January 2022 - Linux-stable-mirror

FAILED: patch "[PATCH] rtc: mc146818-lib: fix RTC presence check" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ea6fa4961aab8f90a8aa03575a98b4bda368d4b6 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Mateusz=20Jo=C5=84czyk?= <mat.jonczyk(a)o2.pl> Date: Fri, 10 Dec 2021 21:01:26 +0100 Subject: [PATCH] rtc: mc146818-lib: fix RTC presence check MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To prevent an infinite loop in mc146818_get_time(), commit 211e5db19d15 ("rtc: mc146818: Detect and handle broken RTCs") added a check for RTC availability. Together with a later fix, it checked if bit 6 in register 0x0d is cleared. This, however, caused a false negative on a motherboard with an AMD SB710 southbridge; according to the specification [1], bit 6 of register 0x0d of this chipset is a scratchbit. This caused a regression in Linux 5.11 - the RTC was determined broken by the kernel and not used by rtc-cmos.c [3]. This problem was also reported in Fedora [4]. As a better alternative, check whether the UIP ("Update-in-progress") bit is set for longer then 10ms. If that is the case, then apparently the RTC is either absent (and all register reads return 0xff) or broken. Also limit the number of loop iterations in mc146818_get_time() to 10 to prevent an infinite loop there. The functions mc146818_get_time() and mc146818_does_rtc_work() will be refactored later in this patch series, in order to fix a separate problem with reading / setting the RTC alarm time. This is done so to avoid a confusion about what is being fixed when. In a previous approach to this problem, I implemented a check whether the RTC_HOURS register contains a value <= 24. This, however, sometimes did not work correctly on my Intel Kaby Lake laptop. According to Intel's documentation [2], "the time and date RAM locations (0-9) are disconnected from the external bus" during the update cycle so reading this register without checking the UIP bit is incorrect. [1] AMD SB700/710/750 Register Reference Guide, page 308, https://developer.amd.com/wordpress/media/2012/10/43009_sb7xx_rrg_pub_1.00.… [2] 7th Generation Intel ® Processor Family I/O for U/Y Platforms [...] Datasheet Volume 1 of 2, page 209 Intel's Document Number: 334658-006, https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/7th… [3] Functions in arch/x86/kernel/rtc.c apparently were using it. [4] https://bugzilla.redhat.com/show_bug.cgi?id=1936688 Fixes: 211e5db19d15 ("rtc: mc146818: Detect and handle broken RTCs") Fixes: ebb22a059436 ("rtc: mc146818: Dont test for bit 0-5 in Register D") Signed-off-by: Mateusz Jończyk <mat.jonczyk(a)o2.pl> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Alessandro Zummo <a.zummo(a)towertech.it> Cc: Alexandre Belloni <alexandre.belloni(a)bootlin.com> Signed-off-by: Alexandre Belloni <alexandre.belloni(a)bootlin.com> Link: https://lore.kernel.org/r/20211210200131.153887-5-mat.jonczyk@o2.pl diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index d0f58cca5c20..b90a603d6b12 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -800,16 +800,14 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq) rename_region(ports, dev_name(&cmos_rtc.rtc->dev)); - spin_lock_irq(&rtc_lock); - - /* Ensure that the RTC is accessible. Bit 6 must be 0! */ - if ((CMOS_READ(RTC_VALID) & 0x40) != 0) { - spin_unlock_irq(&rtc_lock); - dev_warn(dev, "not accessible\n"); + if (!mc146818_does_rtc_work()) { + dev_warn(dev, "broken or not accessible\n"); retval = -ENXIO; goto cleanup1; } + spin_lock_irq(&rtc_lock); + if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) { /* force periodic irq to CMOS reset default of 1024Hz; * diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c index ccd974b8a75a..d8e67a01220e 100644 --- a/drivers/rtc/rtc-mc146818-lib.c +++ b/drivers/rtc/rtc-mc146818-lib.c @@ -8,10 +8,36 @@ #include <linux/acpi.h> #endif +/* + * If the UIP (Update-in-progress) bit of the RTC is set for more then + * 10ms, the RTC is apparently broken or not present. + */ +bool mc146818_does_rtc_work(void) +{ + int i; + unsigned char val; + unsigned long flags; + + for (i = 0; i < 10; i++) { + spin_lock_irqsave(&rtc_lock, flags); + val = CMOS_READ(RTC_FREQ_SELECT); + spin_unlock_irqrestore(&rtc_lock, flags); + + if ((val & RTC_UIP) == 0) + return true; + + mdelay(1); + } + + return false; +} +EXPORT_SYMBOL_GPL(mc146818_does_rtc_work); + unsigned int mc146818_get_time(struct rtc_time *time) { unsigned char ctrl; unsigned long flags; + unsigned int iter_count = 0; unsigned char century = 0; bool retry; @@ -20,13 +46,13 @@ unsigned int mc146818_get_time(struct rtc_time *time) #endif again: - spin_lock_irqsave(&rtc_lock, flags); - /* Ensure that the RTC is accessible. Bit 6 must be 0! */ - if (WARN_ON_ONCE((CMOS_READ(RTC_VALID) & 0x40) != 0)) { - spin_unlock_irqrestore(&rtc_lock, flags); + if (iter_count > 10) { memset(time, 0, sizeof(*time)); return -EIO; } + iter_count++; + + spin_lock_irqsave(&rtc_lock, flags); /* * Check whether there is an update in progress during which the diff --git a/include/linux/mc146818rtc.h b/include/linux/mc146818rtc.h index 0661af17a758..69c80c4325bf 100644 --- a/include/linux/mc146818rtc.h +++ b/include/linux/mc146818rtc.h @@ -123,6 +123,7 @@ struct cmos_rtc_board_info { #define RTC_IO_EXTENT_USED RTC_IO_EXTENT #endif /* ARCH_RTC_LOCATION */ +bool mc146818_does_rtc_work(void); unsigned int mc146818_get_time(struct rtc_time *time); int mc146818_set_time(struct rtc_time *time);

