<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/Documentation, branch v2.6.30-rc5</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>doc: small kernel-parameters updates</title>
<updated>2009-05-06T23:36:10+00:00</updated>
<author>
<name>Randy Dunlap</name>
<email>randy.dunlap@oracle.com</email>
</author>
<published>2009-05-06T23:02:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ca1eda2d75b855f434b1d5458534332ffad92d65'/>
<id>ca1eda2d75b855f434b1d5458534332ffad92d65</id>
<content type='text'>
Change last "i386" to X86-32 as is used throughout the rest of the file.
Change combination of X86-32,X86-64 to just X86, as is done throughout the
rest of the file.

Add a note that hyphens and underscores are equivalent in parameter names,
with examples.

Signed-off-by: Randy Dunlap &lt;randy.dunlap@oracle.com&gt;
Cc: Jan Engelhardt &lt;jengelh@medozas.de&gt;
Cc: Christopher Sylvain &lt;chris.sylvain@gmail.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Change last "i386" to X86-32 as is used throughout the rest of the file.
Change combination of X86-32,X86-64 to just X86, as is done throughout the
rest of the file.

Add a note that hyphens and underscores are equivalent in parameter names,
with examples.

Signed-off-by: Randy Dunlap &lt;randy.dunlap@oracle.com&gt;
Cc: Jan Engelhardt &lt;jengelh@medozas.de&gt;
Cc: Christopher Sylvain &lt;chris.sylvain@gmail.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>doc: hashdist defaults on for 64bit</title>
<updated>2009-05-06T23:36:09+00:00</updated>
<author>
<name>Hugh Dickins</name>
<email>hugh@veritas.com</email>
</author>
<published>2009-05-06T23:02:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=429aa0fca0df702fc9c81d799175a7d920398827'/>
<id>429aa0fca0df702fc9c81d799175a7d920398827</id>
<content type='text'>
kernel boot parameter `hashdist' now defaults on for all 64bit NUMA.

Signed-off-by: Hugh Dickins &lt;hugh@veritas.com&gt;
Acked-by: Mel Gorman &lt;mel@csn.ul.ie&gt;
Acked-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
kernel boot parameter `hashdist' now defaults on for all 64bit NUMA.

Signed-off-by: Hugh Dickins &lt;hugh@veritas.com&gt;
Acked-by: Mel Gorman &lt;mel@csn.ul.ie&gt;
Acked-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip</title>
<updated>2009-05-05T19:08:20+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2009-05-05T19:08:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=da87bbd14299ef43848742c44dfe05fa1da5a21f'/>
<id>da87bbd14299ef43848742c44dfe05fa1da5a21f</id>
<content type='text'>
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  kernel/posix-cpu-timers.c: fix sparse warning
  dma-debug: remove broken dma memory leak detection for 2.6.30
  locking: Documentation: lockdep-design.txt, fix note of state bits
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  kernel/posix-cpu-timers.c: fix sparse warning
  dma-debug: remove broken dma memory leak detection for 2.6.30
  locking: Documentation: lockdep-design.txt, fix note of state bits
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input</title>
<updated>2009-05-02T23:35:45+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2009-05-02T23:35:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8c0c3f7ff0daa119f0bb109148f6f0e39573b429'/>
<id>8c0c3f7ff0daa119f0bb109148f6f0e39573b429</id>
<content type='text'>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: document the multi-touch (MT) protocol
  Input: add detailed multi-touch finger data report protocol
  Input: allow certain EV_ABS events to bypass all filtering
  Input: bcm5974 - add documentation for the driver
  Input: bcm5974 - augment debug information
  Input: bcm5974 - Add support for the Macbook 5 (Unibody)
  Input: bcm5974 - add quad-finger tapping
  Input: bcm5974 - prepare for a new trackpad header type
  Input: appletouch - fix DMA to/from stack buffer
  Input: wacom - fix TabletPC touch bug
  Input: lifebook - add DMI entry for Fujitsu B-2130
  Input: ALPS - add signature for Toshiba Satellite Pro M10
  Input: elantech - make sure touchpad is really in absolute mode
  Input: elantech - provide a workaround for jumpy cursor on firmware 2.34
  Input: ucb1400 - use disable_irq_nosync() in irq handler
  Input: tsc2007 - use disable_irq_nosync() in irq handler
  Input: sa1111ps2 - use disable_irq_nosync() in irq handlers
  Input: omap-keypad - use disable_irq_nosync() in irq handler
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: document the multi-touch (MT) protocol
  Input: add detailed multi-touch finger data report protocol
  Input: allow certain EV_ABS events to bypass all filtering
  Input: bcm5974 - add documentation for the driver
  Input: bcm5974 - augment debug information
  Input: bcm5974 - Add support for the Macbook 5 (Unibody)
  Input: bcm5974 - add quad-finger tapping
  Input: bcm5974 - prepare for a new trackpad header type
  Input: appletouch - fix DMA to/from stack buffer
  Input: wacom - fix TabletPC touch bug
  Input: lifebook - add DMI entry for Fujitsu B-2130
  Input: ALPS - add signature for Toshiba Satellite Pro M10
  Input: elantech - make sure touchpad is really in absolute mode
  Input: elantech - provide a workaround for jumpy cursor on firmware 2.34
  Input: ucb1400 - use disable_irq_nosync() in irq handler
  Input: tsc2007 - use disable_irq_nosync() in irq handler
  Input: sa1111ps2 - use disable_irq_nosync() in irq handlers
  Input: omap-keypad - use disable_irq_nosync() in irq handler
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fixes</title>
<updated>2009-05-02T23:33:56+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2009-05-02T23:33:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=414772fa496273d1a93cefa6dab790f5fdf9de82'/>
<id>414772fa496273d1a93cefa6dab790f5fdf9de82</id>
<content type='text'>
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fixes:
  kbuild, modpost: Check the section flags, to catch missing "ax"/"aw"
  kbuild: fix comment in modpost.c
  kbuild: fix scripts/setlocalversion with git
  kbuild: fix Module.markers permission error under cygwin
  docs: also clean index.html
  kbuild: remove a tag file before it is regenerated
  kbuild: "make prepare" should be "make modules_prepare"
  kbuild: clean Module.markers and modules.order for out-of-tree modules
  avr32: drop unused CLEAN_FILES
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fixes:
  kbuild, modpost: Check the section flags, to catch missing "ax"/"aw"
  kbuild: fix comment in modpost.c
  kbuild: fix scripts/setlocalversion with git
  kbuild: fix Module.markers permission error under cygwin
  docs: also clean index.html
  kbuild: remove a tag file before it is regenerated
  kbuild: "make prepare" should be "make modules_prepare"
  kbuild: clean Module.markers and modules.order for out-of-tree modules
  avr32: drop unused CLEAN_FILES
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: prevent divide error for small values of vm_dirty_bytes</title>
<updated>2009-05-02T22:36:10+00:00</updated>
<author>
<name>Andrea Righi</name>
<email>righi.andrea@gmail.com</email>
</author>
<published>2009-04-30T22:08:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9e4a5bda89034502fb144331e71a0efdfd5fae97'/>
<id>9e4a5bda89034502fb144331e71a0efdfd5fae97</id>
<content type='text'>
Avoid setting less than two pages for vm_dirty_bytes: this is necessary to
avoid potential division by 0 (like the following) in get_dirty_limits().

