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[5.12.227.87]) by smtp.gmail.com with ESMTPSA id u23sm6093781edt.78.2021.01.18.08.17.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Jan 2021 08:17:49 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski , netdev@vger.kernel.org Cc: Andrew Lunn , Florian Fainelli , Vivien Didelot , Richard Cochran , Claudiu Manoil , Alexandru Marginean , Alexandre Belloni , Xiaoliang Yang , Hongbo Wang , Po Liu , Yangbo Lu , Maxim Kochetkov , Eldar Gasanov , Andrey L , UNGLinuxDriver@microchip.com Subject: [PATCH v3 net-next 06/15] net: mscc: ocelot: only drain extraction queue on error Date: Mon, 18 Jan 2021 18:17:22 +0200 Message-Id: <20210118161731.2837700-7-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210118161731.2837700-1-olteanv@gmail.com> References: <20210118161731.2837700-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Vladimir Oltean It appears that the intention of this snippet of code is to not exit ocelot_xtr_irq_handler() while in the middle of extracting a frame. The problem in extracting it word by word is that future extraction attempts are really easy to get desynchronized, since the IRQ handler assumes that the first 16 bytes are the IFH, which give further information about the frame, such as frame length. But during normal operation, "err" will not be 0, but 4, set from here: for (i = 0; i < OCELOT_TAG_LEN / 4; i++) { err = ocelot_rx_frame_word(ocelot, grp, true, &ifh[i]); if (err != 4) break; } if (err != 4) break; In that case, draining the extraction queue is a no-op. So explicitly make this code execute only on negative err. Signed-off-by: Vladimir Oltean --- Changes in v3: None. Changes in v2: Patch is new. drivers/net/ethernet/mscc/ocelot_vsc7514.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/mscc/ocelot_vsc7514.c b/drivers/net/ethernet/mscc/ocelot_vsc7514.c index 917243c4a19d..d4cf6eeff3c9 100644 --- a/drivers/net/ethernet/mscc/ocelot_vsc7514.c +++ b/drivers/net/ethernet/mscc/ocelot_vsc7514.c @@ -701,7 +701,7 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg) dev->stats.rx_packets++; } - if (err) + if (err < 0) while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp)) ocelot_read_rix(ocelot, QS_XTR_RD, grp);