2 years, 11 months

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FAILED: patch "[PATCH] net: axienet: increase default TX ring size to 128" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2d19c3fd80178160dd505ccd7fed1643831227a5 Mon Sep 17 00:00:00 2001 From: Robert Hancock <robert.hancock(a)calian.com> Date: Tue, 18 Jan 2022 15:41:32 -0600 Subject: [PATCH] net: axienet: increase default TX ring size to 128 With previous changes to make the driver handle the TX ring size more correctly, the default TX ring size of 64 appears to significantly bottleneck TX performance to around 600 Mbps on a 1 Gbps link on ZynqMP. Increasing this to 128 seems to bring performance up to near line rate and shouldn't cause excess bufferbloat (this driver doesn't yet support modern byte-based queue management). Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock <robert.hancock(a)calian.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index b4f42ee9b75d..377c94ec2486 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -41,7 +41,7 @@ #include "xilinx_axienet.h" /* Descriptors defines for Tx and Rx DMA */ -#define TX_BD_NUM_DEFAULT 64 +#define TX_BD_NUM_DEFAULT 128 #define RX_BD_NUM_DEFAULT 1024 #define TX_BD_NUM_MIN (MAX_SKB_FRAGS + 1) #define TX_BD_NUM_MAX 4096

2 years, 11 months

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FAILED: patch "[PATCH] net: axienet: increase default TX ring size to 128" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2d19c3fd80178160dd505ccd7fed1643831227a5 Mon Sep 17 00:00:00 2001 From: Robert Hancock <robert.hancock(a)calian.com> Date: Tue, 18 Jan 2022 15:41:32 -0600 Subject: [PATCH] net: axienet: increase default TX ring size to 128 With previous changes to make the driver handle the TX ring size more correctly, the default TX ring size of 64 appears to significantly bottleneck TX performance to around 600 Mbps on a 1 Gbps link on ZynqMP. Increasing this to 128 seems to bring performance up to near line rate and shouldn't cause excess bufferbloat (this driver doesn't yet support modern byte-based queue management). Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock <robert.hancock(a)calian.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index b4f42ee9b75d..377c94ec2486 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -41,7 +41,7 @@ #include "xilinx_axienet.h" /* Descriptors defines for Tx and Rx DMA */ -#define TX_BD_NUM_DEFAULT 64 +#define TX_BD_NUM_DEFAULT 128 #define RX_BD_NUM_DEFAULT 1024 #define TX_BD_NUM_MIN (MAX_SKB_FRAGS + 1) #define TX_BD_NUM_MAX 4096

