diff mbox series

[net-next] tsnep: Fix rotten packets

Message ID 20221119211825.81805-1-gerhard@engleder-embedded.com (mailing list archive)
State Accepted
Commit 2dc4ac91f845b690ddf2ad39172c3698b2769fa2
Delegated to: Netdev Maintainers
Headers show
Series [net-next] tsnep: Fix rotten packets | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 83 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Gerhard Engleder Nov. 19, 2022, 9:18 p.m. UTC
If PTP synchronisation is done every second, then sporadic the interval
is higher than one second:

ptp4l[696.582]: master offset        -17 s2 freq   -1891 path delay 573
ptp4l[697.582]: master offset        -22 s2 freq   -1901 path delay 573
ptp4l[699.368]: master offset         -1 s2 freq   -1887 path delay 573
      ^^^^^^^ Should be 698.582!

This problem is caused by rotten packets, which are received after
polling but before interrupts are enabled again. This can be fixed by
checking for pending work and rescheduling if necessary after interrupts
has been enabled again.

Fixes: 403f69bbdbad ("tsnep: Add TSN endpoint Ethernet MAC driver")
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
---
 drivers/net/ethernet/engleder/tsnep_main.c | 57 +++++++++++++++++++++-
 1 file changed, 56 insertions(+), 1 deletion(-)

Comments

patchwork-bot+netdevbpf@kernel.org Nov. 22, 2022, 2:50 p.m. UTC | #1
Hello:

This patch was applied to netdev/net.git (master)
by Paolo Abeni <pabeni@redhat.com>:

On Sat, 19 Nov 2022 22:18:25 +0100 you wrote:
> If PTP synchronisation is done every second, then sporadic the interval
> is higher than one second:
> 
> ptp4l[696.582]: master offset        -17 s2 freq   -1891 path delay 573
> ptp4l[697.582]: master offset        -22 s2 freq   -1901 path delay 573
> ptp4l[699.368]: master offset         -1 s2 freq   -1887 path delay 573
>       ^^^^^^^ Should be 698.582!
> 
> [...]

Here is the summary with links:
  - [net-next] tsnep: Fix rotten packets
    https://git.kernel.org/netdev/net/c/2dc4ac91f845

You are awesome, thank you!
Paolo Abeni Nov. 22, 2022, 2:51 p.m. UTC | #2
On Sat, 2022-11-19 at 22:18 +0100, Gerhard Engleder wrote:
> If PTP synchronisation is done every second, then sporadic the interval
> is higher than one second:
> 
> ptp4l[696.582]: master offset        -17 s2 freq   -1891 path delay 573
> ptp4l[697.582]: master offset        -22 s2 freq   -1901 path delay 573
> ptp4l[699.368]: master offset         -1 s2 freq   -1887 path delay 573
>       ^^^^^^^ Should be 698.582!
> 
> This problem is caused by rotten packets, which are received after
> polling but before interrupts are enabled again. This can be fixed by
> checking for pending work and rescheduling if necessary after interrupts
> has been enabled again.
> 
> Fixes: 403f69bbdbad ("tsnep: Add TSN endpoint Ethernet MAC driver")
> Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>

For the records, when targeting the net tree, you should include the
'net' tag into the patch prefix, instead of 'net-next'.

Thanks,

Paolo
Gerhard Engleder Nov. 22, 2022, 7:25 p.m. UTC | #3
On 22.11.22 15:51, Paolo Abeni wrote:
> On Sat, 2022-11-19 at 22:18 +0100, Gerhard Engleder wrote:
>> If PTP synchronisation is done every second, then sporadic the interval
>> is higher than one second:
>>
>> ptp4l[696.582]: master offset        -17 s2 freq   -1891 path delay 573
>> ptp4l[697.582]: master offset        -22 s2 freq   -1901 path delay 573
>> ptp4l[699.368]: master offset         -1 s2 freq   -1887 path delay 573
>>        ^^^^^^^ Should be 698.582!
>>
>> This problem is caused by rotten packets, which are received after
>> polling but before interrupts are enabled again. This can be fixed by
>> checking for pending work and rescheduling if necessary after interrupts
>> has been enabled again.
>>
>> Fixes: 403f69bbdbad ("tsnep: Add TSN endpoint Ethernet MAC driver")
>> Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
> 
> For the records, when targeting the net tree, you should include the
> 'net' tag into the patch prefix, instead of 'net-next'.

