diff options
Diffstat (limited to 'Documentation')
20 files changed, 456 insertions, 158 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss b/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss index 4f29e5f1..f5bb0a3 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss +++ b/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss @@ -59,3 +59,15 @@ Kernel Version: 2.6.31 Contact: iss_storagedev@hp.com Description: Displays the usage count (number of opens) of logical drive Y of controller X. + +Where: /sys/bus/pci/devices/<dev>/ccissX/resettable +Date: February 2011 +Kernel Version: 2.6.38 +Contact: iss_storagedev@hp.com +Description: Value of 1 indicates the controller can honor the reset_devices + kernel parameter. Value of 0 indicates reset_devices cannot be + honored. This is to allow, for example, kexec tools to be able + to warn the user if they designate an unresettable device as + a dump device, as kdump requires resetting the device in order + to work reliably. + diff --git a/Documentation/ABI/testing/sysfs-fs-ext4 b/Documentation/ABI/testing/sysfs-fs-ext4 index 5fb7099..f22ac08 100644 --- a/Documentation/ABI/testing/sysfs-fs-ext4 +++ b/Documentation/ABI/testing/sysfs-fs-ext4 @@ -48,7 +48,7 @@ Description: will have its blocks allocated out of its own unique preallocation pool. -What: /sys/fs/ext4/<disk>/inode_readahead +What: /sys/fs/ext4/<disk>/inode_readahead_blks Date: March 2008 Contact: "Theodore Ts'o" <tytso@mit.edu> Description: @@ -85,7 +85,14 @@ Date: June 2008 Contact: "Theodore Ts'o" <tytso@mit.edu> Description: Tuning parameter which (if non-zero) controls the goal - inode used by the inode allocator in p0reference to - all other allocation hueristics. This is intended for + inode used by the inode allocator in preference to + all other allocation heuristics. This is intended for debugging use only, and should be 0 on production systems. + +What: /sys/fs/ext4/<disk>/max_writeback_mb_bump +Date: September 2009 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + The maximum number of megabytes the writeback code will + try to write out before move on to another inode. diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile index 2deb069..8436b01 100644 --- a/Documentation/DocBook/Makefile +++ b/Documentation/DocBook/Makefile @@ -55,7 +55,6 @@ mandocs: $(MAN) build_images = mkdir -p $(objtree)/Documentation/DocBook/media/ && \ cp $(srctree)/Documentation/DocBook/dvb/*.png \ $(srctree)/Documentation/DocBook/v4l/*.gif \ - $(srctree)/Documentation/DocBook/v4l/*.png \ $(objtree)/Documentation/DocBook/media/ xmldoclinks: diff --git a/Documentation/DocBook/rapidio.tmpl b/Documentation/DocBook/rapidio.tmpl index 54eb26b..5047936 100644 --- a/Documentation/DocBook/rapidio.tmpl +++ b/Documentation/DocBook/rapidio.tmpl @@ -133,7 +133,6 @@ !Idrivers/rapidio/rio-sysfs.c </sect1> <sect1 id="PPC32_support"><title>PPC32 support</title> -!Earch/powerpc/sysdev/fsl_rio.c !Iarch/powerpc/sysdev/fsl_rio.c </sect1> </chapter> diff --git a/Documentation/development-process/1.Intro b/Documentation/development-process/1.Intro index 8cc2cba..9b61448 100644 --- a/Documentation/development-process/1.Intro +++ b/Documentation/development-process/1.Intro @@ -56,13 +56,13 @@ information on kernel development. 1.2: WHAT THIS DOCUMENT IS ABOUT -The Linux kernel, at over 6 million lines of code and well over 1000 active -contributors, is one of the largest and most active free software projects -in existence. Since its humble beginning in 1991, this kernel has evolved -into a best-of-breed operating system component which runs on pocket-sized -digital music players, desktop PCs, the largest supercomputers in -existence, and all types of systems in between. It is a robust, efficient, -and scalable solution for almost any situation. +The Linux kernel, at over 8 million lines of code and well over 1000 +contributors to each release, is one of the largest and most active free +software projects in existence. Since its humble beginning in 1991, this +kernel has evolved into a best-of-breed operating system component which +runs on pocket-sized digital music players, desktop PCs, the largest +supercomputers in existence, and all types of systems in between. It is a +robust, efficient, and scalable solution for almost any situation. With the growth of Linux has come an increase in the number of developers (and companies) wishing to participate in its development. Hardware @@ -115,7 +115,7 @@ This document was written by Jonathan Corbet, corbet@lwn.net. It has been improved by comments from Johannes Berg, James Berry, Alex Chiang, Roland Dreier, Randy Dunlap, Jake Edge, Jiri Kosina, Matt Mackall, Arthur Marsh, Amanda McPherson, Andrew Morton, Andrew Price, Tsugikazu Shibata, and -Jochen Voß. +Jochen Voß. This work was supported by the Linux Foundation; thanks especially to Amanda McPherson, who saw the value of this effort and made it all happen. @@ -221,7 +221,7 @@ include: - Everything that was said above about code review applies doubly to closed-source code. Since this code is not available at all, it cannot have been reviewed by the community and will, beyond doubt, have serious - problems. + problems. Makers of embedded systems, in particular, may be tempted to disregard much of what has been said in this section in the belief that they are shipping diff --git a/Documentation/development-process/2.Process b/Documentation/development-process/2.Process index 911a451..4823577 100644 --- a/Documentation/development-process/2.Process +++ b/Documentation/development-process/2.Process @@ -14,16 +14,15 @@ The kernel developers use a loosely time-based release process, with a new major kernel release happening every two or three months. The recent release history looks like this: - 2.6.26 July 13, 2008 - 2.6.25 April 16, 2008 - 2.6.24 January 24, 2008 - 2.6.23 October 9, 2007 - 2.6.22 July 8, 2007 - 2.6.21 April 25, 2007 - 2.6.20 February 4, 2007 + 2.6.38 March 14, 2011 + 2.6.37 January 4, 2011 + 2.6.36 October 20, 2010 + 2.6.35 August 1, 2010 + 2.6.34 May 15, 2010 + 2.6.33 February 24, 2010 Every 2.6.x release is a major kernel release with new features, internal -API changes, and more. A typical 2.6 release can contain over 10,000 +API changes, and more. A typical 2.6 release can contain nearly 10,000 changesets with changes to several hundred thousand lines of code. 2.6 is thus the leading edge of Linux kernel development; the kernel uses a rolling development model which is continually integrating major changes. @@ -42,13 +41,13 @@ merge window do not come out of thin air; they have been collected, tested, and staged ahead of