summaryrefslogtreecommitdiffstats
path: root/Documentation/admin-guide/device-mapper/dm-queue-length.rst
diff options
context:
space:
mode:
authorFan Wu <fanwu01@zju.edu.cn>2026-08-20 13:53:06 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2026-09-01 16:50:04 +0200
commit263f7d61a4201cde16849b2d016251806e7418be (patch)
tree861df7c5b878b85741cf319ece81111b4c41c3b1 /Documentation/admin-guide/device-mapper/dm-queue-length.rst
downloadlinux-stable-263f7d61a4201cde16849b2d016251806e7418be.tar.gz
linux-stable-263f7d61a4201cde16849b2d016251806e7418be.zip
usb: typec: qcom-pmic-typec: disable cc_debounce_dwork on stopgrafted
cc_debounce_dwork is queued from the set_cc() and start_toggling() callbacks, which run from TCPM's kthread worker. port_stop() returns before tcpm_unregister_port() destroys that worker. Flushing the worker during unregister may therefore run a callback which queues the delayed work after port_stop() has returned. The delayed work can then run after devres has freed pmic_typec_port. Use disable_delayed_work_sync() in port_stop() to cancel a pending instance and prevent the TCPM callbacks from queueing another one. This issue was found by an in-house static analysis tool. Fixes: a4422ff22142 ("usb: typec: qcom: Add Qualcomm PMIC Type-C driver") Cc: stable <stable@kernel.org> # v6.10+ Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu <fanwu01@zju.edu.cn> Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Link: https://patch.msgid.link/20260820135307.153773-2-fanwu01@zju.edu.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/admin-guide/device-mapper/dm-queue-length.rst')
-rw-r--r--Documentation/admin-guide/device-mapper/dm-queue-length.rst48
1 files changed, 48 insertions, 0 deletions
diff --git a/Documentation/admin-guide/device-mapper/dm-queue-length.rst b/Documentation/admin-guide/device-mapper/dm-queue-length.rst
new file mode 100644
index 000000000..d8e381c1c
--- /dev/null
+++ b/Documentation/admin-guide/device-mapper/dm-queue-length.rst
@@ -0,0 +1,48 @@
+===============
+dm-queue-length
+===============
+
+dm-queue-length is a path selector module for device-mapper targets,
+which selects a path with the least number of in-flight I/Os.
+The path selector name is 'queue-length'.
+
+Table parameters for each path: [<repeat_count>]
+
+::
+
+ <repeat_count>: The number of I/Os to dispatch using the selected
+ path before switching to the next path.
+ If not given, internal default is used. To check
+ the default value, see the activated table.
+
+Status for each path: <status> <fail-count> <in-flight>
+
+::
+
+ <status>: 'A' if the path is active, 'F' if the path is failed.
+ <fail-count>: The number of path failures.
+ <in-flight>: The number of in-flight I/Os on the path.
+
+
+Algorithm
+=========
+
+dm-queue-length increments/decrements 'in-flight' when an I/O is
+dispatched/completed respectively.
+dm-queue-length selects a path with the minimum 'in-flight'.
+
+
+Examples
+========
+In case that 2 paths (sda and sdb) are used with repeat_count == 128.
+
+::
+
+ # echo "0 10 multipath 0 0 1 1 queue-length 0 2 1 8:0 128 8:16 128" \
+ dmsetup create test
+ #
+ # dmsetup table
+ test: 0 10 multipath 0 0 1 1 queue-length 0 2 1 8:0 128 8:16 128
+ #
+ # dmsetup status
+ test: 0 10 multipath 2 0 0 0 1 1 E 0 2 1 8:0 A 0 0 8:16 A 0 0