index 4f13b58534a002034dc2db71209a3ecb29644ff6..4f0688f9d5baaca1540a5ae9a9e986d43be4d5b8 100644 (file)
--- a/lib/librte_eal/common/eal_common_memory.c
+++ b/lib/librte_eal/common/eal_common_memory.c
@@ -458,6 +458,9 @@ memseg_primary_init(void)
                                break;
 #endif
 
+                       if (total_mem >= max_mem)
+                               break;
+
                        max_type_mem = RTE_MIN(max_mem - total_mem,
                                (uint64_t)RTE_MAX_MEM_MB_PER_TYPE << 20);
                        max_segs = RTE_MAX_MEMSEG_PER_TYPE;