linux-stable.git/kernel/rcu, branch v4.16.2

Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

2018-01-31T19:23:28+00:00

Pull SCSI updates from James Bottomley:
 "This is mostly updates of the usual driver suspects: arcmsr,
  scsi_debug, mpt3sas, lpfc, cxlflash, qla2xxx, aacraid, megaraid_sas,
  hisi_sas.

  We also have a rework of the libsas hotplug handling to make it more
  robust, a slew of 32 bit time conversions and fixes, and a host of the
  usual minor updates and style changes. The biggest potential for
  regressions is the libsas hotplug changes, but so far they seem stable
  under testing"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (313 commits)
  scsi: qla2xxx: Fix logo flag for qlt_free_session_done()
  scsi: arcmsr: avoid do_gettimeofday
  scsi: core: Add VENDOR_SPECIFIC sense code definitions
  scsi: qedi: Drop cqe response during connection recovery
  scsi: fas216: fix sense buffer initialization
  scsi: ibmvfc: Remove unneeded semicolons
  scsi: hisi_sas: fix a bug in hisi_sas_dev_gone()
  scsi: hisi_sas: directly attached disk LED feature for v2 hw
  scsi: hisi_sas: devicetree: bindings: add LED feature for v2 hw
  scsi: megaraid_sas: NVMe passthrough command support
  scsi: megaraid: use ktime_get_real for firmware time
  scsi: fnic: use 64-bit timestamps
  scsi: qedf: Fix error return code in __qedf_probe()
  scsi: devinfo: fix format of the device list
  scsi: qla2xxx: Update driver version to 10.00.00.05-k
  scsi: qla2xxx: Add XCB counters to debugfs
  scsi: qla2xxx: Fix queue ID for async abort with Multiqueue
  scsi: qla2xxx: Fix warning for code intentation in __qla24xx_handle_gpdb_event()
  scsi: qla2xxx: Fix warning during port_name debug print
  scsi: qla2xxx: Fix warning in qla2x00_async_iocb_timeout()
  ...

Merge branches 'cond_resched.2017.12.04a', 'dyntick.2017.11.28a', 'fixes.2017.12.11a', 'srbd.2017.12.05a' and 'torture.2017.12.11a' into HEAD

2017-12-11T17:21:58+00:00

cond_resched.2017.12.04a: Convert cond_resched_rcu_qs() to cond_resched()
dyntick.2017.11.28a: Make RCU dynticks handle interrupts from NMI
fixes.2017.12.11a: Miscellaneous fixes
srbd.2017.12.05a: Remove now-redundant smp_read_barrier_depends()
torture.2017.12.11a: Torture-testing update

torture: Eliminate torture_runnable and perf_runnable

2017-12-11T17:18:29+00:00

The purpose of torture_runnable is to allow rcutorture and locktorture
to be started and stopped via sysfs when they are built into the kernel
(as in not compiled as loadable modules).  However, the 0444 permissions
for both instances of torture_runnable prevent this use case from ever
being put into practice.  Given that there have been no complaints
about this deficiency, it is reasonable to conclude that no one actually
makes use of this sysfs capability.  The perf_runnable module parameter
for rcuperf is in the same situation.

This commit therefore removes both torture_runnable instances as well
as perf_runnable.

Reported-by: Thomas Gleixner 
Signed-off-by: Paul E. McKenney

rcutorture: Preempt RCU-preempt readers more vigorously

2017-12-11T17:18:22+00:00

This commit attempts to make a very rare rcutorture failure happen
more often by increasing the fraction of RCU-preempt read-side critical
sections that are preempted.

Signed-off-by: Paul E. McKenney

torture: Reduce #ifdefs for preempt_schedule()

2017-12-11T17:18:22+00:00

This commit adds a torture_preempt_schedule() that is nothingness
in !PREEMPT builds and is preempt_schedule() otherwise.  Then
torture_preempt_schedule() is used to eliminate several ugly #ifdefs,
both in rcutorture and in locktorture.

Signed-off-by: Paul E. McKenney

rcu: Remove have_rcu_nocb_mask from tree_plugin.h

2017-12-11T17:17:40+00:00

Currently have_rcu_nocb_mask is used to avoid double allocation of
rcu_nocb_mask during boot up. Due to different representation of
cpumask_var_t on different kernel config CPUMASK=y(or n) it was okay.
But now we have a helper cpumask_available(), which can be utilized
to check whether rcu_nocb_mask has been allocated or not without using
a variable.

Removing the variable also reduces vmlinux size.

Unpatched version:
text	   data	    bss	    dec	    hex	filename
13050393	7852470	14543408	35446271	21cddff	vmlinux

Patched version:
 text	   data	    bss	    dec	    hex	filename
13050390	7852438	14543408	35446236	21cdddc	vmlinux

Signed-off-by: Rakib Mullick 
Cc: "Paul E. McKenney" 
Cc: Josh Triplett 
Cc: Steven Rostedt 
Cc: Mathieu Desnoyers 
Cc: Lai Jiangshan 
Signed-off-by: Paul E. McKenney

rcu: Add comment giving debug strategy for double call_rcu()

2017-12-11T17:17:39+00:00

The following statement has for some reason proven non-intuitive:

	WARN_ON_ONCE(rcu_segcblist_empty(&rdp->cblist) != (count == 0));

This commit therefore adds a comment that states that this warning
usually triggers in response to a double call_rcu(), which is sort
of like a double free.  The comment also suggests building with
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y to track down the double call_rcu().

Reported-by: David Howells 
Signed-off-by: Paul E. McKenney

rcu: Export init_rcu_head() and destroy_rcu_head() to GPL modules

2017-12-08T00:51:49+00:00

Use of init_rcu_head() and destroy_rcu_head() from modules results in
the following build-time error with CONFIG_DEBUG_OBJECTS_RCU_HEAD=y:

	ERROR: "init_rcu_head" [drivers/scsi/scsi_mod.ko] undefined!
	ERROR: "destroy_rcu_head" [drivers/scsi/scsi_mod.ko] undefined!

This commit therefore adds EXPORT_SYMBOL_GPL() for each to allow them to
be used by GPL-licensed kernel modules.

Reported-by: Bart Van Assche 
Reported-by: Stephen Rothwell 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Martin K. Petersen

srcu: Prohibit call_srcu() use under raw spinlocks

2017-11-28T23:52:33+00:00

Invoking queue_delayed_work() while holding a raw spinlock is forbidden
in -rt kernels, which is exactly what __call_srcu() does, indirectly via
srcu_funnel_gp_start().  This commit therefore downgrades Tree SRCU's
locking from raw to non-raw spinlocks, which works because call_srcu()
is not ever called while holding a raw spinlock.

Reported-by: Sebastian Andrzej Siewior 
Signed-off-by: Paul E. McKenney

rcu: Simplify rcu_eqs_{enter,exit}() non-idle task debug code

2017-11-28T23:51:21+00:00

The code that checks for non-idle non-nohz_idle-usermode tasks invoking
rcu_eqs_enter() and rcu_eqs_exit() prints a considerable quantity of
helpful information.  However, these checks fire rarely, so the extra
complexity is no longer worth it.  This commit therefore replaces this
debug code with simple WARN_ON_ONCE() statements.

Signed-off-by: Paul E. McKenney