1279399 Commits

Author SHA1 Message Date
Krzysztof Kozlowski
e1e4d37683 scsi: virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-23-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
2024-05-22 08:31:18 -04:00
Krzysztof Kozlowski
f42c7405fd rpmsg: virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Message-Id: <20240331-module-owner-virtio-v2-22-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:18 -04:00
Krzysztof Kozlowski
9dceed1b0a nvdimm: virtio_pmem: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Acked-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Message-Id: <20240331-module-owner-virtio-v2-21-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
2024-05-22 08:31:18 -04:00
Krzysztof Kozlowski
19680c70fa wifi: mac80211_hwsim: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-20-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:18 -04:00
Krzysztof Kozlowski
b1c16d4a33 vsock/virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Message-Id: <20240331-module-owner-virtio-v2-19-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2024-05-22 08:31:17 -04:00
Krzysztof Kozlowski
d26dd255ce net: 9p: virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-18-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:17 -04:00
Krzysztof Kozlowski
9a03bfa108 net: virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-17-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:17 -04:00
Krzysztof Kozlowski
606f1f9f3d net: caif: virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-16-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:17 -04:00
Krzysztof Kozlowski
7249ad5a71 misc: nsm: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-15-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
2024-05-22 08:31:17 -04:00
Krzysztof Kozlowski
ac5990d3ec iommu: virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-14-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:17 -04:00
Krzysztof Kozlowski
41dca8275a drm/virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-13-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:17 -04:00
Krzysztof Kozlowski
2ce0b26c11 gpio: virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Message-Id: <20240331-module-owner-virtio-v2-12-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
2024-05-22 08:31:17 -04:00
Krzysztof Kozlowski
cfffb29c48 firmware: arm_scmi: virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-11-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
2024-05-22 08:31:17 -04:00
Krzysztof Kozlowski
9e00c140f3 crypto: virtio - drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-10-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
2024-05-22 08:31:16 -04:00
Krzysztof Kozlowski
a610e31aa1 virtio_console: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-9-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:16 -04:00
Krzysztof Kozlowski
6098bb3884 hwrng: virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-8-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:16 -04:00
Krzysztof Kozlowski
1e0d03b7d0 bluetooth: virtio: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-7-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:16 -04:00
Krzysztof Kozlowski
bdb8e2f8e8 virtio_blk: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-6-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2024-05-22 08:31:16 -04:00
Krzysztof Kozlowski
9731be4bc8 um: virt-pci: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Message-Id: <20240331-module-owner-virtio-v2-5-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:16 -04:00
Krzysztof Kozlowski
b0e55a950e virtio: mem: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-4-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:16 -04:00
Krzysztof Kozlowski
ebfb92a967 virtio: input: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-3-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:16 -04:00
Krzysztof Kozlowski
7cc5d6caaf virtio: balloon: drop owner assignment
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-2-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:16 -04:00
David Stevens
c578123e63 virtio_balloon: Treat stats requests as wakeup events
Treat stats requests as wakeup events to ensure that the driver responds
to device requests in a timely manner.

Signed-off-by: David Stevens <stevensd@chromium.org>
Acked-by: David Hildenbrand <david@redhat.com>
Message-Id: <20240321012445.1593685-3-stevensd@google.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:16 -04:00
David Stevens
810d831bbb virtio_balloon: Give the balloon its own wakeup source
Wakeup sources don't support nesting multiple events, so sharing a
single object between multiple drivers can result in one driver
overriding the wakeup event processing period specified by another
driver. Have the virtio balloon driver use the wakeup source of the
device it is bound to rather than the wakeup source of the parent
device, to avoid conflicts with the transport layer.

Note that although the virtio balloon's virtio_device itself isn't what
actually wakes up the device, it is responsible for processing wakeup
events. In the same way that EPOLLWAKEUP uses a dedicated wakeup_source
to prevent suspend when userspace is processing wakeup events, a
dedicated wakeup_source is necessary when processing wakeup events in a
higher layer in the kernel.