[   49.951610] divide error: 0000 [#1] PREEMPT SMP
[   49.952195] last sysfs file: /sys/devices/pci0000:00/0000:00:01.1/host0/target0:0:0/0:0:0:0/block/sda/uevent
[   49.952195] CPU 1
[   49.952195] Modules linked in: pcspkr
[   49.952195] Pid: 3064, comm: dd Not tainted 2.6.30-rc3 #1
[   49.952195] RIP: 0010:[&lt;ffffffff802d39a9&gt;]  [&lt;ffffffff802d39a9&gt;] get_dirty_limits+0xe9/0x2c0
[   49.952195] RSP: 0018:ffff88001de03a98  EFLAGS: 00010202
[   49.952195] RAX: 00000000000000c0 RBX: ffff88001de03b80 RCX: 28f5c28f5c28f5c3
[   49.952195] RDX: 0000000000000000 RSI: 00000000000000c0 RDI: 0000000000000000
[   49.952195] RBP: ffff88001de03ae8 R08: 0000000000000000 R09: 0000000000000000
[   49.952195] R10: ffff88001ddda9a0 R11: 0000000000000001 R12: 0000000000000001
[   49.952195] R13: ffff88001fbc8218 R14: ffff88001de03b70 R15: ffff88001de03b78
[   49.952195] FS:  00007fe9a435b6f0(0000) GS:ffff8800025d9000(0000) knlGS:0000000000000000
[   49.952195] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   49.952195] CR2: 00007fe9a39ab000 CR3: 000000001de38000 CR4: 00000000000006e0
[   49.952195] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   49.952195] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[   49.952195] Process dd (pid: 3064, threadinfo ffff88001de02000, task ffff88001ddda250)
[   49.952195] Stack:
[   49.952195]  ffff88001fa0de00 ffff88001f2dbd70 ffff88001f9fe800 000080b900000000
[   49.952195]  00000000000000c0 ffff8800027a6100 0000000000000400 ffff88001fbc8218
[   49.952195]  0000000000000000 0000000000000600 ffff88001de03bb8 ffffffff802d3ed7
[   49.952195] Call Trace:
[   49.952195]  [&lt;ffffffff802d3ed7&gt;] balance_dirty_pages_ratelimited_nr+0x1d7/0x3f0
[   49.952195]  [&lt;ffffffff80368f8e&gt;] ? ext3_writeback_write_end+0x9e/0x120
[   49.952195]  [&lt;ffffffff802cc7df&gt;] generic_file_buffered_write+0x12f/0x330
[   49.952195]  [&lt;ffffffff802cce8d&gt;] __generic_file_aio_write_nolock+0x26d/0x460
[   49.952195]  [&lt;ffffffff802cda32&gt;] ? generic_file_aio_write+0x52/0xd0
[   49.952195]  [&lt;ffffffff802cda49&gt;] generic_file_aio_write+0x69/0xd0
[   49.952195]  [&lt;ffffffff80365fa6&gt;] ext3_file_write+0x26/0xc0
[   49.952195]  [&lt;ffffffff803034d1&gt;] do_sync_write+0xf1/0x140
[   49.952195]  [&lt;ffffffff80290d1a&gt;] ? get_lock_stats+0x2a/0x60
[   49.952195]  [&lt;ffffffff80280730&gt;] ? autoremove_wake_function+0x0/0x40
[   49.952195]  [&lt;ffffffff8030411b&gt;] vfs_write+0xcb/0x190
[   49.952195]  [&lt;ffffffff803042d0&gt;] sys_write+0x50/0x90
[   49.952195]  [&lt;ffffffff8022ff6b&gt;] system_call_fastpath+0x16/0x1b
[   49.952195] Code: 00 00 00 2b 05 09 1c 17 01 48 89 c6 49 0f af f4 48 c1 ee 02 48 89 f0 48 f7 e1 48 89 d6 31 d2 48 c1 ee 02 48 0f af 75 d0 48 89 f0 &lt;48&gt; f7 f7 41 8b 95 ac 01 00 00 48 89 c7 49 0f af d4 48 c1 ea 02
[   49.952195] RIP  [&lt;ffffffff802d39a9&gt;] get_dirty_limits+0xe9/0x2c0
[   49.952195]  RSP &lt;ffff88001de03a98&gt;
[   50.096523] ---[ end trace 008d7aa02f244d7b ]---

Signed-off-by: Andrea Righi &lt;righi.andrea@gmail.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Dave Chinner &lt;david@fromorbit.com&gt;
Cc: Christoph Lameter &lt;cl@linux-foundation.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Avoid setting less than two pages for vm_dirty_bytes: this is necessary to
avoid potential division by 0 (like the following) in get_dirty_limits().

