diff options
Diffstat (limited to 'Documentation')
48 files changed, 1064 insertions, 2445 deletions
diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl index 49c745720f4..2b5ac604948 100644 --- a/Documentation/DocBook/kernel-api.tmpl +++ b/Documentation/DocBook/kernel-api.tmpl @@ -158,6 +158,7 @@ X!Ilib/string.c !Emm/filemap.c !Emm/memory.c !Emm/vmalloc.c +!Imm/page_alloc.c !Emm/mempool.c !Emm/page-writeback.c !Emm/truncate.c diff --git a/Documentation/DocBook/libata.tmpl b/Documentation/DocBook/libata.tmpl index c684abf0d3b..07a635590b3 100644 --- a/Documentation/DocBook/libata.tmpl +++ b/Documentation/DocBook/libata.tmpl @@ -14,7 +14,7 @@ </authorgroup> <copyright> - <year>2003-2005</year> + <year>2003-2006</year> <holder>Jeff Garzik</holder> </copyright> diff --git a/Documentation/HOWTO b/Documentation/HOWTO index d6f3dd1a346..8d51c148f72 100644 --- a/Documentation/HOWTO +++ b/Documentation/HOWTO @@ -395,6 +395,26 @@ bugme-janitor mailing list (every change in the bugzilla is mailed here) +Managing bug reports +-------------------- + +One of the best ways to put into practice your hacking skills is by fixing +bugs reported by other people. Not only you will help to make the kernel +more stable, you'll learn to fix real world problems and you will improve +your skills, and other developers will be aware of your presence. Fixing +bugs is one of the best ways to get merits among other developers, because +not many people like wasting time fixing other people's bugs. + +To work in the already reported bug reports, go to http://bugzilla.kernel.org. +If you want to be advised of the future bug reports, you can subscribe to the +bugme-new mailing list (only new bug reports are mailed here) or to the +bugme-janitor mailing list (every change in the bugzilla is mailed here) + + http://lists.osdl.org/mailman/listinfo/bugme-new + http://lists.osdl.org/mailman/listinfo/bugme-janitors + + + Mailing lists ------------- diff --git a/Documentation/MSI-HOWTO.txt b/Documentation/MSI-HOWTO.txt index c70306abb7b..5c34910665d 100644 --- a/Documentation/MSI-HOWTO.txt +++ b/Documentation/MSI-HOWTO.txt @@ -470,7 +470,68 @@ LOC: 324553 325068 ERR: 0 MIS: 0 -6. FAQ +6. MSI quirks + +Several PCI chipsets or devices are known to not support MSI. +The PCI stack provides 3 possible levels of MSI disabling: +* on a single device +* on all devices behind a specific bridge +* globally + +6.1. Disabling MSI on a single device + +Under some circumstances, it might be required to disable MSI on a +single device, It may be achived by either not calling pci_enable_msi() +or all, or setting the pci_dev->no_msi flag before (most of the time +in a quirk). + +6.2. Disabling MSI below a bridge + +The vast majority of MSI quirks are required by PCI bridges not +being able to route MSI between busses. In this case, MSI have to be +disabled on all devices behind this bridge. It is achieves by setting +the PCI_BUS_FLAGS_NO_MSI flag in the pci_bus->bus_flags of the bridge +subordinate bus. There is no need to set the same flag on bridges that +are below the broken brigde. When pci_enable_msi() is called to enable +MSI on a device, pci_msi_supported() takes care of checking the NO_MSI +flag in all parent busses of the device. + +Some bridges actually support dynamic MSI support enabling/disabling +by changing some bits in their PCI configuration space (especially +the Hypertransport chipsets such as the nVidia nForce and Serverworks +HT2000). It may then be required to update the NO_MSI flag on the +corresponding devices in the sysfs hierarchy. To enable MSI support +on device "0000:00:0e", do: + + echo 1 > /sys/bus/pci/devices/0000:00:0e/msi_bus + +To disable MSI support, echo 0 instead of 1. Note that it should be +used with caution since changing this value might break interrupts. + +6.3. Disabling MSI globally + +Some extreme cases may require to disable