Commit Graph

97 Commits

Author SHA1 Message Date
Chris Mi
388f79fda7 idr: Add new APIs to support unsigned long
The following new APIs are added:

int idr_alloc_ext(struct idr *idr, void *ptr, unsigned long *index,
                  unsigned long start, unsigned long end, gfp_t gfp);
void *idr_remove_ext(struct idr *idr, unsigned long id);
void *idr_find_ext(const struct idr *idr, unsigned long id);
void *idr_replace_ext(struct idr *idr, void *ptr, unsigned long id);
void *idr_get_next_ext(struct idr *idr, unsigned long *nextid);

Signed-off-by: Chris Mi <chrism@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-30 14:36:44 -07:00
Matthew Wilcox
7e73eb0b2d idr: Add missing __rcu annotations
Where we use the radix tree iteration macros, we need to annotate 'slot'
with __rcu.  Make sure we don't forget any new places in the future with
the same CFLAGS check used for radix-tree.c.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
2017-02-13 21:44:10 -05:00
Matthew Wilcox
d37cacc5ad ida: Use exceptional entries for small IDAs
We can use the root entry as a bitmap and save allocating a 128 byte
bitmap for an IDA that contains only a few entries (30 on a 32-bit
machine, 62 on a 64-bit machine).  This costs about 300 bytes of kernel
text on x86-64, so as long as 3 IDAs fall into this category, this
is a net win for memory consumption.

Thanks to Rasmus Villemoes for his work documenting the problem and
collecting statistics on IDAs.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
2017-02-13 21:44:02 -05:00
Matthew Wilcox
7ad3d4d85c ida: Move ida_bitmap to a percpu variable
When we preload the IDA, we allocate an IDA bitmap.  Instead of storing
that preallocated bitmap in the IDA, we store it in a percpu variable.
Generally there are more IDAs in the system than CPUs, so this cuts down
on the number of preallocated bitmaps that are unused, and about half
of the IDA users did not call ida_destroy() so they were leaking IDA
bitmaps.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
2017-02-13 21:44:01 -05:00
Matthew Wilcox
0a835c4f09 Reimplement IDR and IDA using the radix tree
The IDR is very similar to the radix tree.  It has some functionality that
the radix tree did not have (alloc next free, cyclic allocation, a
callback-based for_each, destroy tree), which is readily implementable on
top of the radix tree.  A few small changes were needed in order to use a
tag to represent nodes with free space below them.  More extensive
changes were needed to support storing NULL as a valid entry in an IDR.
Plain radix trees still interpret NULL as a not-present entry.

The IDA is reimplemented as a client of the newly enhanced radix tree.  As
in the current implementation, it uses a bitmap at the last level of the
tree.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2017-02-13 21:44:01 -05:00
Daniel Vetter
a2ef9471c7 lib/ida: document locking requirements a bit better
I wanted to wrap a bunch of ida_simple_get calls into their own locking,
until I dug around and read the original commit message.  Stuff like
this should imo be added to the kernel doc, let's do that.

Link: http://lkml.kernel.org/r/20161027072216.20411-1-daniel.vetter@ffwll.ch
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12 18:55:09 -08:00
Mel Gorman
d0164adc89 mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts.  They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve".  __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".

Over time, callers had a requirement to not block when fallback options
were available.  Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.

This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative.  High priority users continue to use
__GFP_HIGH.  __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim.  __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim.  __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.

This patch then converts a number of sites

o __GFP_ATOMIC is used by callers that are high priority and have memory
  pools for those requests. GFP_ATOMIC uses this flag.

o Callers that have a limited mempool to guarantee forward progress clear
  __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
  into this category where kswapd will still be woken but atomic reserves
  are not used as there is a one-entry mempool to guarantee progress.

o Callers that are checking if they are non-blocking should use the
  helper gfpflags_allow_blocking() where possible. This is because
  checking for __GFP_WAIT as was done historically now can trigger false
  positives. Some exceptions like dm-crypt.c exist where the code intent
  is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
  flag manipulations.

o Callers that built their own GFP flags instead of starting with GFP_KERNEL
  and friends now also need to specify __GFP_KSWAPD_RECLAIM.

The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.

