linux.git/net/core/net-sysfs.c, branch v6.14

net: protect NAPI config fields with netdev_lock()

2025-01-16T03:13:34+00:00

Protect the following members of netdev and napi by netdev_lock:
 - defer_hard_irqs,
 - gro_flush_timeout,
 - irq_suspend_timeout.

The first two are written via sysfs (which this patch switches
to new lock), and netdev genl which holds both netdev and rtnl locks.

irq_suspend_timeout is only written by netdev genl.

Reviewed-by: Joe Damato 
Reviewed-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250115035319.559603-11-kuba@kernel.org
Signed-off-by: Jakub Kicinski

net: protect threaded status of NAPI with netdev_lock()

2025-01-16T03:13:34+00:00

Now that NAPI instances can't come and go without holding
netdev->lock we can trivially switch from rtnl_lock() to
netdev_lock() for setting netdev->threaded via sysfs.

Note that since we do not lock netdev_lock around sysfs
calls in the core we don't have to "trylock" like we do
with rtnl_lock.

Reviewed-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250115035319.559603-9-kuba@kernel.org
Signed-off-by: Jakub Kicinski

net: napi: Make gro_flush_timeout per-NAPI

2024-10-15T00:54:29+00:00

Allow per-NAPI gro_flush_timeout setting.

The existing sysfs parameter is respected; writes to sysfs will write to
all NAPI structs for the device and the net_device gro_flush_timeout
field. Reads from sysfs will read from the net_device field.

The ability to set gro_flush_timeout on specific NAPI instances will be
added in a later commit, via netdev-genl.

Signed-off-by: Joe Damato 
Reviewed-by: Eric Dumazet 
Reviewed-by: Jakub Kicinski 
Link: https://patch.msgid.link/20241011184527.16393-4-jdamato@fastly.com
Signed-off-by: Jakub Kicinski

net: napi: Make napi_defer_hard_irqs per-NAPI

2024-10-15T00:54:28+00:00

Add defer_hard_irqs to napi_struct in preparation for per-NAPI
settings.

The existing sysfs parameter is respected; writes to sysfs will write to
all NAPI structs for the device and the net_device defer_hard_irq field.
Reads from sysfs show the net_device field.

The ability to set defer_hard_irqs on specific NAPI instances will be
added in a later commit, via netdev-genl.

Signed-off-by: Joe Damato 
Reviewed-by: Eric Dumazet 
Reviewed-by: Jakub Kicinski 
Link: https://patch.msgid.link/20241011184527.16393-2-jdamato@fastly.com
Signed-off-by: Jakub Kicinski

net: sysfs: Fix weird usage of class's namespace relevant fields

2024-09-09T09:30:52+00:00

Device class has two namespace relevant fields which are associated by
the following usage:

struct class {
	...
	const struct kobj_ns_type_operations *ns_type;
	const void *(*namespace)(const struct device *dev);
	...
}
if (dev->class && dev->class->ns_type)
	dev->class->namespace(dev);

The usage looks weird since it checks @ns_type but calls namespace()
it is found for all existing class definitions that the other filed is
also assigned once one is assigned in current kernel tree, so fix this
weird usage by checking @namespace to call namespace().

Signed-off-by: Zijun Hu 
Reviewed-by: Simon Horman 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-09-06T03:37:20+00:00

Cross-merge networking fixes after downstream PR.

Conflicts:

drivers/net/phy/phy_device.c
  2560db6ede1a ("net: phy: Fix missing of_node_put() for leds")
  1dce520abd46 ("net: phy: Use for_each_available_child_of_node_scoped()")
https://lore.kernel.org/20240904115823.74333648@canb.auug.org.au

Adjacent changes:

drivers/net/ethernet/xilinx/xilinx_axienet.h
drivers/net/ethernet/xilinx/xilinx_axienet_main.c
  858430db28a5 ("net: xilinx: axienet: Fix race in axienet_stop")
  76abb5d675c4 ("net: xilinx: axienet: Add statistics support")

Signed-off-by: Jakub Kicinski

net: napi: Prevent overflow of napi_defer_hard_irqs

2024-09-06T01:42:56+00:00

In commit 6f8b12d661d0 ("net: napi: add hard irqs deferral feature")
napi_defer_irqs was added to net_device and napi_defer_irqs_count was
added to napi_struct, both as type int.

This value never goes below zero, so there is not reason for it to be a
signed int. Change the type for both from int to u32, and add an
overflow check to sysfs to limit the value to S32_MAX.

The limit of S32_MAX was chosen because the practical limit before this
patch was S32_MAX (anything larger was an overflow) and thus there are
no behavioral changes introduced. If the extra bit is needed in the
future, the limit can be raised.