MSI globally on the system. +For now, the only known case is a Serverworks PCI-X chipsets (MSI are +not supported on several busses that are not all connected to the +chipset in the Linux PCI hierarchy). In the vast majority of other +cases, disabling only behind a specific bridge is enough. + +For debugging purpose, the user may also pass pci=nomsi on the kernel +command-line to explicitly disable MSI globally. But, once the appro- +priate quirks are added to the kernel, this option should not be +required anymore. + +6.4. Finding why MSI cannot be enabled on a device + +Assuming that MSI are not enabled on a device, you should look at +dmesg to find messages that quirks may output when disabling MSI +on some devices, some bridges or even globally. +Then, lspci -t gives the list of bridges above a device. Reading +/sys/bus/pci/devices/0000:00:0e/msi_bus will tell you whether MSI +are enabled (1) or disabled (0). In 0 is found in a single bridge +msi_bus file above the device, MSI cannot be enabled. + +7. FAQ Q1. Are there any limitations on using the MSI? diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt index 1d50cf0c905..f4dffadbcb0 100644 --- a/Documentation/RCU/checklist.txt +++ b/Documentation/RCU/checklist.txt @@ -221,3 +221,41 @@ over a rather long period of time, but improvements are always welcome! disable irq on a given acquisition of that lock will result in deadlock as soon as the RCU callback happens to interrupt that acquisition's critical section. + +13. SRCU (srcu_read_lock(), srcu_read_unlock(), and synchronize_srcu()) + may only be invoked from process context. Unlike other forms of + RCU, it -is- permissible to block in an SRCU read-side critical + section (demarked by srcu_read_lock() and srcu_read_unlock()), + hence the "SRCU": "sleepable RCU". Please note that if you + don't need to sleep in read-side critical sections, you should + be using RCU rather than SRCU, because RCU is almost always + faster and easier to use than is SRCU. + + Also unlike other forms of RCU, explicit initialization + and cleanup is required via init_srcu_struct() and + cleanup_srcu_struct(). These are passed a "struct srcu_struct" + that defines the scope of a given SRCU domain. Once initialized, + the srcu_struct is passed to srcu_read_lock(), srcu_read_unlock() + and synchronize_srcu(). A given synchronize_srcu() waits only + for SRCU read-side critical sections governed by srcu_read_lock() + and srcu_read_unlock() calls that have been passd the same + srcu_struct. This property is what makes sleeping read-side + critical sections tolerable -- a given subsystem delays only + its own updates, not those of other subsystems using SRCU. + Therefore, SRCU is less prone to OOM the system than RCU would + be if RCU's read-side critical sections were permitted to + sleep. + + The ability to sleep in read-side critical sections does not + come for free. First, corresponding srcu_read_lock() and + srcu_read_unlock() calls must be passed the same srcu_struct. + Second, grace-period-detection overhead is amortized only + over those updates sharing a given srcu_struct, rather than + being globally amortized as they are for other forms of RCU. + Therefore, SRCU should be used in preference to rw_semaphore + only in extremely read-intensive situations, or in situations + requiring SRCU's read-side deadlock immunity or low read-side + realtime latency. + + Note that, rcu_assign_pointer() and rcu_dereference() relate to + SRCU just as they do to other forms of RCU. diff --git a/Documentation/RCU/rcu.txt b/Documentation/RCU/rcu.txt index 02e27bf1d36..f84407cba81 100644 --- a/Documentation/RCU/rcu.txt +++ b/Documentation/RCU/rcu.txt @@ -45,7 +45,8 @@ o How can I see where RCU is currently used in the Linux kernel? Search for "rcu_read_lock", "rcu_read_unlock", "call_rcu", "rcu_read_lock_bh", "rcu_read_unlock_bh", "call_rcu_bh", - "synchronize_rcu", and "synchronize_net". + "srcu_read_lock", "srcu_read_unlock", "synchronize_rcu", + "synchronize_net", and "synchronize_srcu". o What guidelines should I follow when writing code that uses RCU? diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt index a4948591607..25a3c3f7d37 100644 --- a/Documentation/RCU/torture.txt +++ b/Documentation/RCU/torture.txt @@ -28,6 +28,15 @@ nreaders This is the number of RCU reading threads supported. To properly exercise RCU implementations with preemptible read-side critical sections. +nfakewriters This is the number of RCU fake writer threads to run. Fake + writer threads repeatedly use the synchronous "wait for + current readers" function of the interface selected by + torture_type, with a delay between calls to allow for various + different numbers of writers running in parallel. + nfakewriters defaults to 4, which provides enough parallelism + to trigger special cases caused by multiple writers, such as + the synchronize_srcu() early return optimization. + stat_interval The number of seconds between output of torture statistics (via printk()). Regardless of the interval, statistics are printed when the module is unloaded. @@ -44,9 +53,12 @@ test_no_idle_hz Whether or not to test the ability of RCU to operate in a kernel that disables the scheduling-clock interrupt to idle CPUs. Boolean parameter, "1" to test, "0" otherwise. -torture_type The type of RCU to test: "rcu" for the rcu_read_lock() - API, "rcu_bh" for the rcu_read_lock_bh() API, and "srcu" - for the "srcu_read_lock()" API. +torture_type The type of RCU to test: "rcu" for the rcu_read_lock() API, + "rcu_sync" for rcu_read_lock() with synchronous reclamation, + "rcu_bh" for the rcu_read_lock_bh() API, "rcu_bh_sync" for + rcu_read_lock_bh() with synchronous reclamation, "srcu" for + the "srcu_read_lock()" API, and "sched" for the use of + preempt_disable() together with synchronize_sched(). verbose Enable debug printk()s. Default is disabled. @@ -118,6 +130,21 @@ o "Free-Block Circulation": Shows the number of torture structures as it is only incremented if a torture structure's counter somehow gets incremented farther than it should. +Different implementations of RCU can provide implementation-specific +additional information. For example, SRCU provides the following: + + srcu-torture: rtc: f8cf46a8 ver: 355 tfle: 0 rta: 356 rtaf: 0 rtf: 346 rtmbe: 0 + srcu-torture: Reader Pipe: 559738 939 0 0 0 0 0 0 0 0 0 + srcu-torture: Reader Batch: 560434 243 0 0 0 0 0 0 0 0 + srcu-torture: Free-Block Circulation: 355 354 353 352 351 350 349 348 347 346 0 + srcu-torture: per-CPU(idx=1): 0(0,1) 1(0,1) 2(0,0) 3(0,1) + +The first four lines are similar to those for RCU. The last line shows +the per-CPU counter state. The numbers in parentheses are the values +of the "old" and "current" counters for the corresponding CPU. The +"idx" value maps the "old" and "current" values to the underlying array, +and is useful for debugging. + USAGE diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt index 820fee23696..e0d6d99b8f9 100644 --- a/Documentation/RCU/whatisRCU.txt +++ b/Documentation/RCU/whatisRCU.txt @@ -778,6 +778,8 @@ Markers for RCU read-side critical sections: rcu_read_unlock rcu_read_lock_bh rcu_read_unlock_bh + srcu_read_lock + srcu_read_unlock RCU pointer/list traversal: @@ -804,6 +806,7 @@ RCU grace period: synchronize_net synchronize_sched synchronize_rcu + synchronize_srcu call_rcu call_rcu_bh diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index bc107cb157a..4868c34f750 100644 --- a/Documentation/cpu-hotplug.txt +++ b/Documentation/cpu-hotplug.txt @@ -46,7 +46,7 @@ maxcpus=n Restrict boot time cpus to n. Say if you have 4 cpus, using maxcpus=2 will only boot 2. You can choose to bring the other cpus later online, read FAQ's for more info. -additional_cpus*=n Use this to limit hotpluggable cpus. This