The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL.  They may
now wish to specify __GFP_KSWAPD_RECLAIM.  It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
Rasmus Villemoes
87d1d16937 lib/idr.c: remove redundant include
idr.c doesn't seem to use anything from hardirq.h (or anything included
from that).  Removing it produces identical objdump -d output, and gives
44 fewer lines in the .idr.o.cmd dependency file.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-12 18:54:15 -08:00
Linus Torvalds
28596c9722 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull "trivial tree" updates from Jiri Kosina:
 "Usual pile from trivial tree everyone is so eagerly waiting for"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
  Remove MN10300_PROC_MN2WS0038
  mei: fix comments
  treewide: Fix typos in Kconfig
  kprobes: update jprobe_example.c for do_fork() change
  Documentation: change "&" to "and" in Documentation/applying-patches.txt
  Documentation: remove obsolete pcmcia-cs from Changes
  Documentation: update links in Changes
  Documentation: Docbook: Fix generated DocBook/kernel-api.xml
  score: Remove GENERIC_HAS_IOMAP
  gpio: fix 'CONFIG_GPIO_IRQCHIP' comments
  tty: doc: Fix grammar in serial/tty
  dma-debug: modify check_for_stack output
  treewide: fix errors in printk
  genirq: fix reference in devm_request_threaded_irq comment
  treewide: fix synchronize_rcu() in comments
  checkstack.pl: port to AArch64
  doc: queue-sysfs: minor fixes
  init/do_mounts: better syntax description
  MIPS: fix comment spelling
  powerpc/simpleboot: fix comment
  ...
2014-10-07 21:16:26 -04:00
Masanari Iida
da3dae54e4 Documentation: Docbook: Fix generated DocBook/kernel-api.xml
This patch fix spelling typo found in DocBook/kernel-api.xml.
It is because the file is generated from the source comments,
I have to fix the comments in source codes.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-09-09 10:34:56 +02:00
Andrey Ryabinin
93b7aca35d lib/idr.c: fix out-of-bounds pointer dereference
I'm working on address sanitizer project for kernel.  Recently we
started experiments with stack instrumentation, to detect out-of-bounds
read/write bugs on stack.

Just after booting I've hit out-of-bounds read on stack in idr_for_each
(and in __idr_remove_all as well):

	struct idr_layer **paa = &pa[0];

	while (id >= 0 && id <= max) {
		...
		while (n < fls(id)) {
			n += IDR_BITS;
			p = *--paa; <--- here we are reading pa[-1] value.
		}
	}

Despite the fact that after this dereference we are exiting out of loop
and never use p, such behaviour is undefined and should be avoided.

Fix this by moving pointer derference to the beggining of the loop,
right before we will use it.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Alexey Preobrazhensky <preobr@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:24 -07:00
Lai Jiangshan
15f3ec3f23 idr: reduce the unneeded check in free_layer()
If "idr->hint == p" is true, it also implies "idr->hint" is true(not NULL).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:12 -07:00
Lai Jiangshan
aefb768297 idr: don't need to shink the free list when idr_remove()
After idr subsystem is changed to RCU-awared, the free layer will not go
to the free list.  The free list will not be filled up when
idr_remove().  So we don't need to shink it too.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:12 -07:00
Lai Jiangshan
b93804b2fc idr: fix idr_replace()'s returned error code
When the smaller id is not found, idr_replace() returns -ENOENT.  But
when the id is bigger enough, idr_replace() returns -EINVAL, actually
there is no difference between these two kinds of ids.

These are all unallocated id, the return values of the idr_replace() for
these ids should be the same: -ENOENT.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:12 -07:00
Lai Jiangshan
aef0f62e87 idr: fix NULL pointer dereference when ida_remove(unallocated_id)
If the ida has at least one existing id, and when an unallocated ID
which meets a certain condition is passed to the ida_remove(), the
system will crash because it hits NULL pointer dereference.

The condition is that the unallocated ID shares the same lowest idr
layer with the existing ID, but the idr slot would be different if the
unallocated ID were to be allocated.

In this case the matching idr slot for the unallocated_id is NULL,
causing @bitmap to be NULL which the function dereferences without
checking crashing the kernel.

