The per-hctx nr_active value can no longer be used to fairly assign a share
of tag depth per request queue for when using a shared sbitmap, as it does
not consider that the tags are shared tags over all hctx's.

For this case, record the nr_active_requests per request_queue, and make
the judgement based on that value.

Co-developed-with: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Tested-by: Don Brace<don.brace@microsemi.com> #SCSI resv cmds patches used
Tested-by: NDouglas Gilbert <dgilbert@interlog.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Some SCSI HBAs (such as HPSA, megaraid, mpt3sas, hisi_sas_v3 ..) support
multiple reply queues with single hostwide tags.

In addition, these drivers want to use interrupt assignment in
pci_alloc_irq_vectors(PCI_IRQ_AFFINITY). However, as discussed in [0],
CPU hotplug may cause in-flight IO completion to not be serviced when an
interrupt is shutdown. That problem is solved in commit bf0beec0
("blk-mq: drain I/O when all CPUs in a hctx are offline").

However, to take advantage of that blk-mq feature, the HBA HW queuess are
required to be mapped to that of the blk-mq hctx's; to do that, the HBA HW
queues need to be exposed to the upper layer.

In making that transition, the per-SCSI command request tags are no
longer unique per Scsi host - they are just unique per hctx. As such, the
HBA LLDD would have to generate this tag internally, which has a certain
performance overhead.

However another problem is that blk-mq assumes the host may accept
(Scsi_host.can_queue * #hw queue) commands. In commit 6eb045e0 ("scsi:
 core: avoid host-wide host_busy counter for scsi_mq"), the Scsi host busy
counter was removed, which would stop the LLDD being sent more than
.can_queue commands; however, it should still be ensured that the block
layer does not issue more than .can_queue commands to the Scsi host.

To solve this problem, introduce a shared sbitmap per blk_mq_tag_set,
which may be requested at init time.

New flag BLK_MQ_F_TAG_HCTX_SHARED should be set when requesting the
tagset to indicate whether the shared sbitmap should be used.

Even when BLK_MQ_F_TAG_HCTX_SHARED is set, a full set of tags and requests
are still allocated per hctx; the reason for this is that if tags and
requests were only allocated for a single hctx - like hctx0 - it may break
block drivers which expect a request be associated with a specific hctx,
i.e. not always hctx0. This will introduce extra memory usage.

This change is based on work originally from Ming Lei in [1] and from
Bart's suggestion in [2].

[0] https://lore.kernel.org/linux-block/alpine.DEB.2.21.1904051331270.1802@nanos.tec.linutronix.de/
[1] https://lore.kernel.org/linux-block/20190531022801.10003-1-ming.lei@redhat.com/
[2] https://lore.kernel.org/linux-block/ff77beff-5fd9-9f05-12b6-826922bace1f@huawei.com/T/#m3db0a602f095cbcbff27e9c884d6b4ae826144beSigned-off-by: NJohn Garry <john.garry@huawei.com>
Tested-by: Don Brace<don.brace@microsemi.com> #SCSI resv cmds patches used
Tested-by: NDouglas Gilbert <dgilbert@interlog.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

BLK_MQ_F_TAG_SHARED actually means that tags is shared among request
queues, all of which should belong to LUNs attached to same HBA.

So rename it to make the point explicitly.

[jpg: rebase a few times, add rnbd-clt.c change]
Suggested-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Tested-by: NDouglas Gilbert <dgilbert@interlog.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Remove the now unused helper.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Acked-by: NSong Liu <song@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Only virtio_blk and xen-blkfront set the revalidate argument to true,
and both do not implement the ->revalidate_disk method.  So switch
to the helper that just updates the size instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

revalidate_disk is a relative awkward helper for driver use, as it first
calls an optional driver method and then updates the block device size,
while most callers either don't need the method call at all, or want to
keep state between the caller and the called method.

Add a revalidate_disk_size helper that just performs the update of the
block device size from the gendisk one, and switch all drivers that do
not implement ->revalidate_disk to use the new helper instead of
revalidate_disk()
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Acked-by: NSong Liu <song@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Replace bd_invalidate with a new BDEV_NEED_PART_SCAN flag in a bd_flags
variable to better describe the condition.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

CAP_SYS_ADMIN is too broad, and ionice fits into CAP_SYS_NICE's grouping.