Ok, I understand. Will do better next time. Thanks!

Gerhard
diff mbox series

Patch

diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c
index 48fb391951dd..13d5ff4e0e02 100644
--- a/drivers/net/ethernet/engleder/tsnep_main.c
+++ b/drivers/net/ethernet/engleder/tsnep_main.c
@@ -542,6 +542,27 @@  static bool tsnep_tx_poll(struct tsnep_tx *tx, int napi_budget)
 	return (budget != 0);
 }
 
+static bool tsnep_tx_pending(struct tsnep_tx *tx)
+{
+	unsigned long flags;
+	struct tsnep_tx_entry *entry;
+	bool pending = false;
+
+	spin_lock_irqsave(&tx->lock, flags);
+
+	if (tx->read != tx->write) {
+		entry = &tx->entry[tx->read];
+		if ((__le32_to_cpu(entry->desc_wb->properties) &
+		     TSNEP_TX_DESC_OWNER_MASK) ==
+		    (entry->properties & TSNEP_TX_DESC_OWNER_MASK))
+			pending = true;
+	}
+
+	spin_unlock_irqrestore(&tx->lock, flags);
+
+	return pending;
+}
+
 static int tsnep_tx_open(struct tsnep_adapter *adapter, void __iomem *addr,
 			 int queue_index, struct tsnep_tx *tx)
 {
@@ -821,6 +842,19 @@  static int tsnep_rx_poll(struct tsnep_rx *rx, struct napi_struct *napi,
 	return done;
 }
 
+static bool tsnep_rx_pending(struct tsnep_rx *rx)
+{
+	struct tsnep_rx_entry *entry;
+
+	entry = &rx->entry[rx->read];
+	if ((__le32_to_cpu(entry->desc_wb->properties) &
+	     TSNEP_DESC_OWNER_COUNTER_MASK) ==
+	    (entry->properties & TSNEP_DESC_OWNER_COUNTER_MASK))
+		return true;
+
+	return false;
+}
+
 static int tsnep_rx_open(struct tsnep_adapter *adapter, void __iomem *addr,
 			 int queue_index, struct tsnep_rx *rx)
 {
@@ -866,6 +900,17 @@  static void tsnep_rx_close(struct tsnep_rx *rx)
 	tsnep_rx_ring_cleanup(rx);
 }
 
+static bool tsnep_pending(struct tsnep_queue *queue)
+{
+	if (queue->tx && tsnep_tx_pending(queue->tx))
+		return true;
+
+	if (queue->rx && tsnep_rx_pending(queue->rx))
+		return true;
+
+	return false;
+}
+
 static int tsnep_poll(struct napi_struct *napi, int budget)
 {
 	struct tsnep_queue *queue = container_of(napi, struct tsnep_queue,
@@ -886,9 +931,19 @@  static int tsnep_poll(struct napi_struct *napi, int budget)
 	if (!complete)
 		return budget;
 
-	if (likely(napi_complete_done(napi, done)))
+	if (likely(napi_complete_done(napi, done))) {
 		tsnep_enable_irq(queue->adapter, queue->irq_mask);
 
+		/* reschedule if work is already pending, prevent rotten packets
+		 * which are transmitted or received after polling but before
+		 * interrupt enable
+		 */
+		if (tsnep_pending(queue)) {
+			tsnep_disable_irq(queue->adapter, queue->irq_mask);
+			napi_schedule(napi);
+		}
+	}
+
 	return min(done, budget - 1);
 }