mm/filemap: use xas_try_split() in __filemap_add_folio()

Patch series "Minimize xa_node allocation during xarry split", v3.

When splitting a multi-index entry in XArray from order-n to order-m,
exi

mm/filemap: use xas_try_split() in __filemap_add_folio()

Patch series "Minimize xa_node allocation during xarry split", v3.

When splitting a multi-index entry in XArray from order-n to order-m,
existing xas_split_alloc()+xas_split() approach requires 2^(n %
XA_CHUNK_SHIFT) xa_node allocations. But its callers,
__filemap_add_folio() and shmem_split_large_entry(), use at most 1
xa_node. To minimize xa_node allocation and remove the limitation of no
split from order-12 (or above) to order-0 (or anything between 0 and
5)[1], xas_try_split() was added[2], which allocates (n / XA_CHUNK_SHIFT -
m / XA_CHUNK_SHIFT) xa_node. It is used for non-uniform folio split, but
can be used by __filemap_add_folio() and shmem_split_large_entry().

xas_split_alloc() and xas_split() split an order-9 to order-0:

---------------------------------
| | | | | | | | |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| | | | | | | | |
---------------------------------
| | | |
------- --- --- -------
| | ... | |
V V V V
----------- ----------- ----------- -----------
| xa_node | | xa_node | ... | xa_node | | xa_node |
----------- ----------- ----------- -----------

xas_try_split() splits an order-9 to order-0:
---------------------------------
| | | | | | | | |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| | | | | | | | |
---------------------------------
|
|
V
-----------
| xa_node |
-----------

xas_try_split() is designed to be called iteratively with n = m + 1.
xas_try_split_mini_order() is added to minmize the number of calls to
xas_try_split() by telling the caller the next minimal order to split to
instead of n - 1. Splitting order-n to order-m when m= l * XA_CHUNK_SHIFT
does not require xa_node allocation and requires 1 xa_node when n=l *
XA_CHUNK_SHIFT and m = n - 1, so it is OK to use xas_try_split() with n >
m + 1 when no new xa_node is needed.

xfstests quick group test passed on xfs and tmpfs.

[1] https://lore.kernel.org/linux-mm/[email protected]/
[2] https://lore.kernel.org/linux-mm/[email protected]/


This patch (of 2):

During __filemap_add_folio(), a shadow entry is covering n slots and a
folio covers m slots with m < n is to be added. Instead of splitting all
n slots, only the m slots covered by the folio need to be split and the
remaining n-m shadow entries can be retained with orders ranging from m to
n-1. This method only requires

(n/XA_CHUNK_SHIFT) - (m/XA_CHUNK_SHIFT)

new xa_nodes instead of

(n % XA_CHUNK_SHIFT) * ((n/XA_CHUNK_SHIFT) - (m/XA_CHUNK_SHIFT))

new xa_nodes, compared to the original xas_split_alloc() + xas_split()
one. For example, to insert an order-0 folio when an order-9 shadow entry
is present (assuming XA_CHUNK_SHIFT is 6), 1 xa_node is needed instead of
8.

xas_try_split_min_order() is introduced to reduce the number of calls to
xas_try_split() during split.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Zi Yan <[email protected]>
Cc: Baolin Wang <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Kairui Song <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: Mattew Wilcox <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Kirill A. Shuemov <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Yang Shi <[email protected]>
Cc: Yu Zhao <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

xarray: add xas_try_split() to split a multi-index entry

Patch series "Buddy allocator like (or non-uniform) folio split", v10.

This patchset adds a new buddy allocator like (or non-uniform) large

xarray: add xas_try_split() to split a multi-index entry

Patch series "Buddy allocator like (or non-uniform) folio split", v10.

This patchset adds a new buddy allocator like (or non-uniform) large folio
split from a order-n folio to order-m with m < n. It reduces

1. the total number of after-split folios from 2^(n-m) to n-m+1;

2. the amount of memory needed for multi-index xarray split from 2^(n/6-m/6) to
n/6-m/6, assuming XA_CHUNK_SHIFT=6;

3. keep more large folios after a split from all order-m folios to
order-(n-1) to order-m folios.