time. How that process works will be described in detail later on). -The merge window lasts for two weeks. At the end of this time, Linus -Torvalds will declare that the window is closed and release the first of -the "rc" kernels. For the kernel which is destined to be 2.6.26, for -example, the release which happens at the end of the merge window will be -called 2.6.26-rc1. The -rc1 release is the signal that the time to merge -new features has passed, and that the time to stabilize the next kernel has -begun. +The merge window lasts for approximately two weeks. At the end of this +time, Linus Torvalds will declare that the window is closed and release the +first of the "rc" kernels. For the kernel which is destined to be 2.6.40, +for example, the release which happens at the end of the merge window will +be called 2.6.40-rc1. The -rc1 release is the signal that the time to +merge new features has passed, and that the time to stabilize the next +kernel has begun. Over the next six to ten weeks, only patches which fix problems should be submitted to the mainline. On occasion a more significant change will be @@ -66,20 +65,19 @@ will get up to somewhere between -rc6 and -rc9 before the kernel is considered to be sufficiently stable and the final 2.6.x release is made. At that point the whole process starts over again. -As an example, here is how the 2.6.25 development cycle went (all dates in -2008): - - January 24 2.6.24 stable release - February 10 2.6.25-rc1, merge window closes - February 15 2.6.25-rc2 - February 24 2.6.25-rc3 - March 4 2.6.25-rc4 - March 9 2.6.25-rc5 - March 16 2.6.25-rc6 - March 25 2.6.25-rc7 - April 1 2.6.25-rc8 - April 11 2.6.25-rc9 - April 16 2.6.25 stable release +As an example, here is how the 2.6.38 development cycle went (all dates in +2011): + + January 4 2.6.37 stable release + January 18 2.6.38-rc1, merge window closes + January 21 2.6.38-rc2 + February 1 2.6.38-rc3 + February 7 2.6.38-rc4 + February 15 2.6.38-rc5 + February 21 2.6.38-rc6 + March 1 2.6.38-rc7 + March 7 2.6.38-rc8 + March 14 2.6.38 stable release How do the developers decide when to close the development cycle and create the stable release? The most significant metric used is the list of @@ -87,7 +85,7 @@ regressions from previous releases. No bugs are welcome, but those which break systems which worked in the past are considered to be especially serious. For this reason, patches which cause regressions are looked upon unfavorably and are quite likely to be reverted during the stabilization -period. +period. The developers' goal is to fix all known regressions before the stable release is made. In the real world, this kind of perfection is hard to @@ -99,26 +97,34 @@ kernels go out with a handful of known regressions though, hopefully, none of them are serious. Once a stable release is made, its ongoing maintenance is passed off to the -"stable team," currently comprised of Greg Kroah-Hartman and Chris Wright. -The stable team will release occasional updates to the stable release using -the 2.6.x.y numbering scheme. To be considered for an update release, a -patch must (1) fix a significant bug, and (2) already be merged into the -mainline for the next development kernel. Continuing our 2.6.25 example, -the history (as of this writing) is: - - May 1 2.6.25.1 - May 6 2.6.25.2 - May 9 2.6.25.3 - May 15 2.6.25.4 - June 7 2.6.25.5 - June 9 2.6.25.6 - June 16 2.6.25.7 - June 21 2.6.25.8 - June 24 2.6.25.9 - -Stable updates for a given kernel are made for approximately six months; -after that, the maintenance of stable releases is solely the responsibility -of the distributors which have shipped that particular kernel. +"stable team," currently consisting of Greg Kroah-Hartman. The stable team +will release occasional updates to the stable release using the 2.6.x.y +numbering scheme. To be considered for an update release, a patch must (1) +fix a significant bug, and (2) already be merged into the mainline for the +next development kernel. Kernels will typically receive stable updates for +a little more than one development cycle past their initial release. So, +for example, the 2.6.36 kernel's history looked like: + + October 10 2.6.36 stable release + November 22 2.6.36.1 + December 9 2.6.36.2 + January 7 2.6.36.3 + February 17 2.6.36.4 + +2.6.36.4 was the final stable update for the 2.6.36 release. + +Some kernels are designated "long term" kernels; they will receive support +for a longer period. As of this writing, the current long term kernels +and their maintainers are: + + 2.6.27 Willy Tarreau (Deep-frozen stable kernel) + 2.6.32 Greg Kroah-Hartman + 2.6.35 Andi Kleen (Embedded flag kernel) + +The selection of a kernel for long-term support is purely a matter of a +maintainer having the need and the time to maintain that release. There +are no known plans for long-term support for any specific upcoming +release. 2.2: THE LIFECYCLE OF A PATCH @@ -130,7 +136,7 @@ each patch implements a change which is desirable to have in the mainline. This process can happen quickly for minor fixes, or, in the case of large and controversial changes, go on for years. Much developer frustration comes from a lack of understanding of this process or from attempts to -circumvent it. +circumvent it. In the hopes of reducing that frustration, this document will describe how a patch gets into the kernel. What follows below is an introduction which @@ -193,8 +199,8 @@ involved. 2.3: HOW PATCHES GET INTO THE KERNEL There is exactly one person who can merge patches into the mainline kernel -repository: Linus Torvalds. But, of the over 12,000 patches which went -into the 2.6.25 kernel, only 250 (around 2%) were directly chosen by Linus +repository: Linus Torvalds. But, of the over 9,500 patches which went +into the 2.6.38 kernel, only 112 (around 1.3%) were directly chosen by Linus himself. The kernel project has long since grown to a size where no single developer could possibly inspect and select every patch unassisted. The way the kernel developers have addressed this growth is through the use of @@ -229,7 +235,7 @@ first in trees dedicated to network device drivers, wireless networking, etc. This chain of repositories can be arbitrarily long, though it rarely exceeds two or three links. Since each maintainer in the chain trusts those managing lower-level trees, this process is known as the "chain of -trust." +trust." Clearly, in a system like this, getting patches into the kernel depends on finding the right maintainer. Sending patches directly to Linus is not @@ -254,7 +260,7 @@ The answer comes in the form of -next trees, where subsystem trees are collected