linux-toradex.git/arch/powerpc/platforms, branch v4.14 Linux kernel for Apalis and Colibri modules License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02T10:10:55+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2017-11-01T14:07:57+00:00 b24413180f5600bcb3bb70fbed5cf186b60864bd Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
powerpc/powernv: Increase memory block size to 1GB on radix 2017-10-06T04:50:45+00:00 Anton Blanchard anton@samba.org 2017-09-07T05:05:51+00:00 53ecde0b9126ff140abe3aefd7f0ec64d6fa36b0 Memory hot unplug on PowerNV radix hosts is broken. Our memory block size is 256MB but since we map the linear region with very large pages, each pte we tear down maps 1GB. A hot unplug of one 256MB memory block results in 768MB of memory getting unintentionally unmapped. At this point we are likely to oops. Fix this by increasing our memory block size to 1GB on PowerNV radix hosts. Fixes: 4b5d62ca17a1 ("powerpc/mm: add radix__remove_section_mapping()") Cc: stable@vger.kernel.org # v4.11+ Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> 
Memory hot unplug on PowerNV radix hosts is broken. Our memory block
size is 256MB but since we map the linear region with very large
pages, each pte we tear down maps 1GB.

A hot unplug of one 256MB memory block results in 768MB of memory
getting unintentionally unmapped. At this point we are likely to oops.

Fix this by increasing our memory block size to 1GB on PowerNV radix
hosts.

Fixes: 4b5d62ca17a1 ("powerpc/mm: add radix__remove_section_mapping()")
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
powerpc/pseries: Fix parent_dn reference leak in add_dt_node() 2017-09-21T09:33:16+00:00 Tyrel Datwyler tyreld@linux.vnet.ibm.com 2017-09-20T21:02:52+00:00 b537ca6fede69a281dc524983e5e633d79a10a08 A reference to the parent device node is held by add_dt_node() for the node to be added. If the call to dlpar_configure_connector() fails add_dt_node() returns ENOENT and that reference is not freed. Add a call to of_node_put(parent_dn) prior to bailing out after a failed dlpar_configure_connector() call. Fixes: 8d5ff320766f ("powerpc/pseries: Make dlpar_configure_connector parent node aware") Cc: stable@vger.kernel.org # v3.12+ Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> 
A reference to the parent device node is held by add_dt_node() for the
node to be added. If the call to dlpar_configure_connector() fails
add_dt_node() returns ENOENT and that reference is not freed.

Add a call to of_node_put(parent_dn) prior to bailing out after a
failed dlpar_configure_connector() call.

Fixes: 8d5ff320766f ("powerpc/pseries: Make dlpar_configure_connector parent node aware")
Cc: stable@vger.kernel.org # v3.12+
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
powerpc/pseries: Fix "OF: ERROR: Bad of_node_put() on /cpus" during DLPAR 2017-09-21T09:30:53+00:00 Tyrel Datwyler tyreld@linux.vnet.ibm.com 2017-09-20T21:02:51+00:00 087ff6a5ae3052bb2835e191094b793789cb8817 Commit 215ee763f8cb ("powerpc: pseries: remove dlpar_attach_node dependency on full path") reworked dlpar_attach_node() to no longer look up the parent node "/cpus", but instead to have the parent node passed by the caller in the function parameter list. As a result dlpar_attach_node() is no longer responsible for freeing the reference to the parent node. However, commit 215ee763f8cb failed to remove the of_node_put(parent) call in dlpar_attach_node(), or to take into account that the reference to the parent in the caller dlpar_cpu_add() needs to be held until after dlpar_attach_node() returns. As a result doing repeated cpu add/remove dlpar operations will eventually result in the following error: OF: ERROR: Bad of_node_put() on /cpus CPU: 0 PID: 10896 Comm: drmgr Not tainted 4.13.0-autotest #1 Call Trace: dump_stack+0x15c/0x1f8 (unreliable) of_node_release+0x1a4/0x1c0 kobject_put+0x1a8/0x310 kobject_del+0xbc/0xf0 __of_detach_node_sysfs+0x144/0x210 of_detach_node+0xf0/0x180 dlpar_detach_node+0xc4/0x120 dlpar_cpu_remove+0x280/0x560 dlpar_cpu_release+0xbc/0x1b0 arch_cpu_release+0x6c/0xb0 cpu_release_store+0xa0/0x100 dev_attr_store+0x68/0xa0 sysfs_kf_write+0xa8/0xf0 kernfs_fop_write+0x2cc/0x400 __vfs_write+0x5c/0x340 vfs_write+0x1a8/0x3d0 SyS_write+0xa8/0x1a0 system_call+0x58/0x6c Fix the issue by removing the of_node_put(parent) call from dlpar_attach_node(), and ensuring that the reference to the parent node is properly held and released by the caller dlpar_cpu_add(). Fixes: 215ee763f8cb ("powerpc: pseries: remove dlpar_attach_node dependency on full path") Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com> [mpe: Add a comment in the code and frob the change log slightly] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> 
Commit 215ee763f8cb ("powerpc: pseries: remove dlpar_attach_node
dependency on full path") reworked dlpar_attach_node() to no longer
look up the parent node "/cpus", but instead to have the parent node
passed by the caller in the function parameter list.

