1 .. _submittingpatches:
2
3 Submitting patches: the essential guide to get
4 ==============================================
5
6 For a person or company who wishes to submit a
7 kernel, the process can sometimes be daunting
8 with "the system." This text is a collection
9 can greatly increase the chances of your chang
10
11 This document contains a large number of sugge
12 format. For detailed information on how the k
13 works, see Documentation/process/development-p
14 Documentation/process/submit-checklist.rst
15 for a list of items to check before submitting
16 For device tree binding patches, read
17 Documentation/devicetree/bindings/submitting-p
18
19 This documentation assumes that you're using `
20 If you're unfamiliar with ``git``, you would b
21 use it, it will make your life as a kernel dev
22 easier.
23
24 Some subsystems and maintainer trees have addi
25 their workflow and expectations, see
26 :ref:`Documentation/process/maintainer-handboo
27
28 Obtain a current source tree
29 ----------------------------
30
31 If you do not have a repository with the curre
32 ``git`` to obtain one. You'll want to start w
33 which can be grabbed with::
34
35 git clone git://git.kernel.org/pub/scm/linux
36
37 Note, however, that you may not want to develo
38 directly. Most subsystem maintainers run thei
39 patches prepared against those trees. See the
40 in the MAINTAINERS file to find that tree, or
41 the tree is not listed there.
42
43 .. _describe_changes:
44
45 Describe your changes
46 ---------------------
47
48 Describe your problem. Whether your patch is
49 5000 lines of a new feature, there must be an
50 motivated you to do this work. Convince the r
51 problem worth fixing and that it makes sense f
52 first paragraph.
53
54 Describe user-visible impact. Straight up cra
55 pretty convincing, but not all bugs are that b
56 problem was spotted during code review, descri
57 it can have on users. Keep in mind that the m
58 installations run kernels from secondary stabl
59 vendor/product-specific trees that cherry-pick
60 from upstream, so include anything that could
61 downstream: provoking circumstances, excerpts
62 descriptions, performance regressions, latency
63
64 Quantify optimizations and trade-offs. If you
65 performance, memory consumption, stack footpri
66 include numbers that back them up. But also d
67 costs. Optimizations usually aren't free but
68 memory, and readability; or, when it comes to
69 different workloads. Describe the expected do
70 optimization so that the reviewer can weigh co
71
72 Once the problem is established, describe what
73 about it in technical detail. It's important
74 in plain English for the reviewer to verify th
75 as you intend it to.
76
77 The maintainer will thank you if you write you
78 form which can be easily pulled into Linux's s
79 system, ``git``, as a "commit log". See :ref:
80
81 Solve only one problem per patch. If your des
82 long, that's a sign that you probably need to
83 See :ref:`split_changes`.
84
85 When you submit or resubmit a patch or patch s
86 complete patch description and justification f
87 say that this is version N of the patch (serie
88 subsystem maintainer to refer back to earlier
89 URLs to find the patch description and put tha
90 I.e., the patch (series) and its description s
91 This benefits both the maintainers and reviewe
92 probably didn't even receive earlier versions
93
94 Describe your changes in imperative mood, e.g.
95 instead of "[This patch] makes xyzzy do frotz"
96 to do frotz", as if you are giving orders to t
97 its behaviour.
98
99 If you want to refer to a specific commit, don
100 SHA-1 ID of the commit. Please also include th
101 the commit, to make it easier for reviewers to
102 Example::
103
104 Commit e21d2170f36602ae2708 ("video: r
105 platform_set_drvdata()") removed the u
106 platform_set_drvdata(), but left the v
107 delete it.
108
109 You should also be sure to use at least the fi
110 SHA-1 ID. The kernel repository holds a *lot*
111 collisions with shorter IDs a real possibility
112 there is no collision with your six-character
113 change five years from now.
114
115 If related discussions or any other background
116 can be found on the web, add 'Link:' tags poin
117 result of some earlier mailing list discussion
118 web, point to it.
119
120 When linking to mailing list archives, prefera
121 message archiver service. To create the link U
122 ``Message-ID`` header of the message without t
123 For example::
124
125 Link: https://lore.kernel.org/30th.anniver
126
127 Please check the link to make sure that it is
128 to the relevant message.
129
130 However, try to make your explanation understa
131 resources. In addition to giving a URL to a ma
132 summarize the relevant points of the discussio
133 patch as submitted.
134
135 In case your patch fixes a bug, use the 'Close
136 the report in the mailing list archives or a p
137
138 Closes: https://example.com/issues/123
139
140 Some bug trackers have the ability to close is
141 commit with such a tag is applied. Some bots m
142 also track such tags and take certain actions.
143 invalid URLs are forbidden.
144
145 If your patch fixes a bug in a specific commit
146 ``git bisect``, please use the 'Fixes:' tag wi
147 the SHA-1 ID, and the one line summary. Do no
148 lines, tags are exempt from the "wrap at 75 co
149 parsing scripts. For example::
150
151 Fixes: 54a4f0239f2e ("KVM: MMU: make k
152
153 The following ``git config`` settings can be u
154 outputting the above style in the ``git log``
155
156 [core]
157 abbrev = 12
158 [pretty]
159 fixes = Fixes: %h (\"%s\")
160
161 An example call::
162
163 $ git log -1 --pretty=fixes 54a4f0239f
164 Fixes: 54a4f0239f2e ("KVM: MMU: make k
165
166 .. _split_changes:
167
168 Separate your changes
169 ---------------------
170
171 Separate each **logical change** into a separa
172
173 For example, if your changes include both bug
174 enhancements for a single driver, separate tho
175 or more patches. If your changes include an A
176 driver which uses that new API, separate those
177
178 On the other hand, if you make a single change
179 group those changes into a single patch. Thus
180 is contained within a single patch.
181
182 The point to remember is that each patch shoul
183 change that can be verified by reviewers. Eac
184 on its own merits.
185
186 If one patch depends on another patch in order
187 complete, that is OK. Simply note **"this pat
188 in your patch description.
189
190 When dividing your change into a series of pat
191 ensure that the kernel builds and runs properl
192 series. Developers using ``git bisect`` to tr
193 splitting your patch series at any point; they
194 introduce bugs in the middle.
195
196 If you cannot condense your patch set into a s
197 then only post say 15 or so at a time and wait
198
199
200
201 Style-check your changes
202 ------------------------
203
204 Check your patch for basic style violations, d
205 found in Documentation/process/coding-style.rs
206 Failure to do so simply wastes
207 the reviewers time and will get your patch rej
208 without even being read.
209
210 One significant exception is when moving code
211 another -- in this case you should not modify
212 the same patch which moves it. This clearly d
213 moving the code and your changes. This greatl
214 actual differences and allows tools to better
215 the code itself.
216
217 Check your patches with the patch style checke
218 (scripts/checkpatch.pl). Note, though, that t
219 viewed as a guide, not as a replacement for hu
220 looks better with a violation then its probabl
221
222 The checker reports at three levels:
223 - ERROR: things that are very likely to be wr
224 - WARNING: things requiring careful review
225 - CHECK: things requiring thought
226
227 You should be able to justify all violations t
228 patch.
229
230
231 Select the recipients for your patch
232 ------------------------------------
233
234 You should always copy the appropriate subsyst
235 any patch to code that they maintain; look thr
236 source code revision history to see who those
237 scripts/get_maintainer.pl can be very useful a
238 patches as arguments to scripts/get_maintainer
239 maintainer for the subsystem you are working o
240 (akpm@linux-foundation.org) serves as a mainta
241
242 linux-kernel@vger.kernel.org should be used by
243 volume on that list has caused a number of dev
244 do not spam unrelated lists and unrelated peop
245
246 Many kernel-related lists are hosted at kernel
247 of them at https://subspace.kernel.org. There
248 hosted elsewhere as well, though.
249
250 Linus Torvalds is the final arbiter of all cha
251 Linux kernel. His e-mail address is <torvalds@
252 He gets a lot of e-mail, and, at this point, v
253 Linus directly, so typically you should do you
254 sending him e-mail.
