linux-toradex.git/Documentation, branch v2.6.27.50

.gitignore updates

2010-08-06T17:53:05+00:00

commit c17dad6905fc82d8f523399e5c3f014e81d61df6 upstream.

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

doc: add the documentation for mpol=local

2010-04-01T22:52:28+00:00

commit 5574169613b40b85d6f4c67208fa4846b897a0a1 upstream.

commit 3f226aa1c (mempolicy: support mpol=local tmpfs mount option) added
new mpol=local mount option.  but it didn't add a documentation.

This patch does it.

Signed-off-by: KOSAKI Motohiro 
Cc: Ravikiran Thirumalai 
Cc: Christoph Lameter 
Cc: Mel Gorman 
Acked-by: Lee Schermerhorn 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ext4: Add fine print for the 32000 subdirectory limit

2009-06-12T03:01:46+00:00

(cherry picked from commit 722bde6875bfb49a0c84e5601eb82dd7ac02d27c)

Some poeple are reading the ext4 feature list too literally and create
dubious test cases involving very long filenames and 1k blocksize and
then complain when they run into an htree-imposed limit.  So add fine
print to the "fix 32000 subdirectory limit" ext4 feature.

Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

mm: close page_mkwrite races

2009-05-20T05:20:09+00:00

commit b827e496c893de0c0f142abfaeb8730a2fd6b37f upstream

mm: close page_mkwrite races

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 ->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
->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 ->fault, and thus avoiding a
  filesystem calldown and page lock/unlock cycle in __do_fault. ]

[akpm@linux-foundation.org: fix derefs of NULL ->mapping]
Cc: Sage Weil 
Cc: Trond Myklebust 
Signed-off-by: Nick Piggin 
Cc: Valdis Kletnieks 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm: page_mkwrite change prototype to match fault

2009-05-20T05:20:09+00:00

commit c2ec175c39f62949438354f603f4aa170846aabb upstream


mm: page_mkwrite change prototype to match fault

Change the page_mkwrite prototype to take a struct vm_fault, and return
VM_FAULT_xxx flags.  There should be no functional change.

This makes it possible to return much more detailed error information to
the VM (and also can provide more information eg.  virtual_address to the
driver, which might be important in some special cases).

This is required for a subsequent fix.  And will also make it easier to
merge page_mkwrite() with fault() in future.

Signed-off-by: Nick Piggin 
Cc: Chris Mason 
Cc: Trond Myklebust 
Cc: Miklos Szeredi 
Cc: Steven Whitehouse 
Cc: Mark Fasheh 
Cc: Joel Becker 
Cc: Artem Bityutskiy 
Cc: Felix Blyakher 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

PCI: return error on failure to read PCI ROMs

2009-02-12T17:31:10+00:00

commit 97c44836cdec1ea713a15d84098a1a908157e68f upstream.

This patch makes the ROM reading code return an error to user space if
the size of the ROM read is equal to 0.

The patch also emits a warnings if the contents of the ROM are invalid,
and documents the effects of the "enable" file on ROM reading.

Signed-off-by: Timothy S. Nelson 
Acked-by: Alex Villacis-Lasso 
Signed-off-by: Jesse Barnes 
Signed-off-by: Greg Kroah-Hartman

ALSA: hda - make laptop-eapd model back for AD1986A

2009-01-25T00:36:21+00:00

commit 1725b82a6e2721612a3572d0336f51f1f1c3cf54 upstream.

The changes specific for Samsung laptops seem unapplicable to other
hardware models like ASUS.  The mic inputs are lost on such hardware
by the change 5d5d5f43f1b835c375de9bd270cce030d16e2871.

This patch adds back the old laptop-eapd model, and create a new
model "samsung" for the new one specific to Samsung laptops with
automatic mic selection feature.

Reference: kernel bugzilla #12070
	http://bugzilla.kernel.org/show_bug.cgi?id=12070

Signed-off-by: Takashi Iwai 
Cc: Daniel Drake 
Signed-off-by: Greg Kroah-Hartman

AMD IOMMU: enable device isolation per default

2008-12-18T17:13:34+00:00

commit 3ce1f93c6d53c3f91c3846cf66b018276c8ac2e7 upstream.

Impact: makes device isolation the default for AMD IOMMU

Some device drivers showed double-free bugs of DMA memory while testing
them with AMD IOMMU. If all devices share the same protection domain
this can lead to data corruption and data loss. Prevent this by putting
each device into its own protection domain per default.

Signed-off-by: Joerg Roedel 
Signed-off-by: Greg Kroah-Hartman

epoll: introduce resource usage limits

2008-12-05T18:55:12+00:00

commit 7ef9964e6d1b911b78709f144000aacadd0ebc21 upstream.

It has been thought that the per-user file descriptors limit would also
limit the resources that a normal user can request via the epoll
interface.  Vegard Nossum reported a very simple program (a modified
version attached) that can make a normal user to request a pretty large
amount of kernel memory, well within the its maximum number of fds.  To
solve such problem, default limits are now imposed, and /proc based
configuration has been introduced.  A new directory has been created,
named /proc/sys/fs/epoll/ and inside there, there are two configuration
points:

  max_user_instances = Maximum number of devices - per user

  max_user_watches   = Maximum number of "watched" fds - per user

The current default for "max_user_watches" limits the memory used by epoll
to store "watches", to 1/32 of the amount of the low RAM.  As example, a
256MB 32bit machine, will have "max_user_watches" set to roughly 90000.
That should be enough to not break existing heavy epoll users.  The
default value for "max_user_instances" is set to 128, that should be
enough too.

This also changes the userspace, because a new error code can now come out
from EPOLL_CTL_ADD (-ENOSPC).  The EMFILE from epoll_create() was already
listed, so that should be ok.

[akpm@linux-foundation.org: use get_current_user()]
Signed-off-by: Davide Libenzi 
Cc: Michael Kerrisk 
Cc: Cyrill Gorcunov 
Reported-by: Vegard Nossum 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

cciss: new hardware support

2008-11-13T17:55:57+00:00

commit 77ca7286d10b798e4907af941f29672bf484db77 upstream

cciss: new hardware support

Add support for 2 new SAS/SATA controllers.

Signed-off-by: Mike Miller 
Cc: Jens Axboe 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman