--- /dev/null
+# SPDX-License-Identifier: GPL-2.0
+#
+# clang-format configuration file. Intended for clang-format >= 4.
+#
+# For more information, see:
+#
+# Documentation/process/clang-format.rst
+# https://clang.llvm.org/docs/ClangFormat.html
+# https://clang.llvm.org/docs/ClangFormatStyleOptions.html
+#
+---
+AccessModifierOffset: -4
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: false
+AlignConsecutiveDeclarations: false
+#AlignEscapedNewlines: Left # Unknown to clang-format-4.0
+AlignOperands: true
+AlignTrailingComments: false
+AllowAllParametersOfDeclarationOnNextLine: false
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: None
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: false
+AlwaysBreakTemplateDeclarations: false
+BinPackArguments: true
+BinPackParameters: true
+BraceWrapping:
+ AfterClass: false
+ AfterControlStatement: false
+ AfterEnum: false
+ AfterFunction: true
+ AfterNamespace: true
+ AfterObjCDeclaration: false
+ AfterStruct: false
+ AfterUnion: false
+ #AfterExternBlock: false # Unknown to clang-format-5.0
+ BeforeCatch: false
+ BeforeElse: false
+ IndentBraces: false
+ #SplitEmptyFunction: true # Unknown to clang-format-4.0
+ #SplitEmptyRecord: true # Unknown to clang-format-4.0
+ #SplitEmptyNamespace: true # Unknown to clang-format-4.0
+BreakBeforeBinaryOperators: None
+BreakBeforeBraces: Custom
+#BreakBeforeInheritanceComma: false # Unknown to clang-format-4.0
+BreakBeforeTernaryOperators: false
+BreakConstructorInitializersBeforeComma: false
+#BreakConstructorInitializers: BeforeComma # Unknown to clang-format-4.0
+BreakAfterJavaFieldAnnotations: false
+BreakStringLiterals: false
+ColumnLimit: 80
+CommentPragmas: '^ IWYU pragma:'
+#CompactNamespaces: false # Unknown to clang-format-4.0
+ConstructorInitializerAllOnOneLineOrOnePerLine: false
+ConstructorInitializerIndentWidth: 8
+ContinuationIndentWidth: 8
+Cpp11BracedListStyle: false
+DerivePointerAlignment: false
+DisableFormat: false
+ExperimentalAutoDetectBinPacking: false
+#FixNamespaceComments: false # Unknown to clang-format-4.0
+
+# Taken from:
+# git grep -h '^#define [^[:space:]]*for_each[^[:space:]]*(' include/ \
+# | sed "s,^#define \([^[:space:]]*for_each[^[:space:]]*\)(.*$, - '\1'," \
+# | sort | uniq
+ForEachMacros:
+ - 'apei_estatus_for_each_section'
+ - 'ata_for_each_dev'
+ - 'ata_for_each_link'
+ - 'ax25_for_each'
+ - 'ax25_uid_for_each'
+ - 'bio_for_each_integrity_vec'
+ - '__bio_for_each_segment'
+ - 'bio_for_each_segment'
+ - 'bio_for_each_segment_all'
+ - 'bio_list_for_each'
+ - 'bip_for_each_vec'
+ - 'blkg_for_each_descendant_post'
+ - 'blkg_for_each_descendant_pre'
+ - 'blk_queue_for_each_rl'
+ - 'bond_for_each_slave'
+ - 'bond_for_each_slave_rcu'
+ - 'btree_for_each_safe128'
+ - 'btree_for_each_safe32'
+ - 'btree_for_each_safe64'
+ - 'btree_for_each_safel'
+ - 'card_for_each_dev'
+ - 'cgroup_taskset_for_each'
+ - 'cgroup_taskset_for_each_leader'
+ - 'cpufreq_for_each_entry'
+ - 'cpufreq_for_each_entry_idx'