Fixes: b12fbc3f787e ("virtio_balloon: stay awake while adjusting balloon")
Signed-off-by: David Stevens <stevensd@chromium.org>
Acked-by: David Hildenbrand <david@redhat.com>
Message-Id: <20240321012445.1593685-2-stevensd@google.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:16 -04:00
David Hildenbrand
e4544c550e virtio-mem: support suspend+resume
With virtio-mem, primarily hibernation is problematic: as the machine shuts
down, the virtio-mem device loses its state. Powering the machine back up
is like losing a bunch of DIMMs. While there would be ways to add limited
support, suspend+resume is more commonly used for VMs and "easier" to
support cleanly.

s2idle can be supported without any device dependencies. Similarly, one
would expect suspend-to-ram (i.e., S3) to work out of the box. However,
QEMU currently unplugs all device memory when resuming the VM, using a
cold reset on the "wakeup" path. In order to support S3, we need a feature
flag for the device to tell us if memory remains plugged when waking up. In
the future, QEMU will implement this feature.

So let's always support s2idle and support S3 with plugged memory only if
the device indicates support. Block hibernation early using the PM
notifier.

Trying to hibernate now fails early:
	# echo disk > /sys/power/state
	[   26.455369] PM: hibernation: hibernation entry
	[   26.458271] virtio_mem virtio0: hibernation is not supported.
	[   26.462498] PM: hibernation: hibernation exit
	-bash: echo: write error: Operation not permitted

s2idle works even without the new feature bit:
	# echo s2idle > /sys/power/mem_sleep
	# echo mem > /sys/power/state
	[   52.083725] PM: suspend entry (s2idle)
	[   52.095950] Filesystems sync: 0.010 seconds
	[   52.101493] Freezing user space processes
	[   52.104213] Freezing user space processes completed (elapsed 0.001 seconds)
	[   52.106520] OOM killer disabled.
	[   52.107655] Freezing remaining freezable tasks
	[   52.110880] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
	[   52.113296] printk: Suspending console(s) (use no_console_suspend to debug)

S3 does not work without the feature bit when memory is plugged:
	# echo deep > /sys/power/mem_sleep
	# echo mem > /sys/power/state
	[   32.788281] PM: suspend entry (deep)
	[   32.816630] Filesystems sync: 0.027 seconds
	[   32.820029] Freezing user space processes
	[   32.823870] Freezing user space processes completed (elapsed 0.001 seconds)
	[   32.827756] OOM killer disabled.
	[   32.829608] Freezing remaining freezable tasks
	[   32.833842] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
	[   32.837953] printk: Suspending console(s) (use no_console_suspend to debug)
	[   32.916172] virtio_mem virtio0: suspend+resume with plugged memory is not supported
	[   32.916181] virtio-pci 0000:00:02.0: PM: pci_pm_suspend(): virtio_pci_freeze+0x0/0x50 returns -1
	[   32.916197] virtio-pci 0000:00:02.0: PM: dpm_run_callback(): pci_pm_suspend+0x0/0x170 returns -1
	[   32.916210] virtio-pci 0000:00:02.0: PM: failed to suspend async: error -1

But S3 works with the new feature bit when memory is plugged (patched
QEMU):
	# echo deep > /sys/power/mem_sleep
	# echo mem > /sys/power/state
	[   33.983694] PM: suspend entry (deep)
	[   34.009828] Filesystems sync: 0.024 seconds
	[   34.013589] Freezing user space processes
	[   34.016722] Freezing user space processes completed (elapsed 0.001 seconds)
	[   34.019092] OOM killer disabled.
	[   34.020291] Freezing remaining freezable tasks
	[   34.023549] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
	[   34.026090] printk: Suspending console(s) (use no_console_suspend to debug)

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20240318120645.105664-1-david@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Mike Christie
240a1853b4 kernel: Remove signal hacks for vhost_tasks
This removes the signal/coredump hacks added for vhost_tasks in:

Commit f9010dbdce91 ("fork, vhost: Use CLONE_THREAD to fix freezer/ps regression")

When that patch was added vhost_tasks did not handle SIGKILL and would
try to ignore/clear the signal and continue on until the device's close
function was called. In the previous patches vhost_tasks and the vhost
drivers were converted to support SIGKILL by cleaning themselves up and
exiting. The hacks are no longer needed so this removes them.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-10-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Mike Christie
db5247d9bf vhost_task: Handle SIGKILL by flushing work and exiting
Instead of lingering until the device is closed, this has us handle
SIGKILL by:

1. marking the worker as killed so we no longer try to use it with
   new virtqueues and new flush operations.
2. setting the virtqueue to worker mapping so no new works are queued.
3. running all the exiting works.

