Based on kernel version 2.6.30. Page generated on 2009-06-11 10:13 EST.
1 2 How to Get Your Change Into the Linux Kernel 3 or 4 Care And Operation Of Your Linus Torvalds 5 6 7 8 For a person or company who wishes to submit a change to the Linux 9 kernel, the process can sometimes be daunting if you're not familiar 10 with "the system." This text is a collection of suggestions which 11 can greatly increase the chances of your change being accepted. 12 13 Read Documentation/SubmitChecklist for a list of items to check 14 before submitting code. If you are submitting a driver, also read 15 Documentation/SubmittingDrivers. 16 17 18 19 -------------------------------------------- 20 SECTION 1 - CREATING AND SENDING YOUR CHANGE 21 -------------------------------------------- 22 23 24 25 1) "diff -up" 26 ------------ 27 28 Use "diff -up" or "diff -uprN" to create patches. 29 30 All changes to the Linux kernel occur in the form of patches, as 31 generated by diff(1). When creating your patch, make sure to create it 32 in "unified diff" format, as supplied by the '-u' argument to diff(1). 33 Also, please use the '-p' argument which shows which C function each 34 change is in - that makes the resultant diff a lot easier to read. 35 Patches should be based in the root kernel source directory, 36 not in any lower subdirectory. 37 38 To create a patch for a single file, it is often sufficient to do: 39 40 SRCTREE= linux-2.6 41 MYFILE= drivers/net/mydriver.c 42 43 cd $SRCTREE 44 cp $MYFILE $MYFILE.orig 45 vi $MYFILE # make your change 46 cd .. 47 diff -up $SRCTREE/$MYFILE{.orig,} > /tmp/patch 48 49 To create a patch for multiple files, you should unpack a "vanilla", 50 or unmodified kernel source tree, and generate a diff against your 51 own source tree. For example: 52 53 MYSRC= /devel/linux-2.6 54 55 tar xvfz linux-2.6.12.tar.gz 56 mv linux-2.6.12 linux-2.6.12-vanilla 57 diff -uprN -X linux-2.6.12-vanilla/Documentation/dontdiff \ 58 linux-2.6.12-vanilla $MYSRC > /tmp/patch 59 60 "dontdiff" is a list of files which are generated by the kernel during 61 the build process, and should be ignored in any diff(1)-generated 62 patch. The "dontdiff" file is included in the kernel tree in 63 2.6.12 and later. For earlier kernel versions, you can get it 64 from <http://www.xenotime.net/linux/doc/dontdiff>. 65 66 Make sure your patch does not include any extra files which do not 67 belong in a patch submission. Make sure to review your patch -after- 68 generated it with diff(1), to ensure accuracy. 69 70 If your changes produce a lot of deltas, you may want to look into 71 splitting them into individual patches which modify things in 72 logical stages. This will facilitate easier reviewing by other 73 kernel developers, very important if you want your patch accepted. 74 There are a number of scripts which can aid in this: 75 76 Quilt: 77 http://savannah.nongnu.org/projects/quilt 78 79 Andrew Morton's patch scripts: 80 http://userweb.kernel.org/~akpm/stuff/patch-scripts.tar.gz 81 Instead of these scripts, quilt is the recommended patch management 82 tool (see above). 83 84 85 86 2) Describe your changes. 87 88 Describe the technical detail of the change(s) your patch includes. 89 90 Be as specific as possible. The WORST descriptions possible include 91 things like "update driver X", "bug fix for driver X", or "this patch 92 includes updates for subsystem X. Please apply." 93 94 If your description starts to get long, that's a sign that you probably 95 need to split up your patch. See #3, next. 96 97 98 99 3) Separate your changes. 100 101 Separate _logical changes_ into a single patch file. 102 103 For example, if your changes include both bug fixes and performance 104 enhancements for a single driver, separate those changes into two 105 or more patches. If your changes include an API update, and a new 106 driver which uses that new API, separate those into two patches. 107 108 On the other hand, if you make a single change to numerous files, 109 group those changes into a single patch. Thus a single logical change 110 is contained within a single patch. 111 112 If one patch depends on another patch in order for a change to be 113 complete, that is OK. Simply note "this patch depends on patch X" 114 in your patch description. 115 116 If you cannot condense your patch set into a smaller set of patches, 117 then only post say 15 or so at a time and wait for review and integration. 118 119 120 121 4) Style check your changes. 