<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/video/fbdev, branch v4.4.80</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>video: fbdev: cobalt_lcdfb: Handle return NULL error from devm_ioremap</title>
<updated>2017-08-07T02:19:46+00:00</updated>
<author>
<name>Arvind Yadav</name>
<email>arvind.yadav.cs@gmail.com</email>
</author>
<published>2016-12-13T08:20:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=93794239c6b93622e722434bfb78b7780e6a790e'/>
<id>93794239c6b93622e722434bfb78b7780e6a790e</id>
<content type='text'>
[ Upstream commit 4dcd19bfabaee8f9f4bcf203afba09b98ccbaf76 ]

Here, If devm_ioremap will fail. It will return NULL.
Kernel can run into a NULL-pointer dereference.
This error check will avoid NULL pointer dereference.

Signed-off-by: Arvind Yadav &lt;arvind.yadav.cs@gmail.com&gt;
Acked-by: Yoichi Yuasa &lt;yuasa@linux-mips.org&gt;
Signed-off-by: Bartlomiej Zolnierkiewicz &lt;b.zolnierkie@samsung.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 4dcd19bfabaee8f9f4bcf203afba09b98ccbaf76 ]

Here, If devm_ioremap will fail. It will return NULL.
Kernel can run into a NULL-pointer dereference.
This error check will avoid NULL pointer dereference.

Signed-off-by: Arvind Yadav &lt;arvind.yadav.cs@gmail.com&gt;
Acked-by: Yoichi Yuasa &lt;yuasa@linux-mips.org&gt;
Signed-off-by: Bartlomiej Zolnierkiewicz &lt;b.zolnierkie@samsung.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xen, fbfront: fix connecting to backend</title>
<updated>2017-04-21T07:30:06+00:00</updated>
<author>
<name>Juergen Gross</name>
<email>jgross@suse.com</email>
</author>
<published>2017-04-07T15:28:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6058cf9929d9bbeb4a781c51e91866716cb5277f'/>
<id>6058cf9929d9bbeb4a781c51e91866716cb5277f</id>
<content type='text'>
commit 9121b15b5628b38b4695282dc18c553440e0f79b upstream.

Connecting to the backend isn't working reliably in xen-fbfront: in
case XenbusStateInitWait of the backend has been missed the backend
transition to XenbusStateConnected will trigger the connected state
only without doing the actions required when the backend has
connected.

Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Reviewed-by: Boris Ostrovsky &lt;boris.ostrovsky@oracle.com&gt;
Signed-off-by: Bartlomiej Zolnierkiewicz &lt;b.zolnierkie@samsung.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 9121b15b5628b38b4695282dc18c553440e0f79b upstream.

Connecting to the backend isn't working reliably in xen-fbfront: in
case XenbusStateInitWait of the backend has been missed the backend
transition to XenbusStateConnected will trigger the connected state
only without doing the actions required when the backend has
connected.

Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Reviewed-by: Boris Ostrovsky &lt;boris.ostrovsky@oracle.com&gt;
Signed-off-by: Bartlomiej Zolnierkiewicz &lt;b.zolnierkie@samsung.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>fbdev: color map copying bounds checking</title>
<updated>2017-02-01T07:30:52+00:00</updated>
<author>
<name>Kees Cook</name>
<email>keescook@chromium.org</email>
</author>
<published>2017-01-24T23:18:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=63db7c91a3c0ebe0e291feea53e4c63391db9465'/>
<id>63db7c91a3c0ebe0e291feea53e4c63391db9465</id>
<content type='text'>
commit 2dc705a9930b4806250fbf5a76e55266e59389f2 upstream.

Copying color maps to userspace doesn't check the value of to-&gt;start,
which will cause kernel heap buffer OOB read due to signedness wraps.

