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Commit cbd83da82b15292337ff2b71e619c9a3a95f6d80

Authored by Linus Torvalds
1 parent 814d8ffd50
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

Update DCO ("signoff") rules to 1.1 

This adds a clause that notes explicitly that the person doing the
sign-off knows that the project (and his sign-off) is public and will
possibly get archived and re-distributed.

Showing 1 changed file with 7 additions and 1 deletions Inline Diff

Documentation/SubmittingPatches
Diff comments   View file @ cbd83da
1 1
2 How to Get Your Change Into the Linux Kernel 2 How to Get Your Change Into the Linux Kernel
3 or 3 or
4 Care And Operation Of Your Linus Torvalds 4 Care And Operation Of Your Linus Torvalds
5 5
6 6
7 7
8 For a person or company who wishes to submit a change to the Linux 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 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 10 with "the system." This text is a collection of suggestions which
11 can greatly increase the chances of your change being accepted. 11 can greatly increase the chances of your change being accepted.
12 12
13 If you are submitting a driver, also read Documentation/SubmittingDrivers. 13 If you are submitting a driver, also read Documentation/SubmittingDrivers.
14 14
15 15
16 16
17 -------------------------------------------- 17 --------------------------------------------
18 SECTION 1 - CREATING AND SENDING YOUR CHANGE 18 SECTION 1 - CREATING AND SENDING YOUR CHANGE
19 -------------------------------------------- 19 --------------------------------------------
20 20
21 21
22 22
23 1) "diff -up" 23 1) "diff -up"
24 ------------ 24 ------------
25 25
26 Use "diff -up" or "diff -uprN" to create patches. 26 Use "diff -up" or "diff -uprN" to create patches.
27 27
28 All changes to the Linux kernel occur in the form of patches, as 28 All changes to the Linux kernel occur in the form of patches, as
29 generated by diff(1). When creating your patch, make sure to create it 29 generated by diff(1). When creating your patch, make sure to create it
30 in "unified diff" format, as supplied by the '-u' argument to diff(1). 30 in "unified diff" format, as supplied by the '-u' argument to diff(1).
31 Also, please use the '-p' argument which shows which C function each 31 Also, please use the '-p' argument which shows which C function each
32 change is in - that makes the resultant diff a lot easier to read. 32 change is in - that makes the resultant diff a lot easier to read.
33 Patches should be based in the root kernel source directory, 33 Patches should be based in the root kernel source directory,
34 not in any lower subdirectory. 34 not in any lower subdirectory.
35 35
36 To create a patch for a single file, it is often sufficient to do: 36 To create a patch for a single file, it is often sufficient to do:
37 37
38 SRCTREE= linux-2.4 38 SRCTREE= linux-2.4
39 MYFILE= drivers/net/mydriver.c 39 MYFILE= drivers/net/mydriver.c
40 40
41 cd $SRCTREE 41 cd $SRCTREE
42 cp $MYFILE $MYFILE.orig 42 cp $MYFILE $MYFILE.orig
43 vi $MYFILE # make your change 43 vi $MYFILE # make your change
44 cd .. 44 cd ..
