linux-toradex.git/include/linux/rculist.h, branch v4.4.93

rculist: Make list_entry_rcu() use lockless_dereference()

2015-10-06T18:16:18+00:00

The current list_entry_rcu() implementation copies the pointer to a stack
variable, then invokes rcu_dereference_raw() on it.  This results in an
additional store-load pair.  Now, most compilers will emit normal store
and load instructions, which might seem to be of negligible overhead,
but this results in a load-hit-store situation that can cause surprisingly
long pipeline stalls, even on modern microprocessors.  The problem is
that it takes time for the store to get the store buffer updated, which
can delay the subsequent load, which immediately follows.

This commit therefore switches to the lockless_dereference() primitive,
which does not expect the __rcu annotations (that are anyway not present
in the list_head structure) and which, like rcu_dereference_raw(),
does not check for an enclosing RCU read-side critical section.
Most importantly, it does not copy the pointer, thus avoiding the
load-hit-store overhead.

Signed-off-by: Patrick Marlier 
[ paulmck: Switched to lockless_dereference() to suppress sparse warnings. ]
Signed-off-by: Paul E. McKenney 
Reviewed-by: Josh Triplett

rculist: Fix another sparse warning

2015-05-27T19:58:04+00:00

This fixes the following sparse warnings:

make C=1 CF=-D__CHECK_ENDIAN__ net/tipc/name_table.o
net/tipc/name_table.c:977:17: error: incompatible types in comparison expression (different address spaces)
net/tipc/name_table.c:977:17: error: incompatible types in comparison expression (different address spaces)

To silence these spare complaints, an RCU annotation should be added to
"next" pointer of hlist_node structure through hlist_next_rcu() macro
when iterating over a hlist with hlist_for_each_entry_from_rcu().

Signed-off-by: Ying Xue 
Signed-off-by: Paul E. McKenney

rcu: Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()

2015-05-27T19:56:15+00:00

This commit moves from the old ACCESS_ONCE() API to the new READ_ONCE()
and WRITE_ONCE() APIs.

Signed-off-by: Paul E. McKenney 
[ paulmck:  Updated to include kernel/torture.c as suggested by Jason Low. ]

rculist: Fix sparse warning

2015-01-06T19:01:13+00:00

This fixes the following sparse warnings:

make C=1 CF=-D__CHECK_ENDIAN__ net/ipv6/addrconf.o
net/ipv6/addrconf.c:3495:9: error: incompatible types in comparison expression (different address spaces)
net/ipv6/addrconf.c:3495:9: error: incompatible types in comparison expression (different address spaces)
net/ipv6/addrconf.c:3495:9: error: incompatible types in comparison expression (different address spaces)
net/ipv6/addrconf.c:3495:9: error: incompatible types in comparison expression (different address spaces)

To silence these spare complaints, an RCU annotation should be added to
"next" pointer of hlist_node structure through hlist_next_rcu() macro
when iterating over a hlist with hlist_for_each_entry_continue_rcu_bh().

By the way, this commit also resolves the same error appearing in
hlist_for_each_entry_continue_rcu().

Signed-off-by: Ying Xue 
Signed-off-by: Paul E. McKenney

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2014-12-12T18:08:06+00:00

Pull trivial tree update from Jiri Kosina:
 "Usual stuff: documentation updates, printk() fixes, etc"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (24 commits)
  intel_ips: fix a type in error message
  cpufreq: cpufreq-dt: Move newline to end of error message
  ps3rom: fix error return code
  treewide: fix typo in printk and Kconfig
  ARM: dts: bcm63138: change "interupts" to "interrupts"
  Replace mentions of "list_struct" to "list_head"
  kernel: trace: fix printk message
  scsi: mpt2sas: fix ioctl in comment
  zbud, zswap: change module author email
  clocksource: Fix 'clcoksource' typo in comment
  arm: fix wording of "Crotex" in CONFIG_ARCH_EXYNOS3 help
  gpio: msm-v1: make boolean argument more obvious
  usb: Fix typo in usb-serial-simple.c
  PCI: Fix comment typo 'COMFIG_PM_OPS'
  powerpc: Fix comment typo 'CONIFG_8xx'
  powerpc: Fix comment typos 'CONFiG_ALTIVEC'
  clk: st: Spelling s/stucture/structure/
  isci: Spelling s/stucture/structure/
  usb: gadget: zero: Spelling s/infrastucture/infrastructure/
  treewide: Fix company name in module descriptions
  ...

tipc: convert name table read-write lock to RCU

2014-12-09T01:39:57+00:00

Convert tipc name table read-write lock to RCU. After this change,
a new spin lock is used to protect name table on write side while
RCU is applied on read side.

Signed-off-by: Ying Xue 
Reviewed-by: Erik Hugne 
Reviewed-by: Jon Maloy 
Tested-by: Erik Hugne 
Signed-off-by: David S. Miller

Replace mentions of "list_struct" to "list_head"

2014-11-20T13:45:15+00:00

There's no such thing as "list_struct".

Signed-off-by: Andrey Utkin 
Acked-by: Steven Rostedt 
Acked-by: Mauro Carvalho Chehab 
Acked-by: Paul E. McKenney 
Acked-by: Alex Deucher 
Signed-off-by: Jiri Kosina

list: fix order of arguments for hlist_add_after(_rcu)

2014-08-07T01:01:24+00:00

All other add functions for lists have the new item as first argument
and the position where it is added as second argument.  This was changed
for no good reason in this function and makes using it unnecessary
confusing.

The name was changed to hlist_add_behind() to cause unconverted code to
generate a compile error instead of using the wrong parameter order.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Ken Helias 
Cc: "Paul E. McKenney" 
Acked-by: Jeff Kirsher 	[intel driver bits]
Cc: Hugh Dickins 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rcu: Indentation and spacing fixes.

2014-02-17T23:01:52+00:00

This commit outdents expression-statement macros, thus repairing a few
line-length complaints.  Also fix some spacing errors called out by
checkpatch.pl.

Signed-off-by: Joe Perches 
Signed-off-by: Paul E. McKenney 
Reviewed-by: Josh Triplett

rcu: Remove "extern" from function declarations in include/linux/rcu.h

2013-12-12T20:34:16+00:00

Function prototypes don't need to have the "extern" keyword since this
is the default behavior. Its explicit use is redundant.  This commit
therefore removes them.

Signed-off-by: Teodora Baluta 
Signed-off-by: Paul E. McKenney