[PATCH 0/3] net: core: Unify dstats with tstats and lstats, add generic collection helper

[PATCH 0/3] net: core: Unify dstats with tstats and lstats, add generic collection helper

[Jeremy Kerr]

The struct pcpu_dstats ("dstats") has a few variations from the other
two stats types (struct pcpu_sw_netstats and struct pcpu_lstats), and
doesn't have generic helpers for collecting the per-cpu stats into a
struct rtnl_link_stats64.

This change unifies dstats with the other types, adds a collection
helper (dev_get_dstats64) for ->ndo_get_stats64, and updates the single
driver (vrf) to use this helper.

Of course, questions/comments/etc are most welcome!

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
---
Jeremy Kerr (3):
      net: core,vrf: Change pcpu_dstat fields to u64_stats_t
      net: core: Implement dstats-type stats collections
      net: vrf: move to generic dstat helpers

 drivers/net/vrf.c         | 48 ++++++++++------------------------------
 include/linux/netdevice.h | 15 ++++++++-----
 net/core/dev.c            | 56 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 76 insertions(+), 43 deletions(-)
---
base-commit: 32f88d65f01bf6f45476d7edbe675e44fb9e1d58
change-id: 20240605-dstats-b6e08c318555

Best regards,
-- 
Jeremy Kerr <jk@codeconstruct.com.au>

[PATCH 1/3] net: core,vrf: Change pcpu_dstat fields to u64_stats_t

[Jeremy Kerr]

The pcpu_sw_netstats and pcpu_lstats structs both contain a set of
u64_stats_t fields for individual stats, but pcpu_dstats uses u64s
instead.

Make this consistent by using u64_stats_t across all stats types.

The per-cpu dstats are only used by the vrf driver at present, so update
that driver as part of this change.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
---
 drivers/net/vrf.c         | 29 +++++++++++++++--------------
 include/linux/netdevice.h | 12 ++++++------
 2 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 3a252ac5dd28..088732871b27 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -126,8 +126,8 @@ static void vrf_rx_stats(struct net_device *dev, int len)
 	struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
 
 	u64_stats_update_begin(&dstats->syncp);
-	dstats->rx_packets++;
-	dstats->rx_bytes += len;
+	u64_stats_inc(&dstats->rx_packets);
+	u64_stats_add(&dstats->rx_bytes, len);
 	u64_stats_update_end(&dstats->syncp);
 }
 
@@ -150,11 +150,11 @@ static void vrf_get_stats64(struct net_device *dev,
 		dstats = per_cpu_ptr(dev->dstats, i);
 		do {
 			start = u64_stats_fetch_begin(&dstats->syncp);
-			tbytes = dstats->tx_bytes;
-			tpkts = dstats->tx_packets;
-			tdrops = dstats->tx_drops;
-			rbytes = dstats->rx_bytes;
-			rpkts = dstats->rx_packets;
+			tbytes = u64_stats_read(&dstats->tx_bytes);
+			tpkts = u64_stats_read(&dstats->tx_packets);
+			tdrops = u64_stats_read(&dstats->tx_drops);
+			rbytes = u64_stats_read(&dstats->rx_bytes);
+			rpkts = u64_stats_read(&dstats->rx_packets);
 		} while (u64_stats_fetch_retry(&dstats->syncp, start));
 		stats->tx_bytes += tbytes;
 		stats->tx_packets += tpkts;
@@ -411,7 +411,7 @@ static int vrf_local_xmit(struct sk_buff *skb, struct net_device *dev,
 	if (likely(__netif_rx(skb) == NET_RX_SUCCESS))
 		vrf_rx_stats(dev, len);
 	else
-		this_cpu_inc(dev->dstats->rx_drops);
+		u64_stats_inc(&dev->dstats->rx_drops);
 
 	return NETDEV_TX_OK;
 }
@@ -599,19 +599,20 @@ static netdev_tx_t is_ip_tx_frame(struct sk_buff *skb, struct net_device *dev)
 
 static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
 {
+	struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
+
 	int len = skb->len;
 	netdev_tx_t ret = is_ip_tx_frame(skb, dev);
 
+	u64_stats_update_begin(&dstats->syncp);
 	if (likely(ret == NET_XMIT_SUCCESS || ret == NET_XMIT_CN)) {
-		struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
 