for testing and review. The older of these trees, maintained by Andrew Morton, is called "-mm" (for memory management, which is how it got started). The -mm tree integrates patches from a long list of subsystem -trees; it also has some patches aimed at helping with debugging. +trees; it also has some patches aimed at helping with debugging. Beyond that, -mm contains a significant collection of patches which have been selected by Andrew directly. These patches may have been posted on a @@ -264,8 +270,8 @@ subsystem tree of last resort; if there is no other obvious path for a patch into the mainline, it is likely to end up in -mm. Miscellaneous patches which accumulate in -mm will eventually either be forwarded on to an appropriate subsystem tree or be sent directly to Linus. In a typical -development cycle, approximately 10% of the patches going into the mainline -get there via -mm. +development cycle, approximately 5-10% of the patches going into the +mainline get there via -mm. The current -mm patch is available in the "mmotm" (-mm of the moment) directory at: @@ -275,7 +281,7 @@ directory at: Use of the MMOTM tree is likely to be a frustrating experience, though; there is a definite chance that it will not even compile. -The other -next tree, started more recently, is linux-next, maintained by +The primary tree for next-cycle patch merging is linux-next, maintained by Stephen Rothwell. The linux-next tree is, by design, a snapshot of what the mainline is expected to look like after the next merge window closes. Linux-next trees are announced on the linux-kernel and linux-next mailing @@ -287,25 +293,14 @@ Some information about linux-next has been gathered at: http://linux.f-seidel.de/linux-next/pmwiki/ -How the linux-next tree will fit into the development process is still -changing. As of this writing, the first full development cycle involving -linux-next (2.6.26) is coming to an end; thus far, it has proved to be a -valuable resource for finding and fixing integration problems before the -beginning of the merge window. See http://lwn.net/Articles/287155/ for -more information on how linux-next has worked to set up the 2.6.27 merge -window. - -Some developers have begun to suggest that linux-next should be used as the -target for future development as well. The linux-next tree does tend to be -far ahead of the mainline and is more representative of the tree into which -any new work will be merged. The downside to this idea is that the -volatility of linux-next tends to make it a difficult development target. -See http://lwn.net/Articles/289013/ for more information on this topic, and -stay tuned; much is still in flux where linux-next is involved. +Linux-next has become an integral part of the kernel development process; +all patches merged during a given merge window should really have found +their way into linux-next some time before the merge window opens. + 2.4.1: STAGING TREES -The kernel source tree now contains the drivers/staging/ directory, where +The kernel source tree contains the drivers/staging/ directory, where many sub-directories for drivers or filesystems that are on their way to being added to the kernel tree live. They remain in drivers/staging while they still need more work; once complete, they can be moved into the @@ -313,15 +308,23 @@ kernel proper. This is a way to keep track of drivers that aren't up to Linux kernel coding or quality standards, but people may want to use them and track development. -Greg Kroah-Hartman currently (as of 2.6.36) maintains the staging tree. -Drivers that still need work are sent to him, with each driver having -its own subdirectory in drivers/staging/. Along with the driver source -files, a TODO file should be present in the directory as well. The TODO -file lists the pending work that the driver needs for acceptance into -the kernel proper, as well as a list of people that should be Cc'd for any -patches to the driver. Staging drivers that don't currently build should -have their config entries depend upon CONFIG_BROKEN. Once they can -be successfully built without outside patches, CONFIG_BROKEN can be removed. +Greg Kroah-Hartman currently maintains the staging tree. Drivers that +still need work are sent to him, with each driver having its own +subdirectory in drivers/staging/. Along with the driver source files, a +TODO file should be present in the directory as well. The TODO file lists +the pending work that the driver needs for acceptance into the kernel +proper, as well as a list of people that should be Cc'd for any patches to +the driver. Current rules require that drivers contributed to staging +must, at a minimum, compile properly. + +Staging can be a relatively easy way to get new drivers into the mainline +where, with luck, they will come to the attention of other developers and +improve quickly. Entry into staging is not the end of the story, though; +code in staging which is not seeing regular progress will eventually be +removed. Distributors also tend to be relatively reluctant to enable +staging drivers. So staging is, at best, a stop on the way toward becoming +a proper mainline driver. + 2.5: TOOLS @@ -347,11 +350,7 @@ page at: http://git-scm.com/ -That page has pointers to documentation and tutorials. One should be -aware, in particular, of the Kernel Hacker's Guide to git, which has -information specific to kernel development: - - http://linux.yyz.us/git-howto.html +That page has pointers to documentation and tutorials. Among the kernel developers who do not use git, the most popular choice is almost certainly Mercurial: @@ -408,7 +407,7 @@ There are a few hints which can help with linux-kernel survival: important to filter on both the topic of interest (though note that long-running conversations can drift away from the original subject without changing the email subject line) and the people who are - participating. + participating. - Do not feed the trolls. If somebody is trying to stir up an angry response, ignore them. diff --git a/Documentation/development-process/3.Early-stage b/Documentation/development-process/3.Early-stage index 307a159..f87ba7b 100644 --- a/Documentation/development-process/3.Early-stage +++ b/Documentation/development-process/3.Early-stage @@ -110,8 +110,8 @@ the kernel community's standards. Some examples include: - The AppArmor security module made use of internal virtual filesystem data structures in ways which were considered to be unsafe and - unreliable. This code has since been significantly reworked, but - remains outside of the mainline. + unreliable. This concern (among others) kept AppArmor out of the + mainline for years. In each of these cases, a great deal of pain and extra work could have been avoided with some early discussion with the kernel developers. @@ -138,6 +138,19 @@ patches, and who, if anybody, is attaching Signed-off-by lines to those patches. Those are the people who will be best placed to help with a new development project. +The task of finding the right maintainer is sometimes challenging enough +that the kernel developers have added a script to ease the process: + + .../scripts/get_maintainer.pl + +This script will return the current maintainer(s) for a given file or +directory when given the "-f" option. If passed a patch on the +command line, it will list the maintainers who should probably receive +copies of the patch. There are a number of options regulating how hard +get_maintainer.pl will search for maintainers; please be careful about +using the more aggressive options as you may end up including developers +who have no real interest in the code you are modifying. + If all else fails, talking to Andrew Morton can be an effective way to track down a maintainer for a specific piece of code. @@ -155,11 +168,15 @@ reaction, but, instead, little or no reaction at all. The sad truth of the matter is (1) kernel developers tend to be busy, (2) there is no shortage of people with grand plans and little code (or even prospect of code) to back them up, and (3) nobody is obligated to review or comment on ideas -posted by others. If a request-for-comments posting yields little in the -way of comments, do not assume that it means there is no interest in the -project. Unfortunately, you also cannot assume that there are no problems -with your idea. The best thing to do in this situation is to proceed, -keeping the community informed as you go. +posted by others. Beyond that, high-level designs often hide problems +which are only reviewed when somebody actually tries to implement those +designs; for that reason, kernel developers would rather see the code. + +If a request-for-comments posting yields little in the way of comments, do +not assume that it means there is no interest in the project. +Unfortunately, you also cannot assume that there are no problems with your +idea. The best thing to do in this situation is to proceed, keeping the +community informed as you go. 3.5: GETTING OFFICIAL BUY-IN diff --git a/Documentation/development-process/4.Coding b/Documentation/development-process/4.Coding index 2278693..f3f1a46 100644 --- a/Documentation/development-process/4.Coding +++ b/Documentation/development-process/4.Coding @@ -131,6 +131,11 @@ classic time/space tradeoff taught in beginning data structures classes often does not apply to contemporary hardware. Space *is* time, in that a larger program will run slower than one which is more compact. +More recent compilers take an increasingly active role in deciding whether +a given function should actually be inlined or not. So the liberal +placement of "inline" keywords may not just be excessive; it could also be +irrelevant. + * Locking @@ -285,6 +290,13 @@ be found at https://sparse.wiki.kernel.org/index.php/Main_Page if your distributor does not package it); it can then be run on the code by adding "C=1" to your make command. +The "Coccinelle" tool (http://coccinelle.lip6.fr/) is able to find a wide +variety of potential coding problems; it can also propose fixes for those +problems. Quite a few "semantic patches" for the kernel have been packaged +under the scripts/coccinelle directory; running "make coccicheck" will run +through those semantic patches and report on any problems found. See +Documentation/coccinelle.txt for more information. + Other kinds of portability errors are best found by compiling your code for other architectures. If you do not happen to have an S/390 system or a Blackfin development board handy, you can still perform the compilation @@ -308,7 +320,9 @@ The first piece of documentation for any patch is its associated changelog. Log entries should describe the problem being solved, the form of the solution, the people who worked on the patch, any relevant effects on performance, and anything else that might be needed to -understand the patch. +understand the patch. Be sure that the changelog says *why* the patch is +worth applying; a surprising number of developers fail to provide that +information. Any code which adds a new user-space interface - including new sysfs or /proc files - should include documentation of that interface which enables @@ -321,7 +335,7 @@ boot-time parameters. Any patch which adds new parameters should add the appropriate entries to this file. Any new configuration options must be accompanied by help text which -clearly explains the options and when the user might want to select them. +clearly explains the options and when the user might want to select them. Internal API information for many subsystems is documented by way of specially-formatted comments; these comments can be extracted and formatted @@ -372,7 +386,8 @@ which is broken by the change. For a widely-used function, this duty can lead to literally hundreds or thousands of changes - many of which are likely to conflict with work being done by other developers. Needless to say, this can be a large job, so it is best to be sure that the -justification is solid. +justification is solid. Note that the Coccinelle tool can help with +wide-ranging API changes. When making an incompatible API change, one should, whenever possible, ensure that code which has not been updated is caught by the compiler. diff --git a/Documentation/development-process/5.Posting b/Documentation/development-process/5.Posting index f622c1e..903a254 100644 --- a/Documentation/development-process/5.Posting +++ b/Documentation/development-process/5.Posting @@ -60,12 +60,15 @@ even in the short term. Patches must be prepared against a specific version of the kernel. As a general rule, a patch should be based on the current mainline as found in -Linus's git tree. It may become necessary to make versions against -mm, -linux-next, or a subsystem tree, though, to facilitate wider testing and -review. Depending on the area of your patch and what is going on -elsewhere, basing a patch against these other trees can require a -significant amount of work resolving conflicts and dealing with API -changes. +Linus's git tree. When basing on mainline, start with a well-known release +point - a stable or -rc release - rather than branching off the mainline at +an arbitrary spot. + +It may become necessary to make versions against -mm, linux-next, or a +subsystem tree, though, to facilitate wider