/*
 *  net/9p/util.c
 *
 *  This file contains some helper functions
 *
 *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/parser.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <net/9p/9p.h>

/**
 * struct p9_idpool - per-connection accounting for tag idpool
 * @lock: protects the pool
 * @pool: idr to allocate tag id from
 *
 */

struct p9_idpool {
	spinlock_t lock;
	struct idr pool;
};

/**
 * p9_idpool_create - create a new per-connection id pool
 *
 */

struct p9_idpool *p9_idpool_create(void)
{
	struct p9_idpool *p;

	p = kmalloc(sizeof(struct p9_idpool), GFP_KERNEL);
	if (!p)
		return ERR_PTR(-ENOMEM);

	spin_lock_init(&p->lock);
	idr_init(&p->pool);

	return p;
}
EXPORT_SYMBOL(p9_idpool_create);

/**
 * p9_idpool_destroy - create a new per-connection id pool
 * @p: idpool to destroy
 */

void p9_idpool_destroy(struct p9_idpool *p)
{
	idr_destroy(&p->pool);
	kfree(p);
}
EXPORT_SYMBOL(p9_idpool_destroy);

/**
 * p9_idpool_get - allocate numeric id from pool
 * @p: pool to allocate from
 *
 * Bugs: This seems to be an awful generic function, should it be in idr.c with
 *            the lock included in struct idr?
 */

int p9_idpool_get(struct p9_idpool *p)
{
	int i;
	unsigned long flags;

	idr_preload(GFP_NOFS);
	spin_lock_irqsave(&p->lock, flags);

	/* no need to store exactly p, we just need something non-null */
	i = idr_alloc(&p->pool, p, 0, 0, GFP_NOWAIT);

	spin_unlock_irqrestore(&p->lock, flags);
	idr_preload_end();
	if (i < 0)
		return -1;

	p9_debug(P9_DEBUG_MUX, " id %d pool %p\n", i, p);
	return i;
}
EXPORT_SYMBOL(p9_idpool_get);

/**
 * p9_idpool_put - release numeric id from pool
 * @id: numeric id which is being released
 * @p: pool to release id into
 *
 * Bugs: This seems to be an awful generic function, should it be in idr.c with
 *            the lock included in struct idr?
 */

void p9_idpool_put(int id, struct p9_idpool *p)
{
	unsigned long flags;

	p9_debug(P9_DEBUG_MUX, " id %d pool %p\n", id, p);

	spin_lock_irqsave(&p->lock, flags);
	idr_remove(&p->pool, id);
	spin_unlock_irqrestore(&p->lock, flags);
}
EXPORT_SYMBOL(p9_idpool_put);

/**
 * p9_idpool_check - check if the specified id is available
 * @id: id to check
 * @p: pool to check
 */

int p9_idpool_check(int id, struct p9_idpool *p)
{
	return idr_find(&p->pool, id) != NULL;
}
EXPORT_SYMBOL(p9_idpool_check);

lass='nohover-highlight'><td/><td colspan='5' class='logmsg'>
Patch series "fix a kernel oops when reading sysfs valid_zones", v2.

A sysfs memory file is created for each 2GiB memory block on x86-64 when
the system has 64GiB or more memory.  [1] When the start address of a
memory block is not backed by struct page, i.e.  a memory range is not
aligned by 2GiB, reading its 'valid_zones' attribute file leads to a
kernel oops.  This issue was observed on multiple x86-64 systems with
more than 64GiB of memory.  This patch-set fixes this issue.

Patch 1 first fixes an issue in test_pages_in_a_zone(), which does not
test the start section.

Patch 2 then fixes the kernel oops by extending test_pages_in_a_zone()
to return valid [start, end).

Note for stable kernels: The memory block size change was made by commit
bdee237c0343 ("x86: mm: Use 2GB memory block size on large-memory x86-64
systems"), which was accepted to 3.9.  However, this patch-set depends
on (and fixes) the change to test_pages_in_a_zone() made by commit
5f0f2887f4de ("mm/memory_hotplug.c: check for missing sections in
test_pages_in_a_zone()"), which was accepted to 4.4.

So, I recommend that we backport it up to 4.4.

[1] 'Commit bdee237c0343 ("x86: mm: Use 2GB memory block size on
    large-memory x86-64 systems")'

This patch (of 2):

test_pages_in_a_zone() does not check 'start_pfn' when it is aligned by
section since 'sec_end_pfn' is set equal to 'pfn'.  Since this function
is called for testing the range of a sysfs memory file, 'start_pfn' is
always aligned by section.

Fix it by properly setting 'sec_end_pfn' to the next section pfn.

Also make sure that this function returns 1 only when the range belongs
to a zone.

