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[net,1/5] mlxsw: spectrum_ptp: Add missing verification before pushing Tx header

Message ID 5145780b07ebbb5d3b3570f311254a3a2d554a44.1729866134.git.petrm@nvidia.com (mailing list archive)
State Accepted
Commit 0a66e5582b5102c4d7b866b977ff7c850c1174ce
Delegated to: Netdev Maintainers
Headers show
Series mlxsw: Fixes | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 10 of 10 maintainers
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
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: 4 this patch: 4
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 19 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-10-26--21-00 (tests: 777)

Commit Message

Petr Machata Oct. 25, 2024, 2:26 p.m. UTC 
From: Amit Cohen <amcohen@nvidia.com>

Tx header should be pushed for each packet which is transmitted via
Spectrum ASICs. The cited commit moved the call to skb_cow_head() from
mlxsw_sp_port_xmit() to functions which handle Tx header.

In case that mlxsw_sp->ptp_ops->txhdr_construct() is used to handle Tx
header, and txhdr_construct() is mlxsw_sp_ptp_txhdr_construct(), there is
no call for skb_cow_head() before pushing Tx header size to SKB. This flow
is relevant for Spectrum-1 and Spectrum-4, for PTP packets.

Add the missing call to skb_cow_head() to make sure that there is both
enough room to push the Tx header and that the SKB header is not cloned and
can be modified.

An additional set will be sent to net-next to centralize the handling of
the Tx header by pushing it to every packet just before transmission.

Cc: Richard Cochran <richardcochran@gmail.com>
Fixes: 24157bc69f45 ("mlxsw: Send PTP packets as data packets to overcome a limitation")
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c | 7 +++++++
 1 file changed, 7 insertions(+)
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Patch

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
index 5b174cb95eb8..d94081c7658e 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
@@ -16,6 +16,7 @@ 
 #include "spectrum.h"
 #include "spectrum_ptp.h"
 #include "core.h"
+#include "txheader.h"
 
 #define MLXSW_SP1_PTP_CLOCK_CYCLES_SHIFT	29
 #define MLXSW_SP1_PTP_CLOCK_FREQ_KHZ		156257 /* 6.4nSec */
@@ -1684,6 +1685,12 @@  int mlxsw_sp_ptp_txhdr_construct(struct mlxsw_core *mlxsw_core,
 				 struct sk_buff *skb,
 				 const struct mlxsw_tx_info *tx_info)
 {
+	if (skb_cow_head(skb, MLXSW_TXHDR_LEN)) {
+		this_cpu_inc(mlxsw_sp_port->pcpu_stats->tx_dropped);
+		dev_kfree_skb_any(skb);
+		return -ENOMEM;
+	}
+
 	mlxsw_sp_txhdr_construct(skb, tx_info);
 	return 0;
 }