-		u64_stats_update_begin(&dstats->syncp);
-		dstats->tx_packets++;
-		dstats->tx_bytes += len;
-		u64_stats_update_end(&dstats->syncp);
+		u64_stats_inc(&dstats->tx_packets);
+		u64_stats_add(&dstats->tx_bytes, len);
 	} else {
-		this_cpu_inc(dev->dstats->tx_drops);
+		u64_stats_inc(&dstats->tx_drops);
 	}
+	u64_stats_update_end(&dstats->syncp);
 
 	return ret;
 }
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d20c6c99eb88..f148a01dd1d1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2731,12 +2731,12 @@ struct pcpu_sw_netstats {
 } __aligned(4 * sizeof(u64));
 
 struct pcpu_dstats {
-	u64			rx_packets;
-	u64			rx_bytes;
-	u64			rx_drops;
-	u64			tx_packets;
-	u64			tx_bytes;
-	u64			tx_drops;
+	u64_stats_t		rx_packets;
+	u64_stats_t		rx_bytes;
+	u64_stats_t		rx_drops;
+	u64_stats_t		tx_packets;
+	u64_stats_t		tx_bytes;
+	u64_stats_t		tx_drops;
 	struct u64_stats_sync	syncp;
 } __aligned(8 * sizeof(u64));
 

-- 
2.39.2

Re: [PATCH 1/3] net: core,vrf: Change pcpu_dstat fields to u64_stats_t

[kernel test robot]

Hi Jeremy,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 32f88d65f01bf6f45476d7edbe675e44fb9e1d58]

url:    https://github.com/intel-lab-lkp/linux/commits/Jeremy-Kerr/net-core-vrf-Change-pcpu_dstat-fields-to-u64_stats_t/20240605-143942
base:   32f88d65f01bf6f45476d7edbe675e44fb9e1d58
patch link:    https://lore.kernel.org/r/20240605-dstats-v1-1-1024396e1670%40codeconstruct.com.au
patch subject: [PATCH 1/3] net: core,vrf: Change pcpu_dstat fields to u64_stats_t
config: i386-randconfig-062-20240607 (https://download.01.org/0day-ci/archive/20240607/202406070424.JtWImJfu-lkp@intel.com/config)
compiler: gcc-10 (Ubuntu 10.5.0-1ubuntu1) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240607/202406070424.JtWImJfu-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406070424.JtWImJfu-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/net/vrf.c:414:35: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct u64_stats_t [usertype] *p @@     got struct u64_stats_t [noderef] __percpu * @@
   drivers/net/vrf.c:414:35: sparse:     expected struct u64_stats_t [usertype] *p
   drivers/net/vrf.c:414:35: sparse:     got struct u64_stats_t [noderef] __percpu *
   drivers/net/vrf.c: note: in included file (through include/linux/smp.h, include/linux/alloc_tag.h, include/linux/percpu.h, ...):
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true

vim +414 drivers/net/vrf.c

   391	
   392	/* Local traffic destined to local address. Reinsert the packet to rx
   393	 * path, similar to loopback handling.
   394	 */
   395	static int vrf_local_xmit(struct sk_buff *skb, struct net_device *dev,
   396				  struct dst_entry *dst)
   397	{
   398		int len = skb->len;
   399	
   400		skb_orphan(skb);
   401	
   402		skb_dst_set(skb, dst);
   403	
   404		/* set pkt_type to avoid skb hitting packet taps twice -
   405		 * once on Tx and again in Rx processing
   406		 */
   407		skb->pkt_type = PACKET_LOOPBACK;
   408	
   409		skb->protocol = eth_type_trans(skb, dev);
   410	
   411		if (likely(__netif_rx(skb) == NET_RX_SUCCESS))
   412			vrf_rx_stats(dev, len);
   413		else
 > 414			u64_stats_inc(&dev->dstats->rx_drops);
   415	
   416		return NETDEV_TX_OK;
   417	}
   418	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH 2/3] net: core: Implement dstats-type stats collections

[Jeremy Kerr]

We currently have dev_get_tstats64() for collecting per-cpu stats of
type pcpu_sw_netstats ("tstats"). However, tstats doesn't allow for
accounting tx/rx drops. We do have a stats variant that does have stats
for dropped packets: struct pcpu_dstats, but there are no core helpers
for using those stats.

The VRF driver uses dstats, by providing its own collation/fetch
functions to do so.

This change adds a common helpers for dstats-type collection, based on
the VRF driver's own (plus the unused tx_drops stat from there). We
will switch the VRF driver to use this in the next change.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
---
 include/linux/netdevice.h |  3 +++
 net/core/dev.c            | 56 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f148a01dd1d1..fdc3d8a6c0f4 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4690,6 +4690,9 @@ void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,
 void dev_fetch_sw_netstats(struct rtnl_link_stats64 *s,
 			   const struct pcpu_sw_netstats __percpu *netstats);
 void dev_get_tstats64(struct net_device *dev, struct rtnl_link_stats64 *s);
+void dev_fetch_dstats(struct rtnl_link_stats64 *s,
+		      const struct pcpu_dstats __percpu *dstats);
+void dev_get_dstats64(struct net_device *dev, struct rtnl_link_stats64 *s);
 
 enum {
 	NESTED_SYNC_IMM_BIT,
diff --git a/net/core/dev.c b/net/core/dev.c
index e1bb6d7856d9..dc77529600ce 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10849,6 +10849,62 @@ void dev_get_tstats64(struct net_device *dev, struct rtnl_link_stats64 *s)
 }
 EXPORT_SYMBOL_GPL(dev_get_tstats64);
 
+/**
+ *	dev_fetch_dstats - collate per-cpu network dstats statistics
+ *	@s: place to store stats
+ *	@dstats: per-cpu network stats to read from
+ *
+ *	Read per-cpu network statistics from dev->dstats and populate the
+ *	related fields in @s.
+ */
+void dev_fetch_dstats(struct rtnl_link_stats64 *s,
+		      const struct pcpu_dstats __percpu *dstats)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		u64 rx_packets, rx_bytes, rx_drops;
+		u64 tx_packets, tx_bytes, tx_drops;
+		const struct pcpu_dstats *dstats;
+		unsigned int start;
+
+		dstats = per_cpu_ptr(dstats, cpu);
+		do {
+			start = u64_stats_fetch_begin(&dstats->syncp);
+			rx_packets = u64_stats_read(&dstats->rx_packets);
+			rx_bytes   = u64_stats_read(&dstats->rx_bytes);
+			rx_drops   = u64_stats_read(&dstats->rx_drops);
+			tx_packets = u64_stats_read(&dstats->tx_packets);
+			tx_bytes   = u64_stats_read(&dstats->tx_bytes);
+			tx_drops   = u64_stats_read(&dstats->tx_drops);
+		} while (u64_stats_fetch_retry(&dstats->syncp, start));
+
+		s->rx_packets += rx_packets;
+		s->rx_bytes   += rx_bytes;
+		s->rx_dropped += rx_drops;
+		s->tx_packets += tx_packets;
+		s->tx_bytes   += tx_bytes;
+		s->tx_dropped += tx_drops;
+	}
+}
+EXPORT_SYMBOL_GPL(dev_fetch_dstats);
+
+/**
+ *	dev_get_dstats64 - ndo_get_stats64 implementation for dtstats-based
+ *	account.
+ *	@dev: device to get statistics from
+ *	@s: place to store stats
+ *
+ *	Populate @s from dev->stats and dev->dstats. Can be used as
+ *	ndo_get_stats64() callback.
+ */
+void dev_get_dstats64(struct net_device *dev, struct rtnl_link_stats64 *s)
+{
+	netdev_stats_to_stats64(s, &dev->stats);
+	dev_fetch_dstats(s, dev->dstats);
+}
+EXPORT_SYMBOL_GPL(dev_get_dstats64);
+
 struct netdev_queue *dev_ingress_queue_create(struct net_device *dev)
 {
 	struct netdev_queue *queue = dev_ingress_queue(dev);

-- 
2.39.2

Re: [PATCH 2/3] net: core: Implement dstats-type stats collections

[kernel test robot]

