[PATCH net] ice: xsk: Fix cleaning of XDP_TX frames

[PATCH net] ice: xsk: Fix cleaning of XDP_TX frames

[Larysa Zaremba]

Incrementation of xsk_frames inside the for-loop produces
infinite loop, if we have both normal AF_XDP-TX and XDP_TXed
buffers to complete.

Split xsk_frames into 2 variables (xsk_frames and completed_frames)
to eliminate this bug.

Fixes: 29322791bc8b ("ice: xsk: change batched Tx descriptor cleaning")
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
---
To Tony: this is urgent and should go directly via net. It's tested and acked.
---
 drivers/net/ethernet/intel/ice/ice_xsk.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index 7105de6fb344..374b7f10b549 100644
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -800,6 +800,7 @@ static void ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring)
 	struct ice_tx_desc *tx_desc;
 	u16 cnt = xdp_ring->count;
 	struct ice_tx_buf *tx_buf;
+	u16 completed_frames = 0;
 	u16 xsk_frames = 0;
 	u16 last_rs;
 	int i;
@@ -809,19 +810,21 @@ static void ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring)
 	if ((tx_desc->cmd_type_offset_bsz &
 	    cpu_to_le64(ICE_TX_DESC_DTYPE_DESC_DONE))) {
 		if (last_rs >= ntc)
-			xsk_frames = last_rs - ntc + 1;
+			completed_frames = last_rs - ntc + 1;
 		else
-			xsk_frames = last_rs + cnt - ntc + 1;
+			completed_frames = last_rs + cnt - ntc + 1;
 	}
 
-	if (!xsk_frames)
+	if (!completed_frames)
 		return;
 
-	if (likely(!xdp_ring->xdp_tx_active))
+	if (likely(!xdp_ring->xdp_tx_active)) {
+		xsk_frames = completed_frames;
 		goto skip;
+	}
 
 	ntc = xdp_ring->next_to_clean;
-	for (i = 0; i < xsk_frames; i++) {
+	for (i = 0; i < completed_frames; i++) {
 		tx_buf = &xdp_ring->tx_buf[ntc];
 
 		if (tx_buf->raw_buf) {
@@ -837,7 +840,7 @@ static void ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring)
 	}
 skip:
 	tx_desc->cmd_type_offset_bsz = 0;
-	xdp_ring->next_to_clean += xsk_frames;
+	xdp_ring->next_to_clean += completed_frames;
 	if (xdp_ring->next_to_clean >= cnt)
 		xdp_ring->next_to_clean -= cnt;
 	if (xsk_frames)
-- 
2.35.3

Re: [PATCH net] ice: xsk: Fix cleaning of XDP_TX frames

[Alexander H Duyck]

On Thu, 2023-02-09 at 17:01 +0100, Larysa Zaremba wrote:
> Incrementation of xsk_frames inside the for-loop produces
> infinite loop, if we have both normal AF_XDP-TX and XDP_TXed
> buffers to complete.
> 
> Split xsk_frames into 2 variables (xsk_frames and completed_frames)
> to eliminate this bug.
> 
> Fixes: 29322791bc8b ("ice: xsk: change batched Tx descriptor cleaning")
> Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
> ---
> To Tony: this is urgent and should go directly via net. It's tested and acked.
> ---
>  drivers/net/ethernet/intel/ice/ice_xsk.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
> index 7105de6fb344..374b7f10b549 100644
> --- a/drivers/net/ethernet/intel/ice/ice_xsk.c
> +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
> @@ -800,6 +800,7 @@ static void ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring)
>  	struct ice_tx_desc *tx_desc;
>  	u16 cnt = xdp_ring->count;
>  	struct ice_tx_buf *tx_buf;
> +	u16 completed_frames = 0;
>  	u16 xsk_frames = 0;
>  	u16 last_rs;
>  	int i;
> @@ -809,19 +810,21 @@ static void ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring)
>  	if ((tx_desc->cmd_type_offset_bsz &
>  	    cpu_to_le64(ICE_TX_DESC_DTYPE_DESC_DONE))) {
>  		if (last_rs >= ntc)
> -			xsk_frames = last_rs - ntc + 1;
> +			completed_frames = last_rs - ntc + 1;
>  		else
> -			xsk_frames = last_rs + cnt - ntc + 1;
> +			completed_frames = last_rs + cnt - ntc + 1;
>  	}
>  
> -	if (!xsk_frames)
> +	if (!completed_frames)
>  		return;
>  
> -	if (likely(!xdp_ring->xdp_tx_active))
> +	if (likely(!xdp_ring->xdp_tx_active)) {
> +		xsk_frames = completed_frames;
>  		goto skip;
> +	}
>  
>  	ntc = xdp_ring->next_to_clean;
> -	for (i = 0; i < xsk_frames; i++) {
> +	for (i = 0; i < completed_frames; i++) {
>  		tx_buf = &xdp_ring->tx_buf[ntc];
>  
>  		if (tx_buf->raw_buf) {
> @@ -837,7 +840,7 @@ static void ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring)
>  	}
>  skip:
>  	tx_desc->cmd_type_offset_bsz = 0;
> -	xdp_ring->next_to_clean += xsk_frames;
> +	xdp_ring->next_to_clean += completed_frames;
>  	if (xdp_ring->next_to_clean >= cnt)
>  		xdp_ring->next_to_clean -= cnt;
>  	if (xsk_frames)

Looks good to me.

Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>

Re: [PATCH net] ice: xsk: Fix cleaning of XDP_TX frames

[Tony Nguyen]

On 2/9/2023 8:01 AM, Zaremba, Larysa wrote:
> Incrementation of xsk_frames inside the for-loop produces
> infinite loop, if we have both normal AF_XDP-TX and XDP_TXed
> buffers to complete.
> 
> Split xsk_frames into 2 variables (xsk_frames and completed_frames)
> to eliminate this bug.
> 
> Fixes: 29322791bc8b ("ice: xsk: change batched Tx descriptor cleaning")
> Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
> ---
> To Tony: this is urgent and should go directly via net. It's tested and acked.

netdev maintainers,

Since it's been tested and reviewed, did you want to take this directly?

Acked-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Re: [PATCH net] ice: xsk: Fix cleaning of XDP_TX frames

[Jakub Kicinski]

On Thu, 9 Feb 2023 09:20:27 -0800 Tony Nguyen wrote:
> Since it's been tested and reviewed, did you want to take this directly?
> 
> Acked-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Sure thing! Already missed today's PR tho.. :(

Re: [PATCH net] ice: xsk: Fix cleaning of XDP_TX frames

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Thu,  9 Feb 2023 17:01:30 +0100 you wrote:
> Incrementation of xsk_frames inside the for-loop produces
> infinite loop, if we have both normal AF_XDP-TX and XDP_TXed
> buffers to complete.
> 
> Split xsk_frames into 2 variables (xsk_frames and completed_frames)
> to eliminate this bug.
> 
> [...]

Here is the summary with links:
  - [net] ice: xsk: Fix cleaning of XDP_TX frames
    https://git.kernel.org/netdev/net/c/1f090494170e

You are awesome, thank you!
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