+ - 'cpufreq_for_each_valid_entry'
+ - 'cpufreq_for_each_valid_entry_idx'
+ - 'css_for_each_child'
+ - 'css_for_each_descendant_post'
+ - 'css_for_each_descendant_pre'
+ - 'device_for_each_child_node'
+ - 'drm_atomic_crtc_for_each_plane'
+ - 'drm_atomic_crtc_state_for_each_plane'
+ - 'drm_atomic_crtc_state_for_each_plane_state'
+ - 'drm_for_each_connector_iter'
+ - 'drm_for_each_crtc'
+ - 'drm_for_each_encoder'
+ - 'drm_for_each_encoder_mask'
+ - 'drm_for_each_fb'
+ - 'drm_for_each_legacy_plane'
+ - 'drm_for_each_plane'
+ - 'drm_for_each_plane_mask'
+ - 'drm_mm_for_each_hole'
+ - 'drm_mm_for_each_node'
+ - 'drm_mm_for_each_node_in_range'
+ - 'drm_mm_for_each_node_safe'
+ - 'for_each_active_drhd_unit'
+ - 'for_each_active_iommu'
+ - 'for_each_available_child_of_node'
+ - 'for_each_bio'
+ - 'for_each_board_func_rsrc'
+ - 'for_each_bvec'
+ - 'for_each_child_of_node'
+ - 'for_each_clear_bit'
+ - 'for_each_clear_bit_from'
+ - 'for_each_cmsghdr'
+ - 'for_each_compatible_node'
+ - 'for_each_console'
+ - 'for_each_cpu'
+ - 'for_each_cpu_and'
+ - 'for_each_cpu_not'
+ - 'for_each_cpu_wrap'
+ - 'for_each_dev_addr'
+ - 'for_each_dma_cap_mask'
+ - 'for_each_drhd_unit'
+ - 'for_each_dss_dev'
+ - 'for_each_efi_memory_desc'
+ - 'for_each_efi_memory_desc_in_map'
+ - 'for_each_endpoint_of_node'
+ - 'for_each_evictable_lru'
+ - 'for_each_fib6_node_rt_rcu'
+ - 'for_each_fib6_walker_rt'
+ - 'for_each_free_mem_range'
+ - 'for_each_free_mem_range_reverse'
+ - 'for_each_func_rsrc'
+ - 'for_each_hstate'
+ - 'for_each_if'
+ - 'for_each_iommu'
+ - 'for_each_ip_tunnel_rcu'
+ - 'for_each_irq_nr'
+ - 'for_each_lru'
+ - 'for_each_matching_node'
+ - 'for_each_matching_node_and_match'
+ - 'for_each_memblock'
+ - 'for_each_memblock_type'
+ - 'for_each_memcg_cache_index'
+ - 'for_each_mem_pfn_range'
+ - 'for_each_mem_range'
+ - 'for_each_mem_range_rev'
+ - 'for_each_migratetype_order'
+ - 'for_each_msi_entry'
+ - 'for_each_net'
+ - 'for_each_netdev'
+ - 'for_each_netdev_continue'
+ - 'for_each_netdev_continue_rcu'
+ - 'for_each_netdev_feature'
+ - 'for_each_netdev_in_bond_rcu'
+ - 'for_each_netdev_rcu'
+ - 'for_each_netdev_reverse'
+ - 'for_each_netdev_safe'
+ - 'for_each_net_rcu'
+ - 'for_each_new_connector_in_state'
+ - 'for_each_new_crtc_in_state'
+ - 'for_each_new_plane_in_state'
+ - 'for_each_new_private_obj_in_state'
+ - 'for_each_node'
+ - 'for_each_node_by_name'
+ - 'for_each_node_by_type'
+ - 'for_each_node_mask'
+ - 'for_each_node_state'
+ - 'for_each_node_with_cpus'
+ - 'for_each_node_with_property'
+ - 'for_each_of_allnodes'
+ - 'for_each_of_allnodes_from'
+ - 'for_each_of_pci_range'
+ - 'for_each_old_connector_in_state'
+ - 'for_each_old_crtc_in_state'
+ - 'for_each_oldnew_connector_in_state'
+ - 'for_each_oldnew_crtc_in_state'
+ - 'for_each_oldnew_plane_in_state'
+ - 'for_each_oldnew_private_obj_in_state'
+ - 'for_each_old_plane_in_state'
+ - 'for_each_old_private_obj_in_state'
+ - 'for_each_online_cpu'
+ - 'for_each_online_node'
+ - 'for_each_online_pgdat'