For example, to split an order-9 to order-0, folio split generates 10 (or
11 for anonymous memory) folios instead of 512, allocates 1 xa_node
instead of 8, and leaves 1 order-8, 1 order-7, ..., 1 order-1 and 2
order-0 folios (or 4 order-0 for anonymous memory) instead of 512 order-0
folios.

Instead of duplicating existing split_huge_page*() code, __folio_split()
is introduced as the shared backend code for both
split_huge_page_to_list_to_order() and folio_split(). __folio_split() can
support both uniform split and buddy allocator like (or non-uniform)
split. All existing split_huge_page*() users can be gradually converted
to use folio_split() if possible. In this patchset, I converted
truncate_inode_partial_folio() to use folio_split().

xfstests quick group passed for both tmpfs and xfs. I also
semi-replicated Hugh's test[12] and ran it without any issue for almost 24
hours.


This patch (of 8):

A preparation patch for non-uniform folio split, which always split a
folio into half iteratively, and minimal xarray entry split.

Currently, xas_split_alloc() and xas_split() always split all slots from a
multi-index entry. They cost the same number of xa_node as the
to-be-split slots. For example, to split an order-9 entry, which takes
2^(9-6)=8 slots, assuming XA_CHUNK_SHIFT is 6 (!CONFIG_BASE_SMALL), 8
xa_node are needed. Instead xas_try_split() is intended to be used
iteratively to split the order-9 entry into 2 order-8 entries, then split
one order-8 entry, based on the given index, to 2 order-7 entries, ...,
and split one order-1 entry to 2 order-0 entries. When splitting the
order-6 entry and a new xa_node is needed, xas_try_split() will try to
allocate one if possible. As a result, xas_try_split() would only need 1
xa_node instead of 8.

When a new xa_node is needed during the split, xas_try_split() can try to
allocate one but no more. -ENOMEM will be return if a node cannot be
allocated. -EINVAL will be return if a sibling node is split or cascade
split happens, where two or more new nodes are needed, and these are not
supported by xas_try_split().

xas_split_alloc() and xas_split() split an order-9 to order-0:

---------------------------------
| | | | | | | | |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| | | | | | | | |
---------------------------------
| | | |
------- --- --- -------
| | ... | |
V V V V
----------- ----------- ----------- -----------
| xa_node | | xa_node | ... | xa_node | | xa_node |
----------- ----------- ----------- -----------

xas_try_split() splits an order-9 to order-0:
---------------------------------
| | | | | | | | |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| | | | | | | | |
---------------------------------
|
|
V
-----------
| xa_node |
-----------

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Zi Yan <[email protected]>
Cc: Baolin Wang <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Kirill A. Shuemov <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Yang Shi <[email protected]>
Cc: Yu Zhao <[email protected]>
Cc: Zi Yan <[email protected]>
Cc: Kairui Song <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

printk: Change type of CONFIG_BASE_SMALL to bool

CONFIG_BASE_SMALL is currently a type int but is only used as a boolean.

So, change its type to bool and adapt all usages:
CONFIG_BASE_SMALL == 0 be

printk: Change type of CONFIG_BASE_SMALL to bool

CONFIG_BASE_SMALL is currently a type int but is only used as a boolean.

So, change its type to bool and adapt all usages:
CONFIG_BASE_SMALL == 0 becomes !IS_ENABLED(CONFIG_BASE_SMALL) and
CONFIG_BASE_SMALL != 0 becomes IS_ENABLED(CONFIG_BASE_SMALL).

Reviewed-by: Petr Mladek <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Reviewed-by: Masahiro Yamada <[email protected]>
Signed-off-by: Yoann Congal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>

show more ...

xarray: don't use "proxy" headers

Update header inclusions to follow IWYU (Include What You Use)
principle.

Link: https://lkml.kernel.org/r/[email protected]

xarray: don't use "proxy" headers

Update header inclusions to follow IWYU (Include What You Use)
principle.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Andy Shevchenko <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

xarray: use BITS_PER_LONGS()

Patch series "xarray: Clean up xarray.h".

Main portion of this change is to get rid of kernel.h included into other
globally available headers. This decreases a depend

xarray: use BITS_PER_LONGS()

Patch series "xarray: Clean up xarray.h".

Main portion of this change is to get rid of kernel.h included into other
globally available headers. This decreases a dependency hell degree. The
first patch makes it possible to avoid math.h to be included as bitops.h
is implied by bitmap.h.