2 years, 11 months

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FAILED: patch "[PATCH] net: axienet: increase default TX ring size to 128" failed to apply to 4.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2d19c3fd80178160dd505ccd7fed1643831227a5 Mon Sep 17 00:00:00 2001 From: Robert Hancock <robert.hancock(a)calian.com> Date: Tue, 18 Jan 2022 15:41:32 -0600 Subject: [PATCH] net: axienet: increase default TX ring size to 128 With previous changes to make the driver handle the TX ring size more correctly, the default TX ring size of 64 appears to significantly bottleneck TX performance to around 600 Mbps on a 1 Gbps link on ZynqMP. Increasing this to 128 seems to bring performance up to near line rate and shouldn't cause excess bufferbloat (this driver doesn't yet support modern byte-based queue management). Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock <robert.hancock(a)calian.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index b4f42ee9b75d..377c94ec2486 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -41,7 +41,7 @@ #include "xilinx_axienet.h" /* Descriptors defines for Tx and Rx DMA */ -#define TX_BD_NUM_DEFAULT 64 +#define TX_BD_NUM_DEFAULT 128 #define RX_BD_NUM_DEFAULT 1024 #define TX_BD_NUM_MIN (MAX_SKB_FRAGS + 1) #define TX_BD_NUM_MAX 4096

2 years, 11 months

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FAILED: patch "[PATCH] net: axienet: increase default TX ring size to 128" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2d19c3fd80178160dd505ccd7fed1643831227a5 Mon Sep 17 00:00:00 2001 From: Robert Hancock <robert.hancock(a)calian.com> Date: Tue, 18 Jan 2022 15:41:32 -0600 Subject: [PATCH] net: axienet: increase default TX ring size to 128 With previous changes to make the driver handle the TX ring size more correctly, the default TX ring size of 64 appears to significantly bottleneck TX performance to around 600 Mbps on a 1 Gbps link on ZynqMP. Increasing this to 128 seems to bring performance up to near line rate and shouldn't cause excess bufferbloat (this driver doesn't yet support modern byte-based queue management). Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock <robert.hancock(a)calian.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index b4f42ee9b75d..377c94ec2486 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -41,7 +41,7 @@ #include "xilinx_axienet.h" /* Descriptors defines for Tx and Rx DMA */ -#define TX_BD_NUM_DEFAULT 64 +#define TX_BD_NUM_DEFAULT 128 #define RX_BD_NUM_DEFAULT 1024 #define TX_BD_NUM_MIN (MAX_SKB_FRAGS + 1) #define TX_BD_NUM_MAX 4096

2 years, 11 months

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FAILED: patch "[PATCH] net: axienet: fix for TX busy handling" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From bb193e3db8b86a63f26889c99e14fd30c9ebd72a Mon Sep 17 00:00:00 2001 From: Robert Hancock <robert.hancock(a)calian.com> Date: Tue, 18 Jan 2022 15:41:31 -0600 Subject: [PATCH] net: axienet: fix for TX busy handling Network driver documentation indicates we should be avoiding returning NETDEV_TX_BUSY from ndo_start_xmit in normal cases, since it requires the packets to be requeued. Instead the queue should be stopped after a packet is added to the TX ring when there may not be enough room for an additional one. Also, when TX ring entries are completed, we should only wake the queue if we know there is room for another full maximally fragmented packet. Print a warning if there is insufficient space at the start of start_xmit, since this should no longer happen. Combined with increasing the default TX ring size (in a subsequent patch), this appears to recover the TX performance lost by previous changes to actually manage the TX ring state properly. Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock <robert.hancock(a)calian.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 8dc9e92e05d2..b4f42ee9b75d 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -660,6 +660,32 @@ static int axienet_free_tx_chain(struct net_device *ndev, u32 first_bd, return i; } +/** + * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy + * @lp: Pointer to the axienet_local structure + * @num_frag: The number of BDs to check for + * + * Return: 0, on success + * NETDEV_TX_BUSY, if any of the descriptors are not free + * + * This function is invoked before BDs are allocated and transmission starts. + * This function returns 0 if a BD or group of BDs can be allocated for + * transmission. If the BD or any of the BDs are not free the function + * returns a busy status. This is invoked from axienet_start_xmit. + */ +static inline int axienet_check_tx_bd_space(struct axienet_local *lp, + int num_frag) +{ + struct axidma_bd *cur_p; + + /* Ensure we see all descriptor updates from device or TX IRQ path */ + rmb(); + cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; + if (cur_p->cntrl) + return NETDEV_TX_BUSY; + return 0; +} + /** * axienet_start_xmit_done - Invoked once a transmit is completed by the * Axi DMA Tx channel. @@ -689,33 +715,8 @@ static void axienet_start_xmit_done(struct net_device *ndev) /* Matches barrier in axienet_start_xmit */ smp_mb(); - netif_wake_queue(ndev); -} - -/** - * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy - * @lp: Pointer to the axienet_local structure - * @num_frag: The number of BDs to check for - * - * Return: 0, on success - * NETDEV_TX_BUSY, if any of the descriptors are not free - * - * This function is invoked before BDs are allocated and transmission starts. - * This function returns 0 if a BD or group of BDs can be allocated for - * transmission. If the BD or any of the BDs are not free the function - * returns a busy status. This is invoked from axienet_start_xmit. - */ -static inline int axienet_check_tx_bd_space(struct axienet_local *lp, - int num_frag) -{ - struct axidma_bd *cur_p; - - /* Ensure we see all descriptor updates from device or TX IRQ path */ - rmb(); - cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; - if (cur_p->cntrl) - return NETDEV_TX_BUSY; - return 0; + if (!axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) + netif_wake_queue(ndev); } /** @@ -748,19 +749,14 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) cur_p = &lp->tx_bd_v[lp->tx_bd_tail]; if (axienet_check_tx_bd_space(lp, num_frag + 1)) { - if (netif_queue_stopped(ndev)) - return NETDEV_TX_BUSY; - + /* Should not happen as last start_xmit call should have + * checked for sufficient space and queue should only be + * woken when sufficient space is available. + */ netif_stop_queue(ndev); - - /* Matches barrier in axienet_start_xmit_done */ - smp_mb(); - - /* Space might have just been freed - check again */ - if (axienet_check_tx_bd_space(lp, num_frag + 1)) - return NETDEV_TX_BUSY; - - netif_wake_queue(ndev); + if (net_ratelimit()) + netdev_warn(ndev, "TX ring unexpectedly full\n"); + return NETDEV_TX_BUSY; } if (skb->ip_summed == CHECKSUM_PARTIAL) { @@ -821,6 +817,18 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) if (++lp->tx_bd_tail >= lp->tx_bd_num) lp->tx_bd_tail = 0; + /* Stop queue if next transmit may not have space */ + if (axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) { + netif_stop_queue(ndev); + + /* Matches barrier in axienet_start_xmit_done */ + smp_mb(); + + /* Space might have just been freed - check again */ + if (!axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) + netif_wake_queue(ndev); + } + return NETDEV_TX_OK; }