option sets +additional_cpus=n (*) Use this to limit hotpluggable cpus. This option sets cpu_possible_map = cpu_present_map + additional_cpus (*) Option valid only for following architectures @@ -101,15 +101,15 @@ cpu_possible_map/for_each_possible_cpu() to iterate. Never use anything other than cpumask_t to represent bitmap of CPUs. -#include <linux/cpumask.h> + #include <linux/cpumask.h> -for_each_possible_cpu - Iterate over cpu_possible_map -for_each_online_cpu - Iterate over cpu_online_map -for_each_present_cpu - Iterate over cpu_present_map -for_each_cpu_mask(x,mask) - Iterate over some random collection of cpu mask. + for_each_possible_cpu - Iterate over cpu_possible_map + for_each_online_cpu - Iterate over cpu_online_map + for_each_present_cpu - Iterate over cpu_present_map + for_each_cpu_mask(x,mask) - Iterate over some random collection of cpu mask. -#include <linux/cpu.h> -lock_cpu_hotplug() and unlock_cpu_hotplug(): + #include <linux/cpu.h> + lock_cpu_hotplug() and unlock_cpu_hotplug(): The above calls are used to inhibit cpu hotplug operations. While holding the cpucontrol mutex, cpu_online_map will not change. If you merely need to avoid @@ -120,7 +120,7 @@ will work as long as stop_machine_run() is used to take a cpu down. CPU Hotplug - Frequently Asked Questions. -Q: How to i enable my kernel to support CPU hotplug? +Q: How to enable my kernel to support CPU hotplug? A: When doing make defconfig, Enable CPU hotplug support "Processor type and Features" -> Support for Hotpluggable CPUs @@ -141,39 +141,39 @@ A: You should now notice an entry in sysfs. Check if sysfs is mounted, using the "mount" command. You should notice an entry as shown below in the output. -.... -none on /sys type sysfs (rw) -.... + .... + none on /sys type sysfs (rw) + .... -if this is not mounted, do the following. +If this is not mounted, do the following. -#mkdir /sysfs -#mount -t sysfs sys /sys + #mkdir /sysfs + #mount -t sysfs sys /sys -now you should see entries for all present cpu, the following is an example +Now you should see entries for all present cpu, the following is an example in a 8-way system. -#pwd -#/sys/devices/system/cpu -#ls -l -total 0 -drwxr-xr-x 10 root root 0 Sep 19 07:44 . -drwxr-xr-x 13 root root 0 Sep 19 07:45 .. -drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu0 -drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu1 -drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu2 -drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu3 -drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu4 -drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu5 -drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu6 -drwxr-xr-x 3 root root 0 Sep 19 07:48 cpu7 + #pwd + #/sys/devices/system/cpu + #ls -l + total 0 + drwxr-xr-x 10 root root 0 Sep 19 07:44 . + drwxr-xr-x 13 root root 0 Sep 19 07:45 .. + drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu0 + drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu1 + drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu2 + drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu3 + drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu4 + drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu5 + drwxr-xr-x 3 root root 0 Sep 19 07:44 cpu6 + drwxr-xr-x 3 root root 0 Sep 19 07:48 cpu7 Under each directory you would find an "online" file which is the control file to logically online/offline a processor. Q: Does hot-add/hot-remove refer to physical add/remove of cpus? A: The usage of hot-add/remove may not be very consistently used in the code. -CONFIG_CPU_HOTPLUG enables logical online/offline capability in the kernel. +CONFIG_HOTPLUG_CPU enables logical online/offline capability in the kernel. To support physical addition/removal, one would need some BIOS hooks and the platform should have something like an attention button in PCI hotplug. CONFIG_ACPI_HOTPLUG_CPU