255
256 If you have a patch that fixes an exploitable
257 to security@kernel.org. For severe bugs, a sh
258 to allow distributors to get the patch out to
259 obviously, the patch should not be sent to any
260 Documentation/process/security-bugs.rst.
261
262 Patches that fix a severe bug in a released ke
263 toward the stable maintainers by putting a lin
264
265 Cc: stable@vger.kernel.org
266
267 into the sign-off area of your patch (note, NO
268 should also read Documentation/process/stable-
269 in addition to this document.
270
271 If changes affect userland-kernel interfaces,
272 maintainer (as listed in the MAINTAINERS file)
273 least a notification of the change, so that so
274 into the manual pages. User-space API changes
275 linux-api@vger.kernel.org.
276
277
278 No MIME, no links, no compression, no attachme
279 ----------------------------------------------
280
281 Linus and other kernel developers need to be a
282 on the changes you are submitting. It is impo
283 developer to be able to "quote" your changes,
284 tools, so that they may comment on specific po
285
286 For this reason, all patches should be submitt
287 easiest way to do this is with ``git send-emai
288 recommended. An interactive tutorial for ``gi
289 https://git-send-email.io.
290
291 If you choose not to use ``git send-email``:
292
293 .. warning::
294
295 Be wary of your editor's word-wrap corruptin
296 if you choose to cut-n-paste your patch.
297
298 Do not attach the patch as a MIME attachment,
299 Many popular e-mail applications will not alwa
300 attachment as plain text, making it impossible
301 code. A MIME attachment also takes Linus a bi
302 decreasing the likelihood of your MIME-attache
303
304 Exception: If your mailer is mangling patches
305 you to re-send them using MIME.
306
307 See Documentation/process/email-clients.rst fo
308 your e-mail client so that it sends your patch
309
310 Respond to review comments
311 --------------------------
312
313 Your patch will almost certainly get comments
314 which the patch can be improved, in the form o
315 respond to those comments; ignoring reviewers
316 return. You can simply reply to their emails t
317 comments or questions that do not lead to a co
318 bring about a comment or changelog entry so th
319 understands what is going on.
320
321 Be sure to tell the reviewers what changes you
322 for their time. Code review is a tiring and t
323 reviewers sometimes get grumpy. Even in that
324 politely and address the problems they have po
325 version, add a ``patch changelog`` to the cove
326 explaining difference against previous submiss
327 :ref:`the_canonical_patch_format`).
328 Notify people that commented on your patch abo
329 the patches CC list.
330
331 See Documentation/process/email-clients.rst fo
332 clients and mailing list etiquette.
333
334 .. _interleaved_replies:
335
336 Use trimmed interleaved replies in email discu
337 ----------------------------------------------
338 Top-posting is strongly discouraged in Linux k
339 discussions. Interleaved (or "inline") replies
340 easier to follow. For more details see:
341 https://en.wikipedia.org/wiki/Posting_style#In
342
343 As is frequently quoted on the mailing list::
344
345 A: http://en.wikipedia.org/wiki/Top_post
346 Q: Were do I find info about this thing call
347 A: Because it messes up the order in which p
348 Q: Why is top-posting such a bad thing?
349 A: Top-posting.
350 Q: What is the most annoying thing in e-mail
351
352 Similarly, please trim all unneeded quotations
353 to your reply. This makes responses easier to
354 space. For more details see: http://daringfire
355
356 A: No.
357 Q: Should I include quotations after my repl
358
359 .. _resend_reminders:
360
361 Don't get discouraged - or impatient
362 ------------------------------------
363
364 After you have submitted your change, be patie
365 busy people and may not get to your patch righ
366
367 Once upon a time, patches used to disappear in
368 but the development process works more smoothl
369 receive comments within a few weeks (typically
370 happen, make sure that you have sent your patc
371 Wait for a minimum of one week before resubmit
372 - possibly longer during busy times like merge
373
374 It's also ok to resend the patch or the patch
375 weeks with the word "RESEND" added to the subj
376
377 [PATCH Vx RESEND] sub/sys: Condensed patch
378
379 Don't add "RESEND" when you are submitting a m
380 patch or patch series - "RESEND" only applies
381 patch or patch series which have not been modi
382 previous submission.
383
384
385 Include PATCH in the subject
386 -----------------------------
387
388 Due to high e-mail traffic to Linus, and to li
389 convention to prefix your subject line with [P
390 and other kernel developers more easily distin
391 e-mail discussions.
392
393 ``git send-email`` will do this for you automa
394
395
396 Sign your work - the Developer's Certificate o
397 ----------------------------------------------
398
399 To improve tracking of who did what, especiall
400 percolate to their final resting place in the
401 layers of maintainers, we've introduced a "sig
402 patches that are being emailed around.
403
404 The sign-off is a simple line at the end of th
405 patch, which certifies that you wrote it or ot
406 pass it on as an open-source patch. The rules
407 can certify the below:
408
409 Developer's Certificate of Origin 1.1
410 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
411
412 By making a contribution to this project, I ce
413
414 (a) The contribution was created in wh
415 have the right to submit it under
416 indicated in the file; or
417
418 (b) The contribution is based upon pre
419 of my knowledge, is covered under
420 license and I have the right under
421 work with modifications, whether c
422 by me, under the same open source
423 permitted to submit under a differ
424 in the file; or
425
426 (c) The contribution was provided dire
427 person who certified (a), (b) or (
428 it.
429
430 (d) I understand and agree that this p
431 are public and that a record of th
432 personal information I submit with
433 maintained indefinitely and may be
434 this project or the open source li
435
436 then you just add a line saying::
437
438 Signed-off-by: Random J Developer <rand
439
440 using a known identity (sorry, no anonymous co
441 This will be done for you automatically if you
442 Reverts should also include "Signed-off-by". `
443 for you.
444
445 Some people also put extra tags at the end. T
446 now, but you can do this to mark internal comp
447 point out some special detail about the sign-o
448
449 Any further SoBs (Signed-off-by:'s) following
450 people handling and transporting the patch, bu
451 development. SoB chains should reflect the **r
452 as it was propagated to the maintainers and ul
453 the first SoB entry signalling primary authors
454
455
456 When to use Acked-by:, Cc:, and Co-developed-b
457 ----------------------------------------------
458
459 The Signed-off-by: tag indicates that the sign
460 development of the patch, or that he/she was i
461
462 If a person was not directly involved in the p
463 patch but wishes to signify and record their a
464 ask to have an Acked-by: line added to the pat
465
466 Acked-by: is often used by the maintainer of t
467 maintainer neither contributed to nor forwarde
468
469 Acked-by: is not as formal as Signed-off-by:.
470 has at least reviewed the patch and has indica
471 mergers will sometimes manually convert an ack
472 into an Acked-by: (but note that it is usually
473 explicit ack).
474
475 Acked-by: does not necessarily indicate acknow
476 For example, if a patch affects multiple subsy
477 one subsystem maintainer then this usually ind
478 the part which affects that maintainer's code.
479 When in doubt people should refer to the origi
480 list archives.
481
482 If a person has had the opportunity to comment
483 provided such comments, you may optionally add
484 This is the only tag which might be added with
485 person it names - but it should indicate that
486 patch. This tag documents that potentially in
487 have been included in the discussion.
488
489 Co-developed-by: states that the patch was co-
490 it is used to give attribution to co-authors (
491 attributed by the From: tag) when several peop
492 Co-developed-by: denotes authorship, every Co-
493 followed by a Signed-off-by: of the associated
494 procedure applies, i.e. the ordering of Signed
495 chronological history of the patch insofar as
496 the author is attributed via From: or Co-devel
497 Signed-off-by: must always be that of the deve
498
499 Note, the From: tag is optional when the From:
500 email) listed in the From: line of the email h
501
502 Example of a patch submitted by the From: auth
503
504 <changelog>
505
506 Co-developed-by: First Co-Author <first
507 Signed-off-by: First Co-Author <first@c
508 Co-developed-by: Second Co-Author <seco
509 Signed-off-by: Second Co-Author <second
510 Signed-off-by: From Author <from@author
511
512 Example of a patch submitted by a Co-developed
513
514 From: From Author <from@author.example.
515
516 <changelog>
517
518 Co-developed-by: Random Co-Author <rand
519 Signed-off-by: Random Co-Author <random
520 Signed-off-by: From Author <from@author
521 Co-developed-by: Submitting Co-Author <
522 Signed-off-by: Submitting Co-Author <su
523
524
525 Using Reported-by:, Tested-by:, Reviewed-by:,
526 ----------------------------------------------
527
528 The Reported-by tag gives credit to people who
529 hopefully inspires them to help us again in th
530 bugs; please do not use it to credit feature r
531 followed by a Closes: tag pointing to the repo
532 available on the web. The Link: tag can be use
533 fixes a part of the issue(s) being reported. P
534 reported in private, then ask for permission f
535 tag.
536
537 A Tested-by: tag indicates that the patch has
538 some environment) by the person named. This t
539 some testing has been performed, provides a me
540 future patches, and ensures credit for the tes
541
542 Reviewed-by:, instead, indicates that the patc
543 acceptable according to the Reviewer's Stateme
544
545 Reviewer's statement of oversight
546 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
547
548 By offering my Reviewed-by: tag, I state that:
549
550 (a) I have carried out a technical re
551 evaluate its appropriateness and
552 the mainline kernel.
553
554 (b) Any problems, concerns, or questi
555 have been communicated back to th
556 with the submitter's response to
557
558 (c) While there may be things that co
559 submission, I believe that it is,
560 worthwhile modification to the ke
561 issues which would argue against
562
563 (d) While I have reviewed the patch a
564 do not (unless explicitly stated
565 warranties or guarantees that it
566 purpose or function properly in a
567
568 A Reviewed-by tag is a statement of opinion th
569 appropriate modification of the kernel without
570 technical issues. Any interested reviewer (wh
571 offer a Reviewed-by tag for a patch. This tag
572 reviewers and to inform maintainers of the deg
573 done on the patch. Reviewed-by: tags, when su
574 understand the subject area and to perform tho
575 increase the likelihood of your patch getting
576
577 Both Tested-by and Reviewed-by tags, once rece
578 or reviewer, should be added by author to the
579 next versions. However if the patch has chang
580 version, these tags might not be applicable an
581 Usually removal of someone's Tested-by or Revi
582 in the patch changelog (after the '---' separa
583
584 A Suggested-by: tag indicates that the patch i
585 named and ensures credit to the person for the
586 tag should not be added without the reporter's
587 idea was not posted in a public forum. That sa
588 idea reporters, they will, hopefully, be inspi
589 future.
590
591 A Fixes: tag indicates that the patch fixes an
592 is used to make it easy to determine where a b
593 review a bug fix. This tag also assists the st
594 which stable kernel versions should receive yo
595 method for indicating a bug fixed by the patch
596 for more details.
597
598 Note: Attaching a Fixes: tag does not subvert
599 process nor the requirement to Cc: stable@vger
600 patch candidates. For more information, please
601 Documentation/process/stable-kernel-rules.rst.
602
603 .. _the_canonical_patch_format:
604
605 The canonical patch format
606 --------------------------
607
608 This section describes how the patch itself sh
609 that, if you have your patches stored in a ``g
610 formatting can be had with ``git format-patch`
611 the necessary text, though, so read the instru
612
613 The canonical patch subject line is::
614
615 Subject: [PATCH 001/123] subsystem: summar
616
617 The canonical patch message body contains the
618
619 - A ``from`` line specifying the patch autho
620 line (only needed if the person sending th
621
622 - The body of the explanation, line wrapped
623 be copied to the permanent changelog to de
624
625 - An empty line.
626
627 - The ``Signed-off-by:`` lines, described ab
628 also go in the changelog.
629
630 - A marker line containing simply ``---``.
631
632 - Any additional comments not suitable for t
633
634 - The actual patch (``diff`` output).
635
636 The Subject line format makes it very easy to
637 alphabetically by subject line - pretty much a
638 support that - since because the sequence numb
639 the numerical and alphabetic sort is the same.
640
641 The ``subsystem`` in the email's Subject shoul
642 area or subsystem of the kernel is being patch
643
644 The ``summary phrase`` in the email's Subject
645 describe the patch which that email contains.
646 phrase`` should not be a filename. Do not use
647 phrase`` for every patch in a whole patch seri
648 series`` is an ordered sequence of multiple, r
649
650 Bear in mind that the ``summary phrase`` of yo
651 globally-unique identifier for that patch. It
652 into the ``git`` changelog. The ``summary phr
653 developer discussions which refer to the patch
654 google for the ``summary phrase`` to read disc
655 patch. It will also be the only thing that pe
656 when, two or three months later, they are goin
657 thousands of patches using tools such as ``git
658 --oneline``.
659
660 For these reasons, the ``summary`` must be no
661 characters, and it must describe both what the
662 as why the patch might be necessary. It is ch
663 succinct and descriptive, but that is what a w
664 should do.
665
666 The ``summary phrase`` may be prefixed by tags
667 brackets: "Subject: [PATCH <tag>...] <summary
668 not considered part of the summary phrase, but
669 should be treated. Common tags might include
670 the multiple versions of the patch have been s
671 comments (i.e., "v1, v2, v3"), or "RFC" to ind
672 comments.
673
674 If there are four patches in a patch series th
675 be numbered like this: 1/4, 2/4, 3/4, 4/4. Thi
676 understand the order in which the patches shou
677 they have reviewed or applied all of the patch
678
679 Here are some good example Subjects::
680
681 Subject: [PATCH 2/5] ext2: improve scalabi
682 Subject: [PATCH v2 01/27] x86: fix eflags
683 Subject: [PATCH v2] sub/sys: Condensed pat
684 Subject: [PATCH v2 M/N] sub/sys: Condensed
685
686 The ``from`` line must be the very first line
687 and has the form:
688
689 From: Patch Author <author@example.com>
690
691 The ``from`` line specifies who will be credit
692 patch in the permanent changelog. If the ``fr
693 then the ``From:`` line from the email header
694 the patch author in the changelog.
695
696 The explanation body will be committed to the
697 changelog, so should make sense to a competent
698 forgotten the immediate details of the discuss
699 this patch. Including symptoms of the failure
700 (kernel log messages, oops messages, etc.) are
701 people who might be searching the commit logs
702 patch. The text should be written in such deta
703 weeks, months or even years later, it can give
704 details to grasp the reasoning for **why** the
705
706 If a patch fixes a compile failure, it may not
707 _all_ of the compile failures; just enough tha
708 someone searching for the patch can find it. A
709 phrase``, it is important to be both succinct
710
711 The ``---`` marker line serves the essential p
712 patch handling tools where the changelog messa
713
714 One good use for the additional comments after
715 for a ``diffstat``, to show what files have ch
716 inserted and deleted lines per file. A ``diffs
717 on bigger patches. If you are going to include
718 ``---`` marker, please use ``diffstat`` option
719 filenames are listed from the top of the kerne
720 use too much horizontal space (easily fit in 8
721 indentation). (``git`` generates appropriate d
722
723 Other comments relevant only to the moment or
724 suitable for the permanent changelog, should a
725 example of such comments might be ``patch chan
726 what has changed between the v1 and v2 version
727
728 Please put this information **after** the ``--
729 the changelog from the rest of the patch. The
730 not part of the changelog which gets committed
731 additional information for the reviewers. If i
732 commit tags, it needs manual interaction to re
733 the separator line, it gets automatically stri
734 patch::
735
736 <commit message>
737 ...
738 Signed-off-by: Author <author@mail>
739 ---
740 V2 -> V3: Removed redundant helper function
741 V1 -> V2: Cleaned up coding style and addres
742
743 path/to/file | 5+++--
744 ...
745
746 See more details on the proper patch format in
747 references.
748
749 .. _backtraces:
750
751 Backtraces in commit messages
752 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
753
754 Backtraces help document the call chain leadin
755 not all backtraces are helpful. For example, e
756 unique and obvious. Copying the full dmesg out
757 adds distracting information like timestamps,
758 stack dumps.
759
760 Therefore, the most useful backtraces should d
761 information from the dump, which makes it easi
762 issue. Here is an example of a well-trimmed ba
763
764 unchecked MSR access error: WRMSR to 0xd51 (
765 at rIP: 0xffffffffae059994 (native_write_msr
766 Call Trace:
767 mba_wrmsr
768 update_domains
769 rdtgroup_mkdir
770
771 .. _explicit_in_reply_to:
772
773 Explicit In-Reply-To headers
774 ----------------------------
775
776 It can be helpful to manually add In-Reply-To:
777 (e.g., when using ``git send-email``) to assoc
778 previous relevant discussion, e.g. to link a b
779 the bug report. However, for a multi-patch se
780 best to avoid using In-Reply-To: to link to ol
781 series. This way multiple versions of the pat
782 unmanageable forest of references in email cli
783 helpful, you can use the https://lore.kernel.o
784 the cover email text) to link to an earlier ve
785
786
787 Providing base tree information
788 -------------------------------
789
790 When other developers receive your patches and
791 it is absolutely necessary for them to know wh
792 commit/branch your work applies on, considerin
793 maintainer trees present nowadays. Note again
794 MAINTAINERS file explained above.
795
796 This is even more important for automated CI p
797 run a series of tests in order to establish th
798 submission before the maintainer starts the re
799
800 If you are using ``git format-patch`` to gener
801 automatically include the base tree informatio
802 using the ``--base`` flag. The easiest and mos
803 this option is with topical branches::
804
805 $ git checkout -t -b my-topical-branch mas
806 Branch 'my-topical-branch' set up to track
807 Switched to a new branch 'my-topical-branc
808
809 [perform your edits and commits]
810
811 $ git format-patch --base=auto --cover-let
812 outgoing/0000-cover-letter.patch
813 outgoing/0001-First-Commit.patch
814 outgoing/...
815
816 When you open ``outgoing/0000-cover-letter.pat
817 notice that it will have the ``base-commit:``
818 bottom, which provides the reviewer and the CI
819 to properly perform ``git am`` without worryin
820
821 $ git checkout -b patch-review [base-commi
822 Switched to a new branch 'patch-review'
823 $ git am patches.mbox
824 Applying: First Commit
825 Applying: ...
826
827 Please see ``man git-format-patch`` for more i
828 option.
829
830 .. note::
831
832 The ``--base`` feature was introduced in g
833
834 If you are not using git to format your patche
835 the same ``base-commit`` trailer to indicate t
836 on which your work is based. You should add it
837 letter or in the first patch of the series and
838 either below the ``---`` line or at the very b
839 content, right before your email signature.
840
841 Make sure that base commit is in an official m
842 and not in some internal, accessible only to y
843 would be worthless.
844
845 Tooling
846 -------
847
848 Many of the technical aspects of this process
849 b4, documented at <https://b4.docs.kernel.org/
850 help with things like tracking dependencies, r
851 with formatting and sending mails.
852
853 References
854 ----------
855
856 Andrew Morton, "The perfect patch" (tpp).
857 <https://www.ozlabs.org/~akpm/stuff/tpp.txt>
858
859 Jeff Garzik, "Linux kernel patch submission fo
860 <https://web.archive.org/web/20180829112450/
861
862 Greg Kroah-Hartman, "How to piss off a kernel
863 <http://www.kroah.com/log/linux/maintainer.h
864
865 <http://www.kroah.com/log/linux/maintainer-0
866
867 <http://www.kroah.com/log/linux/maintainer-0
868
869 <http://www.kroah.com/log/linux/maintainer-0
870
871 <http://www.kroah.com/log/linux/maintainer-0
872
873 <http://www.kroah.com/log/linux/maintainer-0
874
875 Kernel Documentation/process/coding-style.rst
876
877 Linus Torvalds's mail on the canonical patch f
878 <https://lore.kernel.org/r/Pine.LNX.4.58.0504
879
880 Andi Kleen, "On submitting kernel patches"
881 Some strategies to get difficult or controve
882
883 http://halobates.de/on-submitting-patches.pd
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