2 years, 11 months

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FAILED: patch "[PATCH] net: axienet: fix for TX busy handling" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From bb193e3db8b86a63f26889c99e14fd30c9ebd72a Mon Sep 17 00:00:00 2001 From: Robert Hancock <robert.hancock(a)calian.com> Date: Tue, 18 Jan 2022 15:41:31 -0600 Subject: [PATCH] net: axienet: fix for TX busy handling Network driver documentation indicates we should be avoiding returning NETDEV_TX_BUSY from ndo_start_xmit in normal cases, since it requires the packets to be requeued. Instead the queue should be stopped after a packet is added to the TX ring when there may not be enough room for an additional one. Also, when TX ring entries are completed, we should only wake the queue if we know there is room for another full maximally fragmented packet. Print a warning if there is insufficient space at the start of start_xmit, since this should no longer happen. Combined with increasing the default TX ring size (in a subsequent patch), this appears to recover the TX performance lost by previous changes to actually manage the TX ring state properly. Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock <robert.hancock(a)calian.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 8dc9e92e05d2..b4f42ee9b75d 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -660,6 +660,32 @@ static int axienet_free_tx_chain(struct net_device *ndev, u32 first_bd, return i; } +/** + * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy + * @lp: Pointer to the axienet_local structure + * @num_frag: The number of BDs to check for + * + * Return: 0, on success + * NETDEV_TX_BUSY, if any of the descriptors are not free + * + * This function is invoked before BDs are allocated and transmission starts. + * This function returns 0 if a BD or group of BDs can be allocated for + * transmission. If the BD or any of the BDs are not free the function + * returns a busy status. This is invoked from axienet_start_xmit. + */ +static inline int axienet_check_tx_bd_space(struct axienet_local *lp, + int num_frag) +{ + struct axidma_bd *cur_p; + + /* Ensure we see all descriptor updates from device or TX IRQ path */ + rmb(); + cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; + if (cur_p->cntrl) + return NETDEV_TX_BUSY; + return 0; +} + /** * axienet_start_xmit_done - Invoked once a transmit is completed by the * Axi DMA Tx channel. @@ -689,33 +715,8 @@ static void axienet_start_xmit_done(struct net_device *ndev) /* Matches barrier in axienet_start_xmit */ smp_mb(); - netif_wake_queue(ndev); -} - -/** - * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy - * @lp: Pointer to the axienet_local structure - * @num_frag: The number of BDs to check for - * - * Return: 0, on success - * NETDEV_TX_BUSY, if any of the descriptors are not free - * - * This function is invoked before BDs are allocated and transmission starts. - * This function returns 0 if a BD or group of BDs can be allocated for - * transmission. If the BD or any of the BDs are not free the function - * returns a busy status. This is invoked from axienet_start_xmit. - */ -static inline int axienet_check_tx_bd_space(struct axienet_local *lp, - int num_frag) -{ - struct axidma_bd *cur_p; - - /* Ensure we see all descriptor updates from device or TX IRQ path */ - rmb(); - cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; - if (cur_p->cntrl) - return NETDEV_TX_BUSY; - return 0; + if (!axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) + netif_wake_queue(ndev); } /** @@ -748,19 +749,14 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) cur_p = &lp->tx_bd_v[lp->tx_bd_tail]; if (axienet_check_tx_bd_space(lp, num_frag + 1)) { - if (netif_queue_stopped(ndev)) - return NETDEV_TX_BUSY; - + /* Should not happen as last start_xmit call should have + * checked for sufficient space and queue should only be + * woken when sufficient space is available. + */ netif_stop_queue(ndev); - - /* Matches barrier in axienet_start_xmit_done */ - smp_mb(); - - /* Space might have just been freed - check again */ - if (axienet_check_tx_bd_space(lp, num_frag + 1)) - return NETDEV_TX_BUSY; - - netif_wake_queue(ndev); + if (net_ratelimit()) + netdev_warn(ndev, "TX ring unexpectedly full\n"); + return NETDEV_TX_BUSY; } if (skb->ip_summed == CHECKSUM_PARTIAL) { @@ -821,6 +817,18 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) if (++lp->tx_bd_tail >= lp->tx_bd_num) lp->tx_bd_tail = 0; + /* Stop queue if next transmit may not have space */ + if (axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) { + netif_stop_queue(ndev); + + /* Matches barrier in axienet_start_xmit_done */ + smp_mb(); + + /* Space might have just been freed - check again */ + if (!axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) + netif_wake_queue(ndev); + } + return NETDEV_TX_OK; }