Hi Jeremy,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 32f88d65f01bf6f45476d7edbe675e44fb9e1d58]

url:    https://github.com/intel-lab-lkp/linux/commits/Jeremy-Kerr/net-core-vrf-Change-pcpu_dstat-fields-to-u64_stats_t/20240605-143942
base:   32f88d65f01bf6f45476d7edbe675e44fb9e1d58
patch link:    https://lore.kernel.org/r/20240605-dstats-v1-2-1024396e1670%40codeconstruct.com.au
patch subject: [PATCH 2/3] net: core: Implement dstats-type stats collections
config: openrisc-defconfig (https://download.01.org/0day-ci/archive/20240605/202406051725.14UkSYbV-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240605/202406051725.14UkSYbV-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406051725.14UkSYbV-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from ./arch/openrisc/include/generated/asm/rwonce.h:1,
                    from include/linux/compiler.h:299,
                    from include/linux/instrumented.h:10,
                    from include/linux/uaccess.h:6,
                    from net/core/dev.c:71:
   In function '__seqprop_sequence',
       inlined from '__u64_stats_fetch_begin' at include/linux/u64_stats_sync.h:171:9,
       inlined from 'u64_stats_fetch_begin' at include/linux/u64_stats_sync.h:208:9,
       inlined from 'dev_fetch_dstats' at net/core/dev.c:10873:12:
>> include/asm-generic/rwonce.h:44:26: warning: 'dstats' is used uninitialized [-Wuninitialized]
      44 | #define __READ_ONCE(x)  (*(const volatile __unqual_scalar_typeof(x) *)&(x))
         |                         ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/asm-generic/rwonce.h:50:9: note: in expansion of macro '__READ_ONCE'
      50 |         __READ_ONCE(x);                                                 \
         |         ^~~~~~~~~~~
   include/linux/seqlock.h:211:16: note: in expansion of macro 'READ_ONCE'
     211 |         return READ_ONCE(s->sequence);
         |                ^~~~~~~~~
   net/core/dev.c: In function 'dev_fetch_dstats':
   net/core/dev.c:10868:43: note: 'dstats' was declared here
   10868 |                 const struct pcpu_dstats *dstats;
         |                                           ^~~~~~


vim +/dstats +44 include/asm-generic/rwonce.h

e506ea451254ab Will Deacon 2019-10-15  28  
e506ea451254ab Will Deacon 2019-10-15  29  /*
e506ea451254ab Will Deacon 2019-10-15  30   * Yes, this permits 64-bit accesses on 32-bit architectures. These will
e506ea451254ab Will Deacon 2019-10-15  31   * actually be atomic in some cases (namely Armv7 + LPAE), but for others we
e506ea451254ab Will Deacon 2019-10-15  32   * rely on the access being split into 2x32-bit accesses for a 32-bit quantity
e506ea451254ab Will Deacon 2019-10-15  33   * (e.g. a virtual address) and a strong prevailing wind.
e506ea451254ab Will Deacon 2019-10-15  34   */
e506ea451254ab Will Deacon 2019-10-15  35  #define compiletime_assert_rwonce_type(t)					\
e506ea451254ab Will Deacon 2019-10-15  36  	compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long),	\
e506ea451254ab Will Deacon 2019-10-15  37  		"Unsupported access size for {READ,WRITE}_ONCE().")
e506ea451254ab Will Deacon 2019-10-15  38  
e506ea451254ab Will Deacon 2019-10-15  39  /*
e506ea451254ab Will Deacon 2019-10-15  40   * Use __READ_ONCE() instead of READ_ONCE() if you do not require any
3c9184109e78ea Will Deacon 2019-10-30  41   * atomicity. Note that this may result in tears!
e506ea451254ab Will Deacon 2019-10-15  42   */
b78b331a3f5c07 Will Deacon 2019-10-15  43  #ifndef __READ_ONCE
e506ea451254ab Will Deacon 2019-10-15 @44  #define __READ_ONCE(x)	(*(const volatile __unqual_scalar_typeof(x) *)&(x))
b78b331a3f5c07 Will Deacon 2019-10-15  45  #endif
e506ea451254ab Will Deacon 2019-10-15  46  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 2/3] net: core: Implement dstats-type stats collections

[kernel test robot]

