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    Subject[PATCH 3.16 177/306] s390/hypfs: Use get_free_page() instead of kmalloc to ensure page alignment
    3.16.40-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Michael Holzheu <holzheu@linux.vnet.ibm.com>

    commit 237d6e6884136923b6bd26d5141ebe1d065960c9 upstream.

    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.

    Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
    Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    arch/s390/hypfs/hypfs_diag.c | 6 +++---
    1 file changed, 3 insertions(+), 3 deletions(-)

    --- a/arch/s390/hypfs/hypfs_diag.c
    +++ b/arch/s390/hypfs/hypfs_diag.c
    @@ -517,11 +517,11 @@ static int diag224(void *ptr)
    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);
    @@ -530,7 +530,7 @@ 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)
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