linux-stable.git/include/linux/idr.h, branch v5.3.8

idr: introduce idr_for_each_entry_continue_ul()

2019-07-02T02:15:46+00:00

Similarly, other callers of idr_get_next_ul() suffer the same
overflow bug as they don't handle it properly either.

Introduce idr_for_each_entry_continue_ul() to help these callers
iterate from a given ID.

cls_flower needs more care here because it still has overflow when
does arg->cookie++, we have to fold its nested loops into one
and remove the arg->cookie++.

Fixes: 01683a146999 ("net: sched: refactor flower walk to iterate over idr")
Fixes: 12d6066c3b29 ("net/mlx5: Add flow counters idr")
Reported-by: Li Shuang 
Cc: Davide Caratti 
Cc: Vlad Buslov 
Cc: Chris Mi 
Cc: Matthew Wilcox 
Signed-off-by: Cong Wang 
Tested-by: Davide Caratti 
Signed-off-by: David S. Miller

idr: fix overflow case for idr_for_each_entry_ul()

2019-07-02T02:15:46+00:00

idr_for_each_entry_ul() is buggy as it can't handle overflow
case correctly. When we have an ID == UINT_MAX, it becomes an
infinite loop. This happens when running on 32-bit CPU where
unsigned long has the same size with unsigned int.

There is no better way to fix this than casting it to a larger
integer, but we can't just 64 bit integer on 32 bit CPU. Instead
we could just use an additional integer to help us to detect this
overflow case, that is, adding a new parameter to this macro.
Fortunately tc action is its only user right now.

Fixes: 65a206c01e8e ("net/sched: Change act_api and act_xxx modules to use IDR")
Reported-by: Li Shuang 
Tested-by: Davide Caratti 
Cc: Matthew Wilcox 
Cc: Chris Mi 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 220

2019-05-30T18:29:55+00:00

Based on 1 normalized pattern(s):

  distributed under the gnu gpl license version 2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 1 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Alexios Zavras 
Reviewed-by: Steve Winslow 
Reviewed-by: Kate Stewart 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171439.854676954@linutronix.de
Signed-off-by: Greg Kroah-Hartman

ida: Convert to XArray

2018-10-21T14:46:33+00:00

Use the XA_TRACK_FREE ability to track which entries have a free bit,
similarly to how it uses the radix tree's IDR_FREE tag.  This eliminates
the per-cpu ida_bitmap preload, and fixes the memory consumption
regression I introduced when making the IDR able to store any pointer.

Signed-off-by: Matthew Wilcox

Merge branch 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax

2018-08-26T18:48:42+00:00

Pull IDA updates from Matthew Wilcox:
 "A better IDA API:

      id = ida_alloc(ida, GFP_xxx);
      ida_free(ida, id);

  rather than the cumbersome ida_simple_get(), ida_simple_remove().

  The new IDA API is similar to ida_simple_get() but better named.  The
  internal restructuring of the IDA code removes the bitmap
  preallocation nonsense.

  I hope the net -200 lines of code is convincing"

* 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax: (29 commits)
  ida: Change ida_get_new_above to return the id
  ida: Remove old API
  test_ida: check_ida_destroy and check_ida_alloc
  test_ida: Convert check_ida_conv to new API
  test_ida: Move ida_check_max
  test_ida: Move ida_check_leaf
  idr-test: Convert ida_check_nomem to new API
  ida: Start new test_ida module
  target/iscsi: Allocate session IDs from an IDA
  iscsi target: fix session creation failure handling
  drm/vmwgfx: Convert to new IDA API
  dmaengine: Convert to new IDA API
  ppc: Convert vas ID allocation to new IDA API
  media: Convert entity ID allocation to new IDA API
  ppc: Convert mmu context allocation to new IDA API
  Convert net_namespace to new IDA API
  cb710: Convert to new IDA API
  rsxx: Convert to new IDA API
  osd: Convert to new IDA API
  sd: Convert to new IDA API
  ...

ida: Remove old API

2018-08-22T03:54:21+00:00

Delete ida_pre_get(), ida_get_new(), ida_get_new_above() and ida_remove()
from the public API.  Some of these functions still exist as internal
helpers, but they should not be called by consumers.

Signed-off-by: Matthew Wilcox

ida: Add new API

2018-08-22T03:54:13+00:00

Add ida_alloc(), ida_alloc_min(), ida_alloc_max(), ida_alloc_range()
and ida_free().  The ida_alloc_max() and ida_alloc_range() functions
differ from ida_simple_get() in that they take an inclusive 'max'
parameter instead of an exclusive 'end' parameter.  Callers are about
evenly split whether they'd like inclusive or exclusive parameters and
'max' is easier to document than 'end'.

Change the IDA allocation to first attempt to allocate a bit using
existing memory, and only allocate memory afterwards.  Also change the
behaviour of 'min' > INT_MAX from being a BUG() to returning -ENOSPC.