Hi Jeremy,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 32f88d65f01bf6f45476d7edbe675e44fb9e1d58]

url:    https://github.com/intel-lab-lkp/linux/commits/Jeremy-Kerr/net-core-vrf-Change-pcpu_dstat-fields-to-u64_stats_t/20240605-143942
base:   32f88d65f01bf6f45476d7edbe675e44fb9e1d58
patch link:    https://lore.kernel.org/r/20240605-dstats-v1-2-1024396e1670%40codeconstruct.com.au
patch subject: [PATCH 2/3] net: core: Implement dstats-type stats collections
config: um-allmodconfig (https://download.01.org/0day-ci/archive/20240605/202406051710.KozBBK8o-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project d7d2d4f53fc79b4b58e8d8d08151b577c3699d4a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240605/202406051710.KozBBK8o-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406051710.KozBBK8o-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from net/core/dev.c:80:
   In file included from include/linux/sched/isolation.h:5:
   In file included from include/linux/cpuset.h:17:
   In file included from include/linux/mm.h:2253:
   include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   In file included from net/core/dev.c:80:
   In file included from include/linux/sched/isolation.h:7:
   In file included from include/linux/tick.h:8:
   In file included from include/linux/clockchips.h:14:
   In file included from include/linux/clocksource.h:22:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     548 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     561 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from net/core/dev.c:80:
   In file included from include/linux/sched/isolation.h:7:
   In file included from include/linux/tick.h:8:
   In file included from include/linux/clockchips.h:14:
   In file included from include/linux/clocksource.h:22:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     574 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from net/core/dev.c:80:
   In file included from include/linux/sched/isolation.h:7:
   In file included from include/linux/tick.h:8:
   In file included from include/linux/clockchips.h:14:
   In file included from include/linux/clocksource.h:22:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     585 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     595 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     605 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:693:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     693 |         readsb(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:701:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     701 |         readsw(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:709:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     709 |         readsl(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:718:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     718 |         writesb(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:727:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     727 |         writesw(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:736:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     736 |         writesl(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
>> net/core/dev.c:10871:24: warning: variable 'dstats' is uninitialized when used here [-Wuninitialized]
    10871 |                 dstats = per_cpu_ptr(dstats, cpu);
          |                                      ^~~~~~
   include/linux/percpu-defs.h:263:65: note: expanded from macro 'per_cpu_ptr'
     263 | #define per_cpu_ptr(ptr, cpu)   ({ (void)(cpu); VERIFY_PERCPU_PTR(ptr); })
         |                                                                   ^~~
   include/linux/percpu-defs.h:260:38: note: expanded from macro 'VERIFY_PERCPU_PTR'
     260 |         (typeof(*(__p)) __kernel __force *)(__p);                       \
         |                                             ^~~
   net/core/dev.c:10868:35: note: initialize the variable 'dstats' to silence this warning
    10868 |                 const struct pcpu_dstats *dstats;
          |                                                 ^
          |                                                  = NULL
   net/core/dev.c:4128:1: warning: unused function 'sch_handle_ingress' [-Wunused-function]
    4128 | sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret,
         | ^~~~~~~~~~~~~~~~~~
   net/core/dev.c:4135:1: warning: unused function 'sch_handle_egress' [-Wunused-function]
    4135 | sch_handle_egress(struct sk_buff *skb, int *ret, struct net_device *dev)
         | ^~~~~~~~~~~~~~~~~
   net/core/dev.c:5392:19: warning: unused function 'nf_ingress' [-Wunused-function]
    5392 | static inline int nf_ingress(struct sk_buff *skb, struct packet_type **pt_prev,
         |                   ^~~~~~~~~~
   17 warnings generated.


