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tsnep: fix timestamping with a stacked DSA driver

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[ Upstream commit b3ca9eef6646576ad506a96d941d87a69f66732a ]

This driver is susceptible to a form of the bug explained in commit
c26a2c2ddc ("gianfar: Fix TX timestamping with a stacked DSA driver")
and in Documentation/networking/timestamping.rst section "Other caveats
for MAC drivers", specifically it timestamps any skb which has
SKBTX_HW_TSTAMP, and does not consider if timestamping has been enabled
in adapter->hwtstamp_config.tx_type.

Evaluate the proper TX timestamping condition only once on the TX
path (in tsnep_xmit_frame_ring()) and store the result in an additional
TX entry flag. Evaluate the new TX entry flag in the TX confirmation path
(in tsnep_tx_poll()).

This way SKBTX_IN_PROGRESS is set by the driver as required, but never
evaluated. SKBTX_IN_PROGRESS shall not be evaluated as it can be set
by a stacked DSA driver and evaluating it would lead to unwanted
timestamps.

Fixes: 403f69bbdb ("tsnep: Add TSN endpoint Ethernet MAC driver")
Suggested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20250514195657.25874-1-gerhard@engleder-embedded.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Gerhard Engleder
2025-05-14 21:56:57 +02:00
committed by Greg Kroah-Hartman
parent 0980e62ab8
commit c1dd9ccc0f
1 changed files with 19 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/net/ethernet/engleder/tsnep_main.c
View File

@@ -67,6 +67,8 @@
#define TSNEP_TX_TYPE_XDP_NDO_MAP_PAGE (TSNEP_TX_TYPE_XDP_NDO | TSNEP_TX_TYPE_MAP_PAGE)
#define TSNEP_TX_TYPE_XDP (TSNEP_TX_TYPE_XDP_TX | TSNEP_TX_TYPE_XDP_NDO)
#define TSNEP_TX_TYPE_XSK BIT(12)
#define TSNEP_TX_TYPE_TSTAMP BIT(13)
#define TSNEP_TX_TYPE_SKB_TSTAMP (TSNEP_TX_TYPE_SKB | TSNEP_TX_TYPE_TSTAMP)
#define TSNEP_XDP_TX BIT(0)
#define TSNEP_XDP_REDIRECT BIT(1)
@@ -385,8 +387,7 @@ static void tsnep_tx_activate(struct tsnep_tx *tx, int index, int length,
if (entry->skb) {
entry->properties = length & TSNEP_DESC_LENGTH_MASK;
entry->properties |= TSNEP_DESC_INTERRUPT_FLAG;
if ((entry->type & TSNEP_TX_TYPE_SKB) &&
(skb_shinfo(entry->skb)->tx_flags & SKBTX_IN_PROGRESS))
if ((entry->type & TSNEP_TX_TYPE_SKB_TSTAMP) == TSNEP_TX_TYPE_SKB_TSTAMP)
entry->properties |= TSNEP_DESC_EXTENDED_WRITEBACK_FLAG;
/* toggle user flag to prevent false acknowledge
@@ -478,7 +479,8 @@ static int tsnep_tx_map_frag(skb_frag_t *frag, struct tsnep_tx_entry *entry,
return mapped;
}
static int tsnep_tx_map(struct sk_buff *skb, struct tsnep_tx *tx, int count)
static int tsnep_tx_map(struct sk_buff *skb, struct tsnep_tx *tx, int count,
bool do_tstamp)
{
struct device *dmadev = tx->adapter->dmadev;
struct tsnep_tx_entry *entry;
@@ -504,6 +506,9 @@ static int tsnep_tx_map(struct sk_buff *skb, struct tsnep_tx *tx, int count)
entry->type = TSNEP_TX_TYPE_SKB_INLINE;
mapped = 0;
}
if (do_tstamp)
entry->type |= TSNEP_TX_TYPE_TSTAMP;
} else {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i - 1];
@@ -557,11 +562,12 @@ static int tsnep_tx_unmap(struct tsnep_tx *tx, int index, int count)
static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
struct tsnep_tx *tx)
{
int count = 1;
struct tsnep_tx_entry *entry;
bool do_tstamp = false;
int count = 1;
int length;
int i;
int retval;
int i;
if (skb_shinfo(skb)->nr_frags > 0)
count += skb_shinfo(skb)->nr_frags;
@@ -578,7 +584,13 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
entry = &tx->entry[tx->write];
entry->skb = skb;
retval = tsnep_tx_map(skb, tx, count);
if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) &&
tx->adapter->hwtstamp_config.tx_type == HWTSTAMP_TX_ON) {
skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
do_tstamp = true;
}
retval = tsnep_tx_map(skb, tx, count, do_tstamp);
if (retval < 0) {
tsnep_tx_unmap(tx, tx->write, count);
dev_kfree_skb_any(entry->skb);
@@ -590,9 +602,6 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
}
length = retval;
if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)
skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
for (i = 0; i < count; i++)
tsnep_tx_activate(tx, (tx->write + i) & TSNEP_RING_MASK, length,
i == count - 1);
@@ -843,8 +852,7 @@ static bool tsnep_tx_poll(struct tsnep_tx *tx, int napi_budget)
length = tsnep_tx_unmap(tx, tx->read, count);
if ((entry->type & TSNEP_TX_TYPE_SKB) &&
(skb_shinfo(entry->skb)->tx_flags & SKBTX_IN_PROGRESS) &&
if (((entry->type & TSNEP_TX_TYPE_SKB_TSTAMP) == TSNEP_TX_TYPE_SKB_TSTAMP) &&
(__le32_to_cpu(entry->desc_wb->properties) &
TSNEP_DESC_EXTENDED_WRITEBACK_FLAG)) {
struct skb_shared_hwtstamps hwtstamps;