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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Yannick Vignon <yannick.vignon@nxp.com>,
	Jakub Kicinski <kuba@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 41/47] net: stmmac: Do not enable RX FIFO overflow interrupts
Date: Thu, 20 May 2021 11:22:39 +0200	[thread overview]
Message-ID: <20210520092054.871219094@linuxfoundation.org> (raw)
In-Reply-To: <20210520092053.559923764@linuxfoundation.org>

From: Yannick Vignon <yannick.vignon@nxp.com>

[ Upstream commit 8a7cb245cf28cb3e541e0d6c8624b95d079e155b ]

The RX FIFO overflows when the system is not able to process all received
packets and they start accumulating (first in the DMA queue in memory,
then in the FIFO). An interrupt is then raised for each overflowing packet
and handled in stmmac_interrupt(). This is counter-productive, since it
brings the system (or more likely, one CPU core) to its knees to process
the FIFO overflow interrupts.

stmmac_interrupt() handles overflow interrupts by writing the rx tail ptr
into the corresponding hardware register (according to the MAC spec, this
has the effect of restarting the MAC DMA). However, without freeing any rx
descriptors, the DMA stops right away, and another overflow interrupt is
raised as the FIFO overflows again. Since the DMA is already restarted at
the end of stmmac_rx_refill() after freeing descriptors, disabling FIFO
overflow interrupts and the corresponding handling code has no side effect,
and eliminates the interrupt storm when the RX FIFO overflows.

Signed-off-by: Yannick Vignon <yannick.vignon@nxp.com>
Link: https://lore.kernel.org/r/20210506143312.20784-1-yannick.vignon@oss.nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c  |  7 +------
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 14 ++------------
 2 files changed, 3 insertions(+), 18 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
index 62aa0e95beb7..a7249e4071f1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
@@ -222,7 +222,7 @@ static void dwmac4_dma_rx_chan_op_mode(void __iomem *ioaddr, int mode,
 				       u32 channel, int fifosz, u8 qmode)
 {
 	unsigned int rqs = fifosz / 256 - 1;
-	u32 mtl_rx_op, mtl_rx_int;
+	u32 mtl_rx_op;
 
 	mtl_rx_op = readl(ioaddr + MTL_CHAN_RX_OP_MODE(channel));
 
@@ -283,11 +283,6 @@ static void dwmac4_dma_rx_chan_op_mode(void __iomem *ioaddr, int mode,
 	}
 
 	writel(mtl_rx_op, ioaddr + MTL_CHAN_RX_OP_MODE(channel));
-
-	/* Enable MTL RX overflow */
-	mtl_rx_int = readl(ioaddr + MTL_CHAN_INT_CTRL(channel));
-	writel(mtl_rx_int | MTL_RX_OVERFLOW_INT_EN,
-	       ioaddr + MTL_CHAN_INT_CTRL(channel));
 }
 
 static void dwmac4_dma_tx_chan_op_mode(void __iomem *ioaddr, int mode,
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 5b9478dffe10..4374ce4671ad 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4138,7 +4138,6 @@ static irqreturn_t stmmac_interrupt(int irq, void *dev_id)
 	/* To handle GMAC own interrupts */
 	if ((priv->plat->has_gmac) || xmac) {
 		int status = stmmac_host_irq_status(priv, priv->hw, &priv->xstats);
-		int mtl_status;
 
 		if (unlikely(status)) {
 			/* For LPI we need to save the tx status */
@@ -4149,17 +4148,8 @@ static irqreturn_t stmmac_interrupt(int irq, void *dev_id)
 		}
 
 		for (queue = 0; queue < queues_count; queue++) {
-			struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
-
-			mtl_status = stmmac_host_mtl_irq_status(priv, priv->hw,
-								queue);
-			if (mtl_status != -EINVAL)
-				status |= mtl_status;
-
-			if (status & CORE_IRQ_MTL_RX_OVERFLOW)
-				stmmac_set_rx_tail_ptr(priv, priv->ioaddr,
-						       rx_q->rx_tail_addr,
-						       queue);
+			status = stmmac_host_mtl_irq_status(priv, priv->hw,
+							    queue);
 		}
 