See the test code:

  static void test3(void)
  {
        int id;
        DEFINE_IDA(test_ida);

        printk(KERN_INFO "Start test3\n");
        if (ida_pre_get(&test_ida, GFP_KERNEL) < 0) return;
        if (ida_get_new(&test_ida,  &id) < 0) return;
        ida_remove(&test_ida, 4000); /* bug: null deference here */
        printk(KERN_INFO "End of test3\n");
  }

It happens only when the caller tries to free an unallocated ID which is
the caller's fault.  It is not a bug.  But it is better to add the
proper check and complain rather than crashing the kernel.

[tj@kernel.org: updated patch description]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:12 -07:00
Lai Jiangshan
8f9f665a70 idr: fix unexpected ID-removal when idr_remove(unallocated_id)
If unallocated_id = (ANY * idr_max(idp->layers) + existing_id) is passed
to idr_remove().  The existing_id will be removed unexpectedly.

The following test shows this unexpected id-removal:

  static void test4(void)
  {
        int id;
        DEFINE_IDR(test_idr);

        printk(KERN_INFO "Start test4\n");
        id = idr_alloc(&test_idr, (void *)1, 42, 43, GFP_KERNEL);
        BUG_ON(id != 42);
        idr_remove(&test_idr, 42 + IDR_SIZE);
        TEST_BUG_ON(idr_find(&test_idr, 42) != (void *)1);
        idr_destroy(&test_idr);
        printk(KERN_INFO "End of test4\n");
  }

ida_remove() shares the similar problem.

It happens only when the caller tries to free an unallocated ID which is
the caller's fault.  It is not a bug.  But it is better to add the
proper check and complain rather than removing an existing_id silently.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:12 -07:00
Lai Jiangshan
3afb69cb55 idr: fix overflow bug during maximum ID calculation at maximum height
idr_replace() open-codes the logic to calculate the maximum valid ID
given the height of the idr tree; unfortunately, the open-coded logic
doesn't account for the fact that the top layer may have unused slots
and over-shifts the limit to zero when the tree is at its maximum
height.

The following test code shows it fails to replace the value for
id=((1<<27)+42):

  static void test5(void)
  {
        int id;
        DEFINE_IDR(test_idr);
  #define TEST5_START ((1<<27)+42) /* use the highest layer */

        printk(KERN_INFO "Start test5\n");
        id = idr_alloc(&test_idr, (void *)1, TEST5_START, 0, GFP_KERNEL);
        BUG_ON(id != TEST5_START);
        TEST_BUG_ON(idr_replace(&test_idr, (void *)2, TEST5_START) != (void *)1);
        idr_destroy(&test_idr);
        printk(KERN_INFO "End of test5\n");
  }

Fix the bug by using idr_max() which correctly takes into account the
maximum allowed shift.

sub_alloc() shares the same problem and may incorrectly fail with
-EAGAIN; however, this bug doesn't affect correct operation because
idr_get_empty_slot(), which already uses idr_max(), retries with the
increased @id in such cases.

[tj@kernel.org: Updated patch description.]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:12 -07:00
Monam Agarwal
3f59b067c5 lib/idr.c: use RCU_INIT_POINTER(x, NULL)
Replace rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL)

The rcu_assign_pointer() ensures that the initialization of a structure
is carried out before storing a pointer to that structure.  And in the
case of the NULL pointer, there is no structure to initialize.

So, rcu_assign_pointer(p, NULL) can be safely converted to
RCU_INIT_POINTER(p, NULL)

Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:36:07 -07:00
Stephen Hemminger
90ae3ae539 idr: remove dead code
Remove no longer used deprecated code, and make local functions
static.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: George Spelvin <linux@horizon.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:36:07 -07:00
Andreas Gruenbacher
05f7a7d6a7 idr: Add new function idr_is_empty()
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
2014-02-17 16:27:47 +01:00
Jean Delvare
dd04b452f5 idr: print a stack dump after ida_remove warning
We print a dump stack after idr_remove warning.  This is useful to find
the faulty piece of code.  Let's do the same for ida_remove, as it would
be equally useful there.