45 diff -up $SRCTREE/$MYFILE{.orig,} > /tmp/patch 45 diff -up $SRCTREE/$MYFILE{.orig,} > /tmp/patch
46 46
47 To create a patch for multiple files, you should unpack a "vanilla", 47 To create a patch for multiple files, you should unpack a "vanilla",
48 or unmodified kernel source tree, and generate a diff against your 48 or unmodified kernel source tree, and generate a diff against your
49 own source tree. For example: 49 own source tree. For example:
50 50
51 MYSRC= /devel/linux-2.4 51 MYSRC= /devel/linux-2.4
52 52
53 tar xvfz linux-2.4.0-test11.tar.gz 53 tar xvfz linux-2.4.0-test11.tar.gz
54 mv linux linux-vanilla 54 mv linux linux-vanilla
55 wget http://www.moses.uklinux.net/patches/dontdiff 55 wget http://www.moses.uklinux.net/patches/dontdiff
56 diff -uprN -X dontdiff linux-vanilla $MYSRC > /tmp/patch 56 diff -uprN -X dontdiff linux-vanilla $MYSRC > /tmp/patch
57 rm -f dontdiff 57 rm -f dontdiff
58 58
59 "dontdiff" is a list of files which are generated by the kernel during 59 "dontdiff" is a list of files which are generated by the kernel during
60 the build process, and should be ignored in any diff(1)-generated 60 the build process, and should be ignored in any diff(1)-generated
61 patch. dontdiff is maintained by Tigran Aivazian <tigran@veritas.com> 61 patch. dontdiff is maintained by Tigran Aivazian <tigran@veritas.com>
62 62
63 Make sure your patch does not include any extra files which do not 63 Make sure your patch does not include any extra files which do not
64 belong in a patch submission. Make sure to review your patch -after- 64 belong in a patch submission. Make sure to review your patch -after-
65 generated it with diff(1), to ensure accuracy. 65 generated it with diff(1), to ensure accuracy.
66 66
67 If your changes produce a lot of deltas, you may want to look into 67 If your changes produce a lot of deltas, you may want to look into
68 splitting them into individual patches which modify things in 68 splitting them into individual patches which modify things in
69 logical stages, this will facilitate easier reviewing by other 69 logical stages, this will facilitate easier reviewing by other
70 kernel developers, very important if you want your patch accepted. 70 kernel developers, very important if you want your patch accepted.
71 There are a number of scripts which can aid in this; 71 There are a number of scripts which can aid in this;
72 72
73 Quilt: 73 Quilt:
74 http://savannah.nongnu.org/projects/quilt 74 http://savannah.nongnu.org/projects/quilt
75 75
76 Randy Dunlap's patch scripts: 76 Randy Dunlap's patch scripts:
77 http://developer.osdl.org/rddunlap/scripts/patching-scripts.tgz 77 http://developer.osdl.org/rddunlap/scripts/patching-scripts.tgz
78 78
79 Andrew Morton's patch scripts: 79 Andrew Morton's patch scripts:
80 http://www.zip.com.au/~akpm/linux/patches/patch-scripts-0.16 80 http://www.zip.com.au/~akpm/linux/patches/patch-scripts-0.16
81 81
82 2) Describe your changes. 82 2) Describe your changes.
83 83
84 Describe the technical detail of the change(s) your patch includes. 84 Describe the technical detail of the change(s) your patch includes.
85 85
86 Be as specific as possible. The WORST descriptions possible include 86 Be as specific as possible. The WORST descriptions possible include
87 things like "update driver X", "bug fix for driver X", or "this patch 87 things like "update driver X", "bug fix for driver X", or "this patch
88 includes updates for subsystem X. Please apply." 88 includes updates for subsystem X. Please apply."
89 89
90 If your description starts to get long, that's a sign that you probably 90 If your description starts to get long, that's a sign that you probably
91 need to split up your patch. See #3, next. 91 need to split up your patch. See #3, next.
92 92
93 93
94 94
95 3) Separate your changes. 95 3) Separate your changes.
96 96
97 Separate each logical change into its own patch. 97 Separate each logical change into its own patch.
98 98
99 For example, if your changes include both bug fixes and performance 99 For example, if your changes include both bug fixes and performance
100 enhancements for a single driver, separate those changes into two 100 enhancements for a single driver, separate those changes into two
101 or more patches. If your changes include an API update, and a new 101 or more patches. If your changes include an API update, and a new
102 driver which uses that new API, separate those into two patches. 102 driver which uses that new API, separate those into two patches.
103 103
104 On the other hand, if you make a single change to numerous files, 104 On the other hand, if you make a single change to numerous files,
105 group those changes into a single patch. Thus a single logical change 105 group those changes into a single patch. Thus a single logical change
106 is contained within a single patch. 106 is contained within a single patch.