enables ACPI support for physical add/remove of CPUs. @@ -181,17 +181,17 @@ CONFIG_ACPI_HOTPLUG_CPU enables ACPI support for physical add/remove of CPUs. Q: How do i logically offline a CPU? A: Do the following. -#echo 0 > /sys/devices/system/cpu/cpuX/online + #echo 0 > /sys/devices/system/cpu/cpuX/online -once the logical offline is successful, check +Once the logical offline is successful, check -#cat /proc/interrupts + #cat /proc/interrupts -you should now not see the CPU that you removed. Also online file will report +You should now not see the CPU that you removed. Also online file will report the state as 0 when a cpu if offline and 1 when its online. -#To display the current cpu state. -#cat /sys/devices/system/cpu/cpuX/online + #To display the current cpu state. + #cat /sys/devices/system/cpu/cpuX/online Q: Why cant i remove CPU0 on some systems? A: Some architectures may have some special dependency on a certain CPU. @@ -234,8 +234,8 @@ Q: If i have some kernel code that needs to be aware of CPU arrival and departure, how to i arrange for proper notification? A: This is what you would need in your kernel code to receive notifications. - #include <linux/cpu.h> - static int __cpuinit foobar_cpu_callback(struct notifier_block *nfb, + #include <linux/cpu.h> + static int __cpuinit foobar_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { unsigned int cpu = (unsigned long)hcpu; @@ -279,10 +279,10 @@ Q: I don't see my action being called for all CPUs already up and running? A: Yes, CPU notifiers are called only when new CPUs are on-lined or offlined. If you need to perform some action for each cpu already in the system, then - for_each_online_cpu(i) { + for_each_online_cpu(i) { foobar_cpu_callback(&foobar_cpu_notifier, CPU_UP_PREPARE, i); - foobar_cpu_callback(&foobar-cpu_notifier, CPU_ONLINE, i); - } + foobar_cpu_callback(&foobar_cpu_notifier, CPU_ONLINE, i); + } Q: If i would like to develop cpu hotplug support for a new architecture, what do i need at a minimum? @@ -307,38 +307,38 @@ Q: I need to ensure that a particular cpu is not removed when there is some work specific to this cpu is in progress. A: First switch the current thread context to preferred cpu - int my_func_on_cpu(int cpu) - { - cpumask_t saved_mask, new_mask = CPU_MASK_NONE; - int curr_cpu, err = 0; - - saved_mask = current->cpus_allowed; - cpu_set(cpu, new_mask); - err = set_cpus_allowed(current, new_mask); - - if (err) - return err; - - /* - * If we got scheduled out just after the return from - * set_cpus_allowed() before running the work, this ensures - * we stay locked. - */ - curr_cpu = get_cpu(); - - if (curr_cpu != cpu) { - err = -EAGAIN; - goto ret; - } else { - /* - * Do work : But cant sleep, since get_cpu() disables preempt - */ - } - ret: - put_cpu(); - set_cpus_allowed(current, saved_mask); - return err; - } + int my_func_on_cpu(int cpu) + { + cpumask_t saved_mask, new_mask = CPU_MASK_NONE; + int curr_cpu, err = 0; + + saved_mask = current->cpus_allowed; + cpu_set(cpu, new_mask); + err = set_cpus_allowed(current, new_mask); + + if (err) + return err; + + /* + * If we got scheduled out just after the return from + * set_cpus_allowed() before running the work, this ensures + * we stay locked. + */ + curr_cpu = get_cpu(); + + if (curr_cpu != cpu) { + err = -EAGAIN; + goto ret; + } else { + /* + * Do work : But cant sleep, since get_cpu() disables preempt + */ + } + ret: + put_cpu(); + set_cpus_allowed(current, saved_mask); + return err; + } Q: How do we determine how many CPUs are available for hotplug. diff --git a/Documentation/ecryptfs.txt b/Documentation/ecryptfs.txt new file mode 100644 index 00000000000..01d8a08351a --- /dev/null +++ b/Documentation/ecryptfs.txt @@ -0,0 +1,77 @@ +eCryptfs: A stacked cryptographic filesystem for Linux + +eCryptfs is free software. Please see the file COPYING for details. +For documentation, please