[akpm@linux-foundation.org: convert the open-coded printk+dump_stack into WARN()]
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:08:04 -07:00
Jeff Layton
3e6628c4b3 idr: introduce idr_alloc_cyclic()
As Tejun points out, there are several users of the IDR facility that
attempt to use it in a cyclic fashion.  These users are likely to see
-ENOSPC errors after the counter wraps one or more times however.

This patchset adds a new idr_alloc_cyclic routine and converts several
of these users to it.  Many of these users are in obscure parts of the
kernel, and I don't have a good way to test some of them.  The change is
pretty straightforward though, so hopefully it won't be an issue.

There is one other cyclic user of idr_alloc that I didn't touch in
ipc/util.c.  That one is doing some strange stuff that I didn't quite
understand, but it looks like it should probably be converted later
somehow.

This patch:

Thus spake Tejun Heo:

    Ooh, BTW, the cyclic allocation is broken.  It's prone to -ENOSPC
    after the first wraparound.  There are several cyclic users in the
    kernel and I think it probably would be best to implement cyclic
    support in idr.

This patch does that by adding new idr_alloc_cyclic function that such
users in the kernel can use.  With this, there's no need for a caller to
keep track of the last value used as that's now tracked internally.  This
should prevent the ENOSPC problems that can hit when the "last allocated"
counter exceeds INT_MAX.

Later patches will convert existing cyclic users to the new interface.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Jack Morgenstein <jackm@dev.mellanox.co.il>
Cc: John McCutchan <john@johnmccutchan.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Robert Love <rlove@rlove.org>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Cc: Steve Wise <swise@opengridcomputing.com>
Cc: Tom Tucker <tom@opengridcomputing.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 18:28:41 -07:00
Tejun Heo
59bfbcf019 idr: idr_alloc() shouldn't trigger lowmem warning when preloaded
GFP_NOIO is often used for idr_alloc() inside preloaded section as the
allocation mask doesn't really matter.  If the idr tree needs to be
expanded, idr_alloc() first tries to allocate using the specified
allocation mask and if it fails falls back to the preloaded buffer.  This
order prevent non-preloading idr_alloc() users from taking advantage of
preloading ones by using preload buffer without filling it shifting the
burden of allocation to the preload users.

Unfortunately, this allowed/expected-to-fail kmem_cache allocation ends up
generating spurious slab lowmem warning before succeeding the request from
the preload buffer.

This patch makes idr_layer_alloc() add __GFP_NOWARN to the first
kmem_cache attempt and try kmem_cache again w/o __GFP_NOWARN after
allocation from preload_buffer fails so that lowmem warning is generated
if not suppressed by the original @gfp_mask.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: David Teigland <teigland@redhat.com>
Tested-by: David Teigland <teigland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-13 15:21:49 -07:00
Tejun Heo
c8615d3716 idr: deprecate idr_pre_get() and idr_get_new[_above]()
Now that all in-kernel users are converted to ues the new alloc
interface, mark the old interface deprecated.  We should be able to
remove these in a few releases.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-13 15:21:47 -07:00
Randy Dunlap
5857f70c8a idr: fix new kernel-doc warnings
Fix new kernel-doc warnings in idr:

  Warning(include/linux/idr.h:113): No description found for parameter 'idr'
  Warning(include/linux/idr.h:113): Excess function parameter 'idp' description in 'idr_find'
  Warning(lib/idr.c:232): Excess function parameter 'id' description in 'sub_alloc'
  Warning(lib/idr.c:232): Excess function parameter 'id' description in 'sub_alloc'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-12 20:42:09 -07:00
Tejun Heo
2e1c9b2867 idr: remove WARN_ON_ONCE() on negative IDs
idr_find(), idr_remove() and idr_replace() used to silently ignore the
sign bit and perform lookup with the rest of the bits.  The weird behavior
has been changed such that negative IDs are treated as invalid.  As the
behavior change was subtle, WARN_ON_ONCE() was added in the hope of
determining who's calling idr functions with negative IDs so that they can
be examined for problems.

