[PATCH bpf-next 0/2] xsk: remove reduntant 'falltrough' attributes

[PATCH bpf-next 0/2] xsk: remove reduntant 'falltrough' attributes

[Maciej Fijalkowski]

This is a follow-up to recently applied set [0] to fix the build
warnings:

error: attribute 'fallthrough' not preceding a case label or default
label [-Werror]

that Stephen has stumbled upon when merging bpf-next to linux-next.
Apologies for these leftovers.

Thanks,
Maciej

[0]: https://lore.kernel.org/bpf/20220413153015.453864-1-maciej.fijalkowski@intel.com/

Maciej Fijalkowski (2):
  ixgbe: xsk: get rid of redundant 'fallthrough'
  i40e: xsk: get rid of redundant 'fallthrough'

 drivers/net/ethernet/intel/i40e/i40e_xsk.c   | 1 -
 drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 1 -
 2 files changed, 2 deletions(-)

-- 
2.27.0

[PATCH bpf-next 1/2] ixgbe: xsk: get rid of redundant 'fallthrough'

[Maciej Fijalkowski]

Intel drivers translate actions returned from XDP programs to their own
return codes that have the following mapping:

XDP_REDIRECT -> IXGBE_XDP_{REDIR,CONSUMED}
XDP_TX -> IXGBE_XDP_{TX,CONSUMED}
XDP_DROP -> IXGBE_XDP_CONSUMED
XDP_ABORTED -> IXGBE_XDP_CONSUMED
XDP_PASS -> IXGBE_XDP_PASS

Commit c7dd09fd4628 ("ixgbe, xsk: Terminate Rx side of NAPI when XSK Rx
queue gets full") introduced new translation

XDP_REDIRECT -> IXGBE_XDP_EXIT

which is set when XSK RQ gets full and to indicate that driver should
stop further Rx processing. This happens for unsuccessful
xdp_do_redirect() so it is valuable to call trace_xdp_exception() for
this case. In order to avoid IXGBE_XDP_EXIT -> IXGBE_XDP_CONSUMED
overwrite, XDP_DROP case was moved above which in turn made the
'fallthrough' that is in XDP_ABORTED useless as it became the last label
in the switch statement.

Simply drop this leftover.

Fixes: c7dd09fd4628 ("ixgbe, xsk: Terminate Rx side of NAPI when XSK Rx queue gets full")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
index 68532cffd453..1703c640a434 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
@@ -144,7 +144,6 @@ static int ixgbe_run_xdp_zc(struct ixgbe_adapter *adapter,
 		result = IXGBE_XDP_CONSUMED;
 out_failure:
 		trace_xdp_exception(rx_ring->netdev, xdp_prog, act);
-		fallthrough; /* handle aborts by dropping packet */
 	}
 	return result;
 }
-- 
2.27.0

Re: [PATCH bpf-next 1/2] ixgbe: xsk: get rid of redundant 'fallthrough'

[Stephen Rothwell]

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Hi Maciej,

On Thu, 21 Apr 2022 15:21:25 +0200 Maciej Fijalkowski <maciej.fijalkowski@intel.com> wrote:
>
> Intel drivers translate actions returned from XDP programs to their own
> return codes that have the following mapping:
> 
> XDP_REDIRECT -> IXGBE_XDP_{REDIR,CONSUMED}
> XDP_TX -> IXGBE_XDP_{TX,CONSUMED}
> XDP_DROP -> IXGBE_XDP_CONSUMED
> XDP_ABORTED -> IXGBE_XDP_CONSUMED
> XDP_PASS -> IXGBE_XDP_PASS
> 
> Commit c7dd09fd4628 ("ixgbe, xsk: Terminate Rx side of NAPI when XSK Rx
> queue gets full") introduced new translation
> 
> XDP_REDIRECT -> IXGBE_XDP_EXIT
> 
> which is set when XSK RQ gets full and to indicate that driver should
> stop further Rx processing. This happens for unsuccessful
> xdp_do_redirect() so it is valuable to call trace_xdp_exception() for
> this case. In order to avoid IXGBE_XDP_EXIT -> IXGBE_XDP_CONSUMED
> overwrite, XDP_DROP case was moved above which in turn made the
> 'fallthrough' that is in XDP_ABORTED useless as it became the last label
> in the switch statement.
> 
> Simply drop this leftover.
> 
> Fixes: c7dd09fd4628 ("ixgbe, xsk: Terminate Rx side of NAPI when XSK Rx queue gets full")
> Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

Reported-by ?
-- 
Cheers,
Stephen Rothwell

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[PATCH bpf-next 2/2] i40e: xsk: get rid of redundant 'fallthrough'

[Maciej Fijalkowski]

Intel drivers translate actions returned from XDP programs to their own
return codes that have the following mapping:

XDP_REDIRECT -> I40E_XDP_{REDIR,CONSUMED}
XDP_TX -> I40E_XDP_{TX,CONSUMED}
XDP_DROP -> I40E_XDP_CONSUMED
XDP_ABORTED -> I40E_XDP_CONSUMED
XDP_PASS -> I40E_XDP_PASS

Commit b8aef650e549 ("i40e, xsk: Terminate Rx side of NAPI when XSK Rx
queue gets full") introduced new translation

XDP_REDIRECT -> I40E_XDP_EXIT

which is set when XSK RQ gets full and to indicate that driver should
stop further Rx processing. This happens for unsuccessful
xdp_do_redirect() so it is valuable to call trace_xdp_exception() for
this case. In order to avoid I40E_XDP_EXIT -> IXGBE_XDP_CONSUMED
overwrite, XDP_DROP case was moved above which in turn made the
'fallthrough' that is in XDP_ABORTED useless as it became the last label
in the switch statement.

Simply drop this leftover.

Fixes: b8aef650e549 ("i40e, xsk: Terminate Rx side of NAPI when XSK Rx queue gets full")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
---
 drivers/net/ethernet/intel/i40e/i40e_xsk.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
index 050280fd10c1..af3e7e6afc85 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -189,7 +189,6 @@ static int i40e_run_xdp_zc(struct i40e_ring *rx_ring, struct xdp_buff *xdp)
 		result = I40E_XDP_CONSUMED;
 out_failure:
 		trace_xdp_exception(rx_ring->netdev, xdp_prog, act);
-		fallthrough; /* handle aborts by dropping packet */
 	}
 	return result;
 }
-- 
2.27.0

Re: [PATCH bpf-next 0/2] xsk: remove reduntant 'falltrough' attributes

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Thu, 21 Apr 2022 15:21:24 +0200 you wrote:
> This is a follow-up to recently applied set [0] to fix the build
> warnings:
> 
> error: attribute 'fallthrough' not preceding a case label or default
> label [-Werror]
> 
> that Stephen has stumbled upon when merging bpf-next to linux-next.
> Apologies for these leftovers.
> 
> [...]

Here is the summary with links:
  - [bpf-next,1/2] ixgbe: xsk: get rid of redundant 'fallthrough'
    https://git.kernel.org/bpf/bpf-next/c/e130e8d5434b
  - [bpf-next,2/2] i40e: xsk: get rid of redundant 'fallthrough'
    https://git.kernel.org/bpf/bpf-next/c/9d87e41a6d64

You are awesome, thank you!
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