linux-kernel - [PATCH v2 2/2] switchtec: Fix unintended mask of MRPC event

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Date:   Mon, 15 Apr 2019 22:41:42 +0800
From:   Wesley Sheng <wesley.sheng@...rochip.com>
To:     <kurt.schwemmer@...rosemi.com>, <logang@...tatee.com>,
        <bhelgaas@...gle.com>, <linux-pci@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC:     <wesleyshenggit@...a.com>, <wesley.sheng@...rochip.com>
Subject: [PATCH v2 2/2] switchtec: Fix unintended mask of MRPC event

When running application tool switchtec-user's `firmware update` and
`event wait` commands concurrently, sometimes the firmware update
speed reduced evidently.

It is because when the MRPC event happened right after MRPC event
occurrence check but before event mask loop reach to its header
register in event ISR, the MRPC event would be masked unintentionally.
Since there's no chance to enable it again except for a module reload,
all the following MRPC execution completion check will be deferred to
timeout.

Fix this bug by skipping the mask operation for MRPC event in event
ISR, same as what we already do for LINK event.

Fixes: 52eabba5bcdb ("switchtec: Add IOCTLs to the Switchtec driver")
Signed-off-by: Wesley Sheng <wesley.sheng@...rochip.com>
---
 drivers/pci/switch/switchtec.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
index 7df9a69..30f6e08 100644
--- a/drivers/pci/switch/switchtec.c
+++ b/drivers/pci/switch/switchtec.c
@@ -1177,7 +1177,8 @@ static int mask_event(struct switchtec_dev *stdev, int eid, int idx)
 	if (!(hdr & SWITCHTEC_EVENT_OCCURRED && hdr & SWITCHTEC_EVENT_EN_IRQ))
 		return 0;

-	if (eid == SWITCHTEC_IOCTL_EVENT_LINK_STATE)
+	if (eid == SWITCHTEC_IOCTL_EVENT_LINK_STATE ||
+	    eid == SWITCHTEC_IOCTL_EVENT_MRPC_COMP)
 		return 0;

 	dev_dbg(&stdev->dev, "%s: %d %d %x\n", __func__, eid, idx, hdr);
-- 
2.7.4