Suggested-by: Edward Adam Davis <eadavis@qq.com>
Reported-and-tested-by: syzbot+98edc2df894917b3431f@syzkaller.appspotmail.com
Message-Id: <tencent_546DA49414E876EEBECF2C78D26D242EE50A@qq.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-9-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Mike Christie
ba704ff4e1 vhost: Release worker mutex during flushes
In the next patches where the worker can be killed while in use, we
need to be able to take the worker mutex and kill queued works for
new IO and flushes, and set some new flags to prevent new
__vhost_vq_attach_worker calls from swapping in/out killed workers.

If we are holding the worker mutex during a flush and the flush's work
is still in the queue, the worker code that will handle the SIGKILL
cleanup won't be able to take the mutex and perform it's cleanup. So
this patch has us drop the worker mutex while waiting for the flush
to complete.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-8-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Mike Christie
34cf9ba5f0 vhost: Use virtqueue mutex for swapping worker
__vhost_vq_attach_worker uses the vhost_dev mutex to serialize the
swapping of a virtqueue's worker. This was done for simplicity because
we are already holding that mutex.

In the next patches where the worker can be killed while in use, we need
finer grained locking because some drivers will hold the vhost_dev mutex
while flushing. However in the SIGKILL handler in the next patches, we
will need to be able to swap workers (set current one to NULL), kill
queued works and stop new flushes while flushes are in progress.

To prepare us, this has us use the virtqueue mutex for swapping workers
instead of the vhost_dev one.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-7-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Mike Christie
0352c961cb vhost_scsi: Handle vhost_vq_work_queue failures for TMFs
vhost_vq_work_queue will never fail when queueing the TMF's response
handling because a guest can only send us TMFs when the device is fully
setup so there is always a worker at that time. In the next patches we
will modify the worker code so it handles SIGKILL by exiting before
outstanding commands/TMFs have sent their responses. In that case
vhost_vq_work_queue can fail when we try to send a response.

This has us just free the TMF's resources since at this time the guest
won't be able to get a response even if we could send it.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-6-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Mike Christie
d9e59eec4a vhost: Remove vhost_vq_flush
vhost_vq_flush is no longer used so remove it.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-5-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Mike Christie
59b701b99e vhost-scsi: Use system wq to flush dev for TMFs
We flush all the workers that are not also used by the ctl vq to make
sure that responses queued by LIO before the TMF response are sent
before the TMF response. This requires a special vhost_vq_flush
function which, in the next patches where we handle SIGKILL killing
workers while in use, will require extra locking/complexity. To avoid
that, this patch has us flush the entire device from the system work
queue, then queue up sending the response from there.

This is a little less optimal since we now flush all workers but this
will be ok since commands have already timed out and perf is not a
concern.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-4-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Mike Christie
1eceddeeb6 vhost-scsi: Handle vhost_vq_work_queue failures for cmds
In the next patches we will support the vhost_task being killed while in
use. The problem for vhost-scsi is that we can't free some structs until
we get responses for commands we have submitted to the target layer and
we currently process the responses from the vhost_task.

This has just drop the responses and free the command's resources. When
all commands have completed then operations like flush will be woken up
and we can complete device release and endpoint cleanup.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-3-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Mike Christie
b1b2ce58ed vhost-scsi: Handle vhost_vq_work_queue failures for events
Currently, we can try to queue an event's work before the vhost_task is
created. When this happens we just drop it in vhost_scsi_do_plug before
even calling vhost_vq_work_queue. During a device shutdown we do the
same thing after vhost_scsi_clear_endpoint has cleared the backends.

In the next patches we will be able to kill the vhost_task before we
have cleared the endpoint. In that case, vhost_vq_work_queue can fail
and we will leak the event's memory. This has handle the failure by
just freeing the event. This is safe to do, because
vhost_vq_work_queue will only return failure for us when the vhost_task
is killed and so userspace will not be able to handle events if we
sent them.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-2-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Li Zhijian
7b1b5c7fff vdpa: Convert sprintf/snprintf to sysfs_emit
Per filesystems/sysfs.rst, show() should only use sysfs_emit()
or sysfs_emit_at() when formatting the value to be returned to user space.

coccinelle complains that there are still a couple of functions that use
snprintf(). Convert them to sysfs_emit().

sprintf() will be converted as weel if they have.