testing and review. Depending +on the area of your patch and what is going on elsewhere, basing a patch +against these other trees can require a significant amount of work +resolving conflicts and dealing with API changes. Only the most simple changes should be formatted as a single patch; everything else should be made as a logical series of changes. Splitting @@ -100,11 +103,11 @@ rules of thumb, however, which can help considerably: result is a broken kernel, you will make life harder for developers and users who are engaging in the noble work of tracking down problems. - - Do not overdo it, though. One developer recently posted a set of edits + - Do not overdo it, though. One developer once posted a set of edits to a single file as 500 separate patches - an act which did not make him the most popular person on the kernel mailing list. A single patch can be reasonably large as long as it still contains a single *logical* - change. + change. - It can be tempting to add a whole new infrastructure with a series of patches, but to leave that infrastructure unused until the final patch @@ -162,7 +165,8 @@ To that end, the summary line should describe the effects of and motivation for the change as well as possible given the one-line constraint. The detailed description can then amplify on those topics and provide any needed additional information. If the patch fixes a bug, cite the commit -which introduced the bug if possible. If a problem is associated with +which introduced the bug if possible (and please provide both the commit ID +and the title when citing commits). If a problem is associated with specific log or compiler output, include that output to help others searching for a solution to the same problem. If the change is meant to support other changes coming in later patch, say so. If internal APIs are @@ -230,7 +234,7 @@ take care of: which have had gratuitous white-space changes or line wrapping performed by the mail client will not apply at the other end, and often will not be examined in any detail. If there is any doubt at all, mail the patch - to yourself and convince yourself that it shows up intact. + to yourself and convince yourself that it shows up intact. Documentation/email-clients.txt has some helpful hints on making specific mail clients work for sending patches. @@ -287,7 +291,7 @@ something like: where "nn" is the ordinal number of the patch, "mm" is the total number of patches in the series, and "subsys" is the name of the affected subsystem. -Clearly, nn/mm can be omitted for a single, standalone patch. +Clearly, nn/mm can be omitted for a single, standalone patch. If you have a significant series of patches, it is customary to send an introductory description as part zero. This convention is not universally @@ -299,5 +303,5 @@ In general, the second and following parts of a multi-part patch should be sent as a reply to the first part so that they all thread together at the receiving end. Tools like git and quilt have commands to mail out a set of patches with the proper threading. If you have a long series, though, and -are using git, please provide the --no-chain-reply-to option to avoid +are using git, please stay away from the --chain-reply-to option to avoid creating exceptionally deep nesting. diff --git a/Documentation/development-process/6.Followthrough b/Documentation/development-process/6.Followthrough index a8fba3d8..41d324a 100644 --- a/Documentation/development-process/6.Followthrough +++ b/Documentation/development-process/6.Followthrough @@ -66,6 +66,11 @@ be easy to become blinded by your own solution to a problem to the point that you don't realize that something is fundamentally wrong or, perhaps, you're not even solving the right problem. +Andrew Morton has suggested that every review comment which does not result +in a code change should result in an additional code comment instead; that +can help future reviewers avoid the questions which came up the first time +around. + One fatal mistake is to ignore review comments in the hope that they will go away. They will not go away. If you repost code without having responded to the comments you got the time before, you're likely to find @@ -100,7 +105,7 @@ entry into a subsystem maintainer's tree. How that works varies from one subsystem to the next; each maintainer has his or her own way of doing things. In particular, there may be more than one tree - one, perhaps, dedicated to patches planned for the next merge window, and another for -longer-term work. +longer-term work. For patches applying to areas for which there is no obvious subsystem tree (memory management patches, for example), the default tree often ends up @@ -109,11 +114,10 @@ through the -mm tree. Inclusion into a subsystem tree can bring a higher level of visibility to a patch. Now other developers working with that tree will get the patch by -default. Subsystem trees typically feed into -mm and linux-next as well, -making their contents visible to the development community as a whole. At -this point, there's a good chance that you will get more comments from a -new set of reviewers; these comments need to be answered as in the previous -round. +default. Subsystem trees typically feed linux-next as well, making their +contents visible to the development community as a whole. At this point, +there's a good chance that you will get more comments from a new set of +reviewers; these comments need to be answered as in the previous round. What may also happen at this point, depending on the nature of your patch, is that conflicts with work being done by others turn up. In the worst diff --git a/Documentation/development-process/7.AdvancedTopics b/Documentation/development-process/7.AdvancedTopics index 8371794..26dc3fa 100644 --- a/Documentation/development-process/7.AdvancedTopics +++ b/Documentation/development-process/7.AdvancedTopics @@ -119,7 +119,7 @@ can affect your ability to get trees pulled in the future. Quoting Linus: to trust things *without* then having to go and check every individual change by hand. -(http://lwn.net/Articles/224135/). +(http://lwn.net/Articles/224135/). To avoid this kind of situation, ensure that all patches within a given branch stick closely to the associated topic; a "driver fixes" branch @@ -138,7 +138,7 @@ When requesting a pull, be sure to give all the relevant information: where your tree is, what branch to pull, and what changes will result from the pull. The git request-pull command can be helpful in this regard; it will format the request as other developers expect, and will also check to be -sure that you have remembered to push those changes to the public server. +sure that you have remembered to push those changes to the public server. 