From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e19.ny.us.ibm.com (e19.ny.us.ibm.com [129.33.205.209]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id B7F5E1A31B1 for ; Thu, 17 Sep 2015 03:02:30 +1000 (AEST) Received: from /spool/local by e19.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 16 Sep 2015 13:02:28 -0400 Received: from b01cxnp23032.gho.pok.ibm.com (b01cxnp23032.gho.pok.ibm.com [9.57.198.27]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id A899A38C8041 for ; Wed, 16 Sep 2015 13:02:25 -0400 (EDT) Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t8GH2Pc957868540 for ; Wed, 16 Sep 2015 17:02:25 GMT Received: from d01av04.pok.ibm.com (localhost [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t8GH2OIf014091 for ; Wed, 16 Sep 2015 13:02:25 -0400 From: "Matthew R. Ochs" To: linux-scsi@vger.kernel.org, James.Bottomley@HansenPartnership.com, nab@linux-iscsi.org, brking@linux.vnet.ibm.com, imunsie@au1.ibm.com, dja@ozlabs.au.ibm.com, andrew.donnellan@au1.ibm.com Cc: mikey@neuling.org, linuxppc-dev@lists.ozlabs.org, "Manoj N. Kumar" Subject: [PATCH v2 26/30] cxlflash: Fix to prevent EEH recovery failure Date: Wed, 16 Sep 2015 12:02:00 -0500 Message-Id: <1442422920-42077-1-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 --- 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 fb79b79fe..1c5e9ac 100644 --- a/drivers/scsi/cxlflash/superpipe.c +++ b/drivers/scsi/cxlflash/superpipe.c @@ -1790,12 +1790,21 @@ 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