107 107
108 If one patch depends on another patch in order for a change to be 108 If one patch depends on another patch in order for a change to be
109 complete, that is OK. Simply note "this patch depends on patch X" 109 complete, that is OK. Simply note "this patch depends on patch X"
110 in your patch description. 110 in your patch description.
111 111
112 112
113 4) Select e-mail destination. 113 4) Select e-mail destination.
114 114
115 Look through the MAINTAINERS file and the source code, and determine 115 Look through the MAINTAINERS file and the source code, and determine
116 if your change applies to a specific subsystem of the kernel, with 116 if your change applies to a specific subsystem of the kernel, with
117 an assigned maintainer. If so, e-mail that person. 117 an assigned maintainer. If so, e-mail that person.
118 118
119 If no maintainer is listed, or the maintainer does not respond, send 119 If no maintainer is listed, or the maintainer does not respond, send
120 your patch to the primary Linux kernel developer's mailing list, 120 your patch to the primary Linux kernel developer's mailing list,
121 linux-kernel@vger.kernel.org. Most kernel developers monitor this 121 linux-kernel@vger.kernel.org. Most kernel developers monitor this
122 e-mail list, and can comment on your changes. 122 e-mail list, and can comment on your changes.
123 123
124 Linus Torvalds is the final arbiter of all changes accepted into the 124 Linus Torvalds is the final arbiter of all changes accepted into the
125 Linux kernel. His e-mail address is <torvalds@osdl.org>. He gets 125 Linux kernel. His e-mail address is <torvalds@osdl.org>. He gets
126 a lot of e-mail, so typically you should do your best to -avoid- sending 126 a lot of e-mail, so typically you should do your best to -avoid- sending
127 him e-mail. 127 him e-mail.
128 128
129 Patches which are bug fixes, are "obvious" changes, or similarly 129 Patches which are bug fixes, are "obvious" changes, or similarly
130 require little discussion should be sent or CC'd to Linus. Patches 130 require little discussion should be sent or CC'd to Linus. Patches
131 which require discussion or do not have a clear advantage should 131 which require discussion or do not have a clear advantage should
132 usually be sent first to linux-kernel. Only after the patch is 132 usually be sent first to linux-kernel. Only after the patch is
133 discussed should the patch then be submitted to Linus. 133 discussed should the patch then be submitted to Linus.
134 134
135 For small patches you may want to CC the Trivial Patch Monkey 135 For small patches you may want to CC the Trivial Patch Monkey
136 trivial@rustcorp.com.au set up by Rusty Russell; which collects "trivial" 136 trivial@rustcorp.com.au set up by Rusty Russell; which collects "trivial"
137 patches. Trivial patches must qualify for one of the following rules: 137 patches. Trivial patches must qualify for one of the following rules:
138 Spelling fixes in documentation 138 Spelling fixes in documentation
139 Spelling fixes which could break grep(1). 139 Spelling fixes which could break grep(1).
140 Warning fixes (cluttering with useless warnings is bad) 140 Warning fixes (cluttering with useless warnings is bad)
141 Compilation fixes (only if they are actually correct) 141 Compilation fixes (only if they are actually correct)
142 Runtime fixes (only if they actually fix things) 142 Runtime fixes (only if they actually fix things)
143 Removing use of deprecated functions/macros (eg. check_region). 143 Removing use of deprecated functions/macros (eg. check_region).
144 Contact detail and documentation fixes 144 Contact detail and documentation fixes
145 Non-portable code replaced by portable code (even in arch-specific, 145 Non-portable code replaced by portable code (even in arch-specific,
146 since people copy, as long as it's trivial) 146 since people copy, as long as it's trivial)
147 Any fix by the author/maintainer of the file. (ie. patch monkey 147 Any fix by the author/maintainer of the file. (ie. patch monkey
148 in re-transmission mode) 148 in re-transmission mode)
149 149
150 150
151 151
152 5) Select your CC (e-mail carbon copy) list. 152 5) Select your CC (e-mail carbon copy) list.