2 years, 11 months

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FAILED: patch "[PATCH] net: axienet: fix for TX busy handling" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From bb193e3db8b86a63f26889c99e14fd30c9ebd72a Mon Sep 17 00:00:00 2001 From: Robert Hancock <robert.hancock(a)calian.com> Date: Tue, 18 Jan 2022 15:41:31 -0600 Subject: [PATCH] net: axienet: fix for TX busy handling Network driver documentation indicates we should be avoiding returning NETDEV_TX_BUSY from ndo_start_xmit in normal cases, since it requires the packets to be requeued. Instead the queue should be stopped after a packet is added to the TX ring when there may not be enough room for an additional one. Also, when TX ring entries are completed, we should only wake the queue if we know there is room for another full maximally fragmented packet. Print a warning if there is insufficient space at the start of start_xmit, since this should no longer happen. Combined with increasing the default TX ring size (in a subsequent patch), this appears to recover the TX performance lost by previous changes to actually manage the TX ring state properly. Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock <robert.hancock(a)calian.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 8dc9e92e05d2..b4f42ee9b75d 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -660,6 +660,32 @@ static int axienet_free_tx_chain(struct net_device *ndev, u32 first_bd, return i; } +/** + * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy + * @lp: Pointer to the axienet_local structure + * @num_frag: The number of BDs to check for + * + * Return: 0, on success + * NETDEV_TX_BUSY, if any of the descriptors are not free + * + * This function is invoked before BDs are allocated and transmission starts. + * This function returns 0 if a BD or group of BDs can be allocated for + * transmission. If the BD or any of the BDs are not free the function + * returns a busy status. This is invoked from axienet_start_xmit. + */ +static inline int axienet_check_tx_bd_space(struct axienet_local *lp, + int num_frag) +{ + struct axidma_bd *cur_p; + + /* Ensure we see all descriptor updates from device or TX IRQ path */ + rmb(); + cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; + if (cur_p->cntrl) + return NETDEV_TX_BUSY; + return 0; +} + /** * axienet_start_xmit_done - Invoked once a transmit is completed by the * Axi DMA Tx channel. @@ -689,33 +715,8 @@ static void axienet_start_xmit_done(struct net_device *ndev) /* Matches barrier in axienet_start_xmit */ smp_mb(); - netif_wake_queue(ndev); -} - -/** - * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy - * @lp: Pointer to the axienet_local structure - * @num_frag: The number of BDs to check for - * - * Return: 0, on success - * NETDEV_TX_BUSY, if any of the descriptors are not free - * - * This function is invoked before BDs are allocated and transmission starts. - * This function returns 0 if a BD or group of BDs can be allocated for - * transmission. If the BD or any of the BDs are not free the function - * returns a busy status. This is invoked from axienet_start_xmit. - */ -static inline int axienet_check_tx_bd_space(struct axienet_local *lp, - int num_frag) -{ - struct axidma_bd *cur_p; - - /* Ensure we see all descriptor updates from device or TX IRQ path */ - rmb(); - cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; - if (cur_p->cntrl) - return NETDEV_TX_BUSY; - return 0; + if (!axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) + netif_wake_queue(ndev); } /** @@ -748,19 +749,14 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) cur_p = &lp->tx_bd_v[lp->tx_bd_tail]; if (axienet_check_tx_bd_space(lp, num_frag + 1)) { - if (netif_queue_stopped(ndev)) - return NETDEV_TX_BUSY; - + /* Should not happen as last start_xmit call should have + * checked for sufficient space and queue should only be + * woken when sufficient space is available. + */ netif_stop_queue(ndev); - - /* Matches barrier in axienet_start_xmit_done */ - smp_mb(); - - /* Space might have just been freed - check again */ - if (axienet_check_tx_bd_space(lp, num_frag + 1)) - return NETDEV_TX_BUSY; - - netif_wake_queue(ndev); + if (net_ratelimit()) + netdev_warn(ndev, "TX ring unexpectedly full\n"); + return NETDEV_TX_BUSY; } if (skb->ip_summed == CHECKSUM_PARTIAL) { @@ -821,6 +817,18 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) if (++lp->tx_bd_tail >= lp->tx_bd_num) lp->tx_bd_tail = 0; + /* Stop queue if next transmit may not have space */ + if (axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) { + netif_stop_queue(ndev); + + /* Matches barrier in axienet_start_xmit_done */ + smp_mb(); + + /* Space might have just been freed - check again */ + if (!axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) + netif_wake_queue(ndev); + } + return NETDEV_TX_OK; }

