__octep_oq_process_rx() is called during NAPI polling by the driver and
calls build_skb() which may return NULL as skb pointer in case of memory
allocation error. This pointer is dereferenced later without checking for
NULL.

In this series, we introduce two helpers to make the fix more readable and
avoid code duplication. Also we handle build_skb() errors inside
__octep_oq_process_rx() to avoid NULL pointer dereference.

A similar situation is present in the __octep_vf_oq_process_rx() of the
Octeon VF driver. First we want to try the fix on __octep_oq_process_rx().

Compile tested only.

Changelog:
v5:
  - Unmap paged buffer before the skb creation as suggested by Paolo
    (https://lore.kernel.org/all/cf656975-69b4-427e-8769-d16575774bba@redhat.com/)
v4: https://lore.kernel.org/all/20241012094950.9438-1-amishin@t-argos.ru/
  - Split patch up as suggested by Jakub
    (https://lore.kernel.org/all/20241004073311.223efca4@kernel.org/)
v3: https://lore.kernel.org/all/20240930053328.9618-1-amishin@t-argos.ru/
  - Implement helper which frees current packet resources and increase
    index and descriptor as suggested by Simon
    (https://lore.kernel.org/all/20240919134812.GB1571683@kernel.org/)
  - Optimize helper as suggested by Paolo
    (https://lore.kernel.org/all/b9ae8575-f903-425f-aa42-0c2a7605aa94@redhat.com/)
  - v3 has been reviewed-by Simon Horman
    (https://lore.kernel.org/all/20240930162622.GF1310185@kernel.org/)
v2: https://lore.kernel.org/all/20240916060212.12393-1-amishin@t-argos.ru/
  - Implement helper instead of adding multiple checks for '!skb' and
    remove 'rx_bytes' increasing in case of packet dropping as suggested
    by Paolo
    (https://lore.kernel.org/all/ba514498-3706-413b-a09f-f577861eef28@redhat.com/)
v1: https://lore.kernel.org/all/20240906063907.9591-1-amishin@t-argos.ru/

Aleksandr Mishin (2):
  octeon_ep: Implement helper for iterating packets in Rx queue
  octeon_ep: Add SKB allocation failures handling in
    __octep_oq_process_rx()

 .../net/ethernet/marvell/octeon_ep/octep_rx.c | 82 +++++++++++++------
 1 file changed, 59 insertions(+), 23 deletions(-)

-- 
2.30.2