Leave compatibility wrappers in place for ida_simple_get() and
ida_simple_remove() to avoid changing all callers.

Signed-off-by: Matthew Wilcox

IDR: Expose the XArray lock

2018-06-18T17:22:54+00:00

Allow users of the IDR to use the XArray lock for their own
synchronisation purposes.  The IDR continues to rely on the caller to
handle locking, but this lets the caller use the lock embedded in the
IDR data structure instead of allocating their own lock.

Signed-off-by: Matthew Wilcox 
Signed-off-by: Jason Gunthorpe

xarray: add the xa_lock to the radix_tree_root

2018-04-11T17:28:39+00:00

This results in no change in structure size on 64-bit machines as it
fits in the padding between the gfp_t and the void *.  32-bit machines
will grow the structure from 8 to 12 bytes.  Almost all radix trees are
protected with (at least) a spinlock, so as they are converted from
radix trees to xarrays, the data structures will shrink again.

Initialising the spinlock requires a name for the benefit of lockdep, so
RADIX_TREE_INIT() now needs to know the name of the radix tree it's
initialising, and so do IDR_INIT() and IDA_INIT().

Also add the xa_lock() and xa_unlock() family of wrappers to make it
easier to use the lock.  If we could rely on -fplan9-extensions in the
compiler, we could avoid all of this syntactic sugar, but that wasn't
added until gcc 4.6.

Link: http://lkml.kernel.org/r/20180313132639.17387-8-willy@infradead.org
Signed-off-by: Matthew Wilcox 
Reviewed-by: Jeff Layton 
Cc: Darrick J. Wong 
Cc: Dave Chinner 
Cc: Ryusuke Konishi 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

radix tree: use GFP_ZONEMASK bits of gfp_t for flags

2018-04-11T17:28:39+00:00

Patch series "XArray", v9.  (First part thereof).

This patchset is, I believe, appropriate for merging for 4.17.  It
contains the XArray implementation, to eventually replace the radix
tree, and converts the page cache to use it.

This conversion keeps the radix tree and XArray data structures in sync
at all times.  That allows us to convert the page cache one function at
a time and should allow for easier bisection.  Other than renaming some
elements of the structures, the data structures are fundamentally
unchanged; a radix tree walk and an XArray walk will touch the same
number of cachelines.  I have changes planned to the XArray data
structure, but those will happen in future patches.

Improvements the XArray has over the radix tree:

 - The radix tree provides operations like other trees do; 'insert' and
   'delete'. But what most users really want is an automatically
   resizing array, and so it makes more sense to give users an API that
   is like an array -- 'load' and 'store'. We still have an 'insert'
   operation for users that really want that semantic.

 - The XArray considers locking as part of its API. This simplifies a
   lot of users who formerly had to manage their own locking just for
   the radix tree. It also improves code generation as we can now tell
   RCU that we're holding a lock and it doesn't need to generate as much
   fencing code. The other advantage is that tree nodes can be moved
   (not yet implemented).

 - GFP flags are now parameters to calls which may need to allocate
   memory. The radix tree forced users to decide what the allocation
   flags would be at creation time. It's much clearer to specify them at
   allocation time.

 - Memory is not preloaded; we don't tie up dozens of pages on the off
   chance that the slab allocator fails. Instead, we drop the lock,
   allocate a new node and retry the operation. We have to convert all
   the radix tree, IDA and IDR preload users before we can realise this
   benefit, but I have not yet found a user which cannot be converted.

 - The XArray provides a cmpxchg operation. The radix tree forces users
   to roll their own (and at least four have).

 - Iterators take a 'max' parameter. That simplifies many users and will
   reduce the amount of iteration done.

 - Iteration can proceed backwards. We only have one user for this, but
   since it's called as part of the pagefault readahead algorithm, that
   seemed worth mentioning.

 - RCU-protected pointers are not exposed as part of the API. There are
   some fun bugs where the page cache forgets to use rcu_dereference()
   in the current codebase.

 - Value entries gain an extra bit compared to radix tree exceptional
   entries. That gives us the extra bit we need to put huge page swap
   entries in the page cache.

 - Some iterators now take a 'filter' argument instead of having
   separate iterators for tagged/untagged iterations.

The page cache is improved by this:

 - Shorter, easier to read code

 - More efficient iterations

 - Reduction in size of struct address_space

 - Fewer walks from the top of the data structure; the XArray API
   encourages staying at the leaf node and conducting operations there.

This patch (of 8):

None of these bits may be used for slab allocations, so we can use them
as radix tree flags as long as we mask them off before passing them to
the slab allocator. Move the IDR flag from the high bits to the
GFP_ZONEMASK bits.

Link: http://lkml.kernel.org/r/20180313132639.17387-3-willy@infradead.org
Signed-off-by: Matthew Wilcox 
Acked-by: Jeff Layton 
Cc: Darrick J. Wong 
Cc: Dave Chinner 
Cc: Ryusuke Konishi 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds