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From:   'Guanjun' <guanjun@linux.alibaba.com>
To:     dave.jiang@intel.com, dmaengine@vger.kernel.org,
        linux-kernel@vger.kernel.org, vkoul@kernel.org,
        tony.luck@intel.com, fenghua.yu@intel.com
Cc:     jing.lin@intel.com, ashok.raj@intel.com, sanjay.k.kumar@intel.com,
        megha.dey@intel.com, jacob.jun.pan@intel.com, yi.l.liu@intel.com,
        tglx@linutronix.de
Subject: [PATCH v2 1/2] dmaengine: idxd: Protect int_handle field in hw descriptor
Date:   Tue, 31 Oct 2023 10:20:16 +0800
Message-Id: <20231031022017.1515471-2-guanjun@linux.alibaba.com>
In-Reply-To: <20231031022017.1515471-1-guanjun@linux.alibaba.com>
References: <20231031022017.1515471-1-guanjun@linux.alibaba.com>
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From: Guanjun <guanjun@linux.alibaba.com>

The int_handle field in hw descriptor should also be protected
by wmb() before possibly triggering a DMA read.

Fixes: ec0d64231615 (dmaengine: idxd: embed irq_entry in idxd_wq struct)
Signed-off-by: Guanjun <guanjun@linux.alibaba.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
---
 drivers/dma/idxd/submit.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c
index c01db23e3333..3f922518e3a5 100644
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -182,13 +182,6 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 
 	portal = idxd_wq_portal_addr(wq);
 
-	/*
-	 * The wmb() flushes writes to coherent DMA data before
-	 * possibly triggering a DMA read. The wmb() is necessary
-	 * even on UP because the recipient is a device.
-	 */
-	wmb();
-
 	/*
 	 * Pending the descriptor to the lockless list for the irq_entry
 	 * that we designated the descriptor to.
@@ -199,6 +192,13 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 		llist_add(&desc->llnode, &ie->pending_llist);
 	}
 
+	/*
+	 * The wmb() flushes writes to coherent DMA data before
+	 * possibly triggering a DMA read. The wmb() is necessary
+	 * even on UP because the recipient is a device.
+	 */
+	wmb();
+
 	if (wq_dedicated(wq)) {
 		iosubmit_cmds512(portal, desc->hw, 1);
 	} else {
-- 
2.39.3