Up until now, all two reported cases are ID number coming directly from
userland and getting fed into idr_find() and the warnings seem to cause
more problems than being helpful.  Drop the WARN_ON_ONCE()s.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: <markus@trippelsdorf.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-08 15:05:34 -08:00
Tejun Heo
7175c61cc6 idr: explain WARN_ON_ONCE() on negative IDs out-of-range ID
Until recently, when an negative ID is specified, idr functions used to
ignore the sign bit and proceeded with the operation with the rest of
bits, which is bizarre and error-prone.  The behavior recently got changed
so that negative IDs are treated as invalid but we're triggering
WARN_ON_ONCE() on negative IDs just in case somebody was depending on the
sign bit being ignored, so that those can be detected and fixed easily.

We only need this for a while.  Explain why WARN_ON_ONCE()s are there and
that they can be removed later.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:21 -08:00
Tejun Heo
0ffc2a9c80 idr: implement lookup hint
While idr lookup isn't a particularly heavy operation, it still is too
substantial to use in hot paths without worrying about the performance
implications.  With recent changes, each idr_layer covers 256 slots
which should be enough to cover most use cases with single idr_layer
making lookup hint very attractive.

This patch adds idr->hint which points to the idr_layer which
allocated an ID most recently and the fast path lookup becomes

	if (look up target's prefix matches that of the hinted layer)
		return hint->ary[ID's offset in the leaf layer];

which can be inlined.

idr->hint is set to the leaf node on idr_fill_slot() and cleared from
free_layer().

[andriy.shevchenko@linux.intel.com: always do slow path when hint is uninitialized]
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:21 -08:00
Tejun Heo
54616283c2 idr: add idr_layer->prefix
Add a field which carries the prefix of ID the idr_layer covers.  This
will be used to implement lookup hint.

This patch doesn't make use of the new field and doesn't introduce any
behavior difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:20 -08:00
Tejun Heo
1d9b2e1e66 idr: remove length restriction from idr_layer->bitmap
Currently, idr->bitmap is declared as an unsigned long which restricts
the number of bits an idr_layer can contain.  All bitops can handle
arbitrary positive integer bit number and there's no reason for this
restriction.

Declare idr_layer->bitmap using DECLARE_BITMAP() instead of a single
unsigned long.

* idr_layer->bitmap is now an array.  '&' dropped from params to
  bitops.

* Replaced "== IDR_FULL" tests with bitmap_full() and removed
  IDR_FULL.

* Replaced find_next_bit() on ~bitmap with find_next_zero_bit().

* Replaced "bitmap = 0" with bitmap_clear().

This patch doesn't (or at least shouldn't) introduce any behavior
changes.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:20 -08:00
Tejun Heo
e8c8d1bc06 idr: remove MAX_IDR_MASK and move left MAX_IDR_* into idr.c
MAX_IDR_MASK is another weirdness in the idr interface.  As idr covers
whole positive integer range, it's defined as 0x7fffffff or INT_MAX.

Its usage in idr_find(), idr_replace() and idr_remove() is bizarre.
They basically mask off the sign bit and operate on the rest, so if
the caller, by accident, passes in a negative number, the sign bit
will be masked off and the remaining part will be used as if that was
the input, which is worse than crashing.

The constant is visible in idr.h and there are several users in the
kernel.

* drivers/i2c/i2c-core.c:i2c_add_numbered_adapter()

  Basically used to test if adap->nr is a negative number which isn't
  -1 and returns -EINVAL if so.  idr_alloc() already has negative
  @start checking (w/ WARN_ON_ONCE), so this can go away.

* drivers/infiniband/core/cm.c:cm_alloc_id()
  drivers/infiniband/hw/mlx4/cm.c:id_map_alloc()

  Used to wrap cyclic @start.  Can be replaced with max(next, 0).
  Note that this type of cyclic allocation using idr is buggy.  These
  are prone to spurious -ENOSPC failure after the first wraparound.

* fs/super.c:get_anon_bdev()

  The ID allocated from ida is masked off before being tested whether
  it's inside valid range.  ida allocated ID can never be a negative
  number and the masking is unnecessary.

Update idr_*() functions to fail with -EINVAL when negative @id is
specified and update other MAX_IDR_MASK users as described above.