[   49.951610] divide error: 0000 [#1] PREEMPT SMP
[   49.952195] last sysfs file: /sys/devices/pci0000:00/0000:00:01.1/host0/target0:0:0/0:0:0:0/block/sda/uevent
[   49.952195] CPU 1
[   49.952195] Modules linked in: pcspkr
[   49.952195] Pid: 3064, comm: dd Not tainted 2.6.30-rc3 #1
[   49.952195] RIP: 0010:[&lt;ffffffff802d39a9&gt;]  [&lt;ffffffff802d39a9&gt;] get_dirty_limits+0xe9/0x2c0
[   49.952195] RSP: 0018:ffff88001de03a98  EFLAGS: 00010202
[   49.952195] RAX: 00000000000000c0 RBX: ffff88001de03b80 RCX: 28f5c28f5c28f5c3
[   49.952195] RDX: 0000000000000000 RSI: 00000000000000c0 RDI: 0000000000000000
[   49.952195] RBP: ffff88001de03ae8 R08: 0000000000000000 R09: 0000000000000000
[   49.952195] R10: ffff88001ddda9a0 R11: 0000000000000001 R12: 0000000000000001
[   49.952195] R13: ffff88001fbc8218 R14: ffff88001de03b70 R15: ffff88001de03b78
[   49.952195] FS:  00007fe9a435b6f0(0000) GS:ffff8800025d9000(0000) knlGS:0000000000000000
[   49.952195] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   49.952195] CR2: 00007fe9a39ab000 CR3: 000000001de38000 CR4: 00000000000006e0
[   49.952195] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   49.952195] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[   49.952195] Process dd (pid: 3064, threadinfo ffff88001de02000, task ffff88001ddda250)
[   49.952195] Stack:
[   49.952195]  ffff88001fa0de00 ffff88001f2dbd70 ffff88001f9fe800 000080b900000000
[   49.952195]  00000000000000c0 ffff8800027a6100 0000000000000400 ffff88001fbc8218
[   49.952195]  0000000000000000 0000000000000600 ffff88001de03bb8 ffffffff802d3ed7
[   49.952195] Call Trace:
[   49.952195]  [&lt;ffffffff802d3ed7&gt;] balance_dirty_pages_ratelimited_nr+0x1d7/0x3f0
[   49.952195]  [&lt;ffffffff80368f8e&gt;] ? ext3_writeback_write_end+0x9e/0x120
[   49.952195]  [&lt;ffffffff802cc7df&gt;] generic_file_buffered_write+0x12f/0x330
[   49.952195]  [&lt;ffffffff802cce8d&gt;] __generic_file_aio_write_nolock+0x26d/0x460
[   49.952195]  [&lt;ffffffff802cda32&gt;] ? generic_file_aio_write+0x52/0xd0
[   49.952195]  [&lt;ffffffff802cda49&gt;] generic_file_aio_write+0x69/0xd0
[   49.952195]  [&lt;ffffffff80365fa6&gt;] ext3_file_write+0x26/0xc0
[   49.952195]  [&lt;ffffffff803034d1&gt;] do_sync_write+0xf1/0x140
[   49.952195]  [&lt;ffffffff80290d1a&gt;] ? get_lock_stats+0x2a/0x60
[   49.952195]  [&lt;ffffffff80280730&gt;] ? autoremove_wake_function+0x0/0x40
[   49.952195]  [&lt;ffffffff8030411b&gt;] vfs_write+0xcb/0x190
[   49.952195]  [&lt;ffffffff803042d0&gt;] sys_write+0x50/0x90
[   49.952195]  [&lt;ffffffff8022ff6b&gt;] system_call_fastpath+0x16/0x1b
[   49.952195] Code: 00 00 00 2b 05 09 1c 17 01 48 89 c6 49 0f af f4 48 c1 ee 02 48 89 f0 48 f7 e1 48 89 d6 31 d2 48 c1 ee 02 48 0f af 75 d0 48 89 f0 &lt;48&gt; f7 f7 41 8b 95 ac 01 00 00 48 89 c7 49 0f af d4 48 c1 ea 02
[   49.952195] RIP  [&lt;ffffffff802d39a9&gt;] get_dirty_limits+0xe9/0x2c0
[   49.952195]  RSP &lt;ffff88001de03a98&gt;
[   50.096523] ---[ end trace 008d7aa02f244d7b ]---

Signed-off-by: Andrea Righi &lt;righi.andrea@gmail.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Dave Chinner &lt;david@fromorbit.com&gt;
Cc: Christoph Lameter &lt;cl@linux-foundation.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kernel-doc: restrict syntax for private: and public:</title>
<updated>2009-05-02T22:36:10+00:00</updated>
<author>
<name>Randy Dunlap</name>
<email>randy.dunlap@oracle.com</email>
</author>
<published>2009-04-30T22:08:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=52dc5aec9fe2eb591f1490278ae767448860118b'/>
<id>52dc5aec9fe2eb591f1490278ae767448860118b</id>
<content type='text'>
scripts/kernel-doc can (incorrectly) delete struct members that are
surrounded by /* ...  */ &lt;struct members&gt; /* ...  */ if there is a /*
private: */ comment in there somewhere also.

