From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uma Krishnan 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 Message-ID: <1480380153-60497-1-git-send-email-ukrishn@linux.vnet.ibm.com> References: <1480379984-60114-1-git-send-email-ukrishn@linux.vnet.ibm.com> Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44665 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755308AbcK2Aml (ORCPT ); Mon, 28 Nov 2016 19:42:41 -0500 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uAT0cV9f043064 for ; Mon, 28 Nov 2016 19:42:40 -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 270xutsgb3-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 28 Nov 2016 19:42:40 -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 In-Reply-To: <1480379984-60114-1-git-send-email-ukrishn@linux.vnet.ibm.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org 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 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