As a result dlpar_attach_node() is no longer responsible for freeing
the reference to the parent node. However, commit 215ee763f8cb failed
to remove the of_node_put(parent) call in dlpar_attach_node(), or to
take into account that the reference to the parent in the caller
dlpar_cpu_add() needs to be held until after dlpar_attach_node()
returns.

As a result doing repeated cpu add/remove dlpar operations will
eventually result in the following error:

  OF: ERROR: Bad of_node_put() on /cpus
  CPU: 0 PID: 10896 Comm: drmgr Not tainted 4.13.0-autotest #1
  Call Trace:
   dump_stack+0x15c/0x1f8 (unreliable)
   of_node_release+0x1a4/0x1c0
   kobject_put+0x1a8/0x310
   kobject_del+0xbc/0xf0
   __of_detach_node_sysfs+0x144/0x210
   of_detach_node+0xf0/0x180
   dlpar_detach_node+0xc4/0x120
   dlpar_cpu_remove+0x280/0x560
   dlpar_cpu_release+0xbc/0x1b0
   arch_cpu_release+0x6c/0xb0
   cpu_release_store+0xa0/0x100
   dev_attr_store+0x68/0xa0
   sysfs_kf_write+0xa8/0xf0
   kernfs_fop_write+0x2cc/0x400
   __vfs_write+0x5c/0x340
   vfs_write+0x1a8/0x3d0
   SyS_write+0xa8/0x1a0
   system_call+0x58/0x6c

Fix the issue by removing the of_node_put(parent) call from
dlpar_attach_node(), and ensuring that the reference to the parent
node is properly held and released by the caller dlpar_cpu_add().

Fixes: 215ee763f8cb ("powerpc: pseries: remove dlpar_attach_node dependency on full path")
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
[mpe: Add a comment in the code and frob the change log slightly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
powerpc/powernv: Clear LPCR[PECE1] via stop-api only for deep state offline 2017-09-20T03:30:09+00:00 Gautham R. Shenoy ego@linux.vnet.ibm.com 2017-08-31T11:47:41+00:00 5d298baa41883fc421acfd932799c0f4177249ae Commit 24be85a23d1f ("powerpc/powernv: Clear PECE1 in LPCR via stop-api only on Hotplug") clears the PECE1 bit of the LPCR via stop-api during CPU-Hotplug to prevent wakeup due to a decrementer on an offlined CPU which is in a deep stop state. In the case where the stop-api support is found to be lacking, the commit 785a12afdb4a ("powerpc/powernv/idle: Disable LOSE_FULL_CONTEXT states when stop-api fails") disables deep states that lose hypervisor context. Thus in this case, the offlined CPU will be put to some shallow idle state. However, we currently unconditionally clear the PECE1 in LPCR via stop-api during CPU-Hotplug even when deep states are disabled due to stop-api failure. Fix this by clearing PECE1 of LPCR via stop-api during CPU-Hotplug *only* when the offlined CPU will be put to a deep state that loses hypervisor context. Fixes: 24be85a23d1f ("powerpc/powernv: Clear PECE1 in LPCR via stop-api only on Hotplug") Reported-by: Pavithra Prakash <pavirampu@linux.vnet.ibm.com> Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Tested-by: Pavithra Prakash <pavrampu@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> 
Commit 24be85a23d1f ("powerpc/powernv: Clear PECE1 in LPCR via
stop-api only on Hotplug") clears the PECE1 bit of the LPCR via
stop-api during CPU-Hotplug to prevent wakeup due to a decrementer on
an offlined CPU which is in a deep stop state.