vim +/dstats +10871 net/core/dev.c

 10851	
 10852	/**
 10853	 *	dev_fetch_dstats - collate per-cpu network dstats statistics
 10854	 *	@s: place to store stats
 10855	 *	@dstats: per-cpu network stats to read from
 10856	 *
 10857	 *	Read per-cpu network statistics from dev->dstats and populate the
 10858	 *	related fields in @s.
 10859	 */
 10860	void dev_fetch_dstats(struct rtnl_link_stats64 *s,
 10861			      const struct pcpu_dstats __percpu *dstats)
 10862	{
 10863		int cpu;
 10864	
 10865		for_each_possible_cpu(cpu) {
 10866			u64 rx_packets, rx_bytes, rx_drops;
 10867			u64 tx_packets, tx_bytes, tx_drops;
 10868			const struct pcpu_dstats *dstats;
 10869			unsigned int start;
 10870	
 10871			dstats = per_cpu_ptr(dstats, cpu);
 10872			do {
 10873				start = u64_stats_fetch_begin(&dstats->syncp);
 10874				rx_packets = u64_stats_read(&dstats->rx_packets);
 10875				rx_bytes   = u64_stats_read(&dstats->rx_bytes);
 10876				rx_drops   = u64_stats_read(&dstats->rx_drops);
 10877				tx_packets = u64_stats_read(&dstats->tx_packets);
 10878				tx_bytes   = u64_stats_read(&dstats->tx_bytes);
 10879				tx_drops   = u64_stats_read(&dstats->tx_drops);
 10880			} while (u64_stats_fetch_retry(&dstats->syncp, start));
 10881	
 10882			s->rx_packets += rx_packets;
 10883			s->rx_bytes   += rx_bytes;
 10884			s->rx_dropped += rx_drops;
 10885			s->tx_packets += tx_packets;
 10886			s->tx_bytes   += tx_bytes;
 10887			s->tx_dropped += tx_drops;
 10888		}
 10889	}
 10890	EXPORT_SYMBOL_GPL(dev_fetch_dstats);
 10891	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 2/3] net: core: Implement dstats-type stats collections

[kernel test robot]

Hi Jeremy,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 32f88d65f01bf6f45476d7edbe675e44fb9e1d58]

url:    https://github.com/intel-lab-lkp/linux/commits/Jeremy-Kerr/net-core-vrf-Change-pcpu_dstat-fields-to-u64_stats_t/20240605-143942
base:   32f88d65f01bf6f45476d7edbe675e44fb9e1d58
patch link:    https://lore.kernel.org/r/20240605-dstats-v1-2-1024396e1670%40codeconstruct.com.au
patch subject: [PATCH 2/3] net: core: Implement dstats-type stats collections
config: x86_64-randconfig-121-20240606 (https://download.01.org/0day-ci/archive/20240606/202406060345.LfJ8GAJM-lkp@intel.com/config)
compiler: gcc-13 (Ubuntu 13.2.0-4ubuntu3) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240606/202406060345.LfJ8GAJM-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406060345.LfJ8GAJM-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
   net/core/dev.c:3379:23: sparse: sparse: incorrect type in argument 4 (different base types) @@     expected restricted __wsum [usertype] csum @@     got unsigned int @@
   net/core/dev.c:3379:23: sparse:     expected restricted __wsum [usertype] csum
   net/core/dev.c:3379:23: sparse:     got unsigned int
   net/core/dev.c:3379:23: sparse: sparse: cast from restricted __wsum
>> net/core/dev.c:10871:26: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected void const [noderef] __percpu *__vpp_verify @@     got struct pcpu_dstats const * @@
   net/core/dev.c:10871:26: sparse:     expected void const [noderef] __percpu *__vpp_verify
   net/core/dev.c:10871:26: sparse:     got struct pcpu_dstats const *
   net/core/dev.c:3819:17: sparse: sparse: context imbalance in '__dev_queue_xmit' - different lock contexts for basic block
   net/core/dev.c:5257:17: sparse: sparse: context imbalance in 'net_tx_action' - different lock contexts for basic block