7.2: REVIEWING PATCHES diff --git a/Documentation/device-mapper/dm-flakey.txt b/Documentation/device-mapper/dm-flakey.txt new file mode 100644 index 0000000..c8efdfd --- /dev/null +++ b/Documentation/device-mapper/dm-flakey.txt @@ -0,0 +1,17 @@ +dm-flakey +========= + +This target is the same as the linear target except that it returns I/O +errors periodically. It's been found useful in simulating failing +devices for testing purposes. + +Starting from the time the table is loaded, the device is available for +<up interval> seconds, then returns errors for <down interval> seconds, +and then this cycle repeats. + +Parameters: <dev path> <offset> <up interval> <down interval> + <dev path>: Full pathname to the underlying block-device, or a + "major:minor" device-number. + <offset>: Starting sector within the device. + <up interval>: Number of seconds device is available. + <down interval>: Number of seconds device returns errors. diff --git a/Documentation/dynamic-debug-howto.txt b/Documentation/dynamic-debug-howto.txt index e6c4b75..f959909 100644 --- a/Documentation/dynamic-debug-howto.txt +++ b/Documentation/dynamic-debug-howto.txt @@ -6,7 +6,7 @@ This document describes how to use the dynamic debug (ddebug) feature. Dynamic debug is designed to allow you to dynamically enable/disable kernel code to obtain additional kernel information. Currently, if -CONFIG_DYNAMIC_DEBUG is set, then all pr_debug()/dev_debug() calls can be +CONFIG_DYNAMIC_DEBUG is set, then all pr_debug()/dev_dbg() calls can be dynamically enabled per-callsite. Dynamic debug has even more useful features: @@ -26,7 +26,7 @@ Dynamic debug has even more useful features: Controlling dynamic debug Behaviour =================================== -The behaviour of pr_debug()/dev_debug()s are controlled via writing to a +The behaviour of pr_debug()/dev_dbg()s are controlled via writing to a control file in the 'debugfs' filesystem. Thus, you must first mount the debugfs filesystem, in order to make use of this feature. Subsequently, we refer to the control file as: <debugfs>/dynamic_debug/control. For example, if you want to diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 2e994ef..61b31ac 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -128,7 +128,7 @@ alloc_inode: destroy_inode: dirty_inode: (must not sleep) write_inode: -drop_inode: !!!inode_lock!!! +drop_inode: !!!inode->i_lock!!! evict_inode: put_super: write write_super: read diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index 6ab9442..6b05046 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -367,12 +367,47 @@ init_itable=n The lazy itable init code will wait n times the minimizes the impact on the systme performance while file system's inode table is being initialized. -discard Controls whether ext4 should issue discard/TRIM +discard Controls whether ext4 should issue discard/TRIM nodiscard(*) commands to the underlying block device when blocks are freed. This is useful for SSD devices and sparse/thinly-provisioned LUNs, but it is off by default until sufficient testing has been done. +nouid32 Disables 32-bit UIDs and GIDs. This is for + interoperability with older kernels which only + store and expect 16-bit values. + +resize Allows to resize filesystem to the end of the last + existing block group, further resize has to be done + with resize2fs either online, or offline. It can be + used only with conjunction with remount. + +block_validity This options allows to enables/disables the in-kernel +noblock_validity facility for tracking filesystem metadata blocks + within internal data structures. This allows multi- + block allocator and other routines to quickly locate + extents which might overlap with filesystem metadata + blocks. This option is intended for debugging + purposes and since it negatively affects the + performance, it is off by default. + +dioread_lock Controls whether or not ext4 should use the DIO read +dioread_nolock locking. If the dioread_nolock option is specified + ext4 will allocate uninitialized extent before buffer + write and convert the extent to initialized after IO + completes. This approach allows ext4 code to avoid + using inode mutex, which improves scalability on high + speed storages. However this does not work with nobh + option and the mount will fail. Nor does it work with + data journaling and dioread_nolock option will be + ignored with kernel warning. Note that dioread_nolock + code path is only used for extent-based files. + Because of the restrictions this options comprises + it is off by default (e.g. dioread_lock). + +i_version Enable 64-bit inode version support. This option is + off by default. + Data Mode ========= There are 3 different data modes: @@ -400,6 +435,176 @@ needs to be read from and written to disk at the same time where it outperforms all others modes. Currently ext4 does not have delayed allocation support if this data journalling mode is selected. +/proc entries +============= + +Information about mounted ext4 file systems can be found in +/proc/fs/ext4. Each mounted filesystem will have a directory in +/proc/fs/ext4 based on its device name (i.e., /proc/fs/ext4/hdc or +/proc/fs/ext4/dm-0). The files in each per-device directory are shown +in table below. + +Files in /proc/fs/ext4/<devname> +.............................................................................. + File Content + mb_groups details of multiblock allocator buddy cache of free blocks +.............................................................................. + +/sys entries +============ + +Information about mounted ext4 file systems can be found in +/sys/fs/ext4. Each mounted filesystem will have a directory in +/sys/fs/ext4 based on its device name (i.e., /sys/fs/ext4/hdc or +/sys/fs/ext4/dm-0). The files in each per-device directory are shown +in table below. + +Files in /sys/fs/ext4/<devname> +(see also Documentation/ABI/testing/sysfs-fs-ext4) +.............................................................................. + File Content + + delayed_allocation_blocks This file is read-only and shows the number of + blocks that are dirty in the page cache, but + which do not have their location in the + filesystem allocated yet. + + inode_goal Tuning parameter which (if non-zero) controls + the goal inode used by the inode allocator in + preference to all other allocation heuristics. + This is intended for debugging use only, and + should be 0 on production systems. + + inode_readahead_blks Tuning parameter which controls the maximum + number of