In the case where the stop-api support is found to be lacking, the
commit 785a12afdb4a ("powerpc/powernv/idle: Disable LOSE_FULL_CONTEXT
states when stop-api fails") disables deep states that lose hypervisor
context. Thus in this case, the offlined CPU will be put to some
shallow idle state.

However, we currently unconditionally clear the PECE1 in LPCR via
stop-api during CPU-Hotplug even when deep states are disabled due to
stop-api failure.

Fix this by clearing PECE1 of LPCR via stop-api during CPU-Hotplug
*only* when the offlined CPU will be put to a deep state that loses
hypervisor context.

Fixes: 24be85a23d1f ("powerpc/powernv: Clear PECE1 in LPCR via stop-api only on Hotplug")
Reported-by: Pavithra Prakash <pavirampu@linux.vnet.ibm.com>
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Pavithra Prakash <pavrampu@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
mm: treewide: remove GFP_TEMPORARY allocation flag 2017-09-14T01:53:16+00:00 Michal Hocko mhocko@suse.com 2017-09-13T23:28:29+00:00 0ee931c4e31a5efb134c76440405e9219f896e33 GFP_TEMPORARY was introduced by commit e12ba74d8ff3 ("Group short-lived and reclaimable kernel allocations") along with __GFP_RECLAIMABLE. It's primary motivation was to allow users to tell that an allocation is short lived and so the allocator can try to place such allocations close together and prevent long term fragmentation. As much as this sounds like a reasonable semantic it becomes much less clear when to use the highlevel GFP_TEMPORARY allocation flag. How long is temporary? Can the context holding that memory sleep? Can it take locks? It seems there is no good answer for those questions. The current implementation of GFP_TEMPORARY is basically GFP_KERNEL | __GFP_RECLAIMABLE which in itself is tricky because basically none of the existing caller provide a way to reclaim the allocated memory. So this is rather misleading and hard to evaluate for any benefits. I have checked some random users and none of them has added the flag with a specific justification. I suspect most of them just copied from other existing users and others just thought it might be a good idea to use without any measuring. This suggests that GFP_TEMPORARY just motivates for cargo cult usage without any reasoning. I believe that our gfp flags are quite complex already and especially those with highlevel semantic should be clearly defined to prevent from confusion and abuse. Therefore I propose dropping GFP_TEMPORARY and replace all existing users to simply use GFP_KERNEL. Please note that SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and so they will be placed properly for memory fragmentation prevention. I can see reasons we might want some gfp flag to reflect shorterm allocations but I propose starting from a clear semantic definition and only then add users with proper justification. This was been brought up before LSF this year by Matthew [1] and it turned out that GFP_TEMPORARY really doesn't have a clear semantic. It seems to be a heuristic without any measured advantage for most (if not all) its current users. The follow up discussion has revealed that opinions on what might be temporary allocation differ a lot between developers. So rather than trying to tweak existing users into a semantic which they haven't expected I propose to simply remove the flag and start from scratch if we really need a semantic for short term allocations. [1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org [akpm@linux-foundation.org: fix typo] [akpm@linux-foundation.org: coding-style fixes] [sfr@canb.auug.org.au: drm/i915: fix up] Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Neil Brown <neilb@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
GFP_TEMPORARY was introduced by commit e12ba74d8ff3 ("Group short-lived
and reclaimable kernel allocations") along with __GFP_RECLAIMABLE.  It's
primary motivation was to allow users to tell that an allocation is
short lived and so the allocator can try to place such allocations close
together and prevent long term fragmentation.  As much as this sounds
like a reasonable semantic it becomes much less clear when to use the
highlevel GFP_TEMPORARY allocation flag.  How long is temporary? Can the
context holding that memory sleep? Can it take locks? It seems there is
no good answer for those questions.

The current implementation of GFP_TEMPORARY is basically GFP_KERNEL |
__GFP_RECLAIMABLE which in itself is tricky because basically none of
the existing caller provide a way to reclaim the allocated memory.  So
this is rather misleading and hard to evaluate for any benefits.

