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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , , , Subject: [PATCH net v4 2/2] octeon_ep: Add SKB allocation failures handling in __octep_oq_process_rx() Date: Sat, 12 Oct 2024 12:49:50 +0300 Message-ID: <20241012094950.9438-3-amishin@t-argos.ru> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20241012094950.9438-1-amishin@t-argos.ru> References: <20241012094950.9438-1-amishin@t-argos.ru> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: ta-mail-02.ta.t-argos.ru (172.17.13.212) To ta-mail-02 (172.17.13.212) X-KSMG-Rule-ID: 1 X-KSMG-Message-Action: clean X-KSMG-AntiSpam-Lua-Profiles: 188393 [Oct 12 2024] X-KSMG-AntiSpam-Version: 6.1.0.4 X-KSMG-AntiSpam-Envelope-From: amishin@t-argos.ru X-KSMG-AntiSpam-Rate: 0 X-KSMG-AntiSpam-Status: not_detected X-KSMG-AntiSpam-Method: none X-KSMG-AntiSpam-Auth: dkim=none X-KSMG-AntiSpam-Info: LuaCore: 39 0.3.39 e168d0b3ce73b485ab2648dd465313add1404cce, {Tracking_uf_ne_domains}, {Tracking_from_domain_doesnt_match_to}, t-argos.ru:7.1.1;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;mx1.t-argos.ru.ru:7.1.1;lore.kernel.org:7.1.1;127.0.0.199:7.1.2, FromAlignment: s X-MS-Exchange-Organization-SCL: -1 X-KSMG-AntiSpam-Interceptor-Info: scan successful X-KSMG-AntiPhishing: Clean, bases: 2024/10/12 09:22:00 X-KSMG-AntiVirus: Kaspersky Secure Mail Gateway, version 1.1.2.30, bases: 2024/10/12 08:26:00 #26739312 X-KSMG-AntiVirus-Status: Clean, skipped Content-Type: text/plain; charset="utf-8" build_skb() returns NULL in case of a memory allocation failure so handle it inside __octep_oq_process_rx() to avoid NULL pointer dereference. __octep_oq_process_rx() is called during NAPI polling by the driver. If skb allocation fails, keep on pulling packets out of the Rx DMA queue: we shouldn't break the polling immediately and thus falsely indicate to the octep_napi_poll() that the Rx pressure is going down. As there is no associated skb in this case, don't process the packets and don't push them up the network stack - they are skipped. Helper function is implemented to unmmap/flush all the fragment buffers used by the dropped packet. 'alloc_failures' counter is incremented to mark the skb allocation error in driver statistics. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 37d79d059606 ("octeon_ep: add Tx/Rx processing and interrupt support= ") Suggested-by: Paolo Abeni Signed-off-by: Aleksandr Mishin --- Compile tested only. v4: - 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/ - Optimize helper as suggested by Paolo (https://lore.kernel.org/all/b9ae8575-f903-425f-aa42-0c2a7605aa94@redha= t.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@redha= t.com/) v1: https://lore.kernel.org/all/20240906063907.9591-1-amishin@t-argos.ru/ .../net/ethernet/marvell/octeon_ep/octep_rx.c | 27 +++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c b/drivers/ne= t/ethernet/marvell/octeon_ep/octep_rx.c index 62db101b2147..2d9d95071786 100644 --- a/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c +++ b/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c @@ -360,6 +360,27 @@ static void octep_oq_next_pkt(struct octep_oq *oq, *read_idx =3D 0; } =20 +/** + * octep_oq_drop_rx() - Free the resources associated with a packet. + * + * @oq: Octeon Rx queue data structure. + * @buff_info: Current packet buffer info. + * @read_idx: Current packet index in the ring. + * @desc_used: Current packet descriptor number. + * + */ +static void octep_oq_drop_rx(struct octep_oq *oq, + struct octep_rx_buffer *buff_info, + u32 *read_idx, u32 *desc_used) +{ + int data_len =3D buff_info->len - oq->max_single_buffer_size; + + do { + octep_oq_next_pkt(oq, buff_info, read_idx, desc_used); + data_len -=3D oq->buffer_size; + } while (data_len > 0); +} + /** * __octep_oq_process_rx() - Process hardware Rx queue and push to stack. * @@ -417,6 +438,12 @@ static int __octep_oq_process_rx(struct octep_device *= oct, } =20 skb =3D build_skb((void *)resp_hw, PAGE_SIZE); + if (!skb) { + octep_oq_drop_rx(oq, buff_info, + &read_idx, &desc_used); + oq->stats.alloc_failures++; + continue; + } skb_reserve(skb, data_offset); =20 octep_oq_next_pkt(oq, buff_info, &read_idx, &desc_used); --=20 2.30.2