Re: [PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Tyrel Datwyler <tyreld@linux.vnet.ibm.com>]

On 06/03/2019 04:25 PM, Tyrel Datwyler wrote:
> On 06/03/2019 03:19 PM, Nathan Chancellor wrote:
>> clang warns:
>>
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
>> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>>         case IBMVSCSI_HOST_ACTION_NONE:
>>              ^~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
>> here
>>         if (rc) {
>>             ^~
>>
>> Initialize rc to zero in the case statements that clang mentions so that
>> the atomic_set and dev_err statement don't trigger for them.
>>
>> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
>> Link: https://github.com/ClangBuiltLinux/linux/issues/502
>> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
>> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> 
> Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>
> 

On second thought NACK. See my response to Michael earlier in the thread.

I think this is the better solution:

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 727c31dc11a0..c3cf05dd8733 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2123,8 +2123,8 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data
*hostdata)

        spin_lock_irqsave(hostdata->host->host_lock, flags);
        switch (hostdata->action) {
-       case IBMVSCSI_HOST_ACTION_NONE:
        case IBMVSCSI_HOST_ACTION_UNBLOCK:
+               rc = 0;
                break;
        case IBMVSCSI_HOST_ACTION_RESET:
                spin_unlock_irqrestore(hostdata->host->host_lock, flags);
@@ -2142,8 +2142,9 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data
*hostdata)
                if (!rc)
                        rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
                break;
+       case IBMVSCSI_HOST_ACTION_NONE:
        default:
-               break;
+               return;
        }

        hostdata->action = IBMVSCSI_HOST_ACTION_NONE;