I have checked some random users and none of them has added the flag
with a specific justification.  I suspect most of them just copied from
other existing users and others just thought it might be a good idea to
use without any measuring.  This suggests that GFP_TEMPORARY just
motivates for cargo cult usage without any reasoning.

I believe that our gfp flags are quite complex already and especially
those with highlevel semantic should be clearly defined to prevent from
confusion and abuse.  Therefore I propose dropping GFP_TEMPORARY and
replace all existing users to simply use GFP_KERNEL.  Please note that
SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and
so they will be placed properly for memory fragmentation prevention.

I can see reasons we might want some gfp flag to reflect shorterm
allocations but I propose starting from a clear semantic definition and
only then add users with proper justification.

This was been brought up before LSF this year by Matthew [1] and it
turned out that GFP_TEMPORARY really doesn't have a clear semantic.  It
seems to be a heuristic without any measured advantage for most (if not
all) its current users.  The follow up discussion has revealed that
opinions on what might be temporary allocation differ a lot between
developers.  So rather than trying to tweak existing users into a
semantic which they haven't expected I propose to simply remove the flag
and start from scratch if we really need a semantic for short term
allocations.

[1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org

[akpm@linux-foundation.org: fix typo]
[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: drm/i915: fix up]
  Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge tag 'powerpc-4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux 2017-09-07T17:15:40+00:00 Linus Torvalds torvalds@linux-foundation.org 2017-09-07T17:15:40+00:00 bac65d9d87b383471d8d29128319508d71b74180 Pull powerpc updates from Michael Ellerman: "Nothing really major this release, despite quite a lot of activity. Just lots of things all over the place. Some things of note include: - Access via perf to a new type of PMU (IMC) on Power9, which can count both core events as well as nest unit events (Memory controller etc). - Optimisations to the radix MMU TLB flushing, mostly to avoid unnecessary Page Walk Cache (PWC) flushes when the structure of the tree is not changing. - Reworks/cleanups of do_page_fault() to modernise it and bring it closer to other architectures where possible. - Rework of our page table walking so that THP updates only need to send IPIs to CPUs where the affected mm has run, rather than all CPUs. - The size of our vmalloc area is increased to 56T on 64-bit hash MMU systems. This avoids problems with the percpu allocator on systems with very sparse NUMA layouts. - STRICT_KERNEL_RWX support on PPC32. - A new sched domain topology for Power9, to capture the fact that pairs of cores may share an L2 cache. - Power9 support for VAS, which is a new mechanism for accessing coprocessors, and initial support for using it with the NX compression accelerator. - Major work on the instruction emulation support, adding support for many new instructions, and reworking it so it can be used to implement the emulation needed to fixup alignment faults. - Support for guests under PowerVM to use the Power9 XIVE interrupt controller. And probably that many things again that are almost as interesting, but I had to keep the list short. Plus the usual fixes and cleanups as always. Thanks to: Alexey Kardashevskiy, Alistair Popple, Andreas Schwab, Aneesh Kumar K.V, Anju T Sudhakar, Arvind Yadav, Balbir Singh, Benjamin Herrenschmidt, Bhumika Goyal, Breno Leitao, Bryant G. Ly, Christophe Leroy, Cédric Le Goater, Dan Carpenter, Dou Liyang, Frederic Barrat, Gautham R. Shenoy, Geliang Tang, Geoff Levand, Hannes Reinecke, Haren Myneni, Ivan Mikhaylov, John Allen, Julia Lawall, LABBE Corentin, Laurentiu Tudor, Madhavan Srinivasan, Markus Elfring, Masahiro Yamada, Matt Brown, Michael Neuling, Murilo Opsfelder Araujo, Nathan Fontenot, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Rashmica Gupta, Rob Herring, Rui Teng, Sam Bobroff, Santosh Sivaraj, Scott Wood, Shilpasri G Bhat, Sukadev Bhattiprolu, Suraj Jitindar Singh, Tobin C. Harding, Victor Aoqui" * tag 'powerpc-4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (321 commits) powerpc/xive: Fix section __init warning powerpc: Fix kernel crash in emulation of vector loads and stores powerpc/xive: improve debugging macros powerpc/xive: add XIVE Exploitation Mode to CAS powerpc/xive: introduce H_INT_ESB hcall powerpc/xive: add the HW IRQ number under xive_irq_data powerpc/xive: introduce xive_esb_write() powerpc/xive: rename xive_poke_esb() in xive_esb_read() powerpc/xive: guest exploitation of the XIVE interrupt controller powerpc/xive: introduce a common routine xive_queue_page_alloc() powerpc/sstep: Avoid used uninitialized error axonram: Return directly after a failed kzalloc() in axon_ram_probe() axonram: Improve a size determination in axon_ram_probe() axonram: Delete an error message for a failed memory allocation in axon_ram_probe() powerpc/powernv/npu: Move tlb flush before launching ATSD powerpc/macintosh: constify wf_sensor_ops structures powerpc/iommu: Use permission-specific DEVICE_ATTR variants powerpc/eeh: Delete an error out of memory message at init time powerpc/mm: Use seq_putc() in two functions macintosh: Convert to using %pOF instead of full_name ... 
Pull powerpc updates from Michael Ellerman:
 "Nothing really major this release, despite quite a lot of activity.
  Just lots of things all over the place.

