diff --git a/.clang-format b/.clang-format new file mode 100644 index 000000000000..faffc0d5af4e --- /dev/null +++ b/.clang-format @@ -0,0 +1,428 @@ +# 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 +... diff --git a/.gitignore b/.gitignore index 85bcc2696442..a1dfd2acd9c3 100644 --- a/.gitignore +++ b/.gitignore @@ -81,6 +81,7 @@ modules.builtin !.gitignore !.mailmap !.cocciconfig +!.clang-format # # Generated include files diff --git a/Documentation/process/4.Coding.rst b/Documentation/process/4.Coding.rst index 26b106071364..eb4b185d168c 100644 --- a/Documentation/process/4.Coding.rst +++ b/Documentation/process/4.Coding.rst @@ -58,6 +58,14 @@ can never be transgressed. If there is a good reason to go against the style (a line which becomes far less readable if split to fit within the 80-column limit, for example), just do it. +Note that you can also use the ``clang-format`` tool to help you with +these rules, to quickly re-format parts of your code automatically, +and to review full files in order to spot coding style mistakes, +typos and possible improvements. It is also handy for sorting ``#includes``, +for aligning variables/macros, for reflowing text and other similar tasks. +See the file :ref:`Documentation/process/clang-format.rst ` +for more details. + Abstraction layers ****************** diff --git a/Documentation/process/clang-format.rst b/Documentation/process/clang-format.rst new file mode 100644 index 000000000000..6710c0707721 --- /dev/null +++ b/Documentation/process/clang-format.rst @@ -0,0 +1,184 @@ +.. _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 ` +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. diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst index d98deb62c400..4e7c0a1c427a 100644 --- a/Documentation/process/coding-style.rst +++ b/Documentation/process/coding-style.rst @@ -631,6 +631,14 @@ options ``-kr -i8`` (stands for ``K&R, 8 character indents``), or use re-formatting you may want to take a look at the man page. But remember: ``indent`` is not a fix for bad programming. +Note that you can also use the ``clang-format`` tool to help you with +these rules, to quickly re-format parts of your code automatically, +and to review full files in order to spot coding style mistakes, +typos and possible improvements. It is also handy for sorting ``#includes``, +for aligning variables/macros, for reflowing text and other similar tasks. +See the file :ref:`Documentation/process/clang-format.rst ` +for more details. + 10) Kconfig configuration files -------------------------------