+ - 'for_each_pci_bridge'
+ - 'for_each_pci_dev'
+ - 'for_each_pci_msi_entry'
+ - 'for_each_populated_zone'
+ - 'for_each_possible_cpu'
+ - 'for_each_present_cpu'
+ - 'for_each_prime_number'
+ - 'for_each_prime_number_from'
+ - 'for_each_process'
+ - 'for_each_process_thread'
+ - 'for_each_property_of_node'
+ - 'for_each_reserved_mem_region'
+ - 'for_each_resv_unavail_range'
+ - 'for_each_rtdcom'
+ - 'for_each_rtdcom_safe'
+ - 'for_each_set_bit'
+ - 'for_each_set_bit_from'
+ - 'for_each_sg'
+ - 'for_each_sg_page'
+ - '__for_each_thread'
+ - 'for_each_thread'
+ - 'for_each_zone'
+ - 'for_each_zone_zonelist'
+ - 'for_each_zone_zonelist_nodemask'
+ - 'fwnode_for_each_available_child_node'
+ - 'fwnode_for_each_child_node'
+ - 'fwnode_graph_for_each_endpoint'
+ - 'gadget_for_each_ep'
+ - 'hash_for_each'
+ - 'hash_for_each_possible'
+ - 'hash_for_each_possible_rcu'
+ - 'hash_for_each_possible_rcu_notrace'
+ - 'hash_for_each_possible_safe'
+ - 'hash_for_each_rcu'
+ - 'hash_for_each_safe'
+ - 'hctx_for_each_ctx'
+ - 'hlist_bl_for_each_entry'
+ - 'hlist_bl_for_each_entry_rcu'
+ - 'hlist_bl_for_each_entry_safe'
+ - 'hlist_for_each'
+ - 'hlist_for_each_entry'
+ - 'hlist_for_each_entry_continue'
+ - 'hlist_for_each_entry_continue_rcu'
+ - 'hlist_for_each_entry_continue_rcu_bh'
+ - 'hlist_for_each_entry_from'
+ - 'hlist_for_each_entry_from_rcu'
+ - 'hlist_for_each_entry_rcu'
+ - 'hlist_for_each_entry_rcu_bh'
+ - 'hlist_for_each_entry_rcu_notrace'
+ - 'hlist_for_each_entry_safe'
+ - '__hlist_for_each_rcu'
+ - 'hlist_for_each_safe'
+ - 'hlist_nulls_for_each_entry'
+ - 'hlist_nulls_for_each_entry_from'
+ - 'hlist_nulls_for_each_entry_rcu'
+ - 'hlist_nulls_for_each_entry_safe'
+ - 'ide_host_for_each_port'
+ - 'ide_port_for_each_dev'
+ - 'ide_port_for_each_present_dev'
+ - 'idr_for_each_entry'
+ - 'idr_for_each_entry_continue'
+ - 'idr_for_each_entry_ul'
+ - 'inet_bind_bucket_for_each'
+ - 'inet_lhash2_for_each_icsk_rcu'
+ - 'iov_for_each'
+ - 'key_for_each'
+ - 'key_for_each_safe'
+ - 'klp_for_each_func'
+ - 'klp_for_each_object'
+ - 'kvm_for_each_memslot'
+ - 'kvm_for_each_vcpu'
+ - 'list_for_each'
+ - 'list_for_each_entry'
+ - 'list_for_each_entry_continue'
+ - 'list_for_each_entry_continue_rcu'
+ - 'list_for_each_entry_continue_reverse'
+ - 'list_for_each_entry_from'
+ - 'list_for_each_entry_from_reverse'
+ - 'list_for_each_entry_lockless'
+ - 'list_for_each_entry_rcu'
+ - 'list_for_each_entry_reverse'
+ - 'list_for_each_entry_safe'
+ - 'list_for_each_entry_safe_continue'
+ - 'list_for_each_entry_safe_from'
+ - 'list_for_each_entry_safe_reverse'
+ - 'list_for_each_prev'
+ - 'list_for_each_prev_safe'
+ - 'list_for_each_safe'
+ - 'llist_for_each'
+ - 'llist_for_each_entry'
+ - 'llist_for_each_entry_safe'
+ - 'llist_for_each_safe'
+ - 'media_device_for_each_entity'
+ - 'media_device_for_each_intf'
+ - 'media_device_for_each_link'
+ - 'media_device_for_each_pad'
+ - 'netdev_for_each_lower_dev'
+ - 'netdev_for_each_lower_private'
+ - 'netdev_for_each_lower_private_rcu'
