Merge tag 'driver-core-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is a small set of driver core updates and additions for 6.6-rc1.

  Included in here are:

   - stable kernel documentation updates

   - class structure const work from Ivan on various subsystems

   - kernfs tweaks

   - driver core tests!

   - kobject sanity cleanups

   - kobject structure reordering to save space

   - driver core error code handling fixups

   - other minor driver core cleanups

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'driver-core-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits)
  driver core: Call in reversed order in device_platform_notify_remove()
  driver core: Return proper error code when dev_set_name() fails
  kobject: Remove redundant checks for whether ktype is NULL
  kobject: Add sanity check for kset->kobj.ktype in kset_register()
  drivers: base: test: Add missing MODULE_* macros to root device tests
  drivers: base: test: Add missing MODULE_* macros for platform devices tests
  drivers: base: Free devm resources when unregistering a device
  drivers: base: Add basic devm tests for platform devices
  drivers: base: Add basic devm tests for root devices
  kernfs: fix missing kernfs_iattr_rwsem locking
  docs: stable-kernel-rules: mention that regressions must be prevented
  docs: stable-kernel-rules: fine-tune various details
  docs: stable-kernel-rules: make the examples for option 1 a proper list
  docs: stable-kernel-rules: move text around to improve flow
  docs: stable-kernel-rules: improve structure by changing headlines
  base/node: Remove duplicated include
  kernfs: attach uuid for every kernfs and report it in fsid
  kernfs: add stub helper for kernfs_generic_poll()
  x86/resctrl: make pseudo_lock_class a static const structure
  x86/MSR: make msr_class a static const structure
  ...

Author: torvalds

Documentation/process/stable-kernel-rules.rst

@@ -6,30 +6,29 @@ Everything you ever wanted to know about Linux -stable releases
 Rules on what kind of patches are accepted, and which ones are not, into the
 "-stable" tree:
 
+ - It or an equivalent fix must already exist in Linus' tree (upstream).
  - It must be obviously correct and tested.
  - It cannot be bigger than 100 lines, with context.
- - It must fix only one thing.
- - It must fix a real bug that bothers people (not a, "This could be a
-   problem..." type thing).
- - It must fix a problem that causes a build error (but not for things
-   marked CONFIG_BROKEN), an oops, a hang, data corruption, a real
-   security issue, or some "oh, that's not good" issue.  In short, something
-   critical.
- - Serious issues as reported by a user of a distribution kernel may also
-   be considered if they fix a notable performance or interactivity issue.
-   As these fixes are not as obvious and have a higher risk of a subtle
-   regression they should only be submitted by a distribution kernel
-   maintainer and include an addendum linking to a bugzilla entry if it
-   exists and additional information on the user-visible impact.
- - New device IDs and quirks are also accepted.
- - No "theoretical race condition" issues, unless an explanation of how the
-   race can be exploited is also provided.
- - It cannot contain any "trivial" fixes in it (spelling changes,
-   whitespace cleanups, etc).
  - It must follow the
    :ref:`Documentation/process/submitting-patches.rst <submittingpatches>`
    rules.
- - It or an equivalent fix must already exist in Linus' tree (upstream).
+ - It must either fix a real bug that bothers people or just add a device ID.
+   To elaborate on the former:
+
+   - It fixes a problem like an oops, a hang, data corruption, a real security
+     issue, a hardware quirk, a build error (but not for things marked
+     CONFIG_BROKEN), or some "oh, that's not good" issue.
+   - Serious issues as reported by a user of a distribution kernel may also
+     be considered if they fix a notable performance or interactivity issue.
+     As these fixes are not as obvious and have a higher risk of a subtle
+     regression they should only be submitted by a distribution kernel
+     maintainer and include an addendum linking to a bugzilla entry if it
+     exists and additional information on the user-visible impact.
+   - No "This could be a problem..." type of things like a "theoretical race
+     condition", unless an explanation of how the bug can be exploited is also
+     provided.
+   - No "trivial" fixes without benefit for users (spelling changes, whitespace
+     cleanups, etc).
 
 
 Procedure for submitting patches to the -stable tree
@@ -41,111 +40,142 @@ Procedure for submitting patches to the -stable tree
    process but should follow the procedures in
    :ref:`Documentation/process/security-bugs.rst <securitybugs>`.
 
-For all other submissions, choose one of the following procedures
------------------------------------------------------------------
+There are three options to submit a change to -stable trees:
+
+ 1. Add a 'stable tag' to the description of a patch you then submit for
+    mainline inclusion.
+ 2. Ask the stable team to pick up a patch already mainlined.
+ 3. Submit a patch to the stable team that is equivalent to a change already
+    mainlined.
+
+The sections below describe each of the options in more detail.
+
+:ref:`option_1` is **strongly** preferred, it is the easiest and most common.
+:ref:`option_2` is mainly meant for changes where backporting was not considered
+at the time of submission. :ref:`option_3` is an alternative to the two earlier
+options for cases where a mainlined patch needs adjustments to apply in older
+series (for example due to API changes).
+
+When using option 2 or 3 you can ask for your change to be included in specific
+stable series. When doing so, ensure the fix or an equivalent is applicable,
+submitted, or already present in all newer stable trees still supported. This is
+meant to prevent regressions that users might later encounter on updating, if
+e.g. a fix merged for 5.19-rc1 would be backported to 5.10.y, but not to 5.15.y.
 
 .. _option_1:
 
 Option 1
 ********
 
-To have the patch automatically included in the stable tree, add the tag
+To have a patch you submit for mainline inclusion later automatically picked up
+for stable trees, add the tag
 
 .. code-block:: none
 
      Cc: stable@vger.kernel.org
 
-in the sign-off area. Once the patch is merged it will be applied to
-the stable tree without anything else needing to be done by the author
-or subsystem maintainer.
+in the sign-off area. Once the patch is mainlined it will be applied to the
+stable tree without anything else needing to be done by the author or
+subsystem maintainer.
 
-.. _option_2:
+To sent additional instructions to the stable team, use a shell-style inline
+comment:
 
-Option 2
-********
+ * To specify any additional patch prerequisites for cherry picking use the
+   following format in the sign-off area:
 
-After the patch has been merged to Linus' tree, send an email to
-stable@vger.kernel.org containing the subject of the patch, the commit ID,
-why you think it should be applied, and what kernel version you wish it to
-be applied to.
+   .. code-block:: none
 
-.. _option_3:
+     Cc: <stable@vger.kernel.org> # 3.3.x: a1f84a3: sched: Check for idle
+     Cc: <stable@vger.kernel.org> # 3.3.x: 1b9508f: sched: Rate-limit newidle
+     Cc: <stable@vger.kernel.org> # 3.3.x: fd21073: sched: Fix affinity logic
+     Cc: <stable@vger.kernel.org> # 3.3.x
+     Signed-off-by: Ingo Molnar <mingo@elte.hu>
 
-Option 3
-********
+   The tag sequence has the meaning of:
 
-Send the patch, after verifying that it follows the above rules, to
-stable@vger.kernel.org.  You must note the upstream commit ID in the
-changelog of your submission, as well as the kernel version you wish
-it to be applied to.
+   .. code-block:: none
 
-:ref:`option_1` is **strongly** preferred, is the easiest and most common.
-:ref:`option_2` and :ref:`option_3` are more useful if the patch isn't deemed
-worthy at the time it is applied to a public git tree (for instance, because
-it deserves more regression testing first).  :ref:`option_3` is especially
-useful if the original upstream patch needs to be backported (for example
-the backport needs some special handling due to e.g. API changes).
+     git cherry-pick a1f84a3
+     git cherry-pick 1b9508f
+     git cherry-pick fd21073
+     git cherry-pick <this commit>
 
-Note that for :ref:`option_3`, if the patch deviates from the original
-upstream patch (for example because it had to be backported) this must be very
-clearly documented and justified in the patch description.
+ * For patches that may have kernel version prerequisites specify them using
+   the following format in the sign-off area:
 
-The upstream commit ID must be specified with a separate line above the commit
-text, like this:
+   .. code-block:: none
 
-.. code-block:: none
+     Cc: <stable@vger.kernel.org> # 3.3.x
 
-    commit <sha1> upstream.
+   The tag has the meaning of:
 
-or alternatively:
+   .. code-block:: none
 
-.. code-block:: none
+     git cherry-pick <this commit>
 
-    [ Upstream commit <sha1> ]
+   For each "-stable" tree starting with the specified version.
 
-Additionally, some patches submitted via :ref:`option_1` may have additional
-patch prerequisites which can be cherry-picked. This can be specified in the
-following format in the sign-off area:
+   Note, such tagging is unnecessary if the stable team can derive the
+   appropriate versions from Fixes: tags.
 
-.. code-block:: none
+ * To delay pick up of patches, use the following format:
 
-     Cc: <stable@vger.kernel.org> # 3.3.x: a1f84a3: sched: Check for idle
-     Cc: <stable@vger.kernel.org> # 3.3.x: 1b9508f: sched: Rate-limit newidle
-     Cc: <stable@vger.kernel.org> # 3.3.x: fd21073: sched: Fix affinity logic
-     Cc: <stable@vger.kernel.org> # 3.3.x
-     Signed-off-by: Ingo Molnar <mingo@elte.hu>
+   .. code-block:: none
 
-The tag sequence has the meaning of:
+     Cc: <stable@vger.kernel.org> # after 4 weeks in mainline
 
-.. code-block:: none
+ * For any other requests, just add a note to the stable tag. This for example
+   can be used to point out known problems:
 
-     git cherry-pick a1f84a3
-     git cherry-pick 1b9508f
-     git cherry-pick fd21073
-     git cherry-pick <this commit>
+   .. code-block:: none
+
+     Cc: <stable@vger.kernel.org> # see patch description, needs adjustments for <= 6.3
+
+.. _option_2:
+
+Option 2
+********
+
+If the patch already has been merged to mainline, send an email to
+stable@vger.kernel.org containing the subject of the patch, the commit ID,
+why you think it should be applied, and what kernel versions you wish it to
+be applied to.
+
+.. _option_3:
 
-Also, some patches may have kernel version prerequisites.  This can be
-specified in the following format in the sign-off area:
+Option 3
+********
+
+Send the patch, after verifying that it follows the above rules, to
+stable@vger.kernel.org and mention the kernel versions you wish it to be applied
+to. When doing so, you must note the upstream commit ID in the changelog of your
+submission with a separate line above the commit text, like this:
 
 .. code-block:: none
 
-     Cc: <stable@vger.kernel.org> # 3.3.x
+    commit <sha1> upstream.
 
-The tag has the meaning of:
+or alternatively:
 
 .. code-block:: none
 
-     git cherry-pick <this commit>
+    [ Upstream commit <sha1> ]
+
+If the submitted patch deviates from the original upstream patch (for example
+because it had to be adjusted for the older API), this must be very clearly
+documented and justified in the patch description.
 
-For each "-stable" tree starting with the specified version.
 
-Following the submission:
+Following the submission
+------------------------
 
- - The sender will receive an ACK when the patch has been accepted into the
-   queue, or a NAK if the patch is rejected.  This response might take a few
-   days, according to the developer's schedules.
- - If accepted, the patch will be added to the -stable queue, for review by
-   other developers and by the relevant subsystem maintainer.
+The sender will receive an ACK when the patch has been accepted into the
+queue, or a NAK if the patch is rejected.  This response might take a few
+days, according to the schedules of the stable team members.
+
+If accepted, the patch will be added to the -stable queue, for review by other
+developers and by the relevant subsystem maintainer.
 
 
 Review cycle
@@ -174,6 +204,7 @@ Review cycle
    security kernel team, and not go through the normal review cycle.
    Contact the kernel security team for more details on this procedure.
 