inode table blocks that ext4's inode + table readahead algorithm will pre-read into + the buffer cache + + lifetime_write_kbytes This file is read-only and shows the number of + kilobytes of data that have been written to this + filesystem since it was created. + + max_writeback_mb_bump The maximum number of megabytes the writeback + code will try to write out before move on to + another inode. + + mb_group_prealloc The multiblock allocator will round up allocation + requests to a multiple of this tuning parameter if + the stripe size is not set in the ext4 superblock + + mb_max_to_scan The maximum number of extents the multiblock + allocator will search to find the best extent + + mb_min_to_scan The minimum number of extents the multiblock + allocator will search to find the best extent + + mb_order2_req Tuning parameter which controls the minimum size + for requests (as a power of 2) where the buddy + cache is used + + mb_stats Controls whether the multiblock allocator should + collect statistics, which are shown during the + unmount. 1 means to collect statistics, 0 means + not to collect statistics + + mb_stream_req Files which have fewer blocks than this tunable + parameter will have their blocks allocated out + of a block group specific preallocation pool, so + that small files are packed closely together. + Each large file will have its blocks allocated + out of its own unique preallocation pool. + + session_write_kbytes This file is read-only and shows the number of + kilobytes of data that have been written to this + filesystem since it was mounted. +.............................................................................. + +Ioctls +====== + +There is some Ext4 specific functionality which can be accessed by applications +through the system call interfaces. The list of all Ext4 specific ioctls are +shown in the table below. + +Table of Ext4 specific ioctls +.............................................................................. + Ioctl Description + EXT4_IOC_GETFLAGS Get additional attributes associated with inode. + The ioctl argument is an integer bitfield, with + bit values described in ext4.h. This ioctl is an + alias for FS_IOC_GETFLAGS. + + EXT4_IOC_SETFLAGS Set additional attributes associated with inode. + The ioctl argument is an integer bitfield, with + bit values described in ext4.h. This ioctl is an + alias for FS_IOC_SETFLAGS. + + EXT4_IOC_GETVERSION + EXT4_IOC_GETVERSION_OLD + Get the inode i_generation number stored for + each inode. The i_generation number is normally + changed only when new inode is created and it is + particularly useful for network filesystems. The + '_OLD' version of this ioctl is an alias for + FS_IOC_GETVERSION. + + EXT4_IOC_SETVERSION + EXT4_IOC_SETVERSION_OLD + Set the inode i_generation number stored for + each inode. The '_OLD' version of this ioctl + is an alias for FS_IOC_SETVERSION. + + EXT4_IOC_GROUP_EXTEND This ioctl has the same purpose as the resize + mount option. It allows to resize filesystem + to the end of the last existing block group, + further resize has to be done with resize2fs, + either online, or offline. The argument points + to the unsigned logn number representing the + filesystem new block count. + + EXT4_IOC_MOVE_EXT Move the block extents from orig_fd (the one + this ioctl is pointing to) to the donor_fd (the + one specified in move_extent structure passed + as an argument to this ioctl). Then, exchange + inode metadata between orig_fd and donor_fd. + This is especially useful for online + defragmentation, because the allocator has the + opportunity to allocate moved blocks better, + ideally into one contiguous extent. + + EXT4_IOC_GROUP_ADD Add a new group descriptor to an existing or + new group descriptor block. The new group + descriptor is described by ext4_new_group_input + structure, which is passed as an argument to + this ioctl. This is especially useful in + conjunction with EXT4_IOC_GROUP_EXTEND, + which allows online resize of the filesystem + to the end of the last existing block group. + Those two ioctls combined is used in userspace + online resize tool (e.g. resize2fs). + + EXT4_IOC_MIGRATE This ioctl operates on the filesystem itself. + It converts (migrates) ext3 indirect block mapped + inode to ext4 extent mapped inode by walking + through indirect block mapping of the original + inode and converting contiguous block ranges + into ext4 extents of the temporary inode. Then, + inodes are swapped. This ioctl might help, when + migrating from ext3 to ext4 filesystem, however + suggestion is to create fresh ext4 filesystem + and copy data from the backup. Note, that + filesystem has to support extents for this ioctl + to work. + + EXT4_IOC_ALLOC_DA_BLKS Force all of the delay allocated blocks to be + allocated to preserve application-expected ext3 + behaviour. Note that this will also start + triggering a write of the data blocks, but this + behaviour may change in the future as it is + not necessary and has been done this way only + for sake of simplicity. +.............................................................................. + References ========== diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 0c986c9..6e29954 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -298,11 +298,14 @@ be used instead. It gets called whenever the inode is evicted, whether it has remaining links or not. Caller does *not* evict the pagecache or inode-associated metadata buffers; getting rid of those is responsibility of method, as it had been for ->delete_inode(). - ->drop_inode() returns int now; it's called on final iput() with inode_lock -held and it returns true if filesystems wants the inode to be dropped. As before, -generic_drop_inode() is still the default and it's been updated appropriately. -generic_delete_inode() is also alive and it consists simply of return 1. Note that -all actual eviction work is done by caller after ->drop_inode() returns. + + ->drop_inode() returns int now; it's called on final iput() with +inode->i_lock held and it returns true if filesystems wants the inode to be +dropped. As before, generic_drop_inode() is still the default and it's been +updated appropriately. generic_delete_inode() is also alive and it consists +simply of return 1. Note that all actual eviction work is done by caller after +->drop_inode() returns. + clear_inode() is gone; use end_writeback() instead. As before, it must be called exactly once on each call of ->evict_inode() (as it used to be for each call of ->delete_inode()). Unlike before, if you are using inode-associated @@ -397,6 +400,9 @@ a file