net: ena: Set tx_info->xdpf value to NULL

The patch mentioned in the `Fixes` tag removed the explicit assignment
of tx_info->xdpf to NULL with the justification that there's no need
to set tx_info->xdpf to NULL and tx_info->num_of_bufs to 0 in case
of a mapping error. Both values won't be used once the mapping function
returns an error, and their values would be overridden by the next
transmitted packet.

While both values do indeed get overridden in the next transmission
call, the value of tx_info->xdpf is also used to check whether a TX
descriptor's transmission has been completed (i.e. a completion for it
was polled).

An example scenario:
1. Mapping failed, tx_info->xdpf wasn't set to NULL
2. A VF reset occurred leading to IO resource destruction and
a call to ena_free_tx_bufs() function
3. Although the descriptor whose mapping failed was freed by the
transmission function, it still passes the check
if (!tx_info->skb)

(skb and xdp_frame are in a union)
4. The xdp_frame associated with the descriptor is freed twice

This patch returns the assignment of NULL to tx_info->xdpf to make the
cleaning function knows that the descriptor is already freed.

Fixes: 504fd6a5390c ("net: ena: fix DMA mapping function issues in XDP")
Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net: ena: Remove CQ tail pointer update

The functionality was added to allow the drivers to create an
SQ and CQ of different sizes.
When the RX/TX SQ and CQ have the same size, such update isn't
necessary as the device can safely assume it doesn't override
unprocessed completions. However, if the SQ is larger than the CQ,
the device might "have" more completions it wants to update about
than there's room in the CQ.

There's no support for different SQ and CQ sizes, therefore,
removing the API and its usage.

'____cacheline_aligned' compiler attribute was added to
'struct ena_com_io_cq' to ensure that the removal of the
'cq_head_db_reg' field doesn't change the cache-line layout
of this struct.

Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net: ena: Always register RX queue info

The RX queue info contains information about the RX queue which might
be relevant to the kernel.

To avoid configuring this queue for different scenarios, this patch
moves the RX queue configuration to ena_up()/ena_down() function and
makes it configured every interface state toggle.

Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Link: https://lore.kernel.org/r/20240101190855.18739-10-darinzon@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ena: Add more debug prints to XDP related function

Used for better readability and debugging of XDP
flow.

Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Link: https://lore.kernel.org/r/20240101190855.18739-9-darinzon@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ena: Refactor napi functions

This patch focuses on changes to the XDP part of the napi
polling routine.

1. Update the `napi_comp` stat only when napi is actually
complete.
2. Simplify the code by using a function pointer to the right
napi routine (XDP vs non-XDP path)
3. Remove unnecessary local variables.
4. Adjust a debug print to show the processed XDP frame index
rather than the pointer.

Signed-off-by: David Arinzon <darinzon@amazon.com>
Link: https://lore.kernel.org/r/20240101190855.18739-8-darinzon@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ena: Use tx_ring instead of xdp_ring for XDP channel TX

When an XDP program is loaded the existing channels in the driver split
into two halves:
- The first half of the channels contain RX and TX rings, these queues
are used for receiving traffic and sending packets originating from
kernel.
- The second half of the channels contain only a TX ring. These queues
are used for sending packets that were redirected using XDP_TX
or XDP_REDIRECT.

Referring to the queues in the second half of the channels as "xdp_ring"
can be confusing and may give the impression that ENA has the capability
to generate an additional special queue.

This patch ensures that the xdp_ring field is exclusively used to
describe the XDP TX queue that a specific RX queue needs to utilize when
forwarding packets with XDP TX and XDP REDIRECT, preserving the
integrity of the xdp_ring field in ena_ring.

Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Link: https://lore.kernel.org/r/20240101190855.18739-6-darinzon@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ena: Pass ena_adapter instead of net_device to ena_xmit_common()

This change will enable the ability to use ena_xmit_common()
in functions that don't have a net_device pointer.
While it can be retrieved by dereferencing
ena_adapter (adapter->netdev), there's no reason to do it in
fast path code where this pointer is only needed for
debug prints.

Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Link: https://lore.kernel.org/r/20240101190855.18739-3-darinzon@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ena: Move XDP code to its new files

XDP system has a very large footprint in the driver's overall code.
makes the whole driver's code much harder to read.

Moving XDP code to dedicated files.

This patch doesn't make any changes to the code itself and only
cut-pastes the code into ena_xdp.c and ena_xdp.h files so the change
is purely cosmetic.

Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Link: https://lore.kernel.org/r/20240101190855.18739-2-darinzon@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>