c0e69a5bbc
The commit a1ed5b0cff
(klist: don't iterate over deleted entries) introduces use of the
low bit in a pointer to indicate if the knode is dead or not,
assuming that this bit is always free.
This is not true for all architectures, CRIS for example may align data
on byte borders.
The result is a bunch of warnings on bootup, devices not being
added correctly etc, reported by Hinko Kocevar <hinko.kocevar@cetrtapot.si>:
------------[ cut here ]------------
WARNING: at lib/klist.c:62 ()
Modules linked in:
Stack from c1fe1cf0:
c01cc7f4 c1fe1d11 c000eb4e c000e4de 00000000 00000000 c1f4f78f c1f50c2d
c01d008c c1fdd1a0 c1fdd1a0 c1fe1d38 c0192954 c1fe0000 00000000 c1fe1dc0
00000002 7fffffff c1fe1da8 c0192d50 c1fe1dc0 00000002 7fffffff c1ff9fcc
Call Trace: [<c000eb4e>] [<c000e4de>] [<c0192954>] [<c0192d50>] [<c001d49e>] [<c000b688>] [<c0192a3c>]
[<c000b63e>] [<c000b63e>] [<c001a542>] [<c00b55b0>] [<c00411c0>] [<c00b559c>] [<c01918e6>] [<c0191988>]
[<c01919d0>] [<c00cd9c8>] [<c00cdd6a>] [<c0034178>] [<c000409a>] [<c0015576>] [<c0029130>] [<c0029078>]
[<c0029170>] [<c0012336>] [<c00b4076>] [<c00b4770>] [<c006d6e4>] [<c006d974>] [<c006dca0>] [<c0028d6c>]
[<c0028e12>] [<c0006424>] <4>---[ end trace 4eaa2a86a8e2da22 ]---
------------[ cut here ]------------
Repeat ad nauseam.
Wed, Jan 14, 2009 at 12:11:32AM +0100, Bastien ROUCARIES wrote:
> Perhaps using a pointerhackalign trick on this structure where
> #define pointerhackalign(x) __attribute__ ((aligned (x)))
> and declare
> struct klist_node {
> ...
> } pointerhackalign(2);
>
> Because __attribute__ ((aligned (x))) could only increase alignment
> it will safe to do that and serve as documentation purpose :)
That works, but we need to do it not for the struct klist_node,
but for the struct we insert into the void * in klist_node,
which is struct klist.
Reported-by: Hinko Kocevar <hinko.kocevar@cetrtapot.si
Cc: Bastien ROUCARIES <roucaries.bastien@gmail.com>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
/*
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* klist.h - Some generic list helpers, extending struct list_head a bit.
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*
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* Implementations are found in lib/klist.c
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*
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*
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* Copyright (C) 2005 Patrick Mochel
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*
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* This file is rleased under the GPL v2.
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*/
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#ifndef _LINUX_KLIST_H
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#define _LINUX_KLIST_H
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#include <linux/spinlock.h>
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#include <linux/kref.h>
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#include <linux/list.h>
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struct klist_node;
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struct klist {
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spinlock_t k_lock;
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struct list_head k_list;
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void (*get)(struct klist_node *);
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void (*put)(struct klist_node *);
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} __attribute__ ((aligned (4)));
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#define KLIST_INIT(_name, _get, _put) \
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{ .k_lock = __SPIN_LOCK_UNLOCKED(_name.k_lock), \
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.k_list = LIST_HEAD_INIT(_name.k_list), \
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.get = _get, \
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.put = _put, }
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#define DEFINE_KLIST(_name, _get, _put) \
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struct klist _name = KLIST_INIT(_name, _get, _put)
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extern void klist_init(struct klist *k, void (*get)(struct klist_node *),
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void (*put)(struct klist_node *));
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struct klist_node {
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void *n_klist; /* never access directly */
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struct list_head n_node;
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struct kref n_ref;
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};
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extern void klist_add_tail(struct klist_node *n, struct klist *k);
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extern void klist_add_head(struct klist_node *n, struct klist *k);
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extern void klist_add_after(struct klist_node *n, struct klist_node *pos);
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extern void klist_add_before(struct klist_node *n, struct klist_node *pos);
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extern void klist_del(struct klist_node *n);
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extern void klist_remove(struct klist_node *n);
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extern int klist_node_attached(struct klist_node *n);
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struct klist_iter {
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struct klist *i_klist;
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struct klist_node *i_cur;
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};
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extern void klist_iter_init(struct klist *k, struct klist_iter *i);
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extern void klist_iter_init_node(struct klist *k, struct klist_iter *i,
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struct klist_node *n);
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extern void klist_iter_exit(struct klist_iter *i);
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extern struct klist_node *klist_next(struct klist_iter *i);
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#endif
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