[S390] cpcmd with vmalloc addresses.

Change the bounce buffer logic of cpcmd. diag8 needs _real_ memory below
2GB. Therefore vmalloced data does not work. As the data might cross a
page boundary, we cannot use virt_to_page either. The solution is to use
virt_to_page only in the check for a bounce buffer.

There was a redundant check for response==NULL. response < 2GB contains
this check as well.

I also removed the rlen==0 check, since rlen=0 and response!=NULL would
be a caller bug and response==NULL is already checked.

Signed-off-by: Christian Borntraeger <cborntra@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 7 insertions, 7 deletions

diff --git a/arch/s390/kernel/cpcmd.c b/arch/s390/kernel/cpcmd.c
index a5972f1541fe..6c89f30c8e31 100644
--- a/arch/s390/kernel/cpcmd.c
+++ b/arch/s390/kernel/cpcmd.c
@@ -16,6 +16,7 @@
 #include <asm/ebcdic.h>
 #include <asm/cpcmd.h>
 #include <asm/system.h>
+#include <asm/io.h>
 
 static DEFINE_SPINLOCK(cpcmd_lock);
 static char cpcmd_buf[241];
@@ -88,13 +89,8 @@ int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
         int len;
         unsigned long flags;
 
-        if ((rlen == 0) || (response == NULL)
-            || !((unsigned long)response >> 31)) {
-                spin_lock_irqsave(&cpcmd_lock, flags);
-                len = __cpcmd(cmd, response, rlen, response_code);
-                spin_unlock_irqrestore(&cpcmd_lock, flags);
-        }
-        else {
+        if ((virt_to_phys(response) != (unsigned long) response) ||
+                        (((unsigned long)response + rlen) >> 31)) {
                 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
                 if (!lowbuf) {
                         printk(KERN_WARNING
@@ -106,6 +102,10 @@ int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
                 spin_unlock_irqrestore(&cpcmd_lock, flags);
                 memcpy(response, lowbuf, rlen);
                 kfree(lowbuf);
+        } else {
+                spin_lock_irqsave(&cpcmd_lock, flags);
+                len = __cpcmd(cmd, response, rlen, response_code);
+                spin_unlock_irqrestore(&cpcmd_lock, flags);
         }
         return len;
 }