  Some things of note include:

   - Access via perf to a new type of PMU (IMC) on Power9, which can
     count both core events as well as nest unit events (Memory
     controller etc).

   - Optimisations to the radix MMU TLB flushing, mostly to avoid
     unnecessary Page Walk Cache (PWC) flushes when the structure of the
     tree is not changing.

   - Reworks/cleanups of do_page_fault() to modernise it and bring it
     closer to other architectures where possible.

   - Rework of our page table walking so that THP updates only need to
     send IPIs to CPUs where the affected mm has run, rather than all
     CPUs.

   - The size of our vmalloc area is increased to 56T on 64-bit hash MMU
     systems. This avoids problems with the percpu allocator on systems
     with very sparse NUMA layouts.

   - STRICT_KERNEL_RWX support on PPC32.

   - A new sched domain topology for Power9, to capture the fact that
     pairs of cores may share an L2 cache.

   - Power9 support for VAS, which is a new mechanism for accessing
     coprocessors, and initial support for using it with the NX
     compression accelerator.

   - Major work on the instruction emulation support, adding support for
     many new instructions, and reworking it so it can be used to
     implement the emulation needed to fixup alignment faults.

   - Support for guests under PowerVM to use the Power9 XIVE interrupt
     controller.

  And probably that many things again that are almost as interesting,
  but I had to keep the list short. Plus the usual fixes and cleanups as
  always.

  Thanks to: Alexey Kardashevskiy, Alistair Popple, Andreas Schwab,
  Aneesh Kumar K.V, Anju T Sudhakar, Arvind Yadav, Balbir Singh,
  Benjamin Herrenschmidt, Bhumika Goyal, Breno Leitao, Bryant G. Ly,
  Christophe Leroy, Cédric Le Goater, Dan Carpenter, Dou Liyang,
  Frederic Barrat, Gautham R. Shenoy, Geliang Tang, Geoff Levand, Hannes
  Reinecke, Haren Myneni, Ivan Mikhaylov, John Allen, Julia Lawall,
  LABBE Corentin, Laurentiu Tudor, Madhavan Srinivasan, Markus Elfring,
  Masahiro Yamada, Matt Brown, Michael Neuling, Murilo Opsfelder Araujo,
  Nathan Fontenot, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran,
  Paul Mackerras, Rashmica Gupta, Rob Herring, Rui Teng, Sam Bobroff,
  Santosh Sivaraj, Scott Wood, Shilpasri G Bhat, Sukadev Bhattiprolu,
  Suraj Jitindar Singh, Tobin C. Harding, Victor Aoqui"

