Re: [PATCH net] bnxt_en: Write doorbell when linearizing skb fails

[Michael Chan]

On Tue, Aug 25, 2026 at 5:02 PM Joe Damato <joe@xxxxxxx> wrote:
>
> When the driver is handed a burst of packets, the doorbell is deferred
> until the end. If the last packet has a huge number of frags, but fails
> to linearize, the doorbell will not be written adding latency on TX for
> any packets in the ring and holding their DMA mappings until the next
> TX. Note that the queue is not stopped, so this issue would delay
> pending BDs until the next TX.
>
> This issue was discovered by Sashiko and reading the code verifies that,
> while unlikely, it is possible.
>
> Fix this by jumping to tx_free, which replicates the same pre-existing
> logic but also writes the doorbell.
>
> Fixes: b91e82129400 ("bnxt_en: Linearize TX SKB if the fragments exceed the max")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Joe Damato <joe@xxxxxxx>

Thanks.
Reviewed-by: Michael Chan <michael.chan@xxxxxxxxxxxx>

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