This leaves MAX_IDR_MASK without any user, remove it and relocate
other MAX_IDR_* constants to lib/idr.c.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Roland Dreier <roland@kernel.org>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: "Marciniszyn, Mike" <mike.marciniszyn@intel.com>
Cc: Jack Morgenstein <jackm@dev.mellanox.co.il>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Wolfram Sang <wolfram@the-dreams.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:20 -08:00
Tejun Heo
326cf0f0f3 idr: fix top layer handling
Most functions in idr fail to deal with the high bits when the idr
tree grows to the maximum height.

* idr_get_empty_slot() stops growing idr tree once the depth reaches
  MAX_IDR_LEVEL - 1, which is one depth shallower than necessary to
  cover the whole range.  The function doesn't even notice that it
  didn't grow the tree enough and ends up allocating the wrong ID
  given sufficiently high @starting_id.

  For example, on 64 bit, if the starting id is 0x7fffff01,
  idr_get_empty_slot() will grow the tree 5 layer deep, which only
  covers the 30 bits and then proceed to allocate as if the bit 30
  wasn't specified.  It ends up allocating 0x3fffff01 without the bit
  30 but still returns 0x7fffff01.

* __idr_remove_all() will not remove anything if the tree is fully
  grown.

* idr_find() can't find anything if the tree is fully grown.

* idr_for_each() and idr_get_next() can't iterate anything if the tree
  is fully grown.

Fix it by introducing idr_max() which returns the maximum possible ID
given the depth of tree and replacing the id limit checks in all
affected places.

As the idr_layer pointer array pa[] needs to be 1 larger than the
maximum depth, enlarge pa[] arrays by one.

While this plugs the discovered issues, the whole code base is
horrible and in desparate need of rewrite.  It's fragile like hell,

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: <stable@vger.kernel.org>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:20 -08:00
Tejun Heo
d5c7409f79 idr: implement idr_preload[_end]() and idr_alloc()
The current idr interface is very cumbersome.

* For all allocations, two function calls - idr_pre_get() and
  idr_get_new*() - should be made.

* idr_pre_get() doesn't guarantee that the following idr_get_new*()
  will not fail from memory shortage.  If idr_get_new*() returns
  -EAGAIN, the caller is expected to retry pre_get and allocation.

* idr_get_new*() can't enforce upper limit.  Upper limit can only be
  enforced by allocating and then freeing if above limit.

* idr_layer buffer is unnecessarily per-idr.  Each idr ends up keeping
  around MAX_IDR_FREE idr_layers.  The memory consumed per idr is
  under two pages but it makes it difficult to make idr_layer larger.

This patch implements the following new set of allocation functions.

* idr_preload[_end]() - Similar to radix preload but doesn't fail.
  The first idr_alloc() inside preload section can be treated as if it
  were called with @gfp_mask used for idr_preload().

* idr_alloc() - Allocate an ID w/ lower and upper limits.  Takes
  @gfp_flags and can be used w/o preloading.  When used inside
  preloaded section, the allocation mask of preloading can be assumed.

If idr_alloc() can be called from a context which allows sufficiently
relaxed @gfp_mask, it can be used by itself.  If, for example,
idr_alloc() is called inside spinlock protected region, preloading can
be used like the following.

	idr_preload(GFP_KERNEL);
	spin_lock(lock);

	id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT);

	spin_unlock(lock);
	idr_preload_end();
	if (id < 0)
		error;

which is much simpler and less error-prone than idr_pre_get and
idr_get_new*() loop.

The new interface uses per-pcu idr_layer buffer and thus the number of
idr's in the system doesn't affect the amount of memory used for
preloading.

idr_layer_alloc() is introduced to handle idr_layer allocations for
both old and new ID allocation paths.  This is a bit hairy now but the
new interface is expected to replace the old and the internal
implementation eventually will become simpler.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:14 -08:00
Tejun Heo
3594eb2894 idr: refactor idr_get_new_above()
Move slot filling to idr_fill_slot() from idr_get_new_above_int() and
make idr_get_new_above() directly call it.  idr_get_new_above_int() is
no longer needed and removed.

This will be used to implement a new ID allocation interface.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:14 -08:00
Tejun Heo
12d1b4393e idr: remove _idr_rc_to_errno() hack
idr uses -1, IDR_NEED_TO_GROW and IDR_NOMORE_SPACE to communicate
exception conditions internally.  The return value is later translated
to errno values using _idr_rc_to_errno().

