[PATCH] s390/diag324: Preserve -EBUSY return code

[Sumanth Korikkar <sumanthk@linux.ibm.com>]

When diag324 reports -EBUSY, the error code is
overwritten by the result of copy_to_user() and put_user(). As a result,
the ioctl may incorrectly return success instead of -EBUSY.

Preserve the original diag324 return code and only return -EFAULT when
copying data to userspace fails.

Fixes: 90e6f191e1ee ("s390/diag324: Retrieve power readings via diag 0x324")
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
---
 arch/s390/kernel/diag/diag324.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/s390/kernel/diag/diag324.c b/arch/s390/kernel/diag/diag324.c
index fe325c2a2d0d..3eec0cc8fb9e 100644
--- a/arch/s390/kernel/diag/diag324.c
+++ b/arch/s390/kernel/diag/diag324.c
@@ -182,8 +182,7 @@ long diag324_pibbuf(unsigned long arg)
 		goto out;
 	rc = copy_to_user((void __user *)address, data->pib, data->pib->len);
 	rc |= put_user(data->sequence, &udata->sequence);
-	if (rc)
-		rc = -EFAULT;
+	rc = rc ? -EFAULT : data->rc;
 out:
 	mutex_unlock(&pibmutex);
 	return rc;
-- 
2.54.0