This patch (of 2):

Use BITS_PER_LONGS() instead of open coded variant.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Andy Shevchenko <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

lib/xarray: introduce a new helper xas_get_order

It can be used after xas_load to check the order of loaded entries.
Compared to xa_get_order, it saves an XA_STATE and avoid a rewalk.

Added new te

lib/xarray: introduce a new helper xas_get_order

It can be used after xas_load to check the order of loaded entries.
Compared to xa_get_order, it saves an XA_STATE and avoid a rewalk.

Added new test for xas_get_order, to make the test work, we have to export
xas_get_order with EXPORT_SYMBOL_GPL.

Also fix a sparse warning by checking the slot value with xa_entry instead
of accessing it directly, as suggested by Matthew Wilcox.

[[email protected]: simplify comment, sparse warning fix, per Matthew Wilcox]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kairui Song <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

xarray: Document necessary flag in alloc functions

Adds a new line to the docstrings of functions wrapping __xa_alloc() and
__xa_alloc_cyclic(), informing about the necessity of flag XA_FLAGS_ALLOC

xarray: Document necessary flag in alloc functions

Adds a new line to the docstrings of functions wrapping __xa_alloc() and
__xa_alloc_cyclic(), informing about the necessity of flag XA_FLAGS_ALLOC
being set previously.

The documentation so far says that functions wrapping __xa_alloc() and
__xa_alloc_cyclic() are supposed to return either -ENOMEM or -EBUSY in
case of an error. If the xarray has been initialized without the flag
XA_FLAGS_ALLOC, however, they fail with a different, undocumented error
code.

As hinted at in Documentation/core-api/xarray.rst, wrappers around these
functions should only be invoked when the flag has been set. The
functions' documentation should reflect that as well.

Signed-off-by: Philipp Stanner <[email protected]>
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

show more ...

swap_state: update shadow_nodes for anonymous page

Shadow_nodes is for shadow nodes reclaiming of workingset handling, it is
updated when page cache add or delete since long time ago workingset only

swap_state: update shadow_nodes for anonymous page

Shadow_nodes is for shadow nodes reclaiming of workingset handling, it is
updated when page cache add or delete since long time ago workingset only
supported page cache. But when workingset supports anonymous page
detection, we missied updating shadow nodes for it. This caused that
shadow nodes of anonymous page will never be reclaimd by
scan_shadow_nodes() even they use much memory and system memory is tense.

So update shadow_nodes of anonymous page when swap cache is add or delete
by calling xas_set_update(..workingset_update_node).

Link: https://lkml.kernel.org/r/[email protected]
Fixes: aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU")
Signed-off-by: Yang Yang <[email protected]>
Reviewed-by: Ran Xiaokai <[email protected]>
Cc: Bagas Sanjaya <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

XArray: Add calls to might_alloc()

Catch bogus GFP flags deterministically, instead of occasionally
when we actually have to allocate memory.

Reported-by: Nikolay Borisov <[email protected]>
Signed

XArray: Add calls to might_alloc()

Catch bogus GFP flags deterministically, instead of occasionally
when we actually have to allocate memory.

Reported-by: Nikolay Borisov <[email protected]>
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

show more ...

mm/huge_memory: Fix xarray node memory leak

If xas_split_alloc() fails to allocate the necessary nodes to complete the
xarray entry split, it sets the xa_state to -ENOMEM, which xas_nomem()
then int

mm/huge_memory: Fix xarray node memory leak

If xas_split_alloc() fails to allocate the necessary nodes to complete the
xarray entry split, it sets the xa_state to -ENOMEM, which xas_nomem()
then interprets as "Please allocate more memory", not as "Please free
any unnecessary memory" (which was the intended outcome). It's confusing
to use xas_nomem() to free memory in this context, so call xas_destroy()
instead.