This is confusing.  Drop the custom ones and consistently use -EAGAIN
for "tree needs to grow", -ENOMEM for "need more memory" and -ENOSPC for
"ran out of ID space".

Due to the weird memory preloading mechanism, [ra]_get_new*() return
-EAGAIN on memory shortage, so we need to substitute -ENOMEM w/
-EAGAIN on those interface functions.  They'll eventually be cleaned
up and the translations will go away.

This patch doesn't introduce any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:14 -08:00
Tejun Heo
49038ef4fb idr: relocate idr_for_each_entry() and reorganize id[r|a]_get_new()
* Move idr_for_each_entry() definition next to other idr related
  definitions.

* Make id[r|a]_get_new() inline wrappers of id[r|a]_get_new_above().

This changes the implementation of idr_get_new() but the new
implementation is trivial.  This patch doesn't introduce any
functional change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:14 -08:00
Tejun Heo
fe6e24ec90 idr: deprecate idr_remove_all()
There was only one legitimate use of idr_remove_all() and a lot more of
incorrect uses (or lack of it).  Now that idr_destroy() implies
idr_remove_all() and all the in-kernel users updated not to use it,
there's no reason to keep it around.  Mark it deprecated so that we can
later unexport it.

idr_remove_all() is made an inline function calling __idr_remove_all()
to avoid triggering deprecated warning on EXPORT_SYMBOL().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:14 -08:00
Tejun Heo
9bb26bc1ff idr: make idr_destroy() imply idr_remove_all()
idr is silly in quite a few ways, one of which is how it's supposed to
be destroyed - idr_destroy() doesn't release IDs and doesn't even whine
if the idr isn't empty.  If the caller forgets idr_remove_all(), it
simply leaks memory.

Even ida gets this wrong and leaks memory on destruction.  There is
absoltely no reason not to call idr_remove_all() from idr_destroy().
Nobody is abusing idr_destroy() for shrinking free layer buffer and
continues to use idr after idr_destroy(), so it's safe to do remove_all
from destroy.

In the whole kernel, there is only one place where idr_remove_all() is
legitimiately used without following idr_destroy() while there are quite
a few places where the caller forgets either idr_remove_all() or
idr_destroy() leaking memory.

This patch makes idr_destroy() call idr_destroy_all() and updates the
function description accordingly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:13 -08:00
Tejun Heo
6cdae7416a idr: fix a subtle bug in idr_get_next()
The iteration logic of idr_get_next() is borrowed mostly verbatim from
idr_for_each().  It walks down the tree looking for the slot matching
the current ID.  If the matching slot is not found, the ID is
incremented by the distance of single slot at the given level and
repeats.

The implementation assumes that during the whole iteration id is aligned
to the layer boundaries of the level closest to the leaf, which is true
for all iterations starting from zero or an existing element and thus is
fine for idr_for_each().

However, idr_get_next() may be given any point and if the starting id
hits in the middle of a non-existent layer, increment to the next layer
will end up skipping the same offset into it.  For example, an IDR with
IDs filled between [64, 127] would look like the following.

          [  0  64 ... ]
       /----/   |
       |        |
      NULL    [ 64 ... 127 ]

If idr_get_next() is called with 63 as the starting point, it will try
to follow down the pointer from 0.  As it is NULL, it will then try to
proceed to the next slot in the same level by adding the slot distance
at that level which is 64 - making the next try 127.  It goes around the
loop and finds and returns 127 skipping [64, 126].

Note that this bug also triggers in idr_for_each_entry() loop which
deletes during iteration as deletions can make layers go away leaving
the iteration with unaligned ID into missing layers.

Fix it by ensuring proceeding to the next slot doesn't carry over the
unaligned offset - ie.  use round_up(id + 1, slot_distance) instead of
id += slot_distance.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: David Teigland <teigland@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:12 -08:00
Fengguang Wu
125c4c706b idr: rename MAX_LEVEL to MAX_IDR_LEVEL
To avoid name conflicts:

  drivers/video/riva/fbdev.c:281:9: sparse: preprocessor token MAX_LEVEL redefined

While at it, also make the other names more consistent and add
parentheses.

