linux-toradex.git/lib/idr.c, branch v2.6.27.50

lib/idr.c: use kmem_cache_zalloc() for the idr_layer cache

2009-01-25T00:36:23+00:00

commit 5b019e99016f3a692ba45bf68fba73a402d7c01a upstream.

David points out that the idr_remove_all() function returns unused slabs
to the kmem cache, but needs to zero them first or else they will be
uninitialized upon next use.  This causes crashes which have been observed
in the firewire subsystem.

He fixed this by zeroing the object before freeing it in idr_remove_all().

But we agree that simply removing the constructor and zeroing the object
at allocation time is simpler than relying upon slab constructor machinery
and might even be faster.

This problem was introduced by "idr: make idr_remove rcu-safe" (commit
cf481c20c476ad2c0febdace9ce23f5a4db19582), which was first released in
2.6.27.

There are no known codesites which trigger this bug in 2.6.27 or 2.6.28.
The post-2.6.28 firewire changes are the only known triggerer.

There might of course be not-yet-discovered triggerers in 2.6.27 and
2.6.28, and there might be out-of-tree triggerers which are added to those
kernel versions.  I'll let the -stable guys decide whether they want to
backport this fix.

Reported-by: David Moore 
Cc: Stefan Richter 
Cc: Nadia Derbey 
Cc: Paul E. McKenney 
Cc: Manfred Spraul 
Cc: Kristian Hgsberg 
Acked-by: Pekka Enberg 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

lib/idr.c: Fix bug introduced by RCU fix

2008-12-18T17:13:36+00:00

commit 711a49a07f84f914aac26a52143f6e7526571143 upstream.

The last patch to lib/idr.c caused a bug if idr_get_new_above() was
called on an empty idr.

Usually, nodes stay on the same layer.  New layers are added to the top
of the tree.

The exception is idr_get_new_above() on an empty tree: In this case, the
new root node is first added on layer 0, then moved upwards.  p->layer
was not updated.

As usual: You shall never rely on the source code comments, they will
only mislead you.

Signed-off-by: Manfred Spraul 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

lib/idr.c: fix rcu related race with idr_find

2008-12-05T18:55:13+00:00

commit 6ff2d39b91aec3dcae951afa982059e3dd9b49dc upstream.

2nd part of the fixes needed for
http://bugzilla.kernel.org/show_bug.cgi?id=11796.

When the idr tree is either grown or shrunk, then the update to the number
of layers and the top pointer were not atomic.  This race caused crashes.

The attached patch fixes that by replicating the layers counter in each
layer, thus idr_find doesn't need idp->layers anymore.

Signed-off-by: Manfred Spraul 
Cc: Clement Calmels 
Cc: Nadia Derbey 
Cc: Pierre Peiffer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

SL*B: drop kmem cache argument from constructor

2008-07-26T19:00:07+00:00

Kmem cache passed to constructor is only needed for constructors that are
themselves multiplexeres.  Nobody uses this "feature", nor does anybody uses
passed kmem cache in non-trivial way, so pass only pointer to object.

Non-trivial places are:
	arch/powerpc/mm/init_64.c
	arch/powerpc/mm/hugetlbpage.c

This is flag day, yes.

Signed-off-by: Alexey Dobriyan 
Acked-by: Pekka Enberg 
Acked-by: Christoph Lameter 
Cc: Jon Tollefson 
Cc: Nick Piggin 
Cc: Matt Mackall 
[akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c]
[akpm@linux-foundation.org: fix mm/slab.c]
[akpm@linux-foundation.org: fix ubifs]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

idr: make idr_remove rcu-safe

2008-07-25T17:53:42+00:00

Introduce the free_layer() routine: it is the one that actually frees memory
after a grace period has elapsed.

Signed-off-by: Nadia Derbey 
Reviewed-by: "Paul E. McKenney" 
Cc: Manfred Spraul 
Cc: Jim Houston 
Cc: Pierre Peiffer 
Acked-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

idr: make idr_find rcu-safe

2008-07-25T17:53:42+00:00

Make idr_find rcu-safe: it can now be called inside an rcu_read critical
section.

Signed-off-by: Nadia Derbey 
Reviewed-by: "Paul E. McKenney" 
Cc: Manfred Spraul 
Cc: Jim Houston 
Cc: Pierre Peiffer 
Acked-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

idr: make idr_get_new* rcu-safe

2008-07-25T17:53:42+00:00

Make the idr_get_new* routines rcu-safe.

Signed-off-by: Nadia Derbey 
Reviewed-by: "Paul E. McKenney" 
Cc: Manfred Spraul 
Cc: Jim Houston 
Cc: Pierre Peiffer 
Acked-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

idr: error checking factorization

2008-07-25T17:53:41+00:00

Do some code factorization in the return code analysis.

Signed-off-by: Nadia Derbey 
Cc: "Paul E. McKenney" 
Cc: Manfred Spraul 
Cc: Jim Houston 
Cc: Pierre Peiffer 
Acked-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

idr: fix a printk call

2008-07-25T17:53:41+00:00

Fix the incomplete printk call.

Signed-off-by: Nadia Derbey 
Reviewed-by: "Paul E. McKenney" 
Cc: Manfred Spraul 
Cc: Jim Houston 
Cc: Pierre Peiffer 
Acked-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

idr: rename some of the idr APIs internal routines

2008-07-25T17:53:41+00:00

This is a trivial patch that renames:

   . alloc_layer to get_from_free_list since it idr_pre_get that actually
     allocates memory.
   . free_layer to move_to_free_list since memory is not actually freed there.

This makes things more clear for the next patches.

Signed-off-by: Nadia Derbey 
Reviewed-by: "Paul E. McKenney" 
Cc: Manfred Spraul 
Cc: Jim Houston 
Cc: Pierre Peiffer 
Acked-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds