[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>

diff --git a/arch/s390/kernel/cpcmd.c b/arch/s390/kernel/cpcmd.c
index a5972f1541fea7525afc6c12f868cb7aa5d0efbd..6c89f30c8e31ea39f181fe610dffada543254129 100644 (file)
--- 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;
 }