CVE-2016-8405

Link: http://lkml.kernel.org/r/20170105224249.GA50925@beast
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
Reported-by: Peter Pi (@heisecode) of Trend Micro
Cc: Min Chong &lt;mchong@google.com&gt;
Cc: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Cc: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
Cc: Bartlomiej Zolnierkiewicz &lt;b.zolnierkie@samsung.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 2dc705a9930b4806250fbf5a76e55266e59389f2 upstream.

Copying color maps to userspace doesn't check the value of to-&gt;start,
which will cause kernel heap buffer OOB read due to signedness wraps.

CVE-2016-8405

Link: http://lkml.kernel.org/r/20170105224249.GA50925@beast
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
Reported-by: Peter Pi (@heisecode) of Trend Micro
Cc: Min Chong &lt;mchong@google.com&gt;
Cc: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Cc: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
Cc: Bartlomiej Zolnierkiewicz &lt;b.zolnierkie@samsung.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>fbdev/efifb: Fix 16 color palette entry calculation</title>
<updated>2016-10-28T07:01:29+00:00</updated>
<author>
<name>Max Staudt</name>
<email>mstaudt@suse.de</email>
</author>
<published>2016-06-13T17:15:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2add76a428bc6b9e4506d9caa4f8ced9b8bdcb70'/>
<id>2add76a428bc6b9e4506d9caa4f8ced9b8bdcb70</id>
<content type='text'>
commit d50b3f43db739f03fcf8c0a00664b3d2fed0496e upstream.

When using efifb with a 16-bit (5:6:5) visual, fbcon's text is rendered
in the wrong colors - e.g. text gray (#aaaaaa) is rendered as green
(#50bc50) and neighboring pixels have slightly different values
(such as #50bc78).

The reason is that fbcon loads its 16 color palette through
efifb_setcolreg(), which in turn calculates a 32-bit value to write
into memory for each palette index.
Until now, this code could only handle 8-bit visuals and didn't mask
overlapping values when ORing them.

With this patch, fbcon displays the correct colors when a qemu VM is
booted in 16-bit mode (in GRUB: "set gfxpayload=800x600x16").

Fixes: 7c83172b98e5 ("x86_64 EFI boot support: EFI frame buffer driver")  # v2.6.24+
Signed-off-by: Max Staudt &lt;mstaudt@suse.de&gt;
Acked-By: Peter Jones &lt;pjones@redhat.com&gt;
Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit d50b3f43db739f03fcf8c0a00664b3d2fed0496e upstream.

When using efifb with a 16-bit (5:6:5) visual, fbcon's text is rendered
in the wrong colors - e.g. text gray (#aaaaaa) is rendered as green
(#50bc50) and neighboring pixels have slightly different values
(such as #50bc78).

The reason is that fbcon loads its 16 color palette through
efifb_setcolreg(), which in turn calculates a 32-bit value to write
into memory for each palette index.
Until now, this code could only handle 8-bit visuals and didn't mask
overlapping values when ORing them.

With this patch, fbcon displays the correct colors when a qemu VM is
booted in 16-bit mode (in GRUB: "set gfxpayload=800x600x16").

Fixes: 7c83172b98e5 ("x86_64 EFI boot support: EFI frame buffer driver")  # v2.6.24+
Signed-off-by: Max Staudt &lt;mstaudt@suse.de&gt;
Acked-By: Peter Jones &lt;pjones@redhat.com&gt;
Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>fbdev: da8xx-fb: fix videomodes of lcd panels</title>
<updated>2016-05-04T21:48:51+00:00</updated>
<author>
<name>Sushaanth Srirangapathi</name>
<email>sushaanth.s@ti.com</email>
</author>
<published>2016-02-29T13:12:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0658e8c5e8cc02f12f9ae3df1f3b87ee7283bb24'/>
<id>0658e8c5e8cc02f12f9ae3df1f3b87ee7283bb24</id>
<content type='text'>
commit 713fced8d10fa1c759c8fb6bf9aaa681bae68cad upstream.