122 123 Check your patch for basic style violations, details of which can be 124 found in Documentation/CodingStyle. Failure to do so simply wastes 125 the reviewers time and will get your patch rejected, probably 126 without even being read. 127 128 At a minimum you should check your patches with the patch style 129 checker prior to submission (scripts/checkpatch.pl). You should 130 be able to justify all violations that remain in your patch. 131 132 133 134 5) Select e-mail destination. 135 136 Look through the MAINTAINERS file and the source code, and determine 137 if your change applies to a specific subsystem of the kernel, with 138 an assigned maintainer. If so, e-mail that person. 139 140 If no maintainer is listed, or the maintainer does not respond, send 141 your patch to the primary Linux kernel developer's mailing list, 142 linux-kernel[AT]vger.kernel.org[DOT] Most kernel developers monitor this 143 e-mail list, and can comment on your changes. 144 145 146 Do not send more than 15 patches at once to the vger mailing lists!!! 147 148 149 Linus Torvalds is the final arbiter of all changes accepted into the 150 Linux kernel. His e-mail address is <torvalds[AT]linux-foundation.org>[DOT] 151 He gets a lot of e-mail, so typically you should do your best to -avoid- 152 sending him e-mail. 153 154 Patches which are bug fixes, are "obvious" changes, or similarly 155 require little discussion should be sent or CC'd to Linus. Patches 156 which require discussion or do not have a clear advantage should 157 usually be sent first to linux-kernel. Only after the patch is 158 discussed should the patch then be submitted to Linus. 159 160 161 162 6) Select your CC (e-mail carbon copy) list. 163 164 Unless you have a reason NOT to do so, CC linux-kernel[AT]vger.kernel.org[DOT] 165 166 Other kernel developers besides Linus need to be aware of your change, 167 so that they may comment on it and offer code review and suggestions. 168 linux-kernel is the primary Linux kernel developer mailing list. 169 Other mailing lists are available for specific subsystems, such as 170 USB, framebuffer devices, the VFS, the SCSI subsystem, etc. See the 171 MAINTAINERS file for a mailing list that relates specifically to 172 your change. 173 174 Majordomo lists of VGER.KERNEL.ORG at: 175 <http://vger.kernel.org/vger-lists.html> 176 177 If changes affect userland-kernel interfaces, please send 178 the MAN-PAGES maintainer (as listed in the MAINTAINERS file) 179 a man-pages patch, or at least a notification of the change, 180 so that some information makes its way into the manual pages. 181 182 Even if the maintainer did not respond in step #4, make sure to ALWAYS 183 copy the maintainer when you change their code. 184 185 For small patches you may want to CC the Trivial Patch Monkey 186 trivial[AT]kernel[DOT]org managed by Jesper Juhl; which collects "trivial" 187 patches. Trivial patches must qualify for one of the following rules: 188 Spelling fixes in documentation 189 Spelling fixes which could break grep(1) 190 Warning fixes (cluttering with useless warnings is bad) 191 Compilation fixes (only if they are actually correct) 192 Runtime fixes (only if they actually fix things) 193 Removing use of deprecated functions/macros (eg. check_region) 194 Contact detail and documentation fixes 195 Non-portable code replaced by portable code (even in arch-specific, 196 since people copy, as long as it's trivial) 197 Any fix by the author/maintainer of the file (ie. patch monkey 198 in re-transmission mode) 199 URL: <http://www.kernel.org/pub/linux/kernel/people/juhl/trivial/> 200 201 202 203 7) No MIME, no links, no compression, no attachments. Just plain text. 204 205 Linus and other kernel developers need to be able to read and comment 206 on the changes you are submitting. It is important for a kernel 207 developer to be able to "quote" your changes, using standard e-mail 208 tools, so that they may comment on specific portions of your code. 209 210 For this reason, all patches should be submitting e-mail "inline". 211 WARNING: Be wary of your editor's word-wrap corrupting your patch, 212 if you choose to cut-n-paste your patch. 213 214 Do not attach the patch as a MIME attachment, compressed or not. 215 Many popular e-mail applications will not always transmit a MIME 216 attachment as plain text, making it impossible to comment on your 217 code. A MIME attachment also takes Linus a bit more time to process, 218 decreasing the likelihood of your MIME-attached change being accepted. 219 220 Exception: If your mailer is mangling patches then someone may ask 221 you to re-send them using MIME. 222 223 See Documentation/email-clients.txt for hints about configuring 224 your e-mail client so that it sends your patches untouched. 225 226 8) E-mail size. 227 228 When sending patches to Linus, always follow step #7. 