153 153
154 Unless you have a reason NOT to do so, CC linux-kernel@vger.kernel.org. 154 Unless you have a reason NOT to do so, CC linux-kernel@vger.kernel.org.
155 155
156 Other kernel developers besides Linus need to be aware of your change, 156 Other kernel developers besides Linus need to be aware of your change,
157 so that they may comment on it and offer code review and suggestions. 157 so that they may comment on it and offer code review and suggestions.
158 linux-kernel is the primary Linux kernel developer mailing list. 158 linux-kernel is the primary Linux kernel developer mailing list.
159 Other mailing lists are available for specific subsystems, such as 159 Other mailing lists are available for specific subsystems, such as
160 USB, framebuffer devices, the VFS, the SCSI subsystem, etc. See the 160 USB, framebuffer devices, the VFS, the SCSI subsystem, etc. See the
161 MAINTAINERS file for a mailing list that relates specifically to 161 MAINTAINERS file for a mailing list that relates specifically to
162 your change. 162 your change.
163 163
164 Even if the maintainer did not respond in step #4, make sure to ALWAYS 164 Even if the maintainer did not respond in step #4, make sure to ALWAYS
165 copy the maintainer when you change their code. 165 copy the maintainer when you change their code.
166 166
167 For small patches you may want to CC the Trivial Patch Monkey 167 For small patches you may want to CC the Trivial Patch Monkey
168 trivial@rustcorp.com.au set up by Rusty Russell; which collects "trivial" 168 trivial@rustcorp.com.au set up by Rusty Russell; which collects "trivial"
169 patches. Trivial patches must qualify for one of the following rules: 169 patches. Trivial patches must qualify for one of the following rules:
170 Spelling fixes in documentation 170 Spelling fixes in documentation
171 Spelling fixes which could break grep(1). 171 Spelling fixes which could break grep(1).
172 Warning fixes (cluttering with useless warnings is bad) 172 Warning fixes (cluttering with useless warnings is bad)
173 Compilation fixes (only if they are actually correct) 173 Compilation fixes (only if they are actually correct)
174 Runtime fixes (only if they actually fix things) 174 Runtime fixes (only if they actually fix things)
175 Removing use of deprecated functions/macros (eg. check_region). 175 Removing use of deprecated functions/macros (eg. check_region).
176 Contact detail and documentation fixes 176 Contact detail and documentation fixes
177 Non-portable code replaced by portable code (even in arch-specific, 177 Non-portable code replaced by portable code (even in arch-specific,
178 since people copy, as long as it's trivial) 178 since people copy, as long as it's trivial)
179 Any fix by the author/maintainer of the file. (ie. patch monkey 179 Any fix by the author/maintainer of the file. (ie. patch monkey
180 in re-transmission mode) 180 in re-transmission mode)
181 181
182 182
183 183
184 6) No MIME, no links, no compression, no attachments. Just plain text. 184 6) No MIME, no links, no compression, no attachments. Just plain text.
185 185
186 Linus and other kernel developers need to be able to read and comment 186 Linus and other kernel developers need to be able to read and comment
187 on the changes you are submitting. It is important for a kernel 187 on the changes you are submitting. It is important for a kernel
188 developer to be able to "quote" your changes, using standard e-mail 188 developer to be able to "quote" your changes, using standard e-mail
189 tools, so that they may comment on specific portions of your code. 189 tools, so that they may comment on specific portions of your code.
190 190
191 For this reason, all patches should be submitting e-mail "inline". 191 For this reason, all patches should be submitting e-mail "inline".
192 WARNING: Be wary of your editor's word-wrap corrupting your patch, 192 WARNING: Be wary of your editor's word-wrap corrupting your patch,
193 if you choose to cut-n-paste your patch. 193 if you choose to cut-n-paste your patch.
194 194
195 Do not attach the patch as a MIME attachment, compressed or not. 195 Do not attach the patch as a MIME attachment, compressed or not.
196 Many popular e-mail applications will not always transmit a MIME 196 Many popular e-mail applications will not always transmit a MIME
197 attachment as plain text, making it impossible to comment on your 197 attachment as plain text, making it impossible to comment on your
198 code. A MIME attachment also takes Linus a bit more time to process, 198 code. A MIME attachment also takes Linus a bit more time to process,
199 decreasing the likelihood of your MIME-attached change being accepted. 199 decreasing the likelihood of your MIME-attached change being accepted.
200 200
201 Exception: If your mailer is mangling patches then someone may ask 201 Exception: If your mailer is mangling patches then someone may ask
202 you to re-send them using MIME. 202 you to re-send them using MIME.
203 203
204 204
205 205
206 7) E-mail size. 206 7) E-mail size.
207 207
208 When sending patches to Linus, always follow step #6. 208 When sending patches to Linus, always follow step #6.
209 209
210 Large changes are not appropriate for mailing lists, and some 210 Large changes are not appropriate for mailing lists, and some
211 maintainers. If your patch, uncompressed, exceeds 40 kB in size, 211 maintainers. If your patch, uncompressed, exceeds 40 kB in size,
212 it is preferred that you store your patch on an Internet-accessible 212 it is preferred that you store your patch on an Internet-accessible
213 server, and provide instead a URL (link) pointing to your patch. 213 server, and provide instead a URL (link) pointing to your patch.
214 214
215 215
216 216
217 8) Name your kernel version. 217 8) Name your kernel version.
218 218
219 It is important to note, either in the subject line or in the patch 219 It is important to note, either in the subject line or in the patch
220 description, the kernel version to which this patch applies. 220 description, the kernel version to which this patch applies.
221 221
222 If the patch does not apply cleanly to the latest kernel version, 222 If the patch does not apply cleanly to the latest kernel version,
223 Linus will not apply it. 223 Linus will not apply it.
224 224
225 225
226 226
227 9) Don't get discouraged. Re-submit. 227 9) Don't get discouraged. Re-submit.
228 228
229 After you have submitted your change, be patient and wait. If Linus 229 After you have submitted your change, be patient and wait. If Linus
230 likes your change and applies it, it will appear in the next version 230 likes your change and applies it, it will appear in the next version
231 of the kernel that he releases. 231 of the kernel that he releases.
232 232
233 However, if your change doesn't appear in the next version of the 233 However, if your change doesn't appear in the next version of the
234 kernel, there could be any number of reasons. It's YOUR job to 234 kernel, there could be any number of reasons. It's YOUR job to
235 narrow down those reasons, correct what was wrong, and submit your 235 narrow down those reasons, correct what was wrong, and submit your
236 updated change. 236 updated change.
237 237
238 It is quite common for Linus to "drop" your patch without comment. 238 It is quite common for Linus to "drop" your patch without comment.
239 That's the nature of the system. If he drops your patch, it could be 239 That's the nature of the system. If he drops your patch, it could be
240 due to 240 due to
241 * Your patch did not apply cleanly to the latest kernel version 241 * Your patch did not apply cleanly to the latest kernel version
242 * Your patch was not sufficiently discussed on linux-kernel. 242 * Your patch was not sufficiently discussed on linux-kernel.
243 * A style issue (see section 2), 243 * A style issue (see section 2),
244 * An e-mail formatting issue (re-read this section) 244 * An e-mail formatting issue (re-read this section)
245 * A technical problem with your change 245 * A technical problem with your change
246 * He gets tons of e-mail, and yours got lost in the shuffle 246 * He gets tons of e-mail, and yours got lost in the shuffle
247 * You are being annoying (See Figure 1) 247 * You are being annoying (See Figure 1)
248 248
249 When in doubt, solicit comments on linux-kernel mailing list. 249 When in doubt, solicit comments on linux-kernel mailing list.