Before this patch:

$ sudo bash -c 'echo 2147483649 > /sys/class/net/eth4/napi_defer_hard_irqs'
$ cat /sys/class/net/eth4/napi_defer_hard_irqs
-2147483647

After this patch:

$ sudo bash -c 'echo 2147483649 > /sys/class/net/eth4/napi_defer_hard_irqs'
bash: line 0: echo: write error: Numerical result out of range

Similarly, /sys/class/net/XXXXX/tx_queue_len is defined as unsigned:

include/linux/netdevice.h:      unsigned int            tx_queue_len;

And has an overflow check:

dev_change_tx_queue_len(..., unsigned long new_len):

  if (new_len != (unsigned int)new_len)
          return -ERANGE;

Suggested-by: Jakub Kicinski 
Signed-off-by: Joe Damato 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20240904153431.307932-1-jdamato@fastly.com
Signed-off-by: Jakub Kicinski

net: dqs: Do not use extern for unused dql_group

2024-09-03T19:01:38+00:00

When CONFIG_DQL is not enabled, dql_group should be treated as a dead
declaration. However, its current extern declaration assumes the linker
will ignore it, which is generally true across most compiler and
architecture combinations.

But in certain cases, the linker still attempts to resolve the extern
struct, even when the associated code is dead, resulting in a linking
error. For instance the following error in loongarch64:

>> loongarch64-linux-ld: net-sysfs.c:(.text+0x589c): undefined reference to `dql_group'

Modify the declaration of the dead object to be an empty declaration
instead of an extern. This change will prevent the linker from
attempting to resolve an undefined reference.

Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202409012047.eCaOdfQJ-lkp@intel.com/
Fixes: 74293ea1c4db ("net: sysfs: Do not create sysfs for non BQL device")
Signed-off-by: Breno Leitao 
Reviewed-by: Simon Horman 
Tested-by: Simon Horman  # build-tested
Link: https://patch.msgid.link/20240902101734.3260455-1-leitao@debian.org
Signed-off-by: Jakub Kicinski

netdev_features: convert NETIF_F_LLTX to dev->lltx

2024-09-03T09:36:43+00:00

NETIF_F_LLTX can't be changed via Ethtool and is not a feature,
rather an attribute, very similar to IFF_NO_QUEUE (and hot).
Free one netdev_features_t bit and make it a "hot" private flag.

Signed-off-by: Alexander Lobakin 
Signed-off-by: Paolo Abeni

ethtool: check device is present when getting link settings

2024-08-26T21:03:02+00:00

A sysfs reader can race with a device reset or removal, attempting to
read device state when the device is not actually present. eg:

     [exception RIP: qed_get_current_link+17]
  #8 [ffffb9e4f2907c48] qede_get_link_ksettings at ffffffffc07a994a [qede]
  #9 [ffffb9e4f2907cd8] __rh_call_get_link_ksettings at ffffffff992b01a3
 #10 [ffffb9e4f2907d38] __ethtool_get_link_ksettings at ffffffff992b04e4
 #11 [ffffb9e4f2907d90] duplex_show at ffffffff99260300
 #12 [ffffb9e4f2907e38] dev_attr_show at ffffffff9905a01c
 #13 [ffffb9e4f2907e50] sysfs_kf_seq_show at ffffffff98e0145b
 #14 [ffffb9e4f2907e68] seq_read at ffffffff98d902e3
 #15 [ffffb9e4f2907ec8] vfs_read at ffffffff98d657d1
 #16 [ffffb9e4f2907f00] ksys_read at ffffffff98d65c3f
 #17 [ffffb9e4f2907f38] do_syscall_64 at ffffffff98a052fb

 crash> struct net_device.state ffff9a9d21336000
    state = 5,

state 5 is __LINK_STATE_START (0b1) and __LINK_STATE_NOCARRIER (0b100).
The device is not present, note lack of __LINK_STATE_PRESENT (0b10).

This is the same sort of panic as observed in commit 4224cfd7fb65
("net-sysfs: add check for netdevice being present to speed_show").

There are many other callers of __ethtool_get_link_ksettings() which
don't have a device presence check.

Move this check into ethtool to protect all callers.

Fixes: d519e17e2d01 ("net: export device speed and duplex via sysfs")
Fixes: 4224cfd7fb65 ("net-sysfs: add check for netdevice being present to speed_show")
Signed-off-by: Jamie Bainbridge 
Link: https://patch.msgid.link/8bae218864beaa44ed01628140475b9bf641c5b0.1724393671.git.jamie.bainbridge@gmail.com
Signed-off-by: Jakub Kicinski