Retain CAP_SYS_ADMIN permission for backwards compatibility.
Signed-off-by: NKhazhismel Kumykov <khazhy@google.com>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Update and restore the inuse update tracepoints.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Budget donations are inaccurate and could take multiple periods to converge.
To prevent triggering vrate adjustments while surplus transfers were
catching up, vrate adjustment was suppressed if donations were increasing,
which was indicated by non-zero nr_surpluses.

This entangling won't be necessary with the scheduled rewrite of donation
mechanism which will make it precise and immediate. Let's decouple the two
in preparation.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Currently, iocg->usages[] which are used to guide inuse adjustments are
calculated from vtime deltas. This, however, assumes that the hierarchical
inuse weight at the time of calculation held for the entire period, which
often isn't true and can lead to significant errors.

Now that we have absolute usage information collected, we can derive
iocg->usages[] from iocg->local_stat.usage_us so that inuse adjustment
decisions are made based on actual absolute usage. The calculated usage is
clamped between 1 and WEIGHT_ONE and WEIGHT_ONE is also used to signal
saturation regardless of the current hierarchical inuse weight.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

kdev_t is long gone, so we don't need to comment a field isn't one..
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The alignment offset is only used in slow path callers, so just calculate
it on the fly.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The alignment offset is only used in slow path callers, so just calculate
it on the fly.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Move the blk_mq_bio_list_merge() into blk-merge.c and
rename it as a generic name.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Just check if there is private data, in which case the bio must have
originated from bio_copy_user_iov.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We can simply use a boolean flag in the bio_map_data data structure
instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Two different callers use two different mutexes for updating the
block device size, which obviously doesn't help to actually protect
against concurrent updates from the different callers.  In addition
one of the locks, bd_mutex is rather prone to deadlocks with other
parts of the block stack that use it for high level synchronization.

Switch to using a new spinlock protecting just the size updates, as
that is all we need, and make sure everyone does the update through
the proper helper.

This fixes a bug reported with the nvme revalidating disks during a
hot removal operation, which can currently deadlock on bd_mutex.
Reported-by: NXianting Tian <xianting_tian@126.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Replace bd_set_size with a version that takes the number of sectors
instead, as that fits most of the current and future callers much better.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

request_queue.rpm_status is assigned values of the rpm_status enum only,
so reflect that in its type.

Note that including <linux/pm.h> is (currently) a no-op, as it is
already included through <linux/genhd.h> and <linux/device.h>, but it is
better to play it safe.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

I keep getting sparse warnings in crypto such as:

  CHECK   drivers/crypto/ccree/cc_hash.c
   drivers/crypto/ccree/cc_hash.c:49:9: warning: cast truncates bits from constant value (47b5481dbefa4fa4 becomes befa4fa4)
   drivers/crypto/ccree/cc_hash.c:49:26: warning: cast truncates bits from constant value (db0c2e0d64f98fa7 becomes 64f98fa7)
   [.. many more ..]

This patch removes the warning by adding a mask to keep sparse
happy.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The relation can't be invalid here, so if it turns out to be invalid,
just WARN_ON_ONCE() and return 0.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject and changelog edits ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

As virt_to_gfn uses virt_to_phys, it will return invalid addresses when
used with vmalloc'd addresses. This patch introduces a warning, when
virt_to_gfn is used in this way.
Signed-off-by: NSimon Leiner <simon@leiner.me>
Reviewed-by: NStefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20200825093153.35500-2-simon@leiner.meSigned-off-by: NJuergen Gross <jgross@suse.com>

Problem:

  raw_local_irq_save(); // software state on
  local_irq_save(); // software state off
  ...
  local_irq_restore(); // software state still off, because we don't enable IRQs
  raw_local_irq_restore(); // software state still off, *whoopsie*

existing instances:

 - lock_acquire()
     raw_local_irq_save()
     __lock_acquire()
       arch_spin_lock(&graph_lock)
         pv_wait() := kvm_wait() (same or worse for Xen/HyperV)
           local_irq_save()

 - trace_clock_global()
     raw_local_irq_save()
     arch_spin_lock()
       pv_wait() := kvm_wait()
	 local_irq_save()

 - apic_retrigger_irq()
     raw_local_irq_save()
     apic->send_IPI() := default_send_IPI_single_phys()
       local_irq_save()

Possible solutions:

 A) make it work by enabling the tracing inside raw_*()
 B) make it work by keeping tracing disabled inside raw_*()
 C) call it broken and clean it up now

Now, given that the only reason to use the raw_* variant is because you don't
want tracing. Therefore A) seems like a weird option (although it can be done).
C) is tempting, but OTOH it ends up converting a _lot_ of code to raw just
because there is one raw user, this strips the validation/tracing off for all
the other users.