Generally, this patch is generated by
make coccicheck M=<path/to/file> MODE=patch \
COCCI=scripts/coccinelle/api/device_attr_show.cocci

No functional change intended

CC: "Michael S. Tsirkin" <mst@redhat.com>
CC: Jason Wang <jasowang@redhat.com>
CC: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
CC: virtualization@lists.linux.dev
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Message-Id: <20240314095853.1326111-1-lizhijian@fujitsu.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Yuxue Liu
f181a3736b vp_vdpa: Fix return value check vp_vdpa_request_irq
In the vp_vdpa_set_status function, when setting the device status to
VIRTIO_CONFIG_S_DRIVER_OK, the vp_vdpa_request_irq function may fail.
In such cases, the device status should not be set to DRIVER_OK. Add
exception printing to remind the user.

Signed-off-by: Yuxue Liu <yuxue.liu@jaguarmicro.com>
Message-Id: <20240325105448.235-1-gavin.liu@jaguarmicro.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-05-22 08:31:15 -04:00
Ard Biesheuvel
e92bee9f86 arm64/fpsimd: Avoid erroneous elide of user state reload
TIF_FOREIGN_FPSTATE is a 'convenience' flag that should reflect whether
the current CPU holds the most recent user mode FP/SIMD state of the
current task. It combines two conditions:
- whether the current CPU's FP/SIMD state belongs to the task;
- whether that state is the most recent associated with the task (as a
  task may have executed on other CPUs as well).

When a task is scheduled in and TIF_KERNEL_FPSTATE is set, it means the
task was in a kernel mode NEON section when it was scheduled out, and so
the kernel mode FP/SIMD state is restored. Since this implies that the
current CPU is *not* holding the most recent user mode FP/SIMD state of
the current task, the TIF_FOREIGN_FPSTATE flag is set too, so that the
user mode FP/SIMD state is reloaded from memory when returning to
userland.

However, the task may be scheduled out after completing the kernel mode
NEON section, but before returning to userland. When this happens, the
TIF_FOREIGN_FPSTATE flag will not be preserved, but will be set as usual
the next time the task is scheduled in, and will be based on the above
conditions.

This means that, rather than setting TIF_FOREIGN_FPSTATE when scheduling
in a task with TIF_KERNEL_FPSTATE set, the underlying state should be
updated so that TIF_FOREIGN_FPSTATE will assume the expected value as a
result.

So instead, call fpsimd_flush_cpu_state(), which takes care of this.

Closes: https://lore.kernel.org/all/cb8822182231850108fa43e0446a4c7f@kernel.org
Reported-by: Johannes Nixdorf <mixi@shadowice.org>
Fixes: aefbab8e77eb ("arm64: fpsimd: Preserve/restore kernel mode NEON at context switch")
Cc: Mark Brown <broonie@kernel.org>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Janne Grunau <j@jannau.net>
Cc: stable@vger.kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Janne Grunau <j@jannau.net>
Tested-by: Johannes Nixdorf <mixi@shadowice.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240522091335.335346-2-ardb+git@google.com
Signed-off-by: Will Deacon <will@kernel.org>
2024-05-22 12:46:39 +01:00
Will Deacon
f481bb32d6 Reapply "arm64: fpsimd: Implement lazy restore for kernel mode FPSIMD"
This reverts commit b8995a18417088bb53f87c49d200ec72a9dd4ec1.

Ard managed to reproduce the dm-crypt corruption problem and got to the
bottom of it, so re-apply the problematic patch in preparation for
fixing things properly.

Cc: stable@vger.kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
2024-05-22 11:55:00 +01:00
Tony Luck
93022482b2 x86/cpu: Fix x86_match_cpu() to match just X86_VENDOR_INTEL
Code in v6.9 arch/x86/kernel/smpboot.c was changed by commit

  4db64279bc2b ("x86/cpu: Switch to new Intel CPU model defines") from:

  static const struct x86_cpu_id intel_cod_cpu[] = {
          X86_MATCH_INTEL_FAM6_MODEL(HASWELL_X, 0),       /* COD */
          X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_X, 0),     /* COD */
          X86_MATCH_INTEL_FAM6_MODEL(ANY, 1),             /* SNC */	<--- 443
          {}
  };

  static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
  {
          const struct x86_cpu_id *id = x86_match_cpu(intel_cod_cpu);

to:

  static const struct x86_cpu_id intel_cod_cpu[] = {
           X86_MATCH_VFM(INTEL_HASWELL_X,   0),    /* COD */
           X86_MATCH_VFM(INTEL_BROADWELL_X, 0),    /* COD */
           X86_MATCH_VFM(INTEL_ANY,         1),    /* SNC */
           {}
   };

  static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
  {
          const struct x86_cpu_id *id = x86_match_cpu(intel_cod_cpu);

On an Intel CPU with SNC enabled this code previously matched the rule on line
443 to avoid printing messages about insane cache configuration.  The new code
did not match any rules.