2 years, 11 months

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FAILED: patch "[PATCH] net: axienet: fix for TX busy handling" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From bb193e3db8b86a63f26889c99e14fd30c9ebd72a Mon Sep 17 00:00:00 2001 From: Robert Hancock <robert.hancock(a)calian.com> Date: Tue, 18 Jan 2022 15:41:31 -0600 Subject: [PATCH] net: axienet: fix for TX busy handling Network driver documentation indicates we should be avoiding returning NETDEV_TX_BUSY from ndo_start_xmit in normal cases, since it requires the packets to be requeued. Instead the queue should be stopped after a packet is added to the TX ring when there may not be enough room for an additional one. Also, when TX ring entries are completed, we should only wake the queue if we know there is room for another full maximally fragmented packet. Print a warning if there is insufficient space at the start of start_xmit, since this should no longer happen. Combined with increasing the default TX ring size (in a subsequent patch), this appears to recover the TX performance lost by previous changes to actually manage the TX ring state properly. Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock <robert.hancock(a)calian.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 8dc9e92e05d2..b4f42ee9b75d 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -660,6 +660,32 @@ static int axienet_free_tx_chain(struct net_device *ndev, u32 first_bd, return i; } +/** + * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy + * @lp: Pointer to the axienet_local structure + * @num_frag: The number of BDs to check for + * + * Return: 0, on success + * NETDEV_TX_BUSY, if any of the descriptors are not free + * + * This function is invoked before BDs are allocated and transmission starts. + * This function returns 0 if a BD or group of BDs can be allocated for + * transmission. If the BD or any of the BDs are not free the function + * returns a busy status. This is invoked from axienet_start_xmit. + */ +static inline int axienet_check_tx_bd_space(struct axienet_local *lp, + int num_frag) +{ + struct axidma_bd *cur_p; + + /* Ensure we see all descriptor updates from device or TX IRQ path */ + rmb(); + cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; + if (cur_p->cntrl) + return NETDEV_TX_BUSY; + return 0; +} + /** * axienet_start_xmit_done - Invoked once a transmit is completed by the * Axi DMA Tx channel. @@ -689,33 +715,8 @@ static void axienet_start_xmit_done(struct net_device *ndev) /* Matches barrier in axienet_start_xmit */ smp_mb(); - netif_wake_queue(ndev); -} - -/** - * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy - * @lp: Pointer to the axienet_local structure - * @num_frag: The number of BDs to check for - * - * Return: 0, on success - * NETDEV_TX_BUSY, if any of the descriptors are not free - * - * This function is invoked before BDs are allocated and transmission starts. - * This function returns 0 if a BD or group of BDs can be allocated for - * transmission. If the BD or any of the BDs are not free the function - * returns a busy status. This is invoked from axienet_start_xmit. - */ -static inline int axienet_check_tx_bd_space(struct axienet_local *lp, - int num_frag) -{ - struct axidma_bd *cur_p; - - /* Ensure we see all descriptor updates from device or TX IRQ path */ - rmb(); - cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; - if (cur_p->cntrl) - return NETDEV_TX_BUSY; - return 0; + if (!axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) + netif_wake_queue(ndev); } /** @@ -748,19 +749,14 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) cur_p = &lp->tx_bd_v[lp->tx_bd_tail]; if (axienet_check_tx_bd_space(lp, num_frag + 1)) { - if (netif_queue_stopped(ndev)) - return NETDEV_TX_BUSY; - + /* Should not happen as last start_xmit call should have + * checked for sufficient space and queue should only be + * woken when sufficient space is available. + */ netif_stop_queue(ndev); - - /* Matches barrier in axienet_start_xmit_done */ - smp_mb(); - - /* Space might have just been freed - check again */ - if (axienet_check_tx_bd_space(lp, num_frag + 1)) - return NETDEV_TX_BUSY; - - netif_wake_queue(ndev); + if (net_ratelimit()) + netdev_warn(ndev, "TX ring unexpectedly full\n"); + return NETDEV_TX_BUSY; } if (skb->ip_summed == CHECKSUM_PARTIAL) { @@ -821,6 +817,18 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) if (++lp->tx_bd_tail >= lp->tx_bd_num) lp->tx_bd_tail = 0; + /* Stop queue if next transmit may not have space */ + if (axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) { + netif_stop_queue(ndev); + + /* Matches barrier in axienet_start_xmit_done */ + smp_mb(); + + /* Space might have just been freed - check again */ + if (!axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) + netif_wake_queue(ndev); + } + return NETDEV_TX_OK; }