Commit 028cd86b794f4a ("video: da8xx-fb: fix the polarities of the
hsync/vsync pulse") fixes polarities of HSYNC/VSYNC pulse but
forgot to update known_lcd_panels[] which had sync values
according to old logic. This breaks LCD at least on DA850 EVM.

This patch fixes this issue and I have tested this for panel
"Sharp_LK043T1DG01" using DA850 EVM board.

Fixes: 028cd86b794f4a ("video: da8xx-fb: fix the polarities of the hsync/vsync pulse")
Signed-off-by: Sushaanth Srirangapathi &lt;sushaanth.s@ti.com&gt;
Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 713fced8d10fa1c759c8fb6bf9aaa681bae68cad upstream.

Commit 028cd86b794f4a ("video: da8xx-fb: fix the polarities of the
hsync/vsync pulse") fixes polarities of HSYNC/VSYNC pulse but
forgot to update known_lcd_panels[] which had sync values
according to old logic. This breaks LCD at least on DA850 EVM.

This patch fixes this issue and I have tested this for panel
"Sharp_LK043T1DG01" using DA850 EVM board.

Fixes: 028cd86b794f4a ("video: da8xx-fb: fix the polarities of the hsync/vsync pulse")
Signed-off-by: Sushaanth Srirangapathi &lt;sushaanth.s@ti.com&gt;
Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xen kconfig: don't "select INPUT_XEN_KBDDEV_FRONTEND"</title>
<updated>2016-05-04T21:48:45+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2016-02-16T15:03:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4e8d89e8bb8828faf3c955fe9a50e1ae54918326'/>
<id>4e8d89e8bb8828faf3c955fe9a50e1ae54918326</id>
<content type='text'>
commit 13aa38e291bdd4e4018f40dd2f75e464814dcbf3 upstream.

The Xen framebuffer driver selects the xen keyboard driver, so the latter
will be built-in if XEN_FBDEV_FRONTEND=y. However, when CONFIG_INPUT
is a loadable module, this configuration cannot work. On mainline kernels,
the symbol will be enabled but not used, while in combination with
a patch I have to detect such useless configurations, we get the
expected link failure:

drivers/input/built-in.o: In function `xenkbd_remove':
xen-kbdfront.c:(.text+0x2f0): undefined reference to `input_unregister_device'
xen-kbdfront.c:(.text+0x30e): undefined reference to `input_unregister_device'

This removes the extra "select", as it just causes more trouble than
it helps. In theory, some defconfig file might break if it has
XEN_FBDEV_FRONTEND in it but not INPUT_XEN_KBDDEV_FRONTEND. The Kconfig
fragment we ship in the kernel (kernel/configs/xen.config) however
already enables both, and anyone using an old .config file would
keep having both enabled.

Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Suggested-by: David Vrabel &lt;david.vrabel@citrix.com&gt;
Fixes: 36c1132e34bd ("xen kconfig: fix select INPUT_XEN_KBDDEV_FRONTEND")
Acked-by: Stefano Stabellini &lt;stefano.stabellini@eu.citrix.com&gt;
Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 13aa38e291bdd4e4018f40dd2f75e464814dcbf3 upstream.

The Xen framebuffer driver selects the xen keyboard driver, so the latter
will be built-in if XEN_FBDEV_FRONTEND=y. However, when CONFIG_INPUT
is a loadable module, this configuration cannot work. On mainline kernels,
the symbol will be enabled but not used, while in combination with
a patch I have to detect such useless configurations, we get the
expected link failure:

drivers/input/built-in.o: In function `xenkbd_remove':
xen-kbdfront.c:(.text+0x2f0): undefined reference to `input_unregister_device'
xen-kbdfront.c:(.text+0x30e): undefined reference to `input_unregister_device'

This removes the extra "select", as it just causes more trouble than
it helps. In theory, some defconfig file might break if it has
XEN_FBDEV_FRONTEND in it but not INPUT_XEN_KBDDEV_FRONTEND. The Kconfig
fragment we ship in the kernel (kernel/configs/xen.config) however
already enables both, and anyone using an old .config file would
keep having both enabled.

Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Suggested-by: David Vrabel &lt;david.vrabel@citrix.com&gt;
Fixes: 36c1132e34bd ("xen kconfig: fix select INPUT_XEN_KBDDEV_FRONTEND")
Acked-by: Stefano Stabellini &lt;stefano.stabellini@eu.citrix.com&gt;
Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>OMAPDSS: fix timings for VENC to match what omapdrm expects</title>
<updated>2015-12-09T10:57:13+00:00</updated>
<author>
<name>H. Nikolaus Schaller</name>
<email>hns@goldelico.com</email>
</author>
<published>2015-11-13T10:29:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a54c1ddbe3bc07eadb0096c4abe6224e7f363b66'/>
<id>a54c1ddbe3bc07eadb0096c4abe6224e7f363b66</id>
<content type='text'>
Otherwise check_timings fails and we get a "has no modes" message
from xrandr.

This fix makes the venc assume PAL and NTSC timings that match the
timings synthetized by copy_timings_drm_to_omap() from omapdrm
mode settings so that check_timings() succeeds.

Tested on: BeagleBoard XM, GTA04 and OpenPandora

Signed-off-by: H. Nikolaus Schaller &lt;hns@goldelico.com&gt;
Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Otherwise check_timings fails and we get a "has no modes" message
from xrandr.

This fix makes the venc assume PAL and NTSC timings that match the
timings synthetized by copy_timings_drm_to_omap() from omapdrm
mode settings so that check_timings() succeeds.

Tested on: BeagleBoard XM, GTA04 and OpenPandora

Signed-off-by: H. Nikolaus Schaller &lt;hns@goldelico.com&gt;
Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>video: fbdev: fsl: Fix kernel crash when diu_ops is not implemented</title>
<updated>2015-12-09T10:57:06+00:00</updated>
<author>
<name>Wang Dongsheng</name>
<email>dongsheng.wang@freescale.com</email>
</author>
<published>2015-12-03T01:54:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=acfc1cc13fe5bc6d7a10afa624f1e560850ddad3'/>
<id>acfc1cc13fe5bc6d7a10afa624f1e560850ddad3</id>
<content type='text'>
If diu_ops is not implemented on platform, kernel will access a NULL
pointer. We need to check this pointer in DIU initialization.

Signed-off-by: Wang Dongsheng &lt;dongsheng.wang@freescale.com&gt;
Acked-by: Timur Tabi &lt;timur@tabi.org&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If diu_ops is not implemented on platform, kernel will access a NULL
pointer. We need to check this pointer in DIU initialization.

Signed-off-by: Wang Dongsheng &lt;dongsheng.wang@freescale.com&gt;
Acked-by: Timur Tabi &lt;timur@tabi.org&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Tomi Valkeinen &lt;tomi.valkeinen@ti.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'fbdev-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux</title>
<updated>2015-11-10T18:00:09+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-11-10T18:00:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3b13866869b8407497d20a916450594e117583e6'/>
<id>3b13866869b8407497d20a916450594e117583e6</id>
<content type='text'>
Pull fbdev updates from Tomi Valkeinen:
 - omap: fix hdmi audio configuration issue
 - ssd1307fb: add ssd1309 support
 - tridentfb: support DDC
 - gxt4500: enable support for non-PPC platforms

* tag 'fbdev-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux:
  radeonfb: Deinline large functions
  gxt4500: enable panning
  gxt4500: Use arch_phys_wc_* for framebuffer
  gxt4500: fix color order
  gxt4500: fix 16bpp 565 mode
  gxt4500: enable on non-PPC architectures
  tridentfb: Add DDC support
  fb_ddc: Allow I2C adapters without SCL read capability
  fbdev: ssd1307fb: add ssd1309 support
  fbdev: ssd1307fb: alphabetize headers
  video/omap: remove invalid check
  OMAPDSS: hdmi: Reconfigure and restart audio when display is enabled
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull fbdev updates from Tomi Valkeinen:
 - omap: fix hdmi audio configuration issue
 - ssd1307fb: add ssd1309 support
 - tridentfb: support DDC
 - gxt4500: enable support for non-PPC platforms

