weit_for_completion_interruptible returns in (0 on completion and 
-ERESTARTSYS on interruption) - so use an int not long for API conformance
and simplify the logic here a bit: need not check explicitly for == 0 as
this is either -ERESTARTSYS or 0.

Signed-off-by: Nicholas Mc Guire <hof...@osadl.org>
---

Problem located with experimental API conformance checking cocci script

V2: kbuild reported a missing closing comment - seems that I managed
    send out the the initial version before compile testing/checkpatching
    sorry for the noise.

Not sure if making such point-wise fixes makes much sense - this driver has
a number of issues both style-wise and API compliance wise.

Note that kpc_dma_transfer() returns int not long - currently rv (long) is
being returned in most places (some places do return int) - so the return
handling here is a bit inconsistent.

Patch was compile-tested with: x86_64_defconfig + KPC2000=y, KPC2000_DMA=y
(with a number of unrelated sparse warnings about non-declared symbols, and
 smatch warnings about overflowing constants as well as coccicheck warning
 about usless casting)

Patch is against 5.1-rc6 (localversion-next is next-20190426)

 drivers/staging/kpc2000/kpc_dma/fileops.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c 
b/drivers/staging/kpc2000/kpc_dma/fileops.c
index 5741d2b..66f0d5a 100644
--- a/drivers/staging/kpc2000/kpc_dma/fileops.c
+++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
@@ -38,6 +38,7 @@ int  kpc_dma_transfer(struct dev_private_data *priv, struct 
kiocb *kcb, unsigned
 {
        unsigned int i = 0;
        long rv = 0;
+       int ret = 0;
        struct kpc_dma_device *ldev;
        struct aio_cb_data *acd;
        DECLARE_COMPLETION_ONSTACK(done);
@@ -180,16 +181,17 @@ int  kpc_dma_transfer(struct dev_private_data *priv, 
struct kiocb *kcb, unsigned
        
        // If this is a synchronous kiocb, we need to put the calling process 
to sleep until the transfer is complete
        if (kcb == NULL || is_sync_kiocb(kcb)){
-               rv = wait_for_completion_interruptible(&done);
-               // If the user aborted (rv == -ERESTARTSYS), we're no longer 
responsible for cleaning up the acd
-               if (rv == -ERESTARTSYS){
+               ret = wait_for_completion_interruptible(&done);
+               /* If the user aborted (ret == -ERESTARTSYS), we're
+                * no longer responsible for cleaning up the acd
+                */
+               if (ret) {
                        acd->cpl = NULL;
-               }
-               if (rv == 0){
-                       rv = acd->len;
+               } else {
+                       ret = acd->len;
                        kfree(acd);
                }
-               return rv;
+               return ret;
        }
        
        return -EIOCBQUEUED;
-- 
2.1.4

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