* tag 'powerpc-4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (321 commits)
  powerpc/xive: Fix section __init warning
  powerpc: Fix kernel crash in emulation of vector loads and stores
  powerpc/xive: improve debugging macros
  powerpc/xive: add XIVE Exploitation Mode to CAS
  powerpc/xive: introduce H_INT_ESB hcall
  powerpc/xive: add the HW IRQ number under xive_irq_data
  powerpc/xive: introduce xive_esb_write()
  powerpc/xive: rename xive_poke_esb() in xive_esb_read()
  powerpc/xive: guest exploitation of the XIVE interrupt controller
  powerpc/xive: introduce a common routine xive_queue_page_alloc()
  powerpc/sstep: Avoid used uninitialized error
  axonram: Return directly after a failed kzalloc() in axon_ram_probe()
  axonram: Improve a size determination in axon_ram_probe()
  axonram: Delete an error message for a failed memory allocation in axon_ram_probe()
  powerpc/powernv/npu: Move tlb flush before launching ATSD
  powerpc/macintosh: constify wf_sensor_ops structures
  powerpc/iommu: Use permission-specific DEVICE_ATTR variants
  powerpc/eeh: Delete an error out of memory message at init time
  powerpc/mm: Use seq_putc() in two functions
  macintosh: Convert to using %pOF instead of full_name
  ...
Merge tag 'wberr-v4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux 2017-09-06T21:11:03+00:00 Linus Torvalds torvalds@linux-foundation.org 2017-09-06T21:11:03+00:00 ec3604c7a5aae8953545b0d05495357009a960e5 Pull writeback error handling updates from Jeff Layton: "This pile continues the work from last cycle on better tracking writeback errors. In v4.13 we added some basic errseq_t infrastructure and converted a few filesystems to use it. This set continues refining that infrastructure, adds documentation, and converts most of the other filesystems to use it. The main exception at this point is the NFS client" * tag 'wberr-v4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux: ecryptfs: convert to file_write_and_wait in ->fsync mm: remove optimizations based on i_size in mapping writeback waits fs: convert a pile of fsync routines to errseq_t based reporting gfs2: convert to errseq_t based writeback error reporting for fsync fs: convert sync_file_range to use errseq_t based error-tracking mm: add file_fdatawait_range and file_write_and_wait fuse: convert to errseq_t based error tracking for fsync mm: consolidate dax / non-dax checks for writeback Documentation: add some docs for errseq_t errseq: rename __errseq_set to errseq_set 
Pull writeback error handling updates from Jeff Layton:
 "This pile continues the work from last cycle on better tracking
  writeback errors. In v4.13 we added some basic errseq_t infrastructure
  and converted a few filesystems to use it.

  This set continues refining that infrastructure, adds documentation,
  and converts most of the other filesystems to use it. The main
  exception at this point is the NFS client"

* tag 'wberr-v4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
  ecryptfs: convert to file_write_and_wait in ->fsync
  mm: remove optimizations based on i_size in mapping writeback waits
  fs: convert a pile of fsync routines to errseq_t based reporting
  gfs2: convert to errseq_t based writeback error reporting for fsync
  fs: convert sync_file_range to use errseq_t based error-tracking
  mm: add file_fdatawait_range and file_write_and_wait
  fuse: convert to errseq_t based error tracking for fsync
  mm: consolidate dax / non-dax checks for writeback
  Documentation: add some docs for errseq_t
  errseq: rename __errseq_set to errseq_set
powerpc/xive: guest exploitation of the XIVE interrupt controller 2017-09-02T11:02:35+00:00 Cédric Le Goater clg@kaod.org 2017-08-30T19:46:11+00:00 eac1e731b59ee3b5f5e641a7765c7ed41ed26226 This is the framework for using XIVE in a PowerVM guest. The support is very similar to the native one in a much simpler form. Each source is associated with an Event State Buffer (ESB). This is a two bit state machine which is used to trigger events. The bits are named "P" (pending) and "Q" (queued) and can be controlled by MMIO. The Guest OS registers event (or notifications) queues on which the HW will post event data for a target to notify. Instead of OPAL calls, a set of Hypervisors call are used to configure the interrupt sources and the event/notification queues of the guest: - H_INT_GET_SOURCE_INFO used to obtain the address of the MMIO page of the Event State Buffer (PQ bits) entry associated with the source. - H_INT_SET_SOURCE_CONFIG assigns a source to a "target". - H_INT_GET_SOURCE_CONFIG determines to which "target" and "priority" is assigned to a source - H_INT_GET_QUEUE_INFO returns the address of the notification management page associated with the specified "target" and "priority". - H_INT_SET_QUEUE_CONFIG sets or resets the event queue for a given "target" and "priority". It is also used to set the notification config associated with the queue, only unconditional notification for the moment. Reset is performed with a queue size of 0 and queueing is disabled in that case. - H_INT_GET_QUEUE_CONFIG returns the queue settings for a given "target" and "priority". - H_INT_RESET resets all of the partition's interrupt exploitation structures to their initial state, losing all configuration set via the hcalls H_INT_SET_SOURCE_CONFIG and H_INT_SET_QUEUE_CONFIG. - H_INT_SYNC issue a synchronisation on a source to make sure sure all notifications have reached their queue. As for XICS, the XIVE interface for the guest is described in the device tree under the "interrupt-controller" node. A couple of new properties are specific to XIVE : - "reg" contains the base address and size of the thread interrupt managnement areas (TIMA), also called rings, for the User level and for the Guest OS level. Only the Guest OS level is taken into account today. - "ibm,xive-eq-sizes" the size of the event queues. One cell per size supported, contains log2 of size, in ascending order. - "ibm,xive-lisn-ranges" the interrupt numbers ranges assigned to the guest. These are allocated using a simple bitmap. and also : - "/ibm,plat-res-int-priorities" contains a list of priorities that the hypervisor has reserved for its own use. Tested with a QEMU XIVE model for pseries and with the Power hypervisor. Signed-off-by: Cédric Le Goater <clg@kaod.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> 
This is the framework for using XIVE in a PowerVM guest. The support
is very similar to the native one in a much simpler form.

