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Thu, 21 Jan 2021 06:20:09 GMT Received: from b03cxnp08025.gho.boulder.ibm.com (b03cxnp08025.gho.boulder.ibm.com [9.17.130.17]) by ppma04wdc.us.ibm.com with ESMTP id 3668pqhvus-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 21 Jan 2021 06:20:09 +0000 Received: from b03ledav004.gho.boulder.ibm.com (b03ledav004.gho.boulder.ibm.com [9.17.130.235]) by b03cxnp08025.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 10L6K8Pv26607936 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 21 Jan 2021 06:20:08 GMT Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2D27A7805F; Thu, 21 Jan 2021 06:20:08 +0000 (GMT) Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 71FBB7805C; Thu, 21 Jan 2021 06:20:06 +0000 (GMT) Received: from pompom.ibm.com (unknown [9.85.137.249]) by b03ledav004.gho.boulder.ibm.com (Postfix) with ESMTP; Thu, 21 Jan 2021 06:20:06 +0000 (GMT) From: Lijun Pan To: netdev@vger.kernel.org Subject: [PATCH net] ibmvnic: device remove has higher precedence over reset Date: Thu, 21 Jan 2021 00:20:05 -0600 Message-Id: <20210121062005.53271-1-ljp@linux.ibm.com> X-Mailer: git-send-email 2.22.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.343, 18.0.737 definitions=2021-01-21_02:2021-01-20, 2021-01-21 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=986 impostorscore=0 lowpriorityscore=0 priorityscore=1501 bulkscore=0 suspectscore=0 adultscore=0 spamscore=0 phishscore=0 mlxscore=0 clxscore=1015 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101210031 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Lijun Pan , gregkh@linuxfoundation.org, julietk@linux.vnet.ibm.com, =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , paulus@samba.org, kernel@pengutronix.de, drt@linux.ibm.com, kuba@kernel.org, sukadev@linux.ibm.com, linuxppc-dev@lists.ozlabs.org, davem@davemloft.net Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Returning -EBUSY in ibmvnic_remove() does not actually hold the removal procedure since driver core doesn't care for the return value (see __device_release_driver() in drivers/base/dd.c calling dev->bus->remove()) though vio_bus_remove (in arch/powerpc/platforms/pseries/vio.c) records the return value and passes it on. [1] During the device removal precedure, we should not schedule any new reset (ibmvnic_reset check for REMOVING and exit), and should rely on the flush_work and flush_delayed_work to complete the pending resets, specifically we need to let __ibmvnic_reset() keep running while in REMOVING state since flush_work and flush_delayed_work shall call __ibmvnic_reset finally. So we skip the checking for REMOVING in __ibmvnic_reset. [1] https://lore.kernel.org/linuxppc-dev/20210117101242.dpwayq6wdgfdzirl@pengutronix.de/T/#m48f5befd96bc9842ece2a3ad14f4c27747206a53 Reported-by: Uwe Kleine-König Fixes: 7d7195a026ba ("ibmvnic: Do not process device remove during device reset") Signed-off-by: Lijun Pan --- v1 versus RFC: 1/ articulate why remove the REMOVING checking in __ibmvnic_reset and why keep the current checking for REMOVING in ibmvnic_reset. 2/ The locking issue mentioned by Uwe are being addressed separately by https://lists.openwall.net/netdev/2021/01/08/89 3/ This patch does not have merge conflict with 2/ drivers/net/ethernet/ibm/ibmvnic.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c index aed985e08e8a..11f28fd03057 100644 --- a/drivers/net/ethernet/ibm/ibmvnic.c +++ b/drivers/net/ethernet/ibm/ibmvnic.c @@ -2235,8 +2235,7 @@ static void __ibmvnic_reset(struct work_struct *work) while (rwi) { spin_lock_irqsave(&adapter->state_lock, flags); - if (adapter->state == VNIC_REMOVING || - adapter->state == VNIC_REMOVED) { + if (adapter->state == VNIC_REMOVED) { spin_unlock_irqrestore(&adapter->state_lock, flags); kfree(rwi); rc = EBUSY; @@ -5372,11 +5371,6 @@ static int ibmvnic_remove(struct vio_dev *dev) unsigned long flags; spin_lock_irqsave(&adapter->state_lock, flags); - if (test_bit(0, &adapter->resetting)) { - spin_unlock_irqrestore(&adapter->state_lock, flags); - return -EBUSY; - } - adapter->state = VNIC_REMOVING; spin_unlock_irqrestore(&adapter->state_lock, flags); -- 2.22.0