Expanding the macros for the intel_cod_cpu[] array shows that the old is
equivalent to:

  static const struct x86_cpu_id intel_cod_cpu[] = {
  [0] = { .vendor = 0, .family = 6, .model = 0x3F, .steppings = 0, .feature = 0, .driver_data = 0 },
  [1] = { .vendor = 0, .family = 6, .model = 0x4F, .steppings = 0, .feature = 0, .driver_data = 0 },
  [2] = { .vendor = 0, .family = 6, .model = 0x00, .steppings = 0, .feature = 0, .driver_data = 1 },
  [3] = { .vendor = 0, .family = 0, .model = 0x00, .steppings = 0, .feature = 0, .driver_data = 0 }
  }

while the new code expands to:

  static const struct x86_cpu_id intel_cod_cpu[] = {
  [0] = { .vendor = 0, .family = 6, .model = 0x3F, .steppings = 0, .feature = 0, .driver_data = 0 },
  [1] = { .vendor = 0, .family = 6, .model = 0x4F, .steppings = 0, .feature = 0, .driver_data = 0 },
  [2] = { .vendor = 0, .family = 0, .model = 0x00, .steppings = 0, .feature = 0, .driver_data = 1 },
  [3] = { .vendor = 0, .family = 0, .model = 0x00, .steppings = 0, .feature = 0, .driver_data = 0 }
  }

Looking at the code for x86_match_cpu():

  const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match)
  {
           const struct x86_cpu_id *m;
           struct cpuinfo_x86 *c = &boot_cpu_data;

           for (m = match;
                m->vendor | m->family | m->model | m->steppings | m->feature;
                m++) {
       		...
           }
           return NULL;

it is clear that there was no match because the ANY entry in the table (array
index 2) is now the loop termination condition (all of vendor, family, model,
steppings, and feature are zero).

So this code was working before because the "ANY" check was looking for any
Intel CPU in family 6. But fails now because the family is a wild card. So the
root cause is that x86_match_cpu() has never been able to match on a rule with
just X86_VENDOR_INTEL and all other fields set to wildcards.

Add a new flags field to struct x86_cpu_id that has a bit set to indicate that
this entry in the array is valid. Update X86_MATCH*() macros to set that bit.
Change the end-marker check in x86_match_cpu() to just check the flags field
for this bit.

Backporter notes: The commit in Fixes is really the one that is broken:
you can't have m->vendor as part of the loop termination conditional in
x86_match_cpu() because it can happen - as it has happened above
- that that whole conditional is 0 albeit vendor == 0 is a valid case
- X86_VENDOR_INTEL is 0.

However, the only case where the above happens is the SNC check added by
4db64279bc2b1 so you only need this fix if you have backported that
other commit

  4db64279bc2b ("x86/cpu: Switch to new Intel CPU model defines")

Fixes: 644e9cbbe3fc ("Add driver auto probing for x86 features v4")
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable+noautosel@kernel.org> # see above
Link: https://lore.kernel.org/r/20240517144312.GBZkdtAOuJZCvxhFbJ@fat_crate.local
2024-05-22 11:31:10 +02:00
Souradeep Chakrabarti
9c91c7fadb net: mana: Fix the extra HZ in mana_hwc_send_request
Commit 62c1bff593b7 added an extra HZ along with msecs_to_jiffies.
This patch fixes that.

Cc: stable@vger.kernel.org
Fixes: 62c1bff593b7 ("net: mana: Configure hwc timeout from hardware")
Signed-off-by: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/r/1716185104-31658-1-git-send-email-schakrabarti@linux.microsoft.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-05-22 11:17:07 +02:00
Tony Luck
6d85a058cf crypto: x86/aes-xts - switch to new Intel CPU model defines
New CPU #defines encode vendor and family as well as model.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Link: https://lore.kernel.org/r/20240520224620.9480-2-tony.luck@intel.com
2024-05-22 11:10:48 +02:00
Takashi Iwai
c1a8d5f31b ALSA: core: Enable proc module when CONFIG_MODULES=y
We used '#ifdef MODULE' for judging whether the system supports the
sound module or not, and /proc/asound/modules is created only when
'#ifdef MODULE' is true.  The check is not really appropriate, though,
because the flag means only for the sound core and the drivers are
still allowed to be built as modules even if 'MODULE' is not set in
sound/core/init.c.