So we pick B) and declare any code that ends up doing:

	raw_local_irq_save()
	local_irq_save()
	lockdep_assert_irqs_disabled();

broken. AFAICT this problem has existed forever, the only reason it came
up is because commit: 859d069e ("lockdep: Prepare for NMI IRQ
state tracking") changed IRQ tracing vs lockdep recursion and the
first instance is fairly common, the other cases hardly ever happen.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
[rewrote changelog]
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMarco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200723105615.1268126-1-npiggin@gmail.com

Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMarco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.546087214@infradead.org

This allows moving the leave_mm() call into generic code before
rcu_idle_enter(). Gets rid of more trace_*_rcuidle() users.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMarco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.369441600@infradead.org

Sven reported that commit a21ee605 ("lockdep: Change
hardirq{s_enabled,_context} to per-cpu variables") caused trouble on
s390 because their this_cpu_*() primitives disable preemption which
then lands back tracing.

On the one hand, per-cpu ops should use preempt_*able_notrace() and
raw_local_irq_*(), on the other hand, we can trivialy use raw_cpu_*()
ops for this.

Fixes: a21ee605 ("lockdep: Change hardirq{s_enabled,_context} to per-cpu variables")
Reported-by: NSven Schnelle <svens@linux.ibm.com>
Reviewed-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMarco Elver <elver@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200821085348.192346882@infradead.org

is_idle_task() may be used from noinstr functions such as
irqentry_enter(). Since the compiler is free to not inline regular
inline functions, switch to using __always_inline.
Signed-off-by: NMarco Elver <elver@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200820172046.GA177701@elver.google.com

Avoid -Wunused-const-variable warnings for "make W=1".
Reported-by: NLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
Reviewed-by: NLeon Romanovsky <leonro@nvidia.com>

This reverts commit 5c9fa16e.

Since PROT_SAO can still be useful for certain classes of software,
reintroduce it. Concerns about guest migration for LPARs using SAO
will be addressed next.
Signed-off-by: NShawn Anastasio <shawn@anastas.io>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200821185558.35561-2-shawn@anastas.io

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-throughSigned-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>

Also remove trailing whitespaces in bpf_skb_get_tunnel_key example code.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200821133642.18870-1-tklauser@distanz.ch

We add a separate CLINT timer driver for Linux RISC-V M-mode (i.e.
RISC-V NoMMU kernel).

The CLINT MMIO device provides three things:
1. 64bit free running counter register
2. 64bit per-CPU time compare registers
3. 32bit per-CPU inter-processor interrupt registers

Unlike other timer devices, CLINT provides IPI registers along with
timer registers. To use CLINT IPI registers, the CLINT timer driver
provides IPI related callbacks to arch/riscv.
Signed-off-by: NAnup Patel <anup.patel@wdc.com>
Tested-by: NEmil Renner Berhing <kernel@esmil.dk>
Acked-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: NAtish Patra <atish.patra@wdc.com>
Reviewed-by: NPalmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

In the scenario of writing sparse files, the per-inode prealloc list may
be very long, resulting in high overhead for ext4_mb_use_preallocated().
To circumvent this problem, we limit the maximum length of per-inode
prealloc list to 512 and allow users to modify it.

After patching, we observed that the sys ratio of cpu has dropped, and
the system throughput has increased significantly. We created a process
to write the sparse file, and the running time of the process on the
fixed kernel was significantly reduced, as follows:

Running time on unfixed kernel：
[root@TENCENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat
real    0m2.051s
user    0m0.008s
sys     0m2.026s

Running time on fixed kernel：
[root@TENCENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat
real    0m0.471s
user    0m0.004s
sys     0m0.395s
Signed-off-by: NChunguang Xu <brookxu@tencent.com>
Link: https://lore.kernel.org/r/d7a98178-056b-6db5-6bce-4ead23f4a257@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This patch is to do 3 things for ipv6_dev_find():

  As David A. noticed,

  - rt6_lookup() is not really needed. Different from __ip_dev_find(),
    ipv6_dev_find() doesn't have a compatibility problem, so remove it.

