Merge tag 'driver-core-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the big set of driver core and debug printk changes for
  6.1-rc1. Included in here is:

   - dynamic debug updates for the core and the drm subsystem. The drm
     changes have all been acked by the relevant maintainers

   - kernfs fixes for syzbot reported problems

   - kernfs refactors and updates for cgroup requirements

   - magic number cleanups and removals from the kernel tree (they were
     not being used and they really did not actually do anything)

   - other tiny cleanups

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

* tag 'driver-core-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (74 commits)
  docs: filesystems: sysfs: Make text and code for ->show() consistent
  Documentation: NBD_REQUEST_MAGIC isn't a magic number
  a.out: restore CMAGIC
  device property: Add const qualifier to device_get_match_data() parameter
  drm_print: add _ddebug descriptor to drm_*dbg prototypes
  drm_print: prefer bare printk KERN_DEBUG on generic fn
  drm_print: optimize drm_debug_enabled for jump-label
  drm-print: add drm_dbg_driver to improve namespace symmetry
  drm-print.h: include dyndbg header
  drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro
  drm_print: interpose drm_*dbg with forwarding macros
  drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers.
  drm_print: condense enum drm_debug_category
  debugfs: use DEFINE_SHOW_ATTRIBUTE to define debugfs_regset32_fops
  driver core: use IS_ERR_OR_NULL() helper in device_create_groups_vargs()
  Documentation: ENI155_MAGIC isn't a magic number
  Documentation: NBD_REPLY_MAGIC isn't a magic number
  nbd: remove define-only NBD_MAGIC, previously magic number
  Documentation: FW_HEADER_MAGIC isn't a magic number
  Documentation: EEPROM_MAGIC_VALUE isn't a magic number
  ...

Author: torvalds

Documentation/admin-guide/dynamic-debug-howto.rst

@@ -5,143 +5,115 @@ Dynamic debug
 Introduction
 ============
 
-This document describes how to use the dynamic debug (dyndbg) feature.
+Dynamic debug allows you to dynamically enable/disable kernel
+debug-print code to obtain additional kernel information.
 
-Dynamic debug is designed to allow you to dynamically enable/disable
-kernel code to obtain additional kernel information.  Currently, if
-``CONFIG_DYNAMIC_DEBUG`` is set, then all ``pr_debug()``/``dev_dbg()`` and
-``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
-enabled per-callsite.
+If ``/proc/dynamic_debug/control`` exists, your kernel has dynamic
+debug.  You'll need root access (sudo su) to use this.
 
-If you do not want to enable dynamic debug globally (i.e. in some embedded
-system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic
-debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any
-modules which you'd like to dynamically debug later.
-
-If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
-shortcut for ``print_hex_dump(KERN_DEBUG)``.
-
-For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
-its ``prefix_str`` argument, if it is constant string; or ``hexdump``
-in case ``prefix_str`` is built dynamically.
+Dynamic debug provides:
 
-Dynamic debug has even more useful features:
+ * a Catalog of all *prdbgs* in your kernel.
+   ``cat /proc/dynamic_debug/control`` to see them.
 
- * Simple query language allows turning on and off debugging
-   statements by matching any combination of 0 or 1 of:
+ * a Simple query/command language to alter *prdbgs* by selecting on
+   any combination of 0 or 1 of:
 
    - source filename
    - function name
    - line number (including ranges of line numbers)
    - module name
    - format string
-
- * Provides a debugfs control file: ``<debugfs>/dynamic_debug/control``
-   which can be read to display the complete list of known debug
-   statements, to help guide you
-
-Controlling dynamic debug Behaviour
-===================================
-
-The behaviour of ``pr_debug()``/``dev_dbg()`` are controlled via writing to a
-control file in the 'debugfs' filesystem. Thus, you must first mount
-the debugfs filesystem, in order to make use of this feature.
-Subsequently, we refer to the control file as:
-``<debugfs>/dynamic_debug/control``. For example, if you want to enable
-printing from source file ``svcsock.c``, line 1603 you simply do::
-
-  nullarbor:~ # echo 'file svcsock.c line 1603 +p' >
-				<debugfs>/dynamic_debug/control
-
-If you make a mistake with the syntax, the write will fail thus::
-
-  nullarbor:~ # echo 'file svcsock.c wtf 1 +p' >
-				<debugfs>/dynamic_debug/control
-  -bash: echo: write error: Invalid argument
-
-Note, for systems without 'debugfs' enabled, the control file can be
-found in ``/proc/dynamic_debug/control``.
+   - class name (as known/declared by each module)
 
 Viewing Dynamic Debug Behaviour
 ===============================
 
-You can view the currently configured behaviour of all the debug
-statements via::
+You can view the currently configured behaviour in the *prdbg* catalog::
 
-  nullarbor:~ # cat <debugfs>/dynamic_debug/control
+  :#> head -n7 /proc/dynamic_debug/control
   # filename:lineno [module]function flags format
-  net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup =_ "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
-  net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init =_ "\011max_inline       : %d\012"
-  net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init =_ "\011sq_depth         : %d\012"
-  net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init =_ "\011max_requests     : %d\012"
-  ...
+  init/main.c:1179 [main]initcall_blacklist =_ "blacklisting initcall %s\012
+  init/main.c:1218 [main]initcall_blacklisted =_ "initcall %s blacklisted\012"
+  init/main.c:1424 [main]run_init_process =_ "  with arguments:\012"
+  init/main.c:1426 [main]run_init_process =_ "    %s\012"
+  init/main.c:1427 [main]run_init_process =_ "  with environment:\012"
+  init/main.c:1429 [main]run_init_process =_ "    %s\012"
 
+The 3rd space-delimited column shows the current flags, preceded by
+a ``=`` for easy use with grep/cut. ``=p`` shows enabled callsites.
 
-You can also apply standard Unix text manipulation filters to this
-data, e.g.::
+Controlling dynamic debug Behaviour
+===================================
 
-  nullarbor:~ # grep -i rdma <debugfs>/dynamic_debug/control  | wc -l
-  62
+The behaviour of *prdbg* sites are controlled by writing
+query/commands to the control file.  Example::
 
-  nullarbor:~ # grep -i tcp <debugfs>/dynamic_debug/control | wc -l
-  42
+  # grease the interface
+  :#> alias ddcmd='echo $* > /proc/dynamic_debug/control'
 
-The third column shows the currently enabled flags for each debug
-statement callsite (see below for definitions of the flags).  The
-default value, with no flags enabled, is ``=_``.  So you can view all
-the debug statement callsites with any non-default flags::
+  :#> ddcmd '-p; module main func run* +p'
+  :#> grep =p /proc/dynamic_debug/control
+  init/main.c:1424 [main]run_init_process =p "  with arguments:\012"
+  init/main.c:1426 [main]run_init_process =p "    %s\012"
+  init/main.c:1427 [main]run_init_process =p "  with environment:\012"
+  init/main.c:1429 [main]run_init_process =p "    %s\012"
 
-  nullarbor:~ # awk '$3 != "=_"' <debugfs>/dynamic_debug/control
-  # filename:lineno [module]function flags format
-  net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"
+Error messages go to console/syslog::
+
+  :#> ddcmd mode foo +p
+  dyndbg: unknown keyword "mode"
+  dyndbg: query parse failed
+  bash: echo: write error: Invalid argument
+
+If debugfs is also enabled and mounted, ``dynamic_debug/control`` is
+also under the mount-dir, typically ``/sys/kernel/debug/``.
 
 Command Language Reference
 ==========================
 
-At the lexical level, a command comprises a sequence of words separated
+At the basic lexical level, a command is a sequence of words separated
 by spaces or tabs.  So these are all equivalent::
 
-  nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
-				<debugfs>/dynamic_debug/control
-  nullarbor:~ # echo -n '  file   svcsock.c     line  1603 +p  ' >
-				<debugfs>/dynamic_debug/control
-  nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd file svcsock.c line 1603 +p
+  :#> ddcmd "file svcsock.c line 1603 +p"
+  :#> ddcmd '  file   svcsock.c     line  1603 +p  '
 
 Command submissions are bounded by a write() system call.
 Multiple commands can be written together, separated by ``;`` or ``\n``::
 
-  ~# echo "func pnpacpi_get_resources +p; func pnp_assign_mem +p" \
-     > <debugfs>/dynamic_debug/control
+  :#> ddcmd "func pnpacpi_get_resources +p; func pnp_assign_mem +p"
+  :#> ddcmd <<"EOC"
+  func pnpacpi_get_resources +p
+  func pnp_assign_mem +p
+  EOC
+  :#> cat query-batch-file > /proc/dynamic_debug/control
 
-If your query set is big, you can batch them too::
+You can also use wildcards in each query term. The match rule supports
+``*`` (matches zero or more characters) and ``?`` (matches exactly one
+character). For example, you can match all usb drivers::
 
-  ~# cat query-batch-file > <debugfs>/dynamic_debug/control
+  :#> ddcmd file "drivers/usb/*" +p	# "" to suppress shell expansion
 
-Another way is to use wildcards. The match rule supports ``*`` (matches
-zero or more characters) and ``?`` (matches exactly one character). For
-example, you can match all usb drivers::
-
-  ~# echo "file drivers/usb/* +p" > <debugfs>/dynamic_debug/control
-
-At the syntactical level, a command comprises a sequence of match
-specifications, followed by a flags change specification::
+Syntactically, a command is pairs of keyword values, followed by a
+flags change or setting::
 
   command ::= match-spec* flags-spec
 
-The match-spec's are used to choose a subset of the known pr_debug()
-callsites to which to apply the flags-spec.  Think of them as a query
-with implicit ANDs between each pair.  Note that an empty list of
-match-specs will select all debug statement callsites.
+The match-spec's select *prdbgs* from the catalog, upon which to apply
+the flags-spec, all constraints are ANDed together.  An absent keyword
+is the same as keyword "*".
+
 
-A match specification comprises a keyword, which controls the
-attribute of the callsite to be compared, and a value to compare
-against.  Possible keywords are:::
+A match specification is a keyword, which selects the attribute of
+the callsite to be compared, and a value to compare against.  Possible
+keywords are:::
 
   match-spec ::= 'func' string |
 		 'file' string |
 		 'module' string |
 		 'format' string |
+		 'class' string |
 		 'line' line-range
 
   line-range ::= lineno |
@@ -203,6 +175,16 @@ format
 	format "nfsd: SETATTR"  // a neater way to match a format with whitespace
 	format 'nfsd: SETATTR'  // yet another way to match a format with whitespace
 
+class
+    The given class_name is validated against each module, which may
+    have declared a list of known class_names.  If the class_name is
+    found for a module, callsite & class matching and adjustment
+    proceeds.  Examples::
+
+	class DRM_UT_KMS	# a DRM.debug category
+	class JUNK		# silent non-match
+	// class TLD_*		# NOTICE: no wildcard in class names
+
 line
     The given line number or range of line numbers is compared
     against the line number of each ``pr_debug()`` callsite.  A single
@@ -228,17 +210,16 @@ of the characters::
 The flags are::
 
   p    enables the pr_debug() callsite.
-  f    Include the function name in the printed message
-  l    Include line number in the printed message
-  m    Include module name in the printed message
-  t    Include thread ID in messages not generated from interrupt context
-  _    No flags are set. (Or'd with others on input)
+  _    enables no flags.
 
-For ``print_hex_dump_debug()`` and ``print_hex_dump_bytes()``, only ``p`` flag
-have meaning, other flags ignored.
+  Decorator flags add to the message-prefix, in order:
+  t    Include thread ID, or <intr>
+  m    Include module name
+  f    Include the function name
+  l    Include line number
 
-For display, the flags are preceded by ``=``
-(mnemonic: what the flags are currently equal to).
+For ``print_hex_dump_debug()`` and ``print_hex_dump_bytes()``, only
+the ``p`` flag has meaning, other flags are ignored.
 
 Note the regexp ``^[-+=][flmpt_]+$`` matches a flags specification.
 To clear all flags at once, use ``=_`` or ``-flmpt``.
@@ -313,45 +294,39 @@ For ``CONFIG_DYNAMIC_DEBUG`` kernels, any settings given at boot-time (or
 enabled by ``-DDEBUG`` flag during compilation) can be disabled later via
 the debugfs interface if the debug messages are no longer needed::
 
-   echo "module module_name -p" > <debugfs>/dynamic_debug/control
+   echo "module module_name -p" > /proc/dynamic_debug/control
 
 Examples
 ========
 
 ::
 
   // enable the message at line 1603 of file svcsock.c
-  nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'file svcsock.c line 1603 +p'
 
   // enable all the messages in file svcsock.c
-  nullarbor:~ # echo -n 'file svcsock.c +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'file svcsock.c +p'
 
   // enable all the messages in the NFS server module
-  nullarbor:~ # echo -n 'module nfsd +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'module nfsd +p'
 
   // enable all 12 messages in the function svc_process()
-  nullarbor:~ # echo -n 'func svc_process +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'func svc_process +p'
 
   // disable all 12 messages in the function svc_process()
-  nullarbor:~ # echo -n 'func svc_process -p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'func svc_process -p'
 
   // enable messages for NFS calls READ, READLINK, READDIR and READDIR+.
-  nullarbor:~ # echo -n 'format "nfsd: READ" +p' >
-				<debugfs>/dynamic_debug/control
+  :#> ddcmd 'format "nfsd: READ" +p'
 
   // enable messages in files of which the paths include string "usb"
-  nullarbor:~ # echo -n 'file *usb* +p' > <debugfs>/dynamic_debug/control
+  :#> ddcmd 'file *usb* +p' > /proc/dynamic_debug/control
 
   // enable all messages
-  nullarbor:~ # echo -n '+p' > <debugfs>/dynamic_debug/control
+  :#> ddcmd '+p' > /proc/dynamic_debug/control
 
   // add module, function to all enabled messages
-  nullarbor:~ # echo -n '+mf' > <debugfs>/dynamic_debug/control
+  :#> ddcmd '+mf' > /proc/dynamic_debug/control
 
   // boot-args example, with newlines and comments for readability
   Kernel command line: ...
@@ -364,3 +339,38 @@ Examples
     dyndbg="file init/* +p #cmt ; func parse_one +p"
     // enable pr_debugs in 2 functions in a module loaded later
     pc87360.dyndbg="func pc87360_init_device +p; func pc87360_find +p"
+
+Kernel Configuration
+====================
+
+Dynamic Debug is enabled via kernel config items::
+
+  CONFIG_DYNAMIC_DEBUG=y	# build catalog, enables CORE
+  CONFIG_DYNAMIC_DEBUG_CORE=y	# enable mechanics only, skip catalog
+
+If you do not want to enable dynamic debug globally (i.e. in some embedded
+system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic
+debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any
+modules which you'd like to dynamically debug later.
+
+
+Kernel *prdbg* API
+==================
+
+The following functions are cataloged and controllable when dynamic
+debug is enabled::
+
+  pr_debug()
+  dev_dbg()
+  print_hex_dump_debug()
+  print_hex_dump_bytes()
+
+Otherwise, they are off by default; ``ccflags += -DDEBUG`` or
+``#define DEBUG`` in a source file will enable them appropriately.
+
+If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is
+just a shortcut for ``print_hex_dump(KERN_DEBUG)``.
+
+For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
+its ``prefix_str`` argument, if it is constant string; or ``hexdump``
+in case ``prefix_str`` is built dynamically.

Documentation/driver-api/driver-model/devres.rst

@@ -311,7 +311,6 @@ IOMAP
   devm_ioremap()
   devm_ioremap_uc()
   devm_ioremap_wc()
-  devm_ioremap_np()
   devm_ioremap_resource() : checks resource, requests memory region, ioremaps
   devm_ioremap_resource_wc()
   devm_platform_ioremap_resource() : calls devm_ioremap_resource() for platform device

Documentation/filesystems/sysfs.rst

@@ -263,7 +263,7 @@ A very simple (and naive) implementation of a device attribute is::
     static ssize_t show_name(struct device *dev, struct device_attribute *attr,
 			    char *buf)
     {
-	    return scnprintf(buf, PAGE_SIZE, "%s\n", dev->name);
+	    return sysfs_emit(buf, "%s\n", dev->name);
     }
 
     static ssize_t store_name(struct device *dev, struct device_attribute *attr,