+ - 'netdev_for_each_mc_addr'
+ - 'netdev_for_each_uc_addr'
+ - 'netdev_for_each_upper_dev_rcu'
+ - 'netdev_hw_addr_list_for_each'
+ - 'nft_rule_for_each_expr'
+ - 'nla_for_each_attr'
+ - 'nla_for_each_nested'
+ - 'nlmsg_for_each_attr'
+ - 'nlmsg_for_each_msg'
+ - 'nr_neigh_for_each'
+ - 'nr_neigh_for_each_safe'
+ - 'nr_node_for_each'
+ - 'nr_node_for_each_safe'
+ - 'of_for_each_phandle'
+ - 'of_property_for_each_string'
+ - 'of_property_for_each_u32'
+ - 'pci_bus_for_each_resource'
+ - 'ping_portaddr_for_each_entry'
+ - 'plist_for_each'
+ - 'plist_for_each_continue'
+ - 'plist_for_each_entry'
+ - 'plist_for_each_entry_continue'
+ - 'plist_for_each_entry_safe'
+ - 'plist_for_each_safe'
+ - 'pnp_for_each_card'
+ - 'pnp_for_each_dev'
+ - 'protocol_for_each_card'
+ - 'protocol_for_each_dev'
+ - 'queue_for_each_hw_ctx'
+ - 'radix_tree_for_each_contig'
+ - 'radix_tree_for_each_slot'
+ - 'radix_tree_for_each_tagged'
+ - 'rbtree_postorder_for_each_entry_safe'
+ - 'resource_list_for_each_entry'
+ - 'resource_list_for_each_entry_safe'
+ - 'rhl_for_each_entry_rcu'
+ - 'rhl_for_each_rcu'
+ - 'rht_for_each'
+ - 'rht_for_each_continue'
+ - 'rht_for_each_entry'
+ - 'rht_for_each_entry_continue'
+ - 'rht_for_each_entry_rcu'
+ - 'rht_for_each_entry_rcu_continue'
+ - 'rht_for_each_entry_safe'
+ - 'rht_for_each_rcu'
+ - 'rht_for_each_rcu_continue'
+ - '__rq_for_each_bio'
+ - 'rq_for_each_segment'
+ - 'scsi_for_each_prot_sg'
+ - 'scsi_for_each_sg'
+ - 'sctp_for_each_hentry'
+ - 'sctp_skb_for_each'
+ - 'shdma_for_each_chan'
+ - '__shost_for_each_device'
+ - 'shost_for_each_device'
+ - 'sk_for_each'
+ - 'sk_for_each_bound'
+ - 'sk_for_each_entry_offset_rcu'
+ - 'sk_for_each_from'
+ - 'sk_for_each_rcu'
+ - 'sk_for_each_safe'
+ - 'sk_nulls_for_each'
+ - 'sk_nulls_for_each_from'
+ - 'sk_nulls_for_each_rcu'
+ - 'snd_pcm_group_for_each_entry'
+ - 'snd_soc_dapm_widget_for_each_path'
+ - 'snd_soc_dapm_widget_for_each_path_safe'
+ - 'snd_soc_dapm_widget_for_each_sink_path'
+ - 'snd_soc_dapm_widget_for_each_source_path'
+ - 'tb_property_for_each'
+ - 'udp_portaddr_for_each_entry'
+ - 'udp_portaddr_for_each_entry_rcu'
+ - 'usb_hub_for_each_child'
+ - 'v4l2_device_for_each_subdev'
+ - 'v4l2_m2m_for_each_dst_buf'
+ - 'v4l2_m2m_for_each_dst_buf_safe'
+ - 'v4l2_m2m_for_each_src_buf'
+ - 'v4l2_m2m_for_each_src_buf_safe'
+ - 'zorro_for_each_dev'
+
+#IncludeBlocks: Preserve # Unknown to clang-format-5.0
+IncludeCategories:
+ - Regex: '.*'
+ Priority: 1
+IncludeIsMainRegex: '(Test)?$'
+IndentCaseLabels: false
+#IndentPPDirectives: None # Unknown to clang-format-5.0
+IndentWidth: 8
+IndentWrappedFunctionNames: true
+JavaScriptQuotes: Leave
+JavaScriptWrapImports: true
+KeepEmptyLinesAtTheStartOfBlocks: false
+MacroBlockBegin: ''
+MacroBlockEnd: ''
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: Inner
+#ObjCBinPackProtocolList: Auto # Unknown to clang-format-5.0
+ObjCBlockIndentWidth: 8
+ObjCSpaceAfterProperty: true
+ObjCSpaceBeforeProtocolList: true
+