vim +10871 net/core/dev.c

 10851	
 10852	/**
 10853	 *	dev_fetch_dstats - collate per-cpu network dstats statistics
 10854	 *	@s: place to store stats
 10855	 *	@dstats: per-cpu network stats to read from
 10856	 *
 10857	 *	Read per-cpu network statistics from dev->dstats and populate the
 10858	 *	related fields in @s.
 10859	 */
 10860	void dev_fetch_dstats(struct rtnl_link_stats64 *s,
 10861			      const struct pcpu_dstats __percpu *dstats)
 10862	{
 10863		int cpu;
 10864	
 10865		for_each_possible_cpu(cpu) {
 10866			u64 rx_packets, rx_bytes, rx_drops;
 10867			u64 tx_packets, tx_bytes, tx_drops;
 10868			const struct pcpu_dstats *dstats;
 10869			unsigned int start;
 10870	
 10871			dstats = per_cpu_ptr(dstats, cpu);
 10872			do {
 10873				start = u64_stats_fetch_begin(&dstats->syncp);
 10874				rx_packets = u64_stats_read(&dstats->rx_packets);
 10875				rx_bytes   = u64_stats_read(&dstats->rx_bytes);
 10876				rx_drops   = u64_stats_read(&dstats->rx_drops);
 10877				tx_packets = u64_stats_read(&dstats->tx_packets);
 10878				tx_bytes   = u64_stats_read(&dstats->tx_bytes);
 10879				tx_drops   = u64_stats_read(&dstats->tx_drops);
 10880			} while (u64_stats_fetch_retry(&dstats->syncp, start));
 10881	
 10882			s->rx_packets += rx_packets;
 10883			s->rx_bytes   += rx_bytes;
 10884			s->rx_dropped += rx_drops;
 10885			s->tx_packets += tx_packets;
 10886			s->tx_bytes   += tx_bytes;
 10887			s->tx_dropped += tx_drops;
 10888		}
 10889	}
 10890	EXPORT_SYMBOL_GPL(dev_fetch_dstats);
 10891	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 2/3] net: core: Implement dstats-type stats collections

[Dan Carpenter]

Hi Jeremy,

kernel test robot noticed the following build warnings:

url:    https://github.com/intel-lab-lkp/linux/commits/Jeremy-Kerr/net-core-vrf-Change-pcpu_dstat-fields-to-u64_stats_t/20240605-143942
base:   32f88d65f01bf6f45476d7edbe675e44fb9e1d58
patch link:    https://lore.kernel.org/r/20240605-dstats-v1-2-1024396e1670%40codeconstruct.com.au
patch subject: [PATCH 2/3] net: core: Implement dstats-type stats collections
config: x86_64-randconfig-161-20240606 (https://download.01.org/0day-ci/archive/20240606/202406061253.ZgaLHWWp-lkp@intel.com/config)
compiler: gcc-13 (Ubuntu 13.2.0-4ubuntu3) 13.2.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202406061253.ZgaLHWWp-lkp@intel.com/

smatch warnings:
net/core/dev.c:10871 dev_fetch_dstats() error: uninitialized symbol 'dstats'.

vim +/dstats +10871 net/core/dev.c

85bc70c64e8362d Jeremy Kerr     2024-06-05  10860  void dev_fetch_dstats(struct rtnl_link_stats64 *s,
85bc70c64e8362d Jeremy Kerr     2024-06-05  10861  		      const struct pcpu_dstats __percpu *dstats)
                                                                                                         ^^^^^^

85bc70c64e8362d Jeremy Kerr     2024-06-05  10862  {
85bc70c64e8362d Jeremy Kerr     2024-06-05  10863  	int cpu;
85bc70c64e8362d Jeremy Kerr     2024-06-05  10864  
85bc70c64e8362d Jeremy Kerr     2024-06-05  10865  	for_each_possible_cpu(cpu) {
85bc70c64e8362d Jeremy Kerr     2024-06-05  10866  		u64 rx_packets, rx_bytes, rx_drops;
85bc70c64e8362d Jeremy Kerr     2024-06-05  10867  		u64 tx_packets, tx_bytes, tx_drops;
85bc70c64e8362d Jeremy Kerr     2024-06-05  10868  		const struct pcpu_dstats *dstats;
                                                                                          ^^^^^^
Don't declare a local dstats which shadows the function scope variable.

