From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@kernel.org>
Date: Fri, 14 Aug 2026 15:43:51 -0700
Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a',
 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into
 HEAD

Changes:

Make expedited grace periods expedite normal RCU callbacks

Miscellaneous fixes:
 * Improve diagnostic output with character task states.
 * Mark accesses to inform KCSAN of concurrency design.
 * Move from kmalloc() to kmalloc_obj().
 * Documentation updates.
 * Improve handling of RCU deferred quiescent states.
 * Clean up unused function arguments and structure fields.
 * Reduce show_rcu_gp_kthreads() stack space.

Tasks RCU updates:
 * Clean up after SRCU re-implementation of Tasks Trace RCU.
 * Mark accesses to inform KCSAN of concurrency design.
 * Add ->lazy_timer status to diagnostic output.
 * Remove an unnecessary memory barrier.
 * Fix a data race, courtesy of KCSAN.
 * Documentation updates.
 * Convert cond_resched_tasks_rcu_qs() from macro to static inline
   function.

SRCU updates:
 * Add Rust helpers for SRCU.
 * Avoid losing queued work at cleanup_srcu_struct() time.

Torture-test updates:
 * Preparation work for immediate RCU priority deboosting.
 * Test RCU readers from real interrupt handlers (as opposed to softirq).
 * Simplify code through use of cpumask_next_wrap().
 * Improve diagnostic output with character task states.
 * Add rcutorture.nwriters parameter to allow lightweight stall testing,
   and rcutorture.stall_only to make doing so easier.
 * Test an RCU Tasks Trace grace period implying an RCU grace period.
 * Make RCU Tasks Trace torturing track reader batches.
 * Fix a data race, courtesy of KCSAN.
 * Plug a shuffle_tmp_mask memory leak on kthread spawn failure.
---
 Documentation/admin-guide/device-mapper/linear.rst | 63 ++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 Documentation/admin-guide/device-mapper/linear.rst

(limited to 'Documentation/admin-guide/device-mapper/linear.rst')

diff --git a/Documentation/admin-guide/device-mapper/linear.rst b/Documentation/admin-guide/device-mapper/linear.rst
new file mode 100644
index 000000000..9d17fc6e6
--- /dev/null
+++ b/Documentation/admin-guide/device-mapper/linear.rst
@@ -0,0 +1,63 @@
+=========
+dm-linear
+=========
+
+Device-Mapper's "linear" target maps a linear range of the Device-Mapper
+device onto a linear range of another device.  This is the basic building
+block of logical volume managers.
+
+Parameters: <dev path> <offset>
+    <dev path>:
+	Full pathname to the underlying block-device, or a
+        "major:minor" device-number.
+    <offset>:
+	Starting sector within the device.
+
+
+Example scripts
+===============
+
+::
+
+  #!/bin/sh
+  # Create an identity mapping for a device
+  echo "0 `blockdev --getsz $1` linear $1 0" | dmsetup create identity
+
+::
+
+  #!/bin/sh
+  # Join 2 devices together
+  size1=`blockdev --getsz $1`
+  size2=`blockdev --getsz $2`
+  echo "0 $size1 linear $1 0
+  $size1 $size2 linear $2 0" | dmsetup create joined
+
+::
+
+  #!/usr/bin/perl -w
+  # Split a device into 4M chunks and then join them together in reverse order.
+
+  my $name = "reverse";
+  my $extent_size = 4 * 1024 * 2;
+  my $dev = $ARGV[0];
+  my $table = "";
+  my $count = 0;
+
+  if (!defined($dev)) {
+          die("Please specify a device.\n");
+  }
+
+  my $dev_size = `blockdev --getsz $dev`;
+  my $extents = int($dev_size / $extent_size) -
+                (($dev_size % $extent_size) ? 1 : 0);
+
+  while ($extents > 0) {
+          my $this_start = $count * $extent_size;
+          $extents--;
+          $count++;
+          my $this_offset = $extents * $extent_size;
+
+          $table .= "$this_start $extent_size linear $dev $this_offset\n";
+  }
+
+  `echo \"$table\" | dmsetup create $name`;
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