off. -- [mandatory] + +-- +[mandatory] ->get_sb() is gone. Switch to use of ->mount(). Typically it's just a matter of switching from calling get_sb_... to mount_... and changing the function type. If you were doing it manually, just switch from setting ->mnt_root diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 306f0ae..80815ed 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -254,7 +254,7 @@ or bottom half). should be synchronous or not, not all filesystems check this flag. drop_inode: called when the last access to the inode is dropped, - with the inode_lock spinlock held. + with the inode->i_lock spinlock held. This method should be either NULL (normal UNIX filesystem semantics) or "generic_delete_inode" (for filesystems that do not diff --git a/Documentation/hwmon/f71882fg b/Documentation/hwmon/f71882fg index 4d0bc70..df02245 100644 --- a/Documentation/hwmon/f71882fg +++ b/Documentation/hwmon/f71882fg @@ -2,6 +2,10 @@ Kernel driver f71882fg ====================== Supported chips: + * Fintek F71808E + Prefix: 'f71808e' + Addresses scanned: none, address read from Super I/O config space + Datasheet: Not public * Fintek F71858FG Prefix: 'f71858fg' Addresses scanned: none, address read from Super I/O config space @@ -26,10 +30,25 @@ Supported chips: Prefix: 'f71889ed' Addresses scanned: none, address read from Super I/O config space Datasheet: Should become available on the Fintek website soon + * Fintek F71889A + Prefix: 'f71889a' + Addresses scanned: none, address read from Super I/O config space + Datasheet: Should become available on the Fintek website soon * Fintek F8000 Prefix: 'f8000' Addresses scanned: none, address read from Super I/O config space Datasheet: Not public + * Fintek F81801U + Prefix: 'f71889fg' + Addresses scanned: none, address read from Super I/O config space + Datasheet: Not public + Note: This is the 64-pin variant of the F71889FG, they have the + same device ID and are fully compatible as far as hardware + monitoring is concerned. + * Fintek F81865F + Prefix: 'f81865f' + Addresses scanned: none, address read from Super I/O config space + Datasheet: Available from the Fintek website Author: Hans de Goede <hdegoede@redhat.com> diff --git a/Documentation/scheduler/sched-design-CFS.txt b/Documentation/scheduler/sched-design-CFS.txt index 8239ebb..9996199 100644 --- a/Documentation/scheduler/sched-design-CFS.txt +++ b/Documentation/scheduler/sched-design-CFS.txt @@ -164,7 +164,7 @@ This is the (partial) list of the hooks: It puts the scheduling entity (task) into the red-black tree and increments the nr_running variable. - - dequeue_tree(...) + - dequeue_task(...) When a task is no longer runnable, this function is called to keep the corresponding scheduling entity out of the red-black tree. It decrements @@ -195,11 +195,6 @@ This is the (partial) list of the hooks: This function is mostly called from time tick functions; it might lead to process switch. This drives the running preemption. - - task_new(...) - - The core scheduler gives the scheduling module an opportunity to manage new - task startup. The CFS scheduling module uses it for group scheduling, while - the scheduling module for a real-time task does not use it. diff --git a/Documentation/target/tcm_mod_builder.py b/Documentation/target/tcm_mod_builder.py index dbeb8a0..7ef9b84 100755 --- a/Documentation/target/tcm_mod_builder.py +++ b/Documentation/target/tcm_mod_builder.py @@ -239,8 +239,8 @@ def tcm_mod_build_configfs(proto_ident, fabric_mod_dir_var, fabric_mod_name): buf += "#include <target/target_core_configfs.h>\n" buf += "#include <target/target_core_base.h>\n" buf += "#include <target/configfs_macros.h>\n\n" - buf += "#include <" + fabric_mod_name + "_base.h>\n" - buf += "#include <" + fabric_mod_name + "_fabric.h>\n\n" + buf += "#include \"" + fabric_mod_name + "_base.h\"\n" + buf += "#include \"" + fabric_mod_name + "_fabric.h\"\n\n" buf += "/* Local pointer to allocated TCM configfs fabric module */\n" buf += "struct target_fabric_configfs *" + fabric_mod_name + "_fabric_configfs;\n\n" @@ -289,6 +289,7 @@ def tcm_mod_build_configfs(proto_ident, fabric_mod_dir_var, fabric_mod_name): buf += "{\n" buf += " struct " + fabric_mod_name + "_nacl *nacl = container_of(se_acl,\n" buf += " struct " + fabric_mod_name + "_nacl, se_node_acl);\n" + buf += " core_tpg_del_initiator_node_acl(se_acl->se_tpg, se_acl, 1);\n" buf += " kfree(nacl);\n" buf += "}\n\n" @@ -583,9 +584,9 @@ def tcm_mod_dump_fabric_ops(proto_ident, fabric_mod_dir_var, fabric_mod_name): buf += "#include <target/target_core_fabric_lib.h>\n" buf += "#include <target/target_core_device.h>\n" buf += "#include <target/target_core_tpg.h>\n" - buf += "#include <target/target_core_configfs.h>\n" - buf += "#include <" + fabric_mod_name + "_base.h>\n" - buf += "#include <" + fabric_mod_name + "_fabric.h>\n\n" + buf += "#include <target/target_core_configfs.h>\n\n" + buf += "#include \"" + fabric_mod_name + "_base.h\"\n" + buf += "#include \"" + fabric_mod_name + "_fabric.h\"\n\n" buf += "int " + fabric_mod_name + "_check_true(struct se_portal_group *se_tpg)\n" buf += "{\n" @@ -973,14 +974,13 @@ def tcm_mod_dump_fabric_ops(proto_ident, fabric_mod_dir_var, fabric_mod_name): def tcm_mod_build_kbuild(fabric_mod_dir_var, fabric_mod_name): buf = "" - f = fabric_mod_dir_var + "/Kbuild" + f = fabric_mod_dir_var + "/Makefile" print "Writing file: " + f p = open(f, 'w') if not p: tcm_mod_err("Unable to open file: " + f) - buf = "EXTRA_CFLAGS += -I$(srctree)/drivers/target/ -I$(srctree)/include/ -I$(srctree)/drivers/scsi/ -I$(srctree)/include/scsi/ -I$(srctree)/drivers/target/" + fabric_mod_name + "\n\n" buf += fabric_mod_name + "-objs := " + fabric_mod_name + "_fabric.o \\\n" buf += " " + fabric_mod_name + "_configfs.o\n" buf += "obj-$(CONFIG_" + fabric_mod_name.upper() + ") += " + fabric_mod_name + ".o\n" @@ -1018,7 +1018,7 @@ def tcm_mod_build_kconfig(fabric_mod_dir_var, fabric_mod_name): def tcm_mod_add_kbuild(tcm_dir, fabric_mod_name): buf = "obj-$(CONFIG_" + fabric_mod_name.upper() + ") += " + fabric_mod_name.lower() + "/\n" - kbuild = tcm_dir + "/drivers/target/Kbuild" + kbuild = tcm_dir + "/drivers/target/Makefile" f = open(kbuild, 'a') f.write(buf) @@ -1064,7 +1064,7 @@ def main(modname, proto_ident): tcm_mod_build_kbuild(fabric_mod_dir, fabric_mod_name) tcm_mod_build_kconfig(fabric_mod_dir, fabric_mod_name) - input = raw_input("Would you like to add " + fabric_mod_name + "to drivers/target/Kbuild..? [yes,no]: ") + input = raw_input("Would you like to add " + fabric_mod_name + "to drivers/target/Makefile..? [yes,no]: ") if input == "yes" or input == "y": tcm_mod_add_kbuild(tcm_dir, fabric_mod_name) |