From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 73C3E1A2CDC for ; Sat, 26 Sep 2015 09:19:37 +1000 (AEST) Received: from localhost by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 25 Sep 2015 17:19:35 -0600 Received: from b03cxnp07029.gho.boulder.ibm.com (b03cxnp07029.gho.boulder.ibm.com [9.17.130.16]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id CE51D3E40030 for ; Fri, 25 Sep 2015 17:19:32 -0600 (MDT) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t8PNJWSD37093396 for ; Fri, 25 Sep 2015 16:19:32 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t8PNJVCP008181 for ; Fri, 25 Sep 2015 17:19:32 -0600 From: "Matthew R. Ochs" To: linux-scsi@vger.kernel.org, James Bottomley , "Nicholas A. Bellinger" , Brian King , Ian Munsie , Daniel Axtens , Andrew Donnellan , Tomas Henzl , David Laight Cc: Michael Neuling , linuxppc-dev@lists.ozlabs.org, "Manoj N. Kumar" Subject: [PATCH v4 25/32] cxlflash: Fix to prevent EEH recovery failure Date: Fri, 25 Sep 2015 18:18:54 -0500 Message-Id: <1443223134-9886-1-git-send-email-mrochs@linux.vnet.ibm.com> In-Reply-To: <1443222593-8828-1-git-send-email-mrochs@linux.vnet.ibm.com> References: <1443222593-8828-1-git-send-email-mrochs@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The process_sense() routine can perform a read capacity which can take some time to complete. If an EEH occurs while waiting on the read capacity, the EEH handler is unable to obtain the context's mutex in order to put the context in an error state. The EEH handler will sit and wait until the context is free, but this wait can last longer than the EEH handler tolerates, leading to a failed recovery. To address this issue, make the context unavailable to new, non-system owned threads and release the context while calling into process_sense(). After returning from process_sense() the context mutex is reacquired and the context is made available again. The context can be safely moved to the error state if needed during the unavailable window as no other threads will hold its reference. Signed-off-by: Matthew R. Ochs Signed-off-by: Manoj N. Kumar Reviewed-by: Brian King --- drivers/scsi/cxlflash/superpipe.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c index a6316f5..7283e83 100644 --- a/drivers/scsi/cxlflash/superpipe.c +++ b/drivers/scsi/cxlflash/superpipe.c @@ -1787,12 +1787,21 @@ static int cxlflash_disk_verify(struct scsi_device *sdev, * inquiry (i.e. the Unit attention is due to the WWN changing). */ if (verify->hint & DK_CXLFLASH_VERIFY_HINT_SENSE) { + /* Can't hold mutex across process_sense/read_cap16, + * since we could have an intervening EEH event. + */ + ctxi->unavail = true; + mutex_unlock(&ctxi->mutex); rc = process_sense(sdev, verify); if (unlikely(rc)) { dev_err(dev, "%s: Failed to validate sense data (%d)\n", __func__, rc); + mutex_lock(&ctxi->mutex); + ctxi->unavail = false; goto out; } + mutex_lock(&ctxi->mutex); + ctxi->unavail = false; } switch (gli->mode) { -- 2.1.0