 		/* PCS link status */
-- 
2.30.2




  parent reply	other threads:[~2021-05-20  9:30 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-20  9:21 [PATCH 5.10 00/47] 5.10.39-rc1 review Greg Kroah-Hartman
2021-05-20  9:21 ` [PATCH 5.10 01/47] x86/msr: Fix wr/rdmsr_safe_regs_on_cpu() prototypes Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 02/47] drm/i915/display: fix compiler warning about array overrun Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 03/47] airo: work around stack usage warning Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 04/47] kgdb: fix gcc-11 warning on indentation Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 05/47] usb: sl811-hcd: improve misleading indentation Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 06/47] cxgb4: Fix the -Wmisleading-indentation warning Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 07/47] isdn: capi: fix mismatched prototypes Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 08/47] virtio_net: Do not pull payload in skb->head Greg Kroah-Hartman
2021-05-20  9:22   ` Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 09/47] ARM: 9058/1: cache-v7: refactor v7_invalidate_l1 to avoid clobbering r5/r6 Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 10/47] PCI: thunder: Fix compile testing Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 11/47] dmaengine: dw-edma: Fix crash on loading/unloading driver Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 12/47] ARM: 9066/1: ftrace: pause/unpause function graph tracer in cpu_suspend() Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 13/47] ACPI / hotplug / PCI: Fix reference count leak in enable_slot() Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 14/47] PCI: tegra: Fix runtime PM imbalance in pex_ep_event_pex_rst_deassert() Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 15/47] Input: elants_i2c - do not bind to i2c-hid compatible ACPI instantiated devices Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 16/47] Input: silead - add workaround for x86 BIOS-es which bring the chip up in a stuck state Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 17/47] NFS: NFS_INO_REVAL_PAGECACHE should mark the change attribute invalid Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 18/47] um: Mark all kernel symbols as local Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 19/47] um: Disable CONFIG_GCOV with MODULES Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 20/47] PCI: tegra: Add Tegra194 MCFG quirks for ECAM errata Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 21/47] ARM: 9075/1: kernel: Fix interrupted SMC calls Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 22/47] platform/chrome: cros_ec_typec: Add DP mode check Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 23/47] riscv: Use $(LD) instead of $(CC) to link vDSO Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 24/47] scripts/recordmcount.pl: Fix RISC-V regex for clang Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 25/47] riscv: Workaround mcount name prior to clang-13 Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 26/47] scsi: lpfc: Fix illegal memory access on Abort IOCBs Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 27/47] ceph: fix fscache invalidation Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 28/47] ceph: dont clobber i_snap_caps on non-I_NEW inode Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 29/47] ceph: dont allow access to MDS-private inodes Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 30/47] scsi: target: tcmu: Return from tcmu_handle_completions() if cmd_id not found Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 31/47] amdgpu/pm: Prevent force of DCEFCLK on NAVI10 and SIENNA_CICHLID Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 32/47] bridge: Fix possible races between assigning rx_handler_data and setting IFF_BRIDGE_PORT bit Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 33/47] net: hsr: check skb can contain struct hsr_ethhdr in fill_frame_info Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 34/47] nvmet: remove unsupported command noise Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 35/47] drm/amd/display: Fix two cursor duplication when using overlay Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 36/47] gpiolib: acpi: Add quirk to ignore EC wakeups on Dell Venue 10 Pro 5055 Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 37/47] net:CXGB4: fix leak if sk_buff is not used Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 38/47] ALSA: hda: generic: change the DAC ctl name for LO+SPK or LO+HP Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 39/47] block: reexpand iov_iter after read/write Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 40/47] lib: stackdepot: turn depot_lock spinlock to raw_spinlock Greg Kroah-Hartman
2021-05-20  9:22 ` Greg Kroah-Hartman [this message]
2021-05-20  9:22 ` [PATCH 5.10 42/47] ip6_gre: proper dev_{hold|put} in ndo_[un]init methods Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 43/47] sit: " Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 44/47] ip6_tunnel: " Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 45/47] ipv6: remove extra dev_hold() for fallback tunnels Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 46/47] tweewide: Fix most Shebang lines Greg Kroah-Hartman
2021-05-20  9:22 ` [PATCH 5.10 47/47] scripts: switch explicitly to Python 3 Greg Kroah-Hartman
2021-05-20 11:24 ` [PATCH 5.10 00/47] 5.10.39-rc1 review Pavel Machek
2021-05-20 12:32 ` Jon Hunter
2021-05-20 12:59   ` Greg Kroah-Hartman
2021-05-20 14:07 ` Fox Chen

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