250 250
251 251
252 252
253 10) Include PATCH in the subject 253 10) Include PATCH in the subject
254 254
255 Due to high e-mail traffic to Linus, and to linux-kernel, it is common 255 Due to high e-mail traffic to Linus, and to linux-kernel, it is common
256 convention to prefix your subject line with [PATCH]. This lets Linus 256 convention to prefix your subject line with [PATCH]. This lets Linus
257 and other kernel developers more easily distinguish patches from other 257 and other kernel developers more easily distinguish patches from other
258 e-mail discussions. 258 e-mail discussions.
259 259
260 260
261 261
262 11) Sign your work 262 11) Sign your work
263 263
264 To improve tracking of who did what, especially with patches that can 264 To improve tracking of who did what, especially with patches that can
265 percolate to their final resting place in the kernel through several 265 percolate to their final resting place in the kernel through several
266 layers of maintainers, we've introduced a "sign-off" procedure on 266 layers of maintainers, we've introduced a "sign-off" procedure on
267 patches that are being emailed around. 267 patches that are being emailed around.
268 268
269 The sign-off is a simple line at the end of the explanation for the 269 The sign-off is a simple line at the end of the explanation for the
270 patch, which certifies that you wrote it or otherwise have the right to 270 patch, which certifies that you wrote it or otherwise have the right to
271 pass it on as a open-source patch. The rules are pretty simple: if you 271 pass it on as a open-source patch. The rules are pretty simple: if you
272 can certify the below: 272 can certify the below:
273 273
274 Developer's Certificate of Origin 1.0 274 Developer's Certificate of Origin 1.1
275 275
276 By making a contribution to this project, I certify that: 276 By making a contribution to this project, I certify that:
277 277
278 (a) The contribution was created in whole or in part by me and I 278 (a) The contribution was created in whole or in part by me and I
279 have the right to submit it under the open source license 279 have the right to submit it under the open source license
280 indicated in the file; or 280 indicated in the file; or
281 281
282 (b) The contribution is based upon previous work that, to the best 282 (b) The contribution is based upon previous work that, to the best
283 of my knowledge, is covered under an appropriate open source 283 of my knowledge, is covered under an appropriate open source
284 license and I have the right under that license to submit that 284 license and I have the right under that license to submit that
285 work with modifications, whether created in whole or in part 285 work with modifications, whether created in whole or in part
286 by me, under the same open source license (unless I am 286 by me, under the same open source license (unless I am
287 permitted to submit under a different license), as indicated 287 permitted to submit under a different license), as indicated
288 in the file; or 288 in the file; or
289 289
290 (c) The contribution was provided directly to me by some other 290 (c) The contribution was provided directly to me by some other
291 person who certified (a), (b) or (c) and I have not modified 291 person who certified (a), (b) or (c) and I have not modified
292 it. 292 it.
293
294 (d) I understand and agree that this project and the contribution
295 are public and that a record of the contribution (including all
296 personal information I submit with it, including my sign-off) is
297 maintained indefinitely and may be redistributed consistent with
298 this project or the open source license(s) involved.
293 299
294 then you just add a line saying 300 then you just add a line saying
295 301
296 Signed-off-by: Random J Developer <random@developer.org> 302 Signed-off-by: Random J Developer <random@developer.org>
297 303
298 Some people also put extra tags at the end. They'll just be ignored for 304 Some people also put extra tags at the end. They'll just be ignored for
299 now, but you can do this to mark internal company procedures or just 305 now, but you can do this to mark internal company procedures or just
300 point out some special detail about the sign-off. 306 point out some special detail about the sign-off.
301 307
302 308
303 ----------------------------------- 309 -----------------------------------
304 SECTION 2 - HINTS, TIPS, AND TRICKS 310 SECTION 2 - HINTS, TIPS, AND TRICKS
305 ----------------------------------- 311 -----------------------------------
306 312
307 This section lists many of the common "rules" associated with code 313 This section lists many of the common "rules" associated with code
308 submitted to the kernel. There are always exceptions... but you must 314 submitted to the kernel. There are always exceptions... but you must
309 have a really good reason for doing so. You could probably call this 315 have a really good reason for doing so. You could probably call this
310 section Linus Computer Science 101. 316 section Linus Computer Science 101.