see the files in the doc/ subdirectory. For +building and installation instructions please see the INSTALL file. + +Maintainer: Phillip Hellewell +Lead developer: Michael A. Halcrow <mhalcrow@us.ibm.com> +Developers: Michael C. Thompson + Kent Yoder +Web Site: http://ecryptfs.sf.net + +This software is currently undergoing development. Make sure to +maintain a backup copy of any data you write into eCryptfs. + +eCryptfs requires the userspace tools downloadable from the +SourceForge site: + +http://sourceforge.net/projects/ecryptfs/ + +Userspace requirements include: + - David Howells' userspace keyring headers and libraries (version + 1.0 or higher), obtainable from + http://people.redhat.com/~dhowells/keyutils/ + - Libgcrypt + + +NOTES + +In the beta/experimental releases of eCryptfs, when you upgrade +eCryptfs, you should copy the files to an unencrypted location and +then copy the files back into the new eCryptfs mount to migrate the +files. + + +MOUNT-WIDE PASSPHRASE + +Create a new directory into which eCryptfs will write its encrypted +files (i.e., /root/crypt). Then, create the mount point directory +(i.e., /mnt/crypt). Now it's time to mount eCryptfs: + +mount -t ecryptfs /root/crypt /mnt/crypt + +You should be prompted for a passphrase and a salt (the salt may be +blank). + +Try writing a new file: + +echo "Hello, World" > /mnt/crypt/hello.txt + +The operation will complete. Notice that there is a new file in +/root/crypt that is at least 12288 bytes in size (depending on your +host page size). This is the encrypted underlying file for what you +just wrote. To test reading, from start to finish, you need to clear +the user session keyring: + +keyctl clear @u + +Then umount /mnt/crypt and mount again per the instructions given +above. + +cat /mnt/crypt/hello.txt + + +NOTES + +eCryptfs version 0.1 should only be mounted on (1) empty directories +or (2) directories containing files only created by eCryptfs. If you +mount a directory that has pre-existing files not created by eCryptfs, +then behavior is undefined. Do not run eCryptfs in higher verbosity +levels unless you are doing so for the sole purpose of debugging or +development, since secret values will be written out to the system log +in that case. + + +Mike Halcrow +mhalcrow@us.ibm.com diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 42b95e0ad55..1ac3c74646e 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -29,14 +29,6 @@ Who: Adrian Bunk <bunk@stusta.de> --------------------------- -What: drivers that were depending on OBSOLETE_OSS_DRIVER - (config options already removed) -When: before 2.6.19 -Why: OSS drivers with ALSA replacements -Who: Adrian Bunk <bunk@stusta.de> - ---------------------------- - What: raw1394: requests of type RAW1394_REQ_ISO_SEND, RAW1394_REQ_ISO_LISTEN When: November 2006 Why: Deprecated in favour of the new ioctl-based rawiso interface, which is @@ -263,7 +255,7 @@ Who: Stephen Hemminger <shemminger@osdl.org> What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment -When: Oktober 2008 +When: October 2008 Why: The stacking of class devices makes these values misleading and inconsistent. Class devices should not carry any of these properties, and bus diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX index 3c384c0cf86..4dc28cc9350 100644 --- a/Documentation/filesystems/00-INDEX +++ b/Documentation/filesystems/00-INDEX @@ -34,6 +34,8 @@ ext2.txt - info, mount options and specifications for the Ext2 filesystem. ext3.txt - info, mount options and specifications for the Ext3 filesystem. +ext4.txt + - info, mount options and specifications for the Ext4 filesystem. files.txt - info on file management in the Linux kernel. fuse.txt diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt new file mode 100644 index 00000000000..6a4adcae9f9 --- /dev/null +++ b/Documentation/filesystems/ext4.txt @@ -0,0 +1,236 @@ |