[S390] fix "mem=" handling in case of standby memory

Standby memory detected with the sclp interface gets always registered
with add_memory calls without considering the limitationt that the
"mem=" kernel paramater implies.
So fix this and only register standby memory that is below the specified
limit.
This fixes zfcpdump since it uses "mem=32M". In case there is appr.
2GB standby memory present all of usable memory would be used for the
struct pages needed for standby memory.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c
index 506390496416..77ab6e34a100 100644
--- a/drivers/s390/char/sclp_cmd.c
+++ b/drivers/s390/char/sclp_cmd.c
@@ -19,6 +19,7 @@
 #include <linux/memory.h>
 #include <asm/chpid.h>
 #include <asm/sclp.h>
+#include <asm/setup.h>
 
 #include "sclp.h"
 
@@ -474,6 +475,10 @@ static void __init add_memory_merged(u16 rn)
                 goto skip_add;
         if (start + size > VMEM_MAX_PHYS)
                 size = VMEM_MAX_PHYS - start;
+        if (memory_end_set && (start >= memory_end))
+                goto skip_add;
+        if (memory_end_set && (start + size > memory_end))
+                size = memory_end - start;
         add_memory(0, start, size);
 skip_add:
         first_rn = rn;