Each source is associated with an Event State Buffer (ESB). This is a
two bit state machine which is used to trigger events. The bits are
named "P" (pending) and "Q" (queued) and can be controlled by MMIO.
The Guest OS registers event (or notifications) queues on which the HW
will post event data for a target to notify.

Instead of OPAL calls, a set of Hypervisors call are used to configure
the interrupt sources and the event/notification queues of the guest:

 - H_INT_GET_SOURCE_INFO

   used to obtain the address of the MMIO page of the Event State
   Buffer (PQ bits) entry associated with the source.

 - H_INT_SET_SOURCE_CONFIG

   assigns a source to a "target".

 - H_INT_GET_SOURCE_CONFIG

   determines to which "target" and "priority" is assigned to a source

 - H_INT_GET_QUEUE_INFO

   returns the address of the notification management page associated
   with the specified "target" and "priority".

 - H_INT_SET_QUEUE_CONFIG

   sets or resets the event queue for a given "target" and "priority".
   It is also used to set the notification config associated with the
   queue, only unconditional notification for the moment.  Reset is
   performed with a queue size of 0 and queueing is disabled in that
   case.

 - H_INT_GET_QUEUE_CONFIG

   returns the queue settings for a given "target" and "priority".

 - H_INT_RESET

   resets all of the partition's interrupt exploitation structures to
   their initial state, losing all configuration set via the hcalls
   H_INT_SET_SOURCE_CONFIG and H_INT_SET_QUEUE_CONFIG.

 - H_INT_SYNC

   issue a synchronisation on a source to make sure sure all
   notifications have reached their queue.

As for XICS, the XIVE interface for the guest is described in the
device tree under the "interrupt-controller" node. A couple of new
properties are specific to XIVE :

 - "reg"

   contains the base address and size of the thread interrupt
   managnement areas (TIMA), also called rings, for the User level and
   for the Guest OS level. Only the Guest OS level is taken into
   account today.

 - "ibm,xive-eq-sizes"

   the size of the event queues. One cell per size supported, contains
   log2 of size, in ascending order.

 - "ibm,xive-lisn-ranges"

   the interrupt numbers ranges assigned to the guest. These are
   allocated using a simple bitmap.

and also :

 - "/ibm,plat-res-int-priorities"

   contains a list of priorities that the hypervisor has reserved for
   its own use.

Tested with a QEMU XIVE model for pseries and with the Power hypervisor.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
powerpc/powernv/npu: Move tlb flush before launching ATSD 2017-09-01T06:42:55+00:00 Alistair Popple alistair@popple.id.au 2017-08-11T06:22:56+00:00 bab9f954aaf352127725a9b7920226abdb65b604 The nest MMU tlb flush needs to happen before the GPU translation shootdown is launched to avoid the GPU refilling its tlb with stale nmmu translations prior to the nmmu flush completing. Fixes: 1ab66d1fbada ("powerpc/powernv: Introduce address translation services for Nvlink2") Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> 
The nest MMU tlb flush needs to happen before the GPU translation
shootdown is launched to avoid the GPU refilling its tlb with stale
nmmu translations prior to the nmmu flush completing.

Fixes: 1ab66d1fbada ("powerpc/powernv: Introduce address translation services for Nvlink2")
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>