229 230 Large changes are not appropriate for mailing lists, and some 231 maintainers. If your patch, uncompressed, exceeds 40 kB in size, 232 it is preferred that you store your patch on an Internet-accessible 233 server, and provide instead a URL (link) pointing to your patch. 234 235 236 237 9) Name your kernel version. 238 239 It is important to note, either in the subject line or in the patch 240 description, the kernel version to which this patch applies. 241 242 If the patch does not apply cleanly to the latest kernel version, 243 Linus will not apply it. 244 245 246 247 10) Don't get discouraged. Re-submit. 248 249 After you have submitted your change, be patient and wait. If Linus 250 likes your change and applies it, it will appear in the next version 251 of the kernel that he releases. 252 253 However, if your change doesn't appear in the next version of the 254 kernel, there could be any number of reasons. It's YOUR job to 255 narrow down those reasons, correct what was wrong, and submit your 256 updated change. 257 258 It is quite common for Linus to "drop" your patch without comment. 259 That's the nature of the system. If he drops your patch, it could be 260 due to 261 * Your patch did not apply cleanly to the latest kernel version. 262 * Your patch was not sufficiently discussed on linux-kernel. 263 * A style issue (see section 2). 264 * An e-mail formatting issue (re-read this section). 265 * A technical problem with your change. 266 * He gets tons of e-mail, and yours got lost in the shuffle. 267 * You are being annoying. 268 269 When in doubt, solicit comments on linux-kernel mailing list. 270 271 272 273 11) Include PATCH in the subject 274 275 Due to high e-mail traffic to Linus, and to linux-kernel, it is common 276 convention to prefix your subject line with [PATCH]. This lets Linus 277 and other kernel developers more easily distinguish patches from other 278 e-mail discussions. 279 280 281 282 12) Sign your work 283 284 To improve tracking of who did what, especially with patches that can 285 percolate to their final resting place in the kernel through several 286 layers of maintainers, we've introduced a "sign-off" procedure on 287 patches that are being emailed around. 288 289 The sign-off is a simple line at the end of the explanation for the 290 patch, which certifies that you wrote it or otherwise have the right to 291 pass it on as a open-source patch. The rules are pretty simple: if you 292 can certify the below: 293 294 Developer's Certificate of Origin 1.1 295 296 By making a contribution to this project, I certify that: 297 298 (a) The contribution was created in whole or in part by me and I 299 have the right to submit it under the open source license 300 indicated in the file; or 301 302 (b) The contribution is based upon previous work that, to the best 303 of my knowledge, is covered under an appropriate open source 304 license and I have the right under that license to submit that 305 work with modifications, whether created in whole or in part 306 by me, under the same open source license (unless I am 307 permitted to submit under a different license), as indicated 308 in the file; or 309 310 (c) The contribution was provided directly to me by some other 311 person who certified (a), (b) or (c) and I have not modified 312 it. 313 314 (d) I understand and agree that this project and the contribution 315 are public and that a record of the contribution (including all 316 personal information I submit with it, including my sign-off) is 317 maintained indefinitely and may be redistributed consistent with 318 this project or the open source license(s) involved. 319 320 then you just add a line saying 321 322 Signed-off-by: Random J Developer <random[AT]developer.example[DOT]org> 323 324 using your real name (sorry, no pseudonyms or anonymous contributions.) 325 326 Some people also put extra tags at the end. They'll just be ignored for 327 now, but you can do this to mark internal company procedures or just 328 point out some special detail about the sign-off. 329 330 If you are a subsystem or branch maintainer, sometimes you need to slightly 331 modify patches you receive in order to merge them, because the code is not 332 exactly the same in your tree and the submitters'. If you stick strictly to 333 rule (c), you should ask the submitter to rediff, but this is a totally 334 counter-productive waste of time and energy. Rule (b) allows you to adjust 335 the code, but then it is very impolite to change one submitter's code and 336 make him endorse your bugs. To solve this problem, it is recommended that 337 you add a line between the last Signed-off-by header and yours, indicating 338 the nature of your changes. While there is nothing mandatory about this, it 339 seems like prepending the description with your mail and/or name, all 340 enclosed in square brackets, is noticeable enough to make it obvious that 341 you are responsible for last-minute changes. Example : 342 343 Signed-off-by: Random J Developer <random[AT]developer.example[DOT]org> 344 [lucky[AT]maintainer.example.org: struct foo moved from foo.c to foo[DOT]h] 345 Signed-off-by: Lucky K Maintainer <lucky[AT]maintainer.example[DOT]org> 346 347 This practise is particularly helpful if you maintain a stable branch and 348 want at the same time to credit the author, track changes, merge the fix, 349 and protect the submitter from complaints. Note that under no circumstances 350 can you change the author's identity (the From header), as it is the one 351 which appears in the changelog. 352 353 Special note to back-porters: It seems to be a common and useful practise 354 to insert an indication of the origin of a patch at the top of the commit 355 message (just after the subject line) to facilitate tracking. For instance, 356 here's what we see in 2.6-stable : 357 358 Date: Tue May 13 19:10:30 2008 +0000 359 360 SCSI: libiscsi regression in 2.6.25: fix nop timer handling 361 362 commit 4cf1043593db6a337f10e006c23c69e5fc93e722 upstream 363 364 And here's what appears in 2.4 : 365 366 Date: Tue May 13 22:12:27 2008 +0200 367 368 wireless, airo: waitbusy() won't delay 369 370 [backport of 2.6 commit b7acbdfbd1f277c1eb23f344f899cfa4cd0bf36a] 371 372 Whatever the format, this information provides a valuable help to people 373 tracking your trees, and to people trying to trouble-shoot bugs in your 374 tree. 375 376 377 13) When to use Acked-by: and Cc: 378 379 The Signed-off-by: tag indicates that the signer was involved in the 380 development of the patch, or that he/she was in the patch's delivery path. 381 382 If a person was not directly involved in the preparation or handling of a 383 patch but wishes to signify and record their approval of it then they can 384 arrange to have an Acked-by: line added to the patch's changelog. 385 386 Acked-by: is often used by the maintainer of the affected code when that 387 maintainer neither contributed to nor forwarded the patch. 388 389 Acked-by: is not as formal as Signed-off-by:. It is a record that the acker 390 has at least reviewed the patch and has indicated acceptance. Hence patch 391 mergers will sometimes manually convert an acker's "yep, looks good to me" 392 into an Acked-by:. 393 394 Acked-by: does not necessarily indicate acknowledgement of the entire patch. 395 For example, if a patch affects multiple subsystems and has an Acked-by: from 396 one subsystem maintainer then this usually indicates acknowledgement of just 397 the part which affects that maintainer's code. Judgement should be used here. 398 When in doubt people should refer to the original discussion in the mailing 399 list archives. 400 401 If a person has had the opportunity to comment on a patch, but has not 402 provided such comments, you may optionally add a "Cc:" tag to the patch. 403 This is the only tag which might be added without an explicit action by the 404 person it names. This tag documents that potentially interested parties 405 have been included in the discussion 406 407 408 14) Using Tested-by: and Reviewed-by: 409 410 A Tested-by: tag indicates that the patch has been successfully tested (in 411 some environment) by the person named. This tag informs maintainers that 412 some testing has been performed, provides a means to locate testers for 413 future patches, and ensures credit for the testers. 414 415 Reviewed-by:, instead, indicates that the patch has been reviewed and found 416 acceptable according to the Reviewer's Statement: 417 418 Reviewer's statement of oversight 419 420 By offering my Reviewed-by: tag, I state that: 421 422 (a) I have carried out a technical review of this patch to 423 evaluate its appropriateness and readiness for inclusion into 424 the mainline kernel. 425 426 (b) Any problems, concerns, or questions relating to the patch 427 have been communicated back to the submitter. I am satisfied 428 with the submitter's response to my comments. 429 430 (c) While there may be things that could be improved with this 431 submission, I believe that it is, at this time, (1) a 432 worthwhile modification to the kernel, and (2) free of known 433 issues which would argue against its inclusion. 434 435 (d) While I have reviewed the patch and believe it to be sound, I 436 do not (unless explicitly stated elsewhere) make any 437 warranties or guarantees that it will achieve its stated 438 purpose or function properly in any given situation. 439 440 A Reviewed-by tag is a statement of opinion that the patch is an 441 appropriate modification of the kernel without any remaining serious 442 technical issues. Any interested reviewer (who has done the work) can 443 offer a Reviewed-by tag for a patch. This tag serves to give credit to 444 reviewers and to inform maintainers of the degree of review which has been 445 done on the patch. Reviewed-by: tags, when supplied by reviewers known to 446 understand the subject area and to perform thorough reviews, will normally 447 increase the liklihood of your patch getting into the kernel. 448 449 450 15) The canonical patch format 451 452 The canonical patch subject line is: 453 454 Subject: [PATCH 001/123] subsystem: summary phrase 455 456 The canonical patch message body contains the following: 457 458 - A "from" line specifying the patch author. 459 460 - An empty line. 461 462 - The body of the explanation, which will be copied to the 463 permanent changelog to describe this patch. 464 465 - The "Signed-off-by:" lines, described above, which will 466 also go in the changelog. 467 468 - A marker line containing simply "---". 469 470 - Any additional comments not suitable for the changelog. 471 472 - The actual patch (diff output). 473 474 The Subject line format makes it very easy to sort the emails 475 alphabetically by subject line - pretty much any email reader will 476 support that - since because the sequence number is zero-padded, 477 the numerical and alphabetic sort is the same. 478 479 The "subsystem" in the email's Subject should identify which 480 area or subsystem of the kernel is being patched. 481 482 The "summary phrase" in the email's Subject should concisely 483 describe the patch which that email contains. The "summary 484 phrase" should not be a filename. Do not use the same "summary 485 phrase" for every patch in a whole patch series (where a "patch 486 series" is an ordered sequence of multiple, related patches). 487 488 Bear in mind that the "summary phrase" of your email becomes 489 a globally-unique identifier for that patch. It propagates 490 all the way into the git changelog. The "summary phrase" may 491 later be used in developer discussions which refer to the patch. 492 People will want to google for the "summary phrase" to read 493 discussion regarding that patch. 494 495 A couple of example Subjects: 496 497 Subject: [patch 2/5] ext2: improve scalability of bitmap searching 498 Subject: [PATCHv2 001/207] x86: fix eflags tracking 499 500 The "from" line must be the very first line in the message body, 501 and has the form: 502 503 From: Original Author <author[AT]example[DOT]com> 504 505 The "from" line specifies who will be credited as the author of the 506 patch in the permanent changelog. If the "from" line is missing, 507 then the "From:" line from the email header will be used to determine 508 the patch author in the changelog. 509 510 The explanation body will be committed to the permanent source 511 changelog, so should make sense to a competent reader who has long 512 since forgotten the immediate details of the discussion that might 513 have led to this patch. 514 515 The "---" marker line serves the essential purpose of marking for patch 516 handling tools where the changelog message ends. 517 518 One good use for the additional comments after the "---" marker is for 519 a diffstat, to show what files have changed, and the number of inserted 520 and deleted lines per file. A diffstat is especially useful on bigger 521 patches. Other comments relevant only to the moment or the maintainer, 522 not suitable for the permanent changelog, should also go here. 523 Use diffstat options "-p 1 -w 70" so that filenames are listed from the 524 top of the kernel source tree and don't use too much horizontal space 525 (easily fit in 80 columns, maybe with some indentation). 526 527 See more details on the proper patch format in the following 528 references. 529 530 531 16) Sending "git pull" requests (from Linus emails) 532 533 Please write the git repo address and branch name alone on the same line 534 so that I can't even by mistake pull from the wrong branch, and so 535 that a triple-click just selects the whole thing. 536 537 So the proper format is something along the lines of: 538 539 "Please pull from 540 541 git://jdelvare.pck.nerim.net/jdelvare-2.6 i2c-for-linus 542 543 to get these changes:" 544 545 so that I don't have to hunt-and-peck for the address and inevitably 546 get it wrong (actually, I've only gotten it wrong a few times, and 547 checking against the diffstat tells me when I get it wrong, but I'm 548 just a lot more comfortable when I don't have to "look for" the right 549 thing to pull, and double-check that I have the right branch-name). 550 551 552 Please use "git diff -M --stat --summary" to generate the diffstat: 553 the -M enables rename detection, and the summary enables a summary of 554 new/deleted or renamed files. 555 556 With rename detection, the statistics are rather different [...] 557 because git will notice that a fair number of the changes are renames. 558 559 ----------------------------------- 560 SECTION 2 - HINTS, TIPS, AND TRICKS 561 ----------------------------------- 562 563 This section lists many of the common "rules" associated with code 564 submitted to the kernel. There are always exceptions... but you must 565 have a really good reason for doing so. You could probably call this 566 section Linus Computer Science 101. 567 568 569 570 1) Read Documentation/CodingStyle 571 572 Nuff said. If your code deviates too much from this, it is likely 573 to be rejected without further review, and without comment. 574 575 One significant exception is when moving code from one file to 576 another -- in this case you should not modify the moved code at all in 577 the same patch which moves it. This clearly delineates the act of 578 moving the code and your changes. This greatly aids review of the 579 actual differences and allows tools to better track the history of 580 the code itself. 581 582 Check your patches with the patch style checker prior to submission 583 (scripts/checkpatch.pl). The style checker should be viewed as 584 a guide not as the final word. If your code looks better with 585 a violation then its probably best left alone. 586 587 The checker reports at three levels: 588 - ERROR: things that are very likely to be wrong 589 - WARNING: things requiring careful review 590 - CHECK: things requiring thought 591 592 You should be able to justify all violations that remain in your 593 patch. 594 595 596 597 2) #ifdefs are ugly 598 599 Code cluttered with ifdefs is difficult to read and maintain. Don't do 600 it. Instead, put your ifdefs in a header, and conditionally define 601 'static inline' functions, or macros, which are used in the code. 602 Let the compiler optimize away the "no-op" case. 603 604 Simple example, of poor code: 605 606 dev = alloc_etherdev (sizeof(struct funky_private)); 607 if (!dev) 608 return -ENODEV; 609 #ifdef CONFIG_NET_FUNKINESS 610 init_funky_net(dev); 611 #endif 612 613 Cleaned-up example: 614 615 (in header) 616 #ifndef CONFIG_NET_FUNKINESS 617 static inline void init_funky_net (struct net_device *d) {} 618 #endif 619 620 (in the code itself) 621 dev = alloc_etherdev (sizeof(struct funky_private)); 622 if (!dev) 623 return -ENODEV; 624 init_funky_net(dev); 625 626 627 628 3) 'static inline' is better than a macro 629 630 Static inline functions are greatly preferred over macros. 631 They provide type safety, have no length limitations, no formatting 632 limitations, and under gcc they are as cheap as macros. 633 634 Macros should only be used for cases where a static inline is clearly 635 suboptimal [there are a few, isolated cases of this in fast paths], 636 or where it is impossible to use a static inline function [such as 637 string-izing]. 638 639 'static inline' is preferred over 'static __inline__', 'extern inline', 640 and 'extern __inline__'. 641 642 643 644 4) Don't over-design. 645 646 Don't try to anticipate nebulous future cases which may or may not 647 be useful: "Make it as simple as you can, and no simpler." 648 649 650 651 ---------------------- 652 SECTION 3 - REFERENCES 653 ---------------------- 654 655 Andrew Morton, "The perfect patch" (tpp). 656 <http://userweb.kernel.org/~akpm/stuff/tpp.txt> 657 658 Jeff Garzik, "Linux kernel patch submission format". 659 <http://linux.yyz.us/patch-format.html> 660 661 Greg Kroah-Hartman, "How to piss off a kernel subsystem maintainer". 662 <http://www.kroah.com/log/2005/03/31/> 663 <http://www.kroah.com/log/2005/07/08/> 664 <http://www.kroah.com/log/2005/10/19/> 665 <http://www.kroah.com/log/2006/01/11/> 666 667 NO!!!! No more huge patch bombs to linux-kernel[AT]vger.kernel[DOT]org people! 668 <http://marc.theaimsgroup.com/?l=linux-kernel&m=112112749912944&w=2> 669 670 Kernel Documentation/CodingStyle: 671 <http://users.sosdg.org/~qiyong/lxr/source/Documentation/CodingStyle> 672 673 Linus Torvalds's mail on the canonical patch format: 674 <http://lkml.org/lkml/2005/4/7/183> 675 676 Andi Kleen, "On submitting kernel patches" 677 Some strategies to get difficult or controversal changes in. 678 http://halobates.de/on-submitting-patches.pdf 679 680 --