+# Taken from git's rules
+#PenaltyBreakAssignment: 10 # Unknown to clang-format-4.0
+PenaltyBreakBeforeFirstCallParameter: 30
+PenaltyBreakComment: 10
+PenaltyBreakFirstLessLess: 0
+PenaltyBreakString: 10
+PenaltyExcessCharacter: 100
+PenaltyReturnTypeOnItsOwnLine: 60
+
+PointerAlignment: Right
+ReflowComments: false
+SortIncludes: false
+#SortUsingDeclarations: false # Unknown to clang-format-4.0
+SpaceAfterCStyleCast: false
+SpaceAfterTemplateKeyword: true
+SpaceBeforeAssignmentOperators: true
+#SpaceBeforeCtorInitializerColon: true # Unknown to clang-format-5.0
+#SpaceBeforeInheritanceColon: true # Unknown to clang-format-5.0
+SpaceBeforeParens: ControlStatements
+#SpaceBeforeRangeBasedForLoopColon: true # Unknown to clang-format-5.0
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 1
+SpacesInAngles: false
+SpacesInContainerLiterals: false
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+Standard: Cpp03
+TabWidth: 8
+UseTab: Always
+...
--- /dev/null
+.. _clangformat:
+
+clang-format
+============
+
+``clang-format`` is a tool to format C/C++/... code according to
+a set of rules and heuristics. Like most tools, it is not perfect
+nor covers every single case, but it is good enough to be helpful.
+
+``clang-format`` can be used for several purposes:
+
+ - Quickly reformat a block of code to the kernel style. Specially useful
+ when moving code around and aligning/sorting. See clangformatreformat_.
+
+ - Spot style mistakes, typos and possible improvements in files
+ you maintain, patches you review, diffs, etc. See clangformatreview_.
+
+ - Help you follow the coding style rules, specially useful for those
+ new to kernel development or working at the same time in several
+ projects with different coding styles.
+
+Its configuration file is ``.clang-format`` in the root of the kernel tree.
+The rules contained there try to approximate the most common kernel
+coding style. They also try to follow :ref:`Documentation/process/coding-style.rst <codingstyle>`
+as much as possible. Since not all the kernel follows the same style,
+it is possible that you may want to tweak the defaults for a particular
+subsystem or folder. To do so, you can override the defaults by writing
+another ``.clang-format`` file in a subfolder.
+
+The tool itself has already been included in the repositories of popular
+Linux distributions for a long time. Search for ``clang-format`` in
+your repositories. Otherwise, you can either download pre-built
+LLVM/clang binaries or build the source code from:
+
+ http://releases.llvm.org/download.html
+
+See more information about the tool at:
+
+ https://clang.llvm.org/docs/ClangFormat.html
+
+ https://clang.llvm.org/docs/ClangFormatStyleOptions.html
+
+
+.. _clangformatreview:
+
+Review files and patches for coding style
+-----------------------------------------
+
+By running the tool in its inline mode, you can review full subsystems,
+folders or individual files for code style mistakes, typos or improvements.
+
+To do so, you can run something like::
+
+ # Make sure your working directory is clean!
+ clang-format -i kernel/*.[ch]
+
+And then take a look at the git diff.
+
+Counting the lines of such a diff is also useful for improving/tweaking
+the style options in the configuration file; as well as testing new
+``clang-format`` features/versions.
+
+``clang-format`` also supports reading unified diffs, so you can review
+patches and git diffs easily. See the documentation at:
+
+ https://clang.llvm.org/docs/ClangFormat.html#script-for-patch-reformatting
+
+To avoid ``clang-format`` formatting some portion of a file, you can do::
+
+ int formatted_code;
+ // clang-format off
+ void unformatted_code ;
+ // clang-format on
+ void formatted_code_again;
+
+While it might be tempting to use this to keep a file always in sync with
+``clang-format``, specially if you are writing new files or if you are
+a maintainer, please note that people might be running different
+``clang-format`` versions or not have it available at all. Therefore,
+you should probably refrain yourself from using this in kernel sources;
+at least until we see if ``clang-format`` becomes commonplace.
+
+
+.. _clangformatreformat:
+
+Reformatting blocks of code
+---------------------------
+
+By using an integration with your text editor, you can reformat arbitrary
+blocks (selections) of code with a single keystroke. This is specially
+useful when moving code around, for complex code that is deeply intended,
+for multi-line macros (and aligning their backslashes), etc.
+
+Remember that you can always tweak the changes afterwards in those cases
+where the tool did not do an optimal job. But as a first approximation,
+it can be very useful.
+
+There are integrations for many popular text editors. For some of them,
+like vim, emacs, BBEdit and Visual Studio you can find support built-in.
+For instructions, read the appropiate section at:
+
+ https://clang.llvm.org/docs/ClangFormat.html
+
+For Atom, Eclipse, Sublime Text, Visual Studio Code, XCode and other
+editors and IDEs you should be able to find ready-to-use plugins.
+
+For this use case, consider using a secondary ``.clang-format``
+so that you can tweak a few options. See clangformatextra_.
+
+
+.. _clangformatmissing:
+
+Missing support
+---------------
+
+``clang-format`` is missing support for some things that are common
+in kernel code. They are easy to remember, so if you use the tool
+regularly, you will quickly learn to avoid/ignore those.
+
+In particular, some very common ones you will notice are:
+
+ - Aligned blocks of one-line ``#defines``, e.g.::
+
+ #define TRACING_MAP_BITS_DEFAULT 11
+ #define TRACING_MAP_BITS_MAX 17
+ #define TRACING_MAP_BITS_MIN 7
+
+ vs.::
+
+ #define TRACING_MAP_BITS_DEFAULT 11
+ #define TRACING_MAP_BITS_MAX 17
+ #define TRACING_MAP_BITS_MIN 7
+
+ - Aligned designated initializers, e.g.::
+
+ static const struct file_operations uprobe_events_ops = {
+ .owner = THIS_MODULE,
+ .open = probes_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+ .write = probes_write,
+ };
+
+ vs.::
+
+ static const struct file_operations uprobe_events_ops = {
+ .owner = THIS_MODULE,
+ .open = probes_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+ .write = probes_write,
+ };
+
+
+.. _clangformatextra:
+
+Extra features/options
+----------------------
+
+Some features/style options are not enabled by default in the configuration
+file in order to minimize the differences between the output and the current
+code. In other words, to make the difference as small as possible,
+which makes reviewing full-file style, as well diffs and patches as easy
+as possible.
+
+In other cases (e.g. particular subsystems/folders/files), the kernel style
+might be different and enabling some of these options may approximate
+better the style there.
+
+For instance:
+
+ - Aligning assignments (``AlignConsecutiveAssignments``).
+
+ - Aligning declarations (``AlignConsecutiveDeclarations``).
+
+ - Reflowing text in comments (``ReflowComments``).
+
+ - Sorting ``#includes`` (``SortIncludes``).
+
+They are typically useful for block re-formatting, rather than full-file.
+You might want to create another ``.clang-format`` file and use that one
+from your editor/IDE instead.