<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/infiniband/core, branch v4.4.2</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>IB/cma: cma_match_net_dev needs to take into account port_num</title>
<updated>2015-12-23T04:22:50+00:00</updated>
<author>
<name>Matan Barak</name>
<email>matanb@mellanox.com</email>
</author>
<published>2015-12-21T15:01:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fac51590c1a077809984139e9bb9e06ed366f219'/>
<id>fac51590c1a077809984139e9bb9e06ed366f219</id>
<content type='text'>
Previously, cma_match_net_dev called cma_protocol_roce which
tried to verify that the IB device uses RoCE protocol. However,
if rdma_id wasn't bound to a port, then the check would occur
against the first port of the device without regard to whether
that port was even of the same type as the type of port the
incoming packet was received on.

Fix this by passing the port of the request and only checking
against the same port of the device.

Reported-by: Or Gerlitz &lt;gerlitz.or@gmail.com&gt;
Fixes: b8cab5dab15f ('IB/cma: Accept connection without a valid netdev on RoCE')
Signed-off-by: Matan Barak &lt;matanb@mellanox.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Previously, cma_match_net_dev called cma_protocol_roce which
tried to verify that the IB device uses RoCE protocol. However,
if rdma_id wasn't bound to a port, then the check would occur
against the first port of the device without regard to whether
that port was even of the same type as the type of port the
incoming packet was received on.

Fix this by passing the port of the request and only checking
against the same port of the device.

Reported-by: Or Gerlitz &lt;gerlitz.or@gmail.com&gt;
Fixes: b8cab5dab15f ('IB/cma: Accept connection without a valid netdev on RoCE')
Signed-off-by: Matan Barak &lt;matanb@mellanox.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>IB/mad: Require CM send method for everything except ClassPortInfo</title>
<updated>2015-12-08T17:19:11+00:00</updated>
<author>
<name>Hal Rosenstock</name>
<email>hal@dev.mellanox.co.il</email>
</author>
<published>2015-11-13T20:22:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=533708867dd6388f643f12c87465b59e732d729d'/>
<id>533708867dd6388f643f12c87465b59e732d729d</id>
<content type='text'>
Receipt of CM MAD with other than the Send method for an attribute
other than the ClassPortInfo attribute is invalid.

CM attributes other than ClassPortInfo only use the send method.

The SRP initiator does not maintain a timeout policy for CM connect
requests relies on the CM layer to do that. The result was that
the SRP initiator hung as the connect request never completed.

A new SRP target has been observed to respond to Send CM REQ
with GetResp of CM REQ with bad status. This is non conformant
with IBA spec but exposes a vulnerability in the current MAD/CM
code which will respond to the incoming GetResp of CM REQ as if
it was a valid incoming Send of CM REQ rather than tossing
this on the floor. It also causes the MAD layer not to
retransmit the original REQ even though it has not received a REP.

Reviewed-by: Sagi Grimberg &lt;sagig@mellanox.com&gt;
Signed-off-by: Hal Rosenstock &lt;hal@mellanox.com&gt;
Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Receipt of CM MAD with other than the Send method for an attribute
other than the ClassPortInfo attribute is invalid.

CM attributes other than ClassPortInfo only use the send method.

The SRP initiator does not maintain a timeout policy for CM connect
requests relies on the CM layer to do that. The result was that
the SRP initiator hung as the connect request never completed.

A new SRP target has been observed to respond to Send CM REQ
with GetResp of CM REQ with bad status. This is non conformant
with IBA spec but exposes a vulnerability in the current MAD/CM
code which will respond to the incoming GetResp of CM REQ as if
it was a valid incoming Send of CM REQ rather than tossing
this on the floor. It also causes the MAD layer not to
retransmit the original REQ even though it has not received a REP.

Reviewed-by: Sagi Grimberg &lt;sagig@mellanox.com&gt;
Signed-off-by: Hal Rosenstock &lt;hal@mellanox.com&gt;
Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>IB/cma: Add a missing rcu_read_unlock()</title>
<updated>2015-12-08T17:14:43+00:00</updated>
<author>
<name>Bart Van Assche</name>
<email>bart.vanassche@sandisk.com</email>
</author>
<published>2015-11-20T19:04:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d3632493c70b6a866a77264cd8cfdeb89958b906'/>
<id>d3632493c70b6a866a77264cd8cfdeb89958b906</id>
<content type='text'>
Ensure that validate_ipv4_net_dev() calls rcu_read_unlock() if
fib_lookup() fails. Detected by sparse. Compile-tested only.

Fixes: "IB/cma: Validate routing of incoming requests" (commit f887f2ac87c2).
Cc: Haggai Eran &lt;haggaie@mellanox.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Reviewed-by: Sagi Grimberg &lt;sagig@mellanox.com&gt;
Reviewed-by: Haggai Eran &lt;haggaie@mellanox.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgunthorpe@obsidianresearch.com&gt;

Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Ensure that validate_ipv4_net_dev() calls rcu_read_unlock() if
fib_lookup() fails. Detected by sparse. Compile-tested only.

Fixes: "IB/cma: Validate routing of incoming requests" (commit f887f2ac87c2).
Cc: Haggai Eran &lt;haggaie@mellanox.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Reviewed-by: Sagi Grimberg &lt;sagig@mellanox.com&gt;
Reviewed-by: Haggai Eran &lt;haggaie@mellanox.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgunthorpe@obsidianresearch.com&gt;

Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>IB core: Fix ib_sg_to_pages()</title>
<updated>2015-12-07T22:20:12+00:00</updated>
<author>
<name>Bart Van Assche</name>
<email>bart.vanassche@sandisk.com</email>
</author>
<published>2015-12-04T00:04:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8f5ba10ed40a9d3ffe84854984227d011a7428bd'/>
<id>8f5ba10ed40a9d3ffe84854984227d011a7428bd</id>
<content type='text'>
On 12/03/2015 01:18 AM, Christoph Hellwig wrote:
&gt; The patch looks good to me, but while we touch this area, how about
&gt; throwing in a few cosmetic fixes as well?

How about the patch below ? In that version of the ib_sg_to_pages() fix
these concerns have been addressed and additionally to more bugs have been fixed.

------------

[PATCH] IB core: Fix ib_sg_to_pages()

Fix the code for detecting gaps. A gap occurs not only if the
second or later scatterlist element is not aligned but also if
any scatterlist element other than the last does not end at a
page boundary.

In the code for coalescing contiguous elements, ensure that
mr-&gt;length is correct and that last_page_addr is up-to-date.

Ensure that this function returns a negative
error code instead of zero if the first set_page() