As pointed by Nick Piggin, ->page_mkwrite provides a way to keep a page
locked until the associated PTE is marked dirty.
Re-implement the fix by using this mechanism.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 49bbd815fd ("fb_defio:
fix for non-dirty ptes").
Although the fix provided is correct, it's been suggested to avoid the
underlying race in the same way as it is currently done in filesystems
like NFS, for maintainability.
A following patch "fb_defio: redo fix for non-dirty ptes" will provide
such an alternate fix.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Cc: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a problem observed while using fb_defio with a short delay on a
PowerPC platform.
It is possible that page_mkclean() is invoked in the deferred io work
function _before_ a PTE has been marked dirty. In this case, the page is
removed from the defio pagelist but page_mkclean() does not write-protect
the page again. The end result is that defio ignores all subsequent
writes to the page and the corresponding portions of the framebuffer never
get updated.
The fix consists in keeping track of the pages with non-dirty PTEs,
re-checking them again on the next deferred io work iteration. Note that
those pages are not passed to the defio callback as they are not written
by userspace yet.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
* 'xen/fbdev' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
xen pvfb: Inhibit VM_IO flag to be set on vmalloc-ed framebuffers.
fb-defio: Inhibit VM_IO flag to be set on vmalloc-ed framebuffers.
fb-defio: If FBINFO_VIRTFB is defined, do not set VM_IO flag.
Fix toogle whether xenbus driver should be built as module or part of kernel.
fix some typos and punctuation in comments
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Most users (except sh_mobile_lcdcfb.c) get their framebuffer from
vmalloc. Setting VM_IO is not necessary as the memory obtained
from vmalloc is System RAM type and is not susceptible to PCI memory
constraints.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Jaya Kumar <jayakumar.lkml@gmail.com>
* mark struct vm_area_struct::vm_ops as const
* mark vm_ops in AGP code
But leave TTM code alone, something is fishy there with global vm_ops
being used.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <npiggin@suse.de>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Extend the deferred io code from only supporting vmalloc()ed frame
buffer memory to support both vmalloc()ed and physically contiguous
frame buffer memory.
The sh_mobile_lcdcfb hardware does not support scatter gather so
we need physically contiguous memory to back our frame buffer.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Make sure the mmap callback is set to NULL in the deferred io
cleanup function. This way we can enable and disable deferred
io on the fly.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
If CONFIG_FB_DEFERRED_IO is set, but there are framebuffers
registered that does not make use of deferred io, then fsync()
on those framebuffers will result in a crash. Fix that.
This is needed for sh_mobile_lcdcfb since we always enable
deferred io at compile time but we may disable deferred io
for some types of hardware configurations.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Fixes kernel BUG at lib/radix-tree.c:473.
Previously the handler was incidentally provided by tmpfs but this was
removed with:
commit 14fcc23fdc
Author: Hugh Dickins <hugh@veritas.com>
Date: Mon Jul 28 15:46:19 2008 -0700
tmpfs: fix kernel BUG in shmem_delete_inode
relying on this behaviour was incorrect in any case and the BUG also
appeared when the device node was on an ext3 filesystem.
v2: override a_ops at open() time rather than mmap() time to minimise
races per AKPM's concerns.
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Cc: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Johannes Weiner <hannes@saeurebad.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Kel Modderman <kel@otaku42.de>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: <stable@kernel.org> [14fcc23fd is in 2.6.25.14 and 2.6.26.1]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is a bugfix for how defio handles multiple processes manipulating
the same framebuffer.
Thanks to Bernard Blackham for identifying this bug.
It occurs when two applications mmap the same framebuffer and concurrently
write to the same page. Normally, this doesn't occur since only a single
process mmaps the framebuffer. The symptom of the bug is that the mapping
applications will hang. The cause is that defio incorrectly tries to add the
same page twice to the pagelist. The solution I have is to walk the pagelist
and check for a duplicate before adding. Since I needed to walk the pagelist,
I now also keep the pagelist in sorted order.
Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: Bernard Blackham <bernard@largestprime.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement support for the E-Ink Metronome controller. It provides an mmapable
interface to the controller using defio support. It was tested with a gumstix
pxa255 with Vizplex media using Xfbdev and various X clients such as xeyes,
xpdf, xloadimage.
This patch also fixes the following bug: Defio would cause a hang on write
access to the framebuffer as the page fault would be called ad-infinitum. It
fixes fb_defio by setting the mapping to be used by page_mkclean.
Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert fb defio from nopage to fault.
Switch from OOM to SIGBUS if the resource is not available.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch replaces <asm/uaccess.h> with <linux/uaccess.h> after the
checkpatch.pl hint. The include of <asm/uaccess.h> is removed if the driver
does not use it.
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kill the following in fb_defio.c:
drivers/video/fb_defio.c:40:43: warning: incorrect type in argument 1 (different address spaces)
drivers/video/fb_defio.c:40:43: expected void *addr
drivers/video/fb_defio.c:40:43: got char [noderef] *screen_base<asn:2>
The framebuffer memory of these types of devices are allocated from system
RAM.
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are cases when we do not want to wait on the delay for automatically
updating the "real" framebuffer, this implements a simple ->fsync() hook
for explicitly flushing the deferred I/O work. The ->page_mkwrite()
handler will rearm the work queue normally.
(akpm: nuke unneeded ifdefs, forward-delcare struct dentry)
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Cc: Jaya Kumar <jayakumar.lkml@gmail.com>
Acked-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This implements deferred IO support in fbdev. Deferred IO is a way to delay
and repurpose IO. This implementation is done using mm's page_mkwrite and
page_mkclean hooks in order to detect, delay and then rewrite IO. This
functionality is used by hecubafb.
[adaplas]
This is useful for graphics hardware with no directly addressable/mappable
framebuffer. Implementing this will allow the "framebuffer" to be accesible
from user space via mmap().
Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