Link: http://lkml.kernel.org/r/20170127222149.30893-2-toshi.kani@hpe.com
Signed-off-by: Toshi Kani &lt;toshi.kani@hpe.com&gt;
Cc: Andrew Banman &lt;abanman@sgi.com&gt;
Cc: Reza Arbab &lt;arbab@linux.vnet.ibm.com&gt;
Cc: Greg KH &lt;greg@kroah.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[4.4+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;


</td></tr>
<tr class='logheader'><td><span title='2017-02-03 14:13:19 -0800'>2017-02-03</span></td><td class='logsubject'><a href='/cgit.cgi/linux/net-next.git/commit/?id=35f860f9ba6aac56cc38e8b18916d833a83f1157'>jump label: pass kbuild_cflags when checking for asm goto support</a></td><td>David Lin</td><td>1</td><td><span class='deletions'>-1</span>/<span class='insertions'>+1</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
Some versions of ARM GCC compiler such as Android toolchain throws in a
'-fpic' flag by default.  This causes the gcc-goto check script to fail
although some config would have '-fno-pic' flag in the KBUILD_CFLAGS.

This patch passes the KBUILD_CFLAGS to the check script so that the
script does not rely on the default config from different compilers.

Link: http://lkml.kernel.org/r/20170120234329.78868-1-dtwlin@google.com
Signed-off-by: David Lin &lt;dtwlin@google.com&gt;
Acked-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Michal Marek &lt;mmarek@suse.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;


</td></tr>
<tr class='logheader'><td><span title='2017-02-03 14:13:19 -0800'>2017-02-03</span></td><td class='logsubject'><a href='/cgit.cgi/linux/net-next.git/commit/?id=253fd0f02040a19c6fe80e4171659fa3482a422d'>shmem: fix sleeping from atomic context</a></td><td>Kirill A. Shutemov</td><td>1</td><td><span class='deletions'>-2</span>/<span class='insertions'>+9</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
Syzkaller fuzzer managed to trigger this:

    BUG: sleeping function called from invalid context at mm/shmem.c:852
    in_atomic(): 1, irqs_disabled(): 0, pid: 529, name: khugepaged
    3 locks held by khugepaged/529:
     #0:  (shrinker_rwsem){++++..}, at: [&lt;ffffffff818d7ef1&gt;] shrink_slab.part.59+0x121/0xd30 mm/vmscan.c:451
     #1:  (&amp;type-&gt;s_umount_key#29){++++..}, at: [&lt;ffffffff81a63630&gt;] trylock_super+0x20/0x100 fs/super.c:392
     #2:  (&amp;(&amp;sbinfo-&gt;shrinklist_lock)-&gt;rlock){+.+.-.}, at: [&lt;ffffffff818fd83e&gt;] spin_lock include/linux/spinlock.h:302 [inline]
     #2:  (&amp;(&amp;sbinfo-&gt;shrinklist_lock)-&gt;rlock){+.+.-.}, at: [&lt;ffffffff818fd83e&gt;] shmem_unused_huge_shrink+0x28e/0x1490 mm/shmem.c:427
    CPU: 2 PID: 529 Comm: khugepaged Not tainted 4.10.0-rc5+ #201
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    Call Trace:
       shmem_undo_range+0xb20/0x2710 mm/shmem.c:852
       shmem_truncate_range+0x27/0xa0 mm/shmem.c:939
       shmem_evict_inode+0x35f/0xca0 mm/shmem.c:1030
       evict+0x46e/0x980 fs/inode.c:553
       iput_final fs/inode.c:1515 [inline]
       iput+0x589/0xb20 fs/inode.c:1542
       shmem_unused_huge_shrink+0xbad/0x1490 mm/shmem.c:446
       shmem_unused_huge_scan+0x10c/0x170 mm/shmem.c:512
       super_cache_scan+0x376/0x450 fs/super.c:106
       do_shrink_slab mm/vmscan.c:378 [inline]
       shrink_slab.part.59+0x543/0xd30 mm/vmscan.c:481
       shrink_slab mm/vmscan.c:2592 [inline]
       shrink_node+0x2c7/0x870 mm/vmscan.c:2592
       shrink_zones mm/vmscan.c:2734 [inline]
       do_try_to_free_pages+0x369/0xc80 mm/vmscan.c:2776
       try_to_free_pages+0x3c6/0x900 mm/vmscan.c:2982
       __perform_reclaim mm/page_alloc.c:3301 [inline]
       __alloc_pages_direct_reclaim mm/page_alloc.c:3322 [inline]
       __alloc_pages_slowpath+0xa24/0x1c30 mm/page_alloc.c:3683
       __alloc_pages_nodemask+0x544/0xae0 mm/page_alloc.c:3848
       __alloc_pages include/linux/gfp.h:426 [inline]
       __alloc_pages_node include/linux/gfp.h:439 [inline]
       khugepaged_alloc_page+0xc2/0x1b0 mm/khugepaged.c:750
       collapse_huge_page+0x182/0x1fe0 mm/khugepaged.c:955
       khugepaged_scan_pmd+0xfdf/0x12a0 mm/khugepaged.c:1208
       khugepaged_scan_mm_slot mm/khugepaged.c:1727 [inline]
       khugepaged_do_scan mm/khugepaged.c:1808 [inline]
       khugepaged+0xe9b/0x1590 mm/khugepaged.c:1853
       kthread+0x326/0x3f0 kernel/kthread.c:227
       ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430