For fixing the inconsistency, replace those ifdefs with 'ifdef
CONFIG_MODULES'.  One place for a NULL module check is rewritten with
IS_MODULE(CONFIG_SND) to be more intuitive.  It can't be changed to
CONFIG_MODULES; otherwise it would hit a WARN_ON() incorrectly.

This is a slight behavior change; the modules proc entry appears now
no matter whether the sound core is built-in or not as long as modules
are enabled on the kernel in general.  This can't be avoided due to
the nature of kernel builds.

Link: https://lore.kernel.org/r/20240520170349.2417900-1-xu.yang_2@nxp.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20240522070442.17786-2-tiwai@suse.de
2024-05-22 10:10:42 +02:00
Takashi Iwai
39381fe739 ALSA: core: Fix NULL module pointer assignment at card init
The commit 81033c6b584b ("ALSA: core: Warn on empty module")
introduced a WARN_ON() for a NULL module pointer passed at snd_card
object creation, and it also wraps the code around it with '#ifdef
MODULE'.  This works in most cases, but the devils are always in
details.  "MODULE" is defined when the target code (i.e. the sound
core) is built as a module; but this doesn't mean that the caller is
also built-in or not.  Namely, when only the sound core is built-in
(CONFIG_SND=y) while the driver is a module (CONFIG_SND_USB_AUDIO=m),
the passed module pointer is ignored even if it's non-NULL, and
card->module remains as NULL.  This would result in the missing module
reference up/down at the device open/close, leading to a race with the
code execution after the module removal.

For addressing the bug, move the assignment of card->module again out
of ifdef.  The WARN_ON() is still wrapped with ifdef because the
module can be really NULL when all sound drivers are built-in.

Note that we keep 'ifdef MODULE' for WARN_ON(), otherwise it would
lead to a false-positive NULL module check.  Admittedly it won't catch
perfectly, i.e. no check is performed when CONFIG_SND=y.  But, it's no
real problem as it's only for debugging, and the condition is pretty
rare.

Fixes: 81033c6b584b ("ALSA: core: Warn on empty module")
Reported-by: Xu Yang <xu.yang_2@nxp.com>
Closes: https://lore.kernel.org/r/20240520170349.2417900-1-xu.yang_2@nxp.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20240522070442.17786-1-tiwai@suse.de
2024-05-22 10:10:39 +02:00
Horatiu Vultur
eda40be3a5 net: lan966x: Remove ptp traps in case the ptp is not enabled.
Lan966x is adding ptp traps to redirect the ptp frames to the CPU such
that the HW will not forward these frames anywhere. The issue is that in
case ptp is not enabled and the timestamping source is et to
HWTSTAMP_SOURCE_NETDEV then these traps would not be removed on the
error path.
Fix this by removing the traps in this case as they are not needed.

Fixes: 54e1ed69c40a ("net: lan966x: convert to ndo_hwtstamp_get() and ndo_hwtstamp_set()")
Suggested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Link: https://lore.kernel.org/r/20240517135808.3025435-1-horatiu.vultur@microchip.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-05-22 10:09:04 +02:00
Yu Kuai
9a42891c35 block: fix lost bio for plug enabled bio based device
With the following two conditions, bio will be lost:

1) blk plug is not enabled, for example, __blkdev_direct_IO_simple() and
__blkdev_direct_IO_async();
2) bio plug is enabled, for example write IO for raid1/raid10 while
bitmap is enabled;

Root cause is that blk_finish_plug() will add the bio to
curent->bio_list, while such bio will not be handled:

__submit_bio_noacct
 current->bio_list = bio_list_on_stack;
 blk_start_plug

 do {
  dm_submit_bio
   md_handle_request
    raid10_write_request
     -> generate new bio for underlying disks
     raid1_add_bio_to_plug -> bio is added to plug
 } while ((bio = bio_list_pop(&bio_list_on_stack[0])))
 -> previous bio are all handled

 blk_finish_plug
  raid10_unplug
   raid1_submit_write
    submit_bio_noacct
     if (current->bio_list)
      bio_list_add(&current->bio_list[0], bio)
      -> add new bio

 current->bio_list = NULL
 -> new bio is lost

Fix the problem by moving the plug into the while loop, so that
current->bio_list will still be handled after blk_finish_plug().

