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[08/13] s390/block/dcssblk: check the validity of the pointer pfn

Message ID 153077338570.40830.10517740093746798315.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dan Williams July 5, 2018, 6:49 a.m. UTC 
From: Huaisheng Ye <yehs1@lenovo.com>

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@lenovo.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/s390/block/dcssblk.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
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Patch

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;
 }