Reported-by: [email protected]
Fixes: 6b24ca4a1a8d ("mm: Use multi-index entries in the page cache")
Cc: [email protected]
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

show more ...

xarray: use kmem_cache_alloc_lru to allocate xa_node

The workingset will add the xa_node to the shadow_nodes list. So the
allocation of xa_node should be done by kmem_cache_alloc_lru(). Using
xas_

xarray: use kmem_cache_alloc_lru to allocate xa_node

The workingset will add the xa_node to the shadow_nodes list. So the
allocation of xa_node should be done by kmem_cache_alloc_lru(). Using
xas_set_lru() to pass the list_lru which we want to insert xa_node into to
set up the xa_node reclaim context correctly.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Muchun Song <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Acked-by: Roman Gushchin <[email protected]>
Cc: Alex Shi <[email protected]>
Cc: Anna Schumaker <[email protected]>
Cc: Chao Yu <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Fam Zheng <[email protected]>
Cc: Jaegeuk Kim <[email protected]>
Cc: Kari Argillander <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Qi Zheng <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: Theodore Ts'o <[email protected]>
Cc: Trond Myklebust <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Wei Yang <[email protected]>
Cc: Xiongchun Duan <[email protected]>
Cc: Yang Shi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

XArray: Include bitmap.h from xarray.h

xas_find_chunk() calls find_next_bit(), which is defined in find.h,
included from bitmap.h. Inside the kernel, this isn't a problem because
bitmap.h is includ

XArray: Include bitmap.h from xarray.h

xas_find_chunk() calls find_next_bit(), which is defined in find.h,
included from bitmap.h. Inside the kernel, this isn't a problem because
bitmap.h is included from cpumask.h which is dragged in (eventually)
by gfp.h. When building the test-suite, that doesn't happen, so we need
to include bitmap.h explicitly.

Fixes: 4ade0818cf04 ("tools: sync tools/bitmap with mother linux")
Reported-by: Liam Howlett <[email protected]>
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

show more ...

XArray: Add xas_advance()

Add a new helper function to help iterate over multi-index entries.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]

XArray: Add xas_advance()

Add a new helper function to help iterate over multi-index entries.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: William Kucharski <[email protected]>

show more ...

XArray: Add xa_limit_16b

A 16-bit limit is a more common limit than I had realised. Make it
generally available.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

XArray: add xas_split

In order to use multi-index entries for huge pages in the page cache, we
need to be able to split a multi-index entry (eg if a file is truncated in
the middle of a huge page en

XArray: add xas_split

In order to use multi-index entries for huge pages in the page cache, we
need to be able to split a multi-index entry (eg if a file is truncated in
the middle of a huge page entry). This version does not support splitting
more than one level of the tree at a time. This is an acceptable
limitation for the page cache as we do not expect to support order-12
pages in the near future.

[[email protected]: export xas_split_alloc() to modules]
[[email protected]: fix xarray split]
Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: fix xarray]
Link: https://lkml.kernel.org/r/[email protected]

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: "Kirill A . Shutemov" <[email protected]>
Cc: Qian Cai <[email protected]>
Cc: Song Liu <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

XArray: add xa_get_order

Patch series "Fix read-only THP for non-tmpfs filesystems".

As described more verbosely in the [3/3] changelog, we can inadvertently
put an order-0 page in the page cache w

XArray: add xa_get_order

Patch series "Fix read-only THP for non-tmpfs filesystems".

As described more verbosely in the [3/3] changelog, we can inadvertently
put an order-0 page in the page cache which occupies 512 consecutive
entries. Users are running into this if they enable the
READ_ONLY_THP_FOR_FS config option; see
https://bugzilla.kernel.org/show_bug.cgi?id=206569 and Qian Cai has also
reported it here:
https://lore.kernel.org/lkml/[email protected]/

This is a rather intrusive way of fixing the problem, but has the
advantage that I've actually been testing it with the THP patches, which
means that it sees far more use than it does upstream -- indeed, Song has
been entirely unable to reproduce it. It also has the advantage that it
removes a few patches from my gargantuan backlog of THP patches.

This patch (of 3):

This function returns the order of the entry at the index. We need this
because there isn't space in the shadow entry to encode its order.

[[email protected]: export xa_get_order to modules]

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: "Kirill A . Shutemov" <[email protected]>
Cc: Qian Cai <[email protected]>
Cc: Song Liu <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

XArray: Fix xas_reload for multi-index entries

xas_reload() was only checking that the head entry was still at the
head index. If the entry has been split, that's not enough as there
may be a diffe

XArray: Fix xas_reload for multi-index entries

xas_reload() was only checking that the head entry was still at the
head index. If the entry has been split, that's not enough as there
may be a different entry at the specified index now.

Solve this by checking the slot for the requested index instead of the
head index.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

show more ...

XArray: Add private interface for workingset node deletion

Move the tricky bits of dealing with the XArray from the workingset
code to the XArray. Make it clear in the documentation that this is a

XArray: Add private interface for workingset node deletion

Move the tricky bits of dealing with the XArray from the workingset
code to the XArray. Make it clear in the documentation that this is a
private interface, and only export it for the benefit of the test suite.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

show more ...

XArray: Fix xas_for_each_conflict documentation

At one point, xas_for_each_conflict() was going to work this way,
and I forgot to update the documentation when I changed my mind.

Signed-off-by: Mat

XArray: Fix xas_for_each_conflict documentation

At one point, xas_for_each_conflict() was going to work this way,
and I forgot to update the documentation when I changed my mind.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

show more ...

xarray.h: correct return code documentation for xa_store_{bh,irq}()

__xa_store() and xa_store() document that the functions can fail, and
that the return code can be an xa_err() encoded error code.

xarray.h: correct return code documentation for xa_store_{bh,irq}()

__xa_store() and xa_store() document that the functions can fail, and
that the return code can be an xa_err() encoded error code.

xa_store_bh() and xa_store_irq() do not document that the functions can
fail and that they can also return xa_err() encoded error codes.

Thus: Update the documentation.

Signed-off-by: Manfred Spraul <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

xarray: Fix early termination of xas_for_each_marked

xas_for_each_marked() is using entry == NULL as a termination condition
of the iteration. When xas_for_each_marked() is used protected only by
RC

xarray: Fix early termination of xas_for_each_marked

xas_for_each_marked() is using entry == NULL as a termination condition
of the iteration. When xas_for_each_marked() is used protected only by
RCU, this can however race with xas_store(xas, NULL) in the following
way:

TASK1 TASK2
page_cache_delete() find_get_pages_range_tag()
xas_for_each_marked()
xas_find_marked()
off = xas_find_chunk()

xas_store(&xas, NULL)
xas_init_marks(&xas);
...
rcu_assign_pointer(*slot, NULL);
entry = xa_entry(off);

And thus xas_for_each_marked() terminates prematurely possibly leading
to missed entries in the iteration (translating to missing writeback of
some pages or a similar problem).

If we find a NULL entry that has been marked, skip it (unless we're trying
to allocate an entry).

Reported-by: Jan Kara <[email protected]>
CC: [email protected]
Fixes: ef8e5717db01 ("page cache: Convert delete_batch to XArray")
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

show more ...

XArray: Fix incorrect comment in header file

256 means Retry entry and 257 means Zero entry,
so fix it.

Signed-off-by: Chengguang Xu <[email protected]>
Signed-off-by: Matthew Wilcox (Oracle) <w

XArray: Fix incorrect comment in header file

256 means Retry entry and 257 means Zero entry,
so fix it.

Signed-off-by: Chengguang Xu <[email protected]>
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

show more ...

XArray: Add xa_for_each_range

This function supports iterating over a range of an array. Also add
documentation links for xa_for_each_start().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infrade

XArray: Add xa_for_each_range

This function supports iterating over a range of an array. Also add
documentation links for xa_for_each_start().

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

show more ...

XArray: Add wrappers for nested spinlocks

Some users need to take an xarray lock while holding another xarray lock.

Reported-by: Doug Gilbert <[email protected]>
Signed-off-by: Matthew Wilcox (

XArray: Add wrappers for nested spinlocks

Some users need to take an xarray lock while holding another xarray lock.

Reported-by: Doug Gilbert <[email protected]>
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

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xarray.h: fix kernel-doc warning

Fix (Sphinx) kernel-doc warning in <linux/xarray.h>:

include/linux/xarray.h:232: WARNING: Unexpected indentation.

Link: http://lkml.kernel.org/r/89ba2134-ce23-7c

xarray.h: fix kernel-doc warning

Fix (Sphinx) kernel-doc warning in <linux/xarray.h>:

include/linux/xarray.h:232: WARNING: Unexpected indentation.

Link: http://lkml.kernel.org/r/[email protected]
Fixes: a3e4d3f97ec8 ("XArray: Redesign xa_alloc API")
Signed-off-by: Randy Dunlap <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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