Fix that by making the "/* private:" only allow whitespace between /* and
"private:", not anything/everything in the world.

This fixes some erroneous kernel-doc warnings that popped up while
processing include/linux/usb/composite.h.

Signed-off-by: Randy Dunlap &lt;randy.dunlap@oracle.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
scripts/kernel-doc can (incorrectly) delete struct members that are
surrounded by /* ...  */ &lt;struct members&gt; /* ...  */ if there is a /*
private: */ comment in there somewhere also.

Fix that by making the "/* private:" only allow whitespace between /* and
"private:", not anything/everything in the world.

This fixes some erroneous kernel-doc warnings that popped up while
processing include/linux/usb/composite.h.

Signed-off-by: Randy Dunlap &lt;randy.dunlap@oracle.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: close page_mkwrite races</title>
<updated>2009-05-02T22:36:09+00:00</updated>
<author>
<name>Nick Piggin</name>
<email>npiggin@suse.de</email>
</author>
<published>2009-04-30T22:08:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b827e496c893de0c0f142abfaeb8730a2fd6b37f'/>
<id>b827e496c893de0c0f142abfaeb8730a2fd6b37f</id>
<content type='text'>
Change page_mkwrite to allow implementations to return with the page
locked, and also change it's callers (in page fault paths) to hold the
lock until the page is marked dirty.  This allows the filesystem to have
full control of page dirtying events coming from the VM.

Rather than simply hold the page locked over the page_mkwrite call, we
call page_mkwrite with the page unlocked and allow callers to return with
it locked, so filesystems can avoid LOR conditions with page lock.

The problem with the current scheme is this: a filesystem that wants to
associate some metadata with a page as long as the page is dirty, will
perform this manipulation in its -&gt;page_mkwrite.  It currently then must
return with the page unlocked and may not hold any other locks (according
to existing page_mkwrite convention).

In this window, the VM could write out the page, clearing page-dirty.  The
filesystem has no good way to detect that a dirty pte is about to be
attached, so it will happily write out the page, at which point, the
filesystem may manipulate the metadata to reflect that the page is no
longer dirty.

It is not always possible to perform the required metadata manipulation in
-&gt;set_page_dirty, because that function cannot block or fail.  The
filesystem may need to allocate some data structure, for example.

And the VM cannot mark the pte dirty before page_mkwrite, because
page_mkwrite is allowed to fail, so we must not allow any window where the
page could be written to if page_mkwrite does fail.

This solution of holding the page locked over the 3 critical operations
(page_mkwrite, setting the pte dirty, and finally setting the page dirty)
closes out races nicely, preventing page cleaning for writeout being
initiated in that window.  This provides the filesystem with a strong
synchronisation against the VM here.

- Sage needs this race closed for ceph filesystem.
- Trond for NFS (http://bugzilla.kernel.org/show_bug.cgi?id=12913).
- I need it for fsblock.
- I suspect other filesystems may need it too (eg. btrfs).
- I have converted buffer.c to the new locking. Even simple block allocation
  under dirty pages might be susceptible to i_size changing under partial page
  at the end of file (we also have a buffer.c-side problem here, but it cannot
  be fixed properly without this patch).
- Other filesystems (eg. NFS, maybe btrfs) will need to change their
  page_mkwrite functions themselves.

[ This also moves page_mkwrite another step closer to fault, which should
  eventually allow page_mkwrite to be moved into -&gt;fault, and thus avoiding a
  filesystem calldown and page lock/unlock cycle in __do_fault. ]

[akpm@linux-foundation.org: fix derefs of NULL -&gt;mapping]
Cc: Sage Weil &lt;sage@newdream.net&gt;
Cc: Trond Myklebust &lt;trond.myklebust@fys.uio.no&gt;
Signed-off-by: Nick Piggin &lt;npiggin@suse.de&gt;
Cc: Valdis Kletnieks &lt;Valdis.Kletnieks@vt.edu&gt;
Cc: &lt;stable@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Change page_mkwrite to allow implementations to return with the page
locked, and also change it's callers (in page fault paths) to hold the
lock until the page is marked dirty.  This allows the filesystem to have
full control of page dirtying events coming from the VM.

Rather than simply hold the page locked over the page_mkwrite call, we
call page_mkwrite with the page unlocked and allow callers to return with
it locked, so filesystems can avoid LOR conditions with page lock.