The iput() from atomic context was a bad idea: if after igrab() somebody
else calls iput() and we left with the last inode reference, our iput()
would lead to inode eviction and therefore sleeping.

This patch should fix the situation.

Link: http://lkml.kernel.org/r/20170131093141.GA15899@node.shutemov.name
Signed-off-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Reported-by: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;


</td></tr>
<tr class='logheader'><td><span title='2017-02-03 14:13:19 -0800'>2017-02-03</span></td><td class='logsubject'><a href='/cgit.cgi/linux/net-next.git/commit/?id=4f40c6e5627ea73b4e7c615c59631f38cc880885'>kasan: respect /proc/sys/kernel/traceoff_on_warning</a></td><td>Peter Zijlstra</td><td>1</td><td><span class='deletions'>-0</span>/<span class='insertions'>+3</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
After much waiting I finally reproduced a KASAN issue, only to find my
trace-buffer empty of useful information because it got spooled out :/

Make kasan_report honour the /proc/sys/kernel/traceoff_on_warning
interface.

Link: http://lkml.kernel.org/r/20170125164106.3514-1-aryabinin@virtuozzo.com
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Signed-off-by: Andrey Ryabinin &lt;aryabinin@virtuozzo.com&gt;
Acked-by: Alexander Potapenko &lt;glider@google.com&gt;
Cc: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;


</td></tr>
<tr class='logheader'><td><span title='2017-02-03 14:13:19 -0800'>2017-02-03</span></td><td class='logsubject'><a href='/cgit.cgi/linux/net-next.git/commit/?id=d7b028f56a971a2e4d8d7887540a144eeefcd4ab'>zswap: disable changing params if init fails</a></td><td>Dan Streetman</td><td>1</td><td><span class='deletions'>-1</span>/<span class='insertions'>+29</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
Add zswap_init_failed bool that prevents changing any of the module
params, if init_zswap() fails, and set zswap_enabled to false.  Change
'enabled' param to a callback, and check zswap_init_failed before
allowing any change to 'enabled', 'zpool', or 'compressor' params.

Any driver that is built-in to the kernel will not be unloaded if its
init function returns error, and its module params remain accessible for
users to change via sysfs.  Since zswap uses param callbacks, which
assume that zswap has been initialized, changing the zswap params after
a failed initialization will result in WARNING due to the param
callbacks expecting a pool to already exist.  This prevents that by
immediately exiting any of the param callbacks if initialization failed.

This was reported here:
  https://marc.info/?l=linux-mm&amp;m=147004228125528&amp;w=4

And fixes this WARNING:
  [  429.723476] WARNING: CPU: 0 PID: 5140 at mm/zswap.c:503 __zswap_pool_current+0x56/0x60

The warning is just noise, and not serious.  However, when init fails,
zswap frees all its percpu dstmem pages and its kmem cache.  The kmem
cache might be serious, if kmem_cache_alloc(NULL, gfp) has problems; but
the percpu dstmem pages are definitely a problem, as they're used as
temporary buffer for compressed pages before copying into place in the
zpool.

If the user does get zswap enabled after an init failure, then zswap
will likely Oops on the first page it tries to compress (or worse, start
corrupting memory).

Fixes: 90b0fc26d5db ("zswap: change zpool/compressor at runtime")
Link: http://lkml.kernel.org/r/20170124200259.16191-2-ddstreet@ieee.org
Signed-off-by: Dan Streetman &lt;dan.streetman@canonical.com&gt;
Reported-by: Marcin Miroslaw &lt;marcin@mejor.pl&gt;
Cc: Seth Jennings &lt;sjenning@redhat.com&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Sergey Senozhatsky &lt;sergey.senozhatsky.work@gmail.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;


</td></tr>
<tr class='logheader'><td><span title='2017-02-03 11:32:25 -0800'>2017-02-03</span></td><td class='logsubject'><a href='/cgit.cgi/linux/net-next.git/commit/?id=79c9089f97d37ffac88c3ddb6d359b2cf75058b7'>Merge tag 'drm-fixes-for-v4.10-rc7' of ↵</a></td><td>Linus Torvalds