2 years, 11 months

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0 0

FAILED: patch "[PATCH] net: axienet: fix for TX busy handling" failed to apply to 4.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From bb193e3db8b86a63f26889c99e14fd30c9ebd72a Mon Sep 17 00:00:00 2001 From: Robert Hancock <robert.hancock(a)calian.com> Date: Tue, 18 Jan 2022 15:41:31 -0600 Subject: [PATCH] net: axienet: fix for TX busy handling Network driver documentation indicates we should be avoiding returning NETDEV_TX_BUSY from ndo_start_xmit in normal cases, since it requires the packets to be requeued. Instead the queue should be stopped after a packet is added to the TX ring when there may not be enough room for an additional one. Also, when TX ring entries are completed, we should only wake the queue if we know there is room for another full maximally fragmented packet. Print a warning if there is insufficient space at the start of start_xmit, since this should no longer happen. Combined with increasing the default TX ring size (in a subsequent patch), this appears to recover the TX performance lost by previous changes to actually manage the TX ring state properly. Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock <robert.hancock(a)calian.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 8dc9e92e05d2..b4f42ee9b75d 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -660,6 +660,32 @@ static int axienet_free_tx_chain(struct net_device *ndev, u32 first_bd, return i; } +/** + * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy + * @lp: Pointer to the axienet_local structure + * @num_frag: The number of BDs to check for + * + * Return: 0, on success + * NETDEV_TX_BUSY, if any of the descriptors are not free + * + * This function is invoked before BDs are allocated and transmission starts. + * This function returns 0 if a BD or group of BDs can be allocated for + * transmission. If the BD or any of the BDs are not free the function + * returns a busy status. This is invoked from axienet_start_xmit. + */ +static inline int axienet_check_tx_bd_space(struct axienet_local *lp, + int num_frag) +{ + struct axidma_bd *cur_p; + + /* Ensure we see all descriptor updates from device or TX IRQ path */ + rmb(); + cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; + if (cur_p->cntrl) + return NETDEV_TX_BUSY; + return 0; +} + /** * axienet_start_xmit_done - Invoked once a transmit is completed by the * Axi DMA Tx channel. @@ -689,33 +715,8 @@ static void axienet_start_xmit_done(struct net_device *ndev) /* Matches barrier in axienet_start_xmit */ smp_mb(); - netif_wake_queue(ndev); -} - -/** - * axienet_check_tx_bd_space - Checks if a BD/group of BDs are currently busy - * @lp: Pointer to the axienet_local structure - * @num_frag: The number of BDs to check for - * - * Return: 0, on success - * NETDEV_TX_BUSY, if any of the descriptors are not free - * - * This function is invoked before BDs are allocated and transmission starts. - * This function returns 0 if a BD or group of BDs can be allocated for - * transmission. If the BD or any of the BDs are not free the function - * returns a busy status. This is invoked from axienet_start_xmit. - */ -static inline int axienet_check_tx_bd_space(struct axienet_local *lp, - int num_frag) -{ - struct axidma_bd *cur_p; - - /* Ensure we see all descriptor updates from device or TX IRQ path */ - rmb(); - cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; - if (cur_p->cntrl) - return NETDEV_TX_BUSY; - return 0; + if (!axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) + netif_wake_queue(ndev); } /** @@ -748,19 +749,14 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) cur_p = &lp->tx_bd_v[lp->tx_bd_tail]; if (axienet_check_tx_bd_space(lp, num_frag + 1)) { - if (netif_queue_stopped(ndev)) - return NETDEV_TX_BUSY; - + /* Should not happen as last start_xmit call should have + * checked for sufficient space and queue should only be + * woken when sufficient space is available. + */ netif_stop_queue(ndev); - - /* Matches barrier in axienet_start_xmit_done */ - smp_mb(); - - /* Space might have just been freed - check again */ - if (axienet_check_tx_bd_space(lp, num_frag + 1)) - return NETDEV_TX_BUSY; - - netif_wake_queue(ndev); + if (net_ratelimit()) + netdev_warn(ndev, "TX ring unexpectedly full\n"); + return NETDEV_TX_BUSY; } if (skb->ip_summed == CHECKSUM_PARTIAL) { @@ -821,6 +817,18 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) if (++lp->tx_bd_tail >= lp->tx_bd_num) lp->tx_bd_tail = 0; + /* Stop queue if next transmit may not have space */ + if (axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) { + netif_stop_queue(ndev); + + /* Matches barrier in axienet_start_xmit_done */ + smp_mb(); + + /* Space might have just been freed - check again */ + if (!axienet_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) + netif_wake_queue(ndev); + } + return NETDEV_TX_OK; }

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