  As Hideaki suggested,

  - "valid" (non-tentative) check for the address is also needed.
    ipv6_chk_addr() calls ipv6_chk_addr_and_flags(), which will
    traverse the address hash list, but it's heavy to be called
    inside ipv6_dev_find(). This patch is to reuse the code of
    ipv6_chk_addr_and_flags() for ipv6_dev_find().

  - dev parameter is passed into ipv6_dev_find(), as link-local
    addresses from user space has sin6_scope_id set and the dev
    lookup needs it.

Fixes: 81f6cb31 ("ipv6: add ipv6_dev_find()")
Suggested-by: NYOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com>
Reported-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IA-64 is special and treats pgd_offset_k() differently to pgd_offset(),
using different formulae to calculate the indices into the kernel and user
PGDs.  The index into the user PGDs takes into account the region number,
but the index into the kernel (init_mm) PGD always assumes a predefined
kernel region number. Commit 974b9b2c ("mm: consolidate pte_index() and
pte_offset_*() definitions") made IA-64 use a generic pgd_offset_k() which
incorrectly used pgd_index() for kernel page tables.  As a result, the
index into the kernel PGD was going out of bounds and the kernel hung
during early boot.

Allow overrides of pgd_offset_k() and override it on IA-64 with the old
implementation that will correctly index the kernel PGD.

Fixes: 974b9b2c ("mm: consolidate pte_index() and pte_offset_*() definitions")
Reported-by: NJohn Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: NJessica Clarke <jrtc27@jrtc27.com>
Tested-by: NJohn Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Acked-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>

Fix a kernel-doc warning for the pcs_config() function prototype:

../include/linux/phylink.h:406: warning: Excess function parameter 'permit_pause_to_mac' description in 'pcs_config'

Fixes: 7137e18f ("net: phylink: add struct phylink_pcs")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: David S. Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This fell off in the conversion in

commit 9bcaa3fe
Author: Michal Orzel <michalorzel.eng@gmail.com>
Date:   Tue Apr 28 19:10:04 2020 +0200

    drm: Replace drm_modeset_lock/unlock_all with DRM_MODESET_LOCK_ALL_* helpers

but it's caught by the drm_warn_on_modeset_not_all_locked() that the
legacy modeset code uses. Since this is the bkl and it's unclear
what's all protected, play it safe and grab it again for legacy
drivers.

Unfortunately this means we need to sprinkle a few more #includes
around.

Also we need to add the drm_device as a parameter to the _END macro.

Finally remove the mute_lock() from setcrtc, since that's now done by
the macro.

Cc: Alex Deucher <alexdeucher@gmail.com>
References: https://gitlab.freedesktop.org/drm/amd/-/issues/1224
Fixes: 9bcaa3fe ("drm: Replace drm_modeset_lock/unlock_all with DRM_MODESET_LOCK_ALL_* helpers")
Cc: Michal Orzel <michalorzel.eng@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.8+
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200814093842.3048472-1-daniel.vetter@ffwll.ch

Impose a limit on the number of watches that a user can hold so that
they can't use this mechanism to fill up all the available memory.

This is done by putting a counter in user_struct that's incremented when
a watch is allocated and decreased when it is released.  If the number
exceeds the RLIMIT_NOFILE limit, the watch is rejected with EAGAIN.

This can be tested by the following means:

 (1) Create a watch queue and attach it to fd 5 in the program given - in
     this case, bash:

	keyctl watch_session /tmp/nlog /tmp/gclog 5 bash

 (2) In the shell, set the maximum number of files to, say, 99:

	ulimit -n 99

 (3) Add 200 keyrings:

	for ((i=0; i<200; i++)); do keyctl newring a$i @s || break; done

 (4) Try to watch all of the keyrings:

	for ((i=0; i<200; i++)); do echo $i; keyctl watch_add 5 %:a$i || break; done

     This should fail when the number of watches belonging to the user hits
     99.

 (5) Remove all the keyrings and all of those watches should go away:

	for ((i=0; i<200; i++)); do keyctl unlink %:a$i; done

 (6) Kill off the watch queue by exiting the shell spawned by
     watch_session.

Fixes: c73be61c ("pipe: Add general notification queue support")
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With SYSFW ABI 3.0 changes, interrupts coming out of an interrupt
controller is identified by a type and it is consistent across SoCs.
Similarly global events for Interrupt aggregator. So add an API to get
resource range using a resource type.
Signed-off-by: NLokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: NMarc Zyngier <maz@kernel.org>
Acked-by: NNishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20200806074826.24607-4-lokeshvutla@ti.com