iio: proximity: vl53l0x-i2c: claim direct mode for raw readsgrafted

vl53l0x_read_raw() starts a single-shot ranging measurement and reads
back the result. Once the triggered buffer is enabled the sensor runs in
continuous mode and its data-ready interrupt is routed to the trigger,
so a concurrent in_distance_raw read disturbs the streaming setup and
never gets its completion, returning -ETIMEDOUT.

The original submission claimed direct mode here, but it was dropped
during review because the driver had no buffer support at the time [1].
Continuous (buffered) mode was later added without restoring the
claim [2], reintroducing the conflict.

Reject direct reads while buffered capture is active by claiming direct
mode around the measurement, as the vl53l1x sibling already does.

Fixes: 762186c6e7b1 ("iio: proximity: vl53l0x-i2c: Added continuous mode support")
Link: https://lore.kernel.org/linux-iio/20180911160300.GA9212@himanshu-Vostro-3559/ [1]
Link: https://lore.kernel.org/linux-iio/20240909101508.263085-3-abhashkumarjha123@gmail.com/ [2]
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/Documentation/admin-guide/sysctl/user.rst b/Documentation/admin-guide/sysctl/user.rst
new file mode 100644
index 000000000..c45824589
--- /dev/null
+++ b/Documentation/admin-guide/sysctl/user.rst
@@ -0,0 +1,84 @@
+=================================
+Documentation for /proc/sys/user/
+=================================
+
+kernel version 4.9.0
+
+Copyright (c) 2016		Eric Biederman <ebiederm@xmission.com>
+
+------------------------------------------------------------------------------
+
+This file contains the documentation for the sysctl files in
+/proc/sys/user.
+
+The files in this directory can be used to override the default
+limits on the number of namespaces and other objects that have
+per user per user namespace limits.
+
+The primary purpose of these limits is to stop programs that
+malfunction and attempt to create a ridiculous number of objects,
+before the malfunction becomes a system wide problem.  It is the
+intention that the defaults of these limits are set high enough that
+no program in normal operation should run into these limits.
+
+The creation of per user per user namespace objects are charged to
+the user in the user namespace who created the object and
+verified to be below the per user limit in that user namespace.
+
+The creation of objects is also charged to all of the users
+who created user namespaces the creation of the object happens
+in (user namespaces can be nested) and verified to be below the per user
+limits in the user namespaces of those users.
+
+This recursive counting of created objects ensures that creating a
+user namespace does not allow a user to escape their current limits.
+
+Currently, these files are in /proc/sys/user:
+
+max_cgroup_namespaces
+=====================
+
+  The maximum number of cgroup namespaces that any user in the current
+  user namespace may create.
+
+max_ipc_namespaces
+==================
+
+  The maximum number of ipc namespaces that any user in the current
+  user namespace may create.
+
+max_mnt_namespaces
+==================
+
+  The maximum number of mount namespaces that any user in the current
+  user namespace may create.
+
+max_net_namespaces
+==================
+
+  The maximum number of network namespaces that any user in the
+  current user namespace may create.
+
+max_pid_namespaces
+==================
+
+  The maximum number of pid namespaces that any user in the current
+  user namespace may create.
+
+max_time_namespaces
+===================
+
+  The maximum number of time namespaces that any user in the current
+  user namespace may create.
+
+max_user_namespaces
+===================
+
+  The maximum number of user namespaces that any user in the current
+  user namespace may create.
+
+max_uts_namespaces
+==================
+
+  The maximum number of user namespaces that any user in the current
+  user namespace may create.