4 Commits

Author SHA1 Message Date
Thomas Gleixner
a53b59ece8 net: enic: Cure the enic api locking trainwreck
enic_dev_wait() has a BUG_ON(in_interrupt()).

Chasing the callers of enic_dev_wait() revealed the gems of enic_reset()
and enic_tx_hang_reset() which are both invoked through work queues in
order to be able to call rtnl_lock(). So far so good.

After locking rtnl both functions acquire enic::enic_api_lock which
serializes against the (ab)use from infiniband. This is where the
trainwreck starts.

enic::enic_api_lock is a spin_lock() which implicitly disables preemption,
but both functions invoke a ton of functions under that lock which can
sleep. The BUG_ON(in_interrupt()) does not trigger in that case because it
can't detect the preempt disabled condition.

This clearly has never been tested with any of the mandatory debug options
for 7+ years, which would have caught that for sure.

Cure it by adding a enic_api_busy member to struct enic, which is modified
and evaluated with enic::enic_api_lock held.

If enic_api_devcmd_proxy_by_index() observes enic::enic_api_busy as true,
it drops enic::enic_api_lock and busy waits for enic::enic_api_busy to
become false.

It would be smarter to wait for a completion of that busy period, but
enic_api_devcmd_proxy_by_index() is called with other spin locks held which
obviously can't sleep.

Remove the BUG_ON(in_interrupt()) check as well because it's incomplete and
with proper debugging enabled the problem would have been caught from the
debug checks in schedule_timeout().

Fixes: 0b038566c0ea ("drivers/net: enic: Add an interface for USNIC to interact with firmware")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-29 14:02:53 -07:00
Jesse Brandeburg
d0ea5cbdc2 drivers/net/ethernet: clean up mis-targeted comments
As part of the W=1 cleanups for ethernet, a million [*] driver
comments had to be cleaned up to get the W=1 compilation to
succeed. This change finally makes the drivers/net/ethernet tree
compile with W=1 set on the command line. NOTE: The kernel uses
kdoc style (see Documentation/process/kernel-doc.rst) when
documenting code, not doxygen or other styles.

After this patch the x86_64 build has no warnings from W=1, however
scripts/kernel-doc says there are 1545 more warnings in source files, that
I need to develop a script to fix in a followup patch.

The errors fixed here are all kdoc of a few classes, with a few outliers:
In file included from drivers/net/ethernet/qlogic/netxen/netxen_nic_hw.c:10:
drivers/net/ethernet/qlogic/netxen/netxen_nic.h:1193:18: warning: ‘FW_DUMP_LEVELS’ defined but not used [-Wunused-const-variable=]
 1193 | static const u32 FW_DUMP_LEVELS[] = { 0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff };
      |                  ^~~~~~~~~~~~~~
... repeats 4 times...
drivers/net/ethernet/sun/cassini.c:2084:24: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body]
 2084 |    RX_USED_ADD(page, i);
drivers/net/ethernet/natsemi/ns83820.c: In function ‘phy_intr’:
drivers/net/ethernet/natsemi/ns83820.c:603:6: warning: variable ‘tbisr’ set but not used [-Wunused-but-set-variable]
  603 |  u32 tbisr, tanar, tanlpar;
      |      ^~~~~
drivers/net/ethernet/natsemi/ns83820.c: In function ‘ns83820_get_link_ksettings’:
drivers/net/ethernet/natsemi/ns83820.c:1207:11: warning: variable ‘tanar’ set but not used [-Wunused-but-set-variable]
 1207 |  u32 cfg, tanar, tbicr;
      |           ^~~~~
drivers/net/ethernet/packetengines/yellowfin.c:1063:18: warning: variable ‘yf_size’ set but not used [-Wunused-but-set-variable]
 1063 |   int data_size, yf_size;
      |                  ^~~~~~~

Normal kdoc fixes:
warning: Function parameter or member 'x' not described in 'y'
warning: Excess function parameter 'x' description in 'y'
warning: Cannot understand <string> on line <NNN> - I thought it was a doc line

[*] - ok it wasn't quite a million, but it felt like it.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-25 16:29:00 -07:00
Tony Camuso
8e091340cf enic: fix lockdep around devcmd_lock
We were experiencing occasional "BUG: scheduling while atomic" splats
in our testing. Enabling DEBUG_SPINLOCK and DEBUG_LOCKDEP in the kernel
exposed a lockdep in the enic driver.

enic 0000:0b:00.0 eth2: Link UP

======================================================
[ INFO: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected ]
3.12.0-rc1.x86_64-dbg+ #2 Tainted: GF       W
------------------------------------------------------
NetworkManager/4209 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire:
(&(&enic->devcmd_lock)->rlock){+.+...}, at: [<ffffffffa026b7e4>] enic_dev_packet_filter+0x44/0x90 [enic]

The fix was to replace spin_lock with spin_lock_bh for the enic
devcmd_lock, so that soft irqs would be disabled while the lock
is held.

Signed-off-by: Sujith Sankar <ssujith@cisco.com>
Signed-off-by: Tony Camuso <tcamuso@redhat.com>
Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-23 14:32:19 -07:00
Neel Patel
0b038566c0 drivers/net: enic: Add an interface for USNIC to interact with firmware
This patch adds an interface for USNIC to proxy firmware commands
through ENIC.

Signed-off-by: Neel Patel <neepatel@cisco.com>
Signed-off-by: Nishank Trivedi <nistrive@cisco.com>
Signed-off-by: Christian Benvenuti <benve@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-20 13:41:01 -07:00