85bc70c64e8362d Jeremy Kerr     2024-06-05  10869  		unsigned int start;
85bc70c64e8362d Jeremy Kerr     2024-06-05  10870  
85bc70c64e8362d Jeremy Kerr     2024-06-05 @10871  		dstats = per_cpu_ptr(dstats, cpu);
85bc70c64e8362d Jeremy Kerr     2024-06-05  10872  		do {
85bc70c64e8362d Jeremy Kerr     2024-06-05  10873  			start = u64_stats_fetch_begin(&dstats->syncp);
85bc70c64e8362d Jeremy Kerr     2024-06-05  10874  			rx_packets = u64_stats_read(&dstats->rx_packets);
85bc70c64e8362d Jeremy Kerr     2024-06-05  10875  			rx_bytes   = u64_stats_read(&dstats->rx_bytes);
85bc70c64e8362d Jeremy Kerr     2024-06-05  10876  			rx_drops   = u64_stats_read(&dstats->rx_drops);
85bc70c64e8362d Jeremy Kerr     2024-06-05  10877  			tx_packets = u64_stats_read(&dstats->tx_packets);
85bc70c64e8362d Jeremy Kerr     2024-06-05  10878  			tx_bytes   = u64_stats_read(&dstats->tx_bytes);
85bc70c64e8362d Jeremy Kerr     2024-06-05  10879  			tx_drops   = u64_stats_read(&dstats->tx_drops);
85bc70c64e8362d Jeremy Kerr     2024-06-05  10880  		} while (u64_stats_fetch_retry(&dstats->syncp, start));
85bc70c64e8362d Jeremy Kerr     2024-06-05  10881  
85bc70c64e8362d Jeremy Kerr     2024-06-05  10882  		s->rx_packets += rx_packets;
85bc70c64e8362d Jeremy Kerr     2024-06-05  10883  		s->rx_bytes   += rx_bytes;
85bc70c64e8362d Jeremy Kerr     2024-06-05  10884  		s->rx_dropped += rx_drops;
85bc70c64e8362d Jeremy Kerr     2024-06-05  10885  		s->tx_packets += tx_packets;
85bc70c64e8362d Jeremy Kerr     2024-06-05  10886  		s->tx_bytes   += tx_bytes;
85bc70c64e8362d Jeremy Kerr     2024-06-05  10887  		s->tx_dropped += tx_drops;
85bc70c64e8362d Jeremy Kerr     2024-06-05  10888  	}
85bc70c64e8362d Jeremy Kerr     2024-06-05  10889  }

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH 3/3] net: vrf: move to generic dstat helpers

[Jeremy Kerr]

The vrf driver has its own dstats-to-rtnl_link_stats64 collection, but
we now have a generic helper for this.

Switch to the generic helper.

In doing so, we fix a minor issue where the (non-percpu)
dev->stats->tx_errors value was never collected into rtnl_link_stats64,
as the generic dev_get_dstats64() consumes the starting values from
dev->stats.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
---
 drivers/net/vrf.c | 29 +----------------------------
 1 file changed, 1 insertion(+), 28 deletions(-)

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 088732871b27..19d4bd25aca6 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -137,33 +137,6 @@ static void vrf_tx_error(struct net_device *vrf_dev, struct sk_buff *skb)
 	kfree_skb(skb);
 }
 
-static void vrf_get_stats64(struct net_device *dev,
-			    struct rtnl_link_stats64 *stats)
-{
-	int i;
-
-	for_each_possible_cpu(i) {
-		const struct pcpu_dstats *dstats;
-		u64 tbytes, tpkts, tdrops, rbytes, rpkts;
-		unsigned int start;
-
-		dstats = per_cpu_ptr(dev->dstats, i);
-		do {
-			start = u64_stats_fetch_begin(&dstats->syncp);
-			tbytes = u64_stats_read(&dstats->tx_bytes);
-			tpkts = u64_stats_read(&dstats->tx_packets);
-			tdrops = u64_stats_read(&dstats->tx_drops);
-			rbytes = u64_stats_read(&dstats->rx_bytes);
-			rpkts = u64_stats_read(&dstats->rx_packets);
-		} while (u64_stats_fetch_retry(&dstats->syncp, start));
-		stats->tx_bytes += tbytes;
-		stats->tx_packets += tpkts;
-		stats->tx_dropped += tdrops;
-		stats->rx_bytes += rbytes;
-		stats->rx_packets += rpkts;
-	}
-}
-
 static struct vrf_map *netns_vrf_map(struct net *net)
 {
 	struct netns_vrf *nn_vrf = net_generic(net, vrf_net_id);
@@ -1196,7 +1169,7 @@ static const struct net_device_ops vrf_netdev_ops = {
 	.ndo_uninit		= vrf_dev_uninit,
 	.ndo_start_xmit		= vrf_xmit,
 	.ndo_set_mac_address	= eth_mac_addr,
-	.ndo_get_stats64	= vrf_get_stats64,
+	.ndo_get_stats64	= dev_get_dstats64,
 	.ndo_add_slave		= vrf_add_slave,
 	.ndo_del_slave		= vrf_del_slave,
 };

-- 
2.39.2