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authorHuaisheng Ye <yehs1@lenovo.com>2018-07-30 15:15:44 +0800
committerDave Jiang <dave.jiang@intel.com>2018-07-30 09:33:03 -0700
commit036a82ca90328960d66b7a5c0e1908475d534d62 (patch)
tree50053f26cf4512ba0bdcc9e305d2696d8d0641de
parent46a590cde0bd17cc983e40e74c195311cc8ba555 (diff)
s390, dcssblk: kaddr and pfn can be NULL to ->direct_access()
dcssblk_direct_access() needs to check the validity of pointers kaddr and pfn for NULL assignment. If anyone equals to NULL, it doesn't need to calculate the value. If either of them is equal to NULL, that is to say callers may have no need for kaddr or pfn, so this patch is prepared for allowing them to pass in NULL instead of having to pass in a pointer or local variable that they then just throw away. Signed-off-by: Huaisheng Ye <yehs1@lenovo.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Dave Jiang <dave.jianig@intel.com>
-rw-r--r--drivers/s390/block/dcssblk.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index ed607288e696..23e526cda5c1 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -922,9 +922,11 @@ __dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff,
unsigned long dev_sz;
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 (kaddr)
+ *kaddr = (void *) dev_info->start + offset;
+ if (pfn)
+ *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset),
+ PFN_DEV|PFN_SPECIAL);
return (dev_sz - offset) / PAGE_SIZE;
}