* tag 'fbdev-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux:
  radeonfb: Deinline large functions
  gxt4500: enable panning
  gxt4500: Use arch_phys_wc_* for framebuffer
  gxt4500: fix color order
  gxt4500: fix 16bpp 565 mode
  gxt4500: enable on non-PPC architectures
  tridentfb: Add DDC support
  fb_ddc: Allow I2C adapters without SCL read capability
  fbdev: ssd1307fb: add ssd1309 support
  fbdev: ssd1307fb: alphabetize headers
  video/omap: remove invalid check
  OMAPDSS: hdmi: Reconfigure and restart audio when display is enabled
</pre>
</div>
</content>
</entry>
<entry>
<title>mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd</title>
<updated>2015-11-07T01:50:42+00:00</updated>
<author>
<name>Mel Gorman</name>
<email>mgorman@techsingularity.net</email>
</author>
<published>2015-11-07T00:28:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d0164adc89f6bb374d304ffcc375c6d2652fe67d'/>
<id>d0164adc89f6bb374d304ffcc375c6d2652fe67d</id>
<content type='text'>
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts.  They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve".  __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".

Over time, callers had a requirement to not block when fallback options
were available.  Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.

This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative.  High priority users continue to use
__GFP_HIGH.  __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim.  __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim.  __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.

This patch then converts a number of sites

o __GFP_ATOMIC is used by callers that are high priority and have memory
  pools for those requests. GFP_ATOMIC uses this flag.

o Callers that have a limited mempool to guarantee forward progress clear
  __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
  into this category where kswapd will still be woken but atomic reserves
  are not used as there is a one-entry mempool to guarantee progress.

o Callers that are checking if they are non-blocking should use the
  helper gfpflags_allow_blocking() where possible. This is because
  checking for __GFP_WAIT as was done historically now can trigger false
  positives. Some exceptions like dm-crypt.c exist where the code intent
  is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
  flag manipulations.

o Callers that built their own GFP flags instead of starting with GFP_KERNEL
  and friends now also need to specify __GFP_KSWAPD_RECLAIM.

The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.

The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL.  They may
now wish to specify __GFP_KSWAPD_RECLAIM.  It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.

Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Christoph Lameter &lt;cl@linux.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Vitaly Wool &lt;vitalywool@gmail.com&gt;
Cc: Rik van Riel &lt;riel@redhat.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>
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts.  They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve".  __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".

Over time, callers had a requirement to not block when fallback options
were available.  Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.

This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative.  High priority users continue to use
__GFP_HIGH.  __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim.  __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim.  __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.

This patch then converts a number of sites

o __GFP_ATOMIC is used by callers that are high priority and have memory
  pools for those requests. GFP_ATOMIC uses this flag.

o Callers that have a limited mempool to guarantee forward progress clear
  __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
  into this category where kswapd will still be woken but atomic reserves
  are not used as there is a one-entry mempool to guarantee progress.

o Callers that are checking if they are non-blocking should use the
  helper gfpflags_allow_blocking() where possible. This is because
  checking for __GFP_WAIT as was done historically now can trigger false
  positives. Some exceptions like dm-crypt.c exist where the code intent
  is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
  flag manipulations.

o Callers that built their own GFP flags instead of starting with GFP_KERNEL
  and friends now also need to specify __GFP_KSWAPD_RECLAIM.

The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.

The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL.  They may
now wish to specify __GFP_KSWAPD_RECLAIM.  It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.

Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Christoph Lameter &lt;cl@linux.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Vitaly Wool &lt;vitalywool@gmail.com&gt;
Cc: Rik van Riel &lt;riel@redhat.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>
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