By the way, enable plug for raid1/raid10 in this case will also prevent
delay IO handling into daemon thread, which should also improve IO
performance.

Fixes: 060406c61c7c ("block: add plug while submitting IO")
Reported-by: Changhui Zhong <czhong@redhat.com>
Closes: https://lore.kernel.org/all/CAGVVp+Xsmzy2G9YuEatfMT6qv1M--YdOCQ0g7z7OVmcTbBxQAg@mail.gmail.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Tested-by: Changhui Zhong <czhong@redhat.com>
Link: https://lore.kernel.org/r/20240521200308.983986-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-05-21 19:37:33 -06:00
Dave Airlie
3e3eb55e2b Merge tag 'drm-misc-next-fixes-2024-05-16' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-next
drm-misc-next-fixes for v6.10-rc1:
- VM_BIND fix for nouveau.
- Lots of panthor fixes:
  * Fixes for panthor's heap logical block.
  * Reset on unrecoverable fault
  * Fix VM references.
  * Reset fix.
- xlnx compile and doc fixes.

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/54d2c8b9-8b04-45fc-b483-200ffac9d344@linux.intel.com
2024-05-22 10:39:16 +10:00
Yang Li
1e8b7b3dbb rv: Update rv_en(dis)able_monitor doc to match kernel-doc
The patch updates the function documentation comment for
rv_en(dis)able_monitor to adhere to the kernel-doc specification.

Link: https://lore.kernel.org/linux-trace-kernel/20240520054239.61784-1-yang.lee@linux.alibaba.com

Fixes: 102227b970a15 ("rv: Add Runtime Verification (RV) interface")
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-05-21 19:03:35 -04:00
Jeff Johnson
23748e3e0f tracing: Add MODULE_DESCRIPTION() to preemptirq_delay_test
Fix the 'make W=1' warning:

WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/trace/preemptirq_delay_test.o

Link: https://lore.kernel.org/linux-trace-kernel/20240518-md-preemptirq_delay_test-v1-1-387d11b30d85@quicinc.com

Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: f96e8577da10 ("lib: Add module for testing preemptoff/irqsoff latency tracers")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-05-21 19:03:35 -04:00
Petr Pavlu
c2274b908d ring-buffer: Fix a race between readers and resize checks
The reader code in rb_get_reader_page() swaps a new reader page into the
ring buffer by doing cmpxchg on old->list.prev->next to point it to the
new page. Following that, if the operation is successful,
old->list.next->prev gets updated too. This means the underlying
doubly-linked list is temporarily inconsistent, page->prev->next or
page->next->prev might not be equal back to page for some page in the
ring buffer.

The resize operation in ring_buffer_resize() can be invoked in parallel.
It calls rb_check_pages() which can detect the described inconsistency
and stop further tracing:

[  190.271762] ------------[ cut here ]------------
[  190.271771] WARNING: CPU: 1 PID: 6186 at kernel/trace/ring_buffer.c:1467 rb_check_pages.isra.0+0x6a/0xa0
[  190.271789] Modules linked in: [...]
[  190.271991] Unloaded tainted modules: intel_uncore_frequency(E):1 skx_edac(E):1
[  190.272002] CPU: 1 PID: 6186 Comm: cmd.sh Kdump: loaded Tainted: G            E      6.9.0-rc6-default #5 158d3e1e6d0b091c34c3b96bfd99a1c58306d79f
[  190.272011] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552c-rebuilt.opensuse.org 04/01/2014
[  190.272015] RIP: 0010:rb_check_pages.isra.0+0x6a/0xa0
[  190.272023] Code: [...]
[  190.272028] RSP: 0018:ffff9c37463abb70 EFLAGS: 00010206
[  190.272034] RAX: ffff8eba04b6cb80 RBX: 0000000000000007 RCX: ffff8eba01f13d80
[  190.272038] RDX: ffff8eba01f130c0 RSI: ffff8eba04b6cd00 RDI: ffff8eba0004c700
[  190.272042] RBP: ffff8eba0004c700 R08: 0000000000010002 R09: 0000000000000000
[  190.272045] R10: 00000000ffff7f52 R11: ffff8eba7f600000 R12: ffff8eba0004c720
[  190.272049] R13: ffff8eba00223a00 R14: 0000000000000008 R15: ffff8eba067a8000
[  190.272053] FS:  00007f1bd64752c0(0000) GS:ffff8eba7f680000(0000) knlGS:0000000000000000
[  190.272057] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  190.272061] CR2: 00007f1bd6662590 CR3: 000000010291e001 CR4: 0000000000370ef0
[  190.272070] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  190.272073] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  190.272077] Call Trace:
[  190.272098]  <TASK>
[  190.272189]  ring_buffer_resize+0x2ab/0x460
[  190.272199]  __tracing_resize_ring_buffer.part.0+0x23/0xa0
[  190.272206]  tracing_resize_ring_buffer+0x65/0x90
[  190.272216]  tracing_entries_write+0x74/0xc0
[  190.272225]  vfs_write+0xf5/0x420
[  190.272248]  ksys_write+0x67/0xe0
[  190.272256]  do_syscall_64+0x82/0x170
[  190.272363]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  190.272373] RIP: 0033:0x7f1bd657d263
[  190.272381] Code: [...]
[  190.272385] RSP: 002b:00007ffe72b643f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[  190.272391] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f1bd657d263
[  190.272395] RDX: 0000000000000002 RSI: 0000555a6eb538e0 RDI: 0000000000000001
[  190.272398] RBP: 0000555a6eb538e0 R08: 000000000000000a R09: 0000000000000000
[  190.272401] R10: 0000555a6eb55190 R11: 0000000000000246 R12: 00007f1bd6662500
[  190.272404] R13: 0000000000000002 R14: 00007f1bd6667c00 R15: 0000000000000002
[  190.272412]  </TASK>
[  190.272414] ---[ end trace 0000000000000000 ]---

