From: Huaisheng Ye <yehs1@xxxxxxxxxx> direct_access needs to check the validity of pointer pfn for NULL assignment. If pfn equals to NULL, it doesn't need to calculate the value. Signed-off-by: Huaisheng Ye <yehs1@xxxxxxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> --- drivers/s390/block/dcssblk.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index ed607288e696..a645b2c93c34 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -923,8 +923,9 @@ __dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff, dev_sz = dev_info->end - dev_info->start + 1; *kaddr = (void *) dev_info->start + offset; - *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), - PFN_DEV|PFN_SPECIAL); + if (pfn) + *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), + PFN_DEV|PFN_SPECIAL); return (dev_sz - offset) / PAGE_SIZE; }
