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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 4 Jun 2019 00:35:54 +0100 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp23033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x53NZrHf25756138 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 3 Jun 2019 23:35:53 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AC28AAC059; Mon, 3 Jun 2019 23:35:53 +0000 (GMT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8AB16AC062; Mon, 3 Jun 2019 23:35:52 +0000 (GMT) Received: from oc6857751186.ibm.com (unknown [9.85.191.102]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Mon, 3 Jun 2019 23:35:52 +0000 (GMT) Subject: Re: [PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work From: Tyrel Datwyler To: Nathan Chancellor , Tyrel Datwyler , "James E.J. Bottomley" , "Martin K. Petersen" Cc: linux-scsi@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Michael Ellerman References: <20190531185306.41290-1-natechancellor@gmail.com> <20190603221941.65432-1-natechancellor@gmail.com> <6fa1dd2e-676f-b12a-5bb6-e86f5c5628fa@linux.vnet.ibm.com> <8598d642-82e3-daad-a487-693208e13c90@linux.vnet.ibm.com> Date: Mon, 3 Jun 2019 16:35:52 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <8598d642-82e3-daad-a487-693208e13c90@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19060323-0040-0000-0000-000004F82A9E X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011210; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000286; SDB=6.01212851; UDB=6.00637412; IPR=6.00993912; MB=3.00027171; MTD=3.00000008; XFM=3.00000015; UTC=2019-06-03 23:35:56 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19060323-0041-0000-0000-00000904484E Message-Id: <3416c496-9f5d-ea3c-8df5-85227007d29d@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-03_19:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906030158 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/03/2019 04:34 PM, Tyrel Datwyler wrote: > 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 >>> Signed-off-by: Nathan Chancellor >> >> Acked-by: Tyrel Datwyler >> > > 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; Need a spin_unlock_irqrestore() here before the return. -Tyrel > + return; > } > > hostdata->action = IBMVSCSI_HOST_ACTION_NONE; >