311 317
312 318
313 319
314 1) Read Documentation/CodingStyle 320 1) Read Documentation/CodingStyle
315 321
316 Nuff said. If your code deviates too much from this, it is likely 322 Nuff said. If your code deviates too much from this, it is likely
317 to be rejected without further review, and without comment. 323 to be rejected without further review, and without comment.
318 324
319 325
320 326
321 2) #ifdefs are ugly 327 2) #ifdefs are ugly
322 328
323 Code cluttered with ifdefs is difficult to read and maintain. Don't do 329 Code cluttered with ifdefs is difficult to read and maintain. Don't do
324 it. Instead, put your ifdefs in a header, and conditionally define 330 it. Instead, put your ifdefs in a header, and conditionally define
325 'static inline' functions, or macros, which are used in the code. 331 'static inline' functions, or macros, which are used in the code.
326 Let the compiler optimize away the "no-op" case. 332 Let the compiler optimize away the "no-op" case.
327 333
328 Simple example, of poor code: 334 Simple example, of poor code:
329 335
330 dev = alloc_etherdev (sizeof(struct funky_private)); 336 dev = alloc_etherdev (sizeof(struct funky_private));
331 if (!dev) 337 if (!dev)
332 return -ENODEV; 338 return -ENODEV;
333 #ifdef CONFIG_NET_FUNKINESS 339 #ifdef CONFIG_NET_FUNKINESS
334 init_funky_net(dev); 340 init_funky_net(dev);
335 #endif 341 #endif
336 342
337 Cleaned-up example: 343 Cleaned-up example:
338 344
339 (in header) 345 (in header)
340 #ifndef CONFIG_NET_FUNKINESS 346 #ifndef CONFIG_NET_FUNKINESS
341 static inline void init_funky_net (struct net_device *d) {} 347 static inline void init_funky_net (struct net_device *d) {}
342 #endif 348 #endif
343 349
344 (in the code itself) 350 (in the code itself)
345 dev = alloc_etherdev (sizeof(struct funky_private)); 351 dev = alloc_etherdev (sizeof(struct funky_private));
346 if (!dev) 352 if (!dev)
347 return -ENODEV; 353 return -ENODEV;
348 init_funky_net(dev); 354 init_funky_net(dev);
349 355
350 356
351 357
352 3) 'static inline' is better than a macro 358 3) 'static inline' is better than a macro
353 359
354 Static inline functions are greatly preferred over macros. 360 Static inline functions are greatly preferred over macros.
355 They provide type safety, have no length limitations, no formatting 361 They provide type safety, have no length limitations, no formatting
356 limitations, and under gcc they are as cheap as macros. 362 limitations, and under gcc they are as cheap as macros.
357 363
358 Macros should only be used for cases where a static inline is clearly 364 Macros should only be used for cases where a static inline is clearly
359 suboptimal [there a few, isolated cases of this in fast paths], 365 suboptimal [there a few, isolated cases of this in fast paths],
360 or where it is impossible to use a static inline function [such as 366 or where it is impossible to use a static inline function [such as
361 string-izing]. 367 string-izing].
362 368
363 'static inline' is preferred over 'static __inline__', 'extern inline', 369 'static inline' is preferred over 'static __inline__', 'extern inline',
364 and 'extern __inline__'. 370 and 'extern __inline__'.
365 371
366 372
367 373
368 4) Don't over-design. 374 4) Don't over-design.
369 375
370 Don't try to anticipate nebulous future cases which may or may not 376 Don't try to anticipate nebulous future cases which may or may not
371 be useful: "Make it as simple as you can, and no simpler" 377 be useful: "Make it as simple as you can, and no simpler"
372 378
373 379
374 380
375 381