[akpm@linux-foundation.org: repair fallout]
[sfr@canb.auug.org.au: IB/mlx4: fix for MAX_ID_MASK to MAX_IDR_MASK name change]
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: walter harms <wharms@bfs.de>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06 03:04:56 +09:00
Linus Torvalds
11bcb32848 The following text was taken from the original review request:
"[PATCH 0/3] RFC - module.h usage cleanups in fs/ and lib/"
 		https://lkml.org/lkml/2012/2/29/589
 --
 
 Fix up files in fs/ and lib/ dirs to only use module.h if they really
 need it.
 
 These are trivial in scope vs. the work done previously.  We now have
 things where any few remaining cleanups can be farmed out to arch or
 subsystem maintainers, and I have done so when possible.  What is
 remaining here represents the bits that don't clearly lie within a
 single arch/subsystem boundary, like the fs dir and the lib dir.
 
 Some duplicate includes arising from overlapping fixes from
 independent subsystem maintainer submissions are also quashed.
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Merge tag 'module-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

Pull cleanup of fs/ and lib/ users of module.h from Paul Gortmaker:
 "Fix up files in fs/ and lib/ dirs to only use module.h if they really
  need it.

  These are trivial in scope vs the work done previously.  We now have
  things where any few remaining cleanups can be farmed out to arch or
  subsystem maintainers, and I have done so when possible.  What is
  remaining here represents the bits that don't clearly lie within a
  single arch/subsystem boundary, like the fs dir and the lib dir.

  Some duplicate includes arising from overlapping fixes from
  independent subsystem maintainer submissions are also quashed."

Fix up trivial conflicts due to clashes with other include file cleanups
(including some due to the previous bug.h cleanup pull).

* tag 'module-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
  lib: reduce the use of module.h wherever possible
  fs: reduce the use of module.h wherever possible
  includecheck: delete any duplicate instances of module.h
2012-03-24 10:24:31 -07:00
Hugh Dickins
9f7de8275b idr: make idr_get_next() good for rcu_read_lock()
Make one small adjustment to idr_get_next(): take the height from the top
layer (stable under RCU) instead of from the root (unprotected by RCU), as
idr_find() does: so that it can be used with RCU locking.  Copied comment
on RCU locking from idr_find().

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-21 17:55:01 -07:00
Paul Gortmaker
8bc3bcc93a lib: reduce the use of module.h wherever possible
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include.  Fix up any implicit
include dependencies that were being masked by module.h along
the way.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-03-07 15:04:04 -05:00
Tejun Heo
46cbc1d398 ida: make ida_simple_get/put() IRQ safe
It's often convenient to be able to release resource from IRQ context.
Make ida_simple_*() use irqsave/restore spin ops so that they are IRQ
safe.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-02 16:07:00 -07:00
Wang Sheng-Hui
e3816c5407 lib/idr.c: fix comment for ida_get_new_above()
Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31 17:30:56 -07:00
Jiri Kosina
e060c38434 Merge branch 'master' into for-next
Fast-forward merge with Linus to be able to merge patches
based on more recent version of the tree.
2011-09-15 15:08:18 +02:00
Paul Bolle
f5c3dd719d Fix kernel-doc comment typo '@id'
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-08-04 15:42:05 +02:00
Rusty Russell
88eca0207c ida: simplified functions for id allocation
The current hyper-optimized functions are overkill if you simply want to
allocate an id for a device.  Create versions which use an internal
lock.

In followup patches, numerous drivers are converted to use this
interface.

Thanks to Tejun for feedback.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-03 14:25:20 -10:00
Randy Dunlap
56083ab17e docbook: add idr/ida to kernel-api docbook
Add idr/ida to kernel-api docbook.
Fix typos and kernel-doc notation.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Naohiro Aota <naota@elisp.net>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 17:40:56 -07:00
Naohiro Aota
066a9be6c0 idr: fix idr_pre_get() locking description
Despite the idr_pre_get() kernel-doc, there are some cases where you can
call idr_pre_get() from within locked regions.  Add a description for such
cases.

See also: http://lkml.org/lkml/2010/9/16/462

[akpm@linux-foundation.org: cleanups, grammatical fixes]
Signed-off-by: Naohiro Aota <naota@elisp.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:18 -07:00