+
 Trees
 -----
 

arch/x86/kernel/cpu/resctrl/pseudo_lock.c

@@ -45,7 +45,21 @@ static u64 prefetch_disable_bits;
  */
 static unsigned int pseudo_lock_major;
 static unsigned long pseudo_lock_minor_avail = GENMASK(MINORBITS, 0);
-static struct class *pseudo_lock_class;
+
+static char *pseudo_lock_devnode(const struct device *dev, umode_t *mode)
+{
+	const struct rdtgroup *rdtgrp;
+
+	rdtgrp = dev_get_drvdata(dev);
+	if (mode)
+		*mode = 0600;
+	return kasprintf(GFP_KERNEL, "pseudo_lock/%s", rdtgrp->kn->name);
+}
+
+static const struct class pseudo_lock_class = {
+	.name = "pseudo_lock",
+	.devnode = pseudo_lock_devnode,
+};
 
 /**
  * get_prefetch_disable_bits - prefetch disable bits of supported platforms
@@ -1353,7 +1367,7 @@ int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp)
 					    &pseudo_measure_fops);
 	}
 
-	dev = device_create(pseudo_lock_class, NULL,
+	dev = device_create(&pseudo_lock_class, NULL,
 			    MKDEV(pseudo_lock_major, new_minor),
 			    rdtgrp, "%s", rdtgrp->kn->name);
 
@@ -1383,7 +1397,7 @@ int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp)
 	goto out;
 
 out_device:
-	device_destroy(pseudo_lock_class, MKDEV(pseudo_lock_major, new_minor));
+	device_destroy(&pseudo_lock_class, MKDEV(pseudo_lock_major, new_minor));
 out_debugfs:
 	debugfs_remove_recursive(plr->debugfs_dir);
 	pseudo_lock_minor_release(new_minor);
@@ -1424,7 +1438,7 @@ void rdtgroup_pseudo_lock_remove(struct rdtgroup *rdtgrp)
 
 	pseudo_lock_cstates_relax(plr);
 	debugfs_remove_recursive(rdtgrp->plr->debugfs_dir);
-	device_destroy(pseudo_lock_class, MKDEV(pseudo_lock_major, plr->minor));
+	device_destroy(&pseudo_lock_class, MKDEV(pseudo_lock_major, plr->minor));
 	pseudo_lock_minor_release(plr->minor);
 
 free:
@@ -1560,16 +1574,6 @@ static const struct file_operations pseudo_lock_dev_fops = {
 	.mmap =		pseudo_lock_dev_mmap,
 };
 
-static char *pseudo_lock_devnode(const struct device *dev, umode_t *mode)
-{
-	const struct rdtgroup *rdtgrp;
-
-	rdtgrp = dev_get_drvdata(dev);
-	if (mode)
-		*mode = 0600;
-	return kasprintf(GFP_KERNEL, "pseudo_lock/%s", rdtgrp->kn->name);
-}
-
 int rdt_pseudo_lock_init(void)
 {
 	int ret;
@@ -1580,21 +1584,18 @@ int rdt_pseudo_lock_init(void)
 
 	pseudo_lock_major = ret;
 
-	pseudo_lock_class = class_create("pseudo_lock");
-	if (IS_ERR(pseudo_lock_class)) {
-		ret = PTR_ERR(pseudo_lock_class);
+	ret = class_register(&pseudo_lock_class);
+	if (ret) {
 		unregister_chrdev(pseudo_lock_major, "pseudo_lock");
 		return ret;
 	}
 
-	pseudo_lock_class->devnode = pseudo_lock_devnode;
 	return 0;
 }
 
 void rdt_pseudo_lock_release(void)
 {
-	class_destroy(pseudo_lock_class);
-	pseudo_lock_class = NULL;
+	class_unregister(&pseudo_lock_class);
 	unregister_chrdev(pseudo_lock_major, "pseudo_lock");
 	pseudo_lock_major = 0;
 }