From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3tSPsH5BnJzDvvp for ; Tue, 29 Nov 2016 11:42:43 +1100 (AEDT) Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uAT0cWJx131632 for ; Mon, 28 Nov 2016 19:42:41 -0500 Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) by mx0a-001b2d01.pphosted.com with ESMTP id 270w686fct-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 28 Nov 2016 19:42:41 -0500 Received: from localhost by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 28 Nov 2016 17:42:39 -0700 From: Uma Krishnan To: linux-scsi@vger.kernel.org, James Bottomley , "Martin K. Petersen" , "Matthew R. Ochs" , "Manoj N. Kumar" Cc: Brian King , linuxppc-dev@lists.ozlabs.org, Ian Munsie , Andrew Donnellan , Frederic Barrat , Christophe Lombard Subject: [PATCH v2 09/14] cxlflash: Wait for active AFU commands to timeout upon tear down Date: Mon, 28 Nov 2016 18:42:33 -0600 In-Reply-To: <1480379984-60114-1-git-send-email-ukrishn@linux.vnet.ibm.com> References: <1480379984-60114-1-git-send-email-ukrishn@linux.vnet.ibm.com> Message-Id: <1480380153-60497-1-git-send-email-ukrishn@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: "Matthew R. Ochs" With the removal of the static private command pool, the ability to 'complete' outstanding commands was lost. While not an issue for the commands originating outside the driver, internal AFU commands are synchronous and therefore have a timeout associated with them. To avoid a stale memory access, the tear down sequence needs to ensure that there are not any active commands before proceeding. As these internal AFU commands are rare events, the simplest way to accomplish this is detecting the activity and waiting for it to timeout. Signed-off-by: Matthew R. Ochs --- drivers/scsi/cxlflash/common.h | 1 + drivers/scsi/cxlflash/main.c | 6 +++++- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/cxlflash/common.h b/drivers/scsi/cxlflash/common.h index 7e4ba31..6211677 100644 --- a/drivers/scsi/cxlflash/common.h +++ b/drivers/scsi/cxlflash/common.h @@ -180,6 +180,7 @@ struct afu { u64 *hrrq_end; u64 *hrrq_curr; bool toggle; + atomic_t cmds_active; /* Number of currently active AFU commands */ s64 room; spinlock_t rrin_slock; /* Lock to rrin queuing and cmd_room updates */ u64 hb; diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c index 19156ad..839eca4 100644 --- a/drivers/scsi/cxlflash/main.c +++ b/drivers/scsi/cxlflash/main.c @@ -531,7 +531,7 @@ static void free_mem(struct cxlflash_cfg *cfg) * * Safe to call with AFU in a partially allocated/initialized state. * - * Cleans up all state associated with the command queue, and unmaps + * Waits for any active internal AFU commands to timeout and then unmaps * the MMIO space. */ static void stop_afu(struct cxlflash_cfg *cfg) @@ -539,6 +539,8 @@ static void stop_afu(struct cxlflash_cfg *cfg) struct afu *afu = cfg->afu; if (likely(afu)) { + while (atomic_read(&afu->cmds_active)) + ssleep(1); if (likely(afu->afu_map)) { cxl_psa_unmap((void __iomem *)afu->afu_map); afu->afu_map = NULL; @@ -1721,6 +1723,7 @@ int cxlflash_afu_sync(struct afu *afu, ctx_hndl_t ctx_hndl_u, } mutex_lock(&sync_active); + atomic_inc(&afu->cmds_active); buf = kzalloc(sizeof(*cmd) + __alignof__(*cmd) - 1, GFP_KERNEL); if (unlikely(!buf)) { dev_err(dev, "%s: no memory for command\n", __func__); @@ -1762,6 +1765,7 @@ int cxlflash_afu_sync(struct afu *afu, ctx_hndl_t ctx_hndl_u, (cmd->sa.host_use_b[0] & B_ERROR))) rc = -1; out: + atomic_dec(&afu->cmds_active); mutex_unlock(&sync_active); kfree(buf); pr_debug("%s: returning rc=%d\n", __func__, rc); -- 2.1.0