This allows a list_head (or hlist_head, etc.) to be used from places
that used to be impractical, in particular <asm/processor.h>, which
used to cause include file recursion: <linux/list.h> includes
<linux/prefetch.h>, which always includes <asm/processor.h> for the
prefetch macros, as well as <asm/system.h>, which often includes
<asm/processor.h> directly or indirectly.
This avoids a lot of painful workaround hackery on the tile
architecture, where we use a list_head in the thread_struct to chain
together tasks that are activated on a particular hardwall.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Reviewed-by: Matthew Wilcox <willy@linux.intel.com>
list_for_each_entry_safe is not suitable to protect against concurrent
modification of the list. 6754af6 introduced a race in sb walking.
list_for_each_entry can use the trick of pinning the current entry in
the list before we drop and retake the lock because it subsequently
follows cur->next. However list_for_each_entry_safe saves n=cur->next
for following before entering the loop body, so when the lock is
dropped, n may be deleted.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Frank Mayhar <fmayhar@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bring a new list_rotate_left() helper that rotates a list to
the left. This is useful for codes that need to round roubin
elements which queue priority increases from tail to head.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Daniel J. Blueman reported:
> =======================================================
> [ INFO: possible circular locking dependency detected ]
> 2.6.27-rc4-224c #1
> -------------------------------------------------------
> hald/4680 is trying to acquire lock:
> (&n->list_lock){++..}, at: [<ffffffff802bfa26>] add_partial+0x26/0x80
>
> but task is already holding lock:
> (&obj_hash[i].lock){++..}, at: [<ffffffff8041cfdc>]
> debug_object_free+0x5c/0x120
We fix it by moving the actual freeing to outside the lock (the lock
now only protects the list).
The pool lock is also promoted to irq-safe (suggested by Dan). It's
necessary because free_pool is now called outside the irq disabled
region. So we need to protect against an interrupt handler which calls
debug_object_init().
[tglx@linutronix.de: added hlist_move_list helper to avoid looping
through the list twice]
Reported-by: Daniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Fix fatal multi-line kernel-doc error in list.h:
function short description must be on one line.
Error(linux-2.6.27-rc2-git3//include/linux/list.h:318): duplicate section name 'Description'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds list_cut_position() which lets you cut a list into
two lists given a pivot in the list.
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
If you are using linked lists for queues list_splice() will not do what
you would expect even if you use the elements passed reversed. We need
to handle these differently. We add list_splice_tail() and
list_splice_tail_init().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Remove the conditional surrounding the definition of list_add() from list.h
since, if you define CONFIG_DEBUG_LIST, the definition you will subsequently
pick up from lib/list_debug.c will be absolutely identical, at which point you
can remove that redundant definition from list_debug.c as well.
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move rcu-protected lists from list.h into a new header file rculist.h.
This is done because list are a very used primitive structure all over the
kernel and it's currently impossible to include other header files in this
list.h without creating some circular dependencies.
For example, list.h implements rcu-protected list and uses rcu_dereference()
without including rcupdate.h. It actually compiles because users of
rcu_dereference() are macros. Others RCU functions could be used too but
aren't probably because of this.
Therefore this patch creates rculist.h which includes rcupdates without to
many changes/troubles.
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Josh Triplett <josh@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since neither the list_splice() nor __list_splice() routines modify their
first argument, might as well declare them "const".
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add list_is_singular() to check a list has just one entry.
list_is_singular() is useful to check whether a list_head which have been
temporarily allocated for listing objects can be released or not.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The RCU iterators used 'rcu_dereference()' on an already-fetched RCU
pointer value, which defeats the whole point of the exercise.
When we dereference a pointer protected by RCU, we need to make sure
that we only fetch the value _once_, because if the compiler ends up
re-loading it due to register pressure, the newly reloaded value could
be different from the previously fetched one, and you get inconsistent
results.
Cleaned-up, fixed, and the pointless list_for_each_safe_rcu #define
deleted by Paul Kenney.
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix kernel-api docbook contents problems.
docproc: linux-2.6.23-git13/include/asm-x86/unaligned_32.h: No such file or directory
Warning(linux-2.6.23-git13//include/linux/list.h:482): bad line: of list entry
Warning(linux-2.6.23-git13//mm/filemap.c:864): No description found for parameter 'ra'
Warning(linux-2.6.23-git13//block/ll_rw_blk.c:3760): No description found for parameter 'req'
Warning(linux-2.6.23-git13//include/linux/input.h:1077): No description found for parameter 'private'
Warning(linux-2.6.23-git13//include/linux/input.h:1077): No description found for parameter 'cdev'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: WU Fengguang <wfg@mail.ustc.edu.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch makes shrink_dcache_sb consistent with dentry pruning policy.
On the first pass we iterate over dentry unused list and prepare some
dentries for removal.
However, since the existing code moves evicted dentries to the beginning of
the LRU it can happen that fresh dentries from other superblocks will be
inserted *before* our dentries.
This can result in significant slowdown of shrink_dcache_sb(). Moreover,
for virtual filesystems like unionfs which can call dput() during dentries
kill existing code results in O(n^2) complexity.
We observed 2 minutes shrink_dcache_sb() with only 35000 dentries.
To avoid this effects we propose to isolate sb dentries at the end
of LRU list.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Andrey Mirkin <amirkin@openvz.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I proposed introducing a list_for_each_entry_continue_reverse macro
to be used in setup_net() when unrolling the failed ->init callback.
Here is the macro and some more cleanup in the setup_net() itself
to remove one variable from the stack :) The same thing is for the
cleanup_net() - the existing list_for_each_entry_reverse() is used.
Minor, but the code looks nicer.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are many places in the kernel where the construction like
foo = list_entry(head->next, struct foo_struct, list);
are used.
The code might look more descriptive and neat if using the macro
list_first_entry(head, type, member) \
list_entry((head)->next, type, member)
Here is the macro itself and the examples of its usage in the generic code.
If it will turn out to be useful, I can prepare the set of patches to
inject in into arch-specific code, drivers, networking, etc.
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A variety of (mostly) innocuous fixes to the embedded kernel-doc content in
source files, including:
* make multi-line initial descriptions single line
* denote some function names, constants and structs as such
* change erroneous opening '/*' to '/**' in a few places
* reword some text for clarity
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is in support of the IPMI driver. I have tested this with the
IPMI driver changes coming in the next patch.
Add a list_splice_init_rcu() function to splice an RCU-protected list into
another list. This takes the sync function as an argument, so one would do
something like:
INIT_LIST_HEAD(&list);
list_splice_init_rcu(&source, &dest, synchronize_rcu);
The idea being to keep the RCU API proliferation down to a dull roar.
[akpm@osdl.org: build fix]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a number of kernel-doc entries for header files in include/linux by
making sure they begin with the appropriate '/**' notation and use @var
notation.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add another list utility function to check for last element in a list.
Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