Note that ring_buffer_resize() calls rb_check_pages() only if the parent
trace_buffer has recording disabled. Recent commit d78ab792705c
("tracing: Stop current tracer when resizing buffer") causes that it is
now always the case which makes it more likely to experience this issue.

The window to hit this race is nonetheless very small. To help
reproducing it, one can add a delay loop in rb_get_reader_page():

 ret = rb_head_page_replace(reader, cpu_buffer->reader_page);
 if (!ret)
 	goto spin;
 for (unsigned i = 0; i < 1U << 26; i++)  /* inserted delay loop */
 	__asm__ __volatile__ ("" : : : "memory");
 rb_list_head(reader->list.next)->prev = &cpu_buffer->reader_page->list;

.. and then run the following commands on the target system:

 echo 1 > /sys/kernel/tracing/events/sched/sched_switch/enable
 while true; do
 	echo 16 > /sys/kernel/tracing/buffer_size_kb; sleep 0.1
 	echo 8 > /sys/kernel/tracing/buffer_size_kb; sleep 0.1
 done &
 while true; do
 	for i in /sys/kernel/tracing/per_cpu/*; do
 		timeout 0.1 cat $i/trace_pipe; sleep 0.2
 	done
 done

To fix the problem, make sure ring_buffer_resize() doesn't invoke
rb_check_pages() concurrently with a reader operating on the same
ring_buffer_per_cpu by taking its cpu_buffer->reader_lock.

Link: https://lore.kernel.org/linux-trace-kernel/20240517134008.24529-3-petr.pavlu@suse.com

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 659f451ff213 ("ring-buffer: Add integrity check at end of iter read")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
[ Fixed whitespace ]
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-05-21 19:03:35 -04:00
Petr Pavlu
ea70a9628e ring-buffer: Correct stale comments related to non-consuming readers
Adjust the following code documentation:

* Kernel-doc comments for ring_buffer_read_prepare() and
  ring_buffer_read_finish() mention that recording to the ring buffer is
  disabled when the read is active. Remove mention of this restriction
  because it was already lifted in commit 1039221cc278 ("ring-buffer: Do
  not disable recording when there is an iterator").

* Function ring_buffer_read_finish() performs a self-check of the
  ring-buffer by locking cpu_buffer->reader_lock and then calling
  rb_check_pages(). The preceding comment explains that the lock is
  needed because rb_check_pages() clears the HEAD flag required by
  readers which might be running in parallel. Remove this explanation
  because commit 8843e06f67b1 ("ring-buffer: Handle race between
  rb_move_tail and rb_check_pages") simplified the function so it no
  longer resets the mentioned flag. Nonetheless, the lock is still
  needed because a reader swapping a page into the ring buffer can make
  the underlying doubly-linked list temporarily inconsistent.

This is a non-functional change.

Link: https://lore.kernel.org/linux-trace-kernel/20240517134008.24529-2-petr.pavlu@suse.com

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-05-21 19:03:35 -04:00