s390/crash: make copy_oldmem_page() return number of bytes copied

Callback copy_oldmem_page() returns either error code or zero.
Instead, it should return the error code or number of bytes copied.

Fixes: df9694c7975f ("s390/dump: streamline oldmem copy functions")
Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Tested-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index 2534a31..28124d0 100644 (file)
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -233,9 +233,10 @@ ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t csize,
                rc = copy_oldmem_user(iter->iov->iov_base, src, csize);
        else
                rc = copy_oldmem_kernel(iter->kvec->iov_base, src, csize);
-       if (!rc)
-               iov_iter_advance(iter, csize);
-       return rc;
+       if (rc < 0)
+               return rc;
+       iov_iter_advance(iter, csize);
+       return csize;
 }
 
 /*