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From:   trix@redhat.com
To:     jesse.brandeburg@intel.com, anthony.l.nguyen@intel.com,
        davem@davemloft.net, kuba@kernel.org, nathan@kernel.org,
        ndesaulniers@google.com
Cc:     intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        Tom Rix <trix@redhat.com>
Subject: [PATCH] igb: zero hwtstamp by default
Date:   Sun, 13 Mar 2022 08:02:10 -0700
Message-Id: <20220313150210.1508203-1-trix@redhat.com>
MIME-Version: 1.0
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From: Tom Rix <trix@redhat.com>

Clang static analysis reports this representative issue
igb_ptp.c:997:3: warning: The left operand of '+' is a
  garbage value
  ktime_add_ns(shhwtstamps.hwtstamp, adjust);
  ^            ~~~~~~~~~~~~~~~~~~~~

shhwtstamps.hwtstamp is set by a call to
igb_ptp_systim_to_hwtstamp().  In the switch-statement
for the hw type, the hwtstamp is zeroed for matches
but not the default case.  Move the memset out of
switch-statement.  This degarbages the default case
and reduces the size.

Some whitespace cleanup of empty lines

Signed-off-by: Tom Rix <trix@redhat.com>
---
 drivers/net/ethernet/intel/igb/igb_ptp.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index 6580fcddb4be5..02fec948ce642 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -165,23 +165,21 @@ static void igb_ptp_systim_to_hwtstamp(struct igb_adapter *adapter,
 	unsigned long flags;
 	u64 ns;
 
+	memset(hwtstamps, 0, sizeof(*hwtstamps));
+
 	switch (adapter->hw.mac.type) {
 	case e1000_82576:
 	case e1000_82580:
 	case e1000_i354:
 	case e1000_i350:
 		spin_lock_irqsave(&adapter->tmreg_lock, flags);
-
 		ns = timecounter_cyc2time(&adapter->tc, systim);
-
 		spin_unlock_irqrestore(&adapter->tmreg_lock, flags);
 
-		memset(hwtstamps, 0, sizeof(*hwtstamps));
 		hwtstamps->hwtstamp = ns_to_ktime(ns);
 		break;
 	case e1000_i210:
 	case e1000_i211:
-		memset(hwtstamps, 0, sizeof(*hwtstamps));
 		/* Upper 32 bits contain s, lower 32 bits contain ns. */
 		hwtstamps->hwtstamp = ktime_set(systim >> 32,
 						systim & 0xFFFFFFFF);
-- 
2.26.3