s390/hypfs: Use get_free_page() instead of kmalloc to ensure page alignment

Since commit d86bd1bece6f ("mm/slub: support left redzone") it is no longer
guaranteed that kmalloc(PAGE_SIZE) returns page aligned memory.

After the above commit we get an error for diag224 because aligned
memory is required. This leads to the following user visible error:

 # mount none -t s390_hypfs /sys/hypervisor/
 mount: unknown filesystem type 's390_hypfs'

 # dmesg | grep hypfs
 hypfs.cccfb8: The hardware system does not provide all functions
               required by hypfs
 hypfs.7a79f0: Initialization of hypfs failed with rc=-61

Fix this problem and use get_free_page() instead of kmalloc() to get
correctly aligned memory.

Cc: stable@vger.kernel.org # v3.6+
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/hypfs/hypfs_diag.c b/arch/s390/hypfs/hypfs_diag.c
index 28f03ca..794bebb 100644 (file)
--- a/arch/s390/hypfs/hypfs_diag.c
+++ b/arch/s390/hypfs/hypfs_diag.c
@@ -363,11 +363,11 @@ out:
 static int diag224_get_name_table(void)
 {
        /* memory must be below 2GB */
-       diag224_cpu_names = kmalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA);
+       diag224_cpu_names = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
        if (!diag224_cpu_names)
                return -ENOMEM;
        if (diag224(diag224_cpu_names)) {
-               kfree(diag224_cpu_names);
+               free_page((unsigned long) diag224_cpu_names);
                return -EOPNOTSUPP;
        }
        EBCASC(diag224_cpu_names + 16, (*diag224_cpu_names + 1) * 16);
@@ -376,7 +376,7 @@ static int diag224_get_name_table(void)
 
 static void diag224_delete_name_table(void)
 {
-       kfree(diag224_cpu_names);
+       free_page((unsigned long) diag224_cpu_names);
 }
 
 static int diag224_idx2name(int index, char *name)