The problem with the current scheme is this: a filesystem that wants to
associate some metadata with a page as long as the page is dirty, will
perform this manipulation in its -&gt;page_mkwrite.  It currently then must
return with the page unlocked and may not hold any other locks (according
to existing page_mkwrite convention).

In this window, the VM could write out the page, clearing page-dirty.  The
filesystem has no good way to detect that a dirty pte is about to be
attached, so it will happily write out the page, at which point, the
filesystem may manipulate the metadata to reflect that the page is no
longer dirty.

It is not always possible to perform the required metadata manipulation in
-&gt;set_page_dirty, because that function cannot block or fail.  The
filesystem may need to allocate some data structure, for example.

And the VM cannot mark the pte dirty before page_mkwrite, because
page_mkwrite is allowed to fail, so we must not allow any window where the
page could be written to if page_mkwrite does fail.

This solution of holding the page locked over the 3 critical operations
(page_mkwrite, setting the pte dirty, and finally setting the page dirty)
closes out races nicely, preventing page cleaning for writeout being
initiated in that window.  This provides the filesystem with a strong
synchronisation against the VM here.

- Sage needs this race closed for ceph filesystem.
- Trond for NFS (http://bugzilla.kernel.org/show_bug.cgi?id=12913).
- I need it for fsblock.
- I suspect other filesystems may need it too (eg. btrfs).
- I have converted buffer.c to the new locking. Even simple block allocation
  under dirty pages might be susceptible to i_size changing under partial page
  at the end of file (we also have a buffer.c-side problem here, but it cannot
  be fixed properly without this patch).
- Other filesystems (eg. NFS, maybe btrfs) will need to change their
  page_mkwrite functions themselves.

[ This also moves page_mkwrite another step closer to fault, which should
  eventually allow page_mkwrite to be moved into -&gt;fault, and thus avoiding a
  filesystem calldown and page lock/unlock cycle in __do_fault. ]

[akpm@linux-foundation.org: fix derefs of NULL -&gt;mapping]
Cc: Sage Weil &lt;sage@newdream.net&gt;
Cc: Trond Myklebust &lt;trond.myklebust@fys.uio.no&gt;
Signed-off-by: Nick Piggin &lt;npiggin@suse.de&gt;
Cc: Valdis Kletnieks &lt;Valdis.Kletnieks@vt.edu&gt;
Cc: &lt;stable@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>docs: also clean index.html</title>
<updated>2009-05-01T08:54:03+00:00</updated>
<author>
<name>Randy Dunlap</name>
<email>randy.dunlap@oracle.com</email>
</author>
<published>2009-04-18T01:28:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=64e3da109404eed27f825ee3eb1fe465ded47979'/>
<id>64e3da109404eed27f825ee3eb1fe465ded47979</id>
<content type='text'>
Missed index.html in "make cleandocs", so add it.

Signed-off-by: Randy Dunlap &lt;randy.dunlap@oracle.com&gt;
Signed-off-by: Sam Ravnborg &lt;sam@ravnborg.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Missed index.html in "make cleandocs", so add it.

Signed-off-by: Randy Dunlap &lt;randy.dunlap@oracle.com&gt;
Signed-off-by: Sam Ravnborg &lt;sam@ravnborg.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Input: document the multi-touch (MT) protocol</title>
<updated>2009-04-30T17:41:39+00:00</updated>
<author>
<name>Henrik Rydberg</name>
<email>rydberg@euromail.se</email>
</author>
<published>2009-04-28T14:49:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=eacaad01b4e67336b5b3f4db6dc15ef92c64b47d'/>
<id>eacaad01b4e67336b5b3f4db6dc15ef92c64b47d</id>
<content type='text'>
This patchs adds documentation for the multi-touch protocol to
Documentation/input/.

[randy.dunlap@oracle.com: grammar fixes]
Signed-off-by: Henrik Rydberg &lt;rydberg@euromail.se&gt;
Signed-off-by: Dmitry Torokhov &lt;dtor@mail.ru&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patchs adds documentation for the multi-touch protocol to
Documentation/input/.

[randy.dunlap@oracle.com: grammar fixes]
Signed-off-by: Henrik Rydberg &lt;rydberg@euromail.se&gt;
Signed-off-by: Dmitry Torokhov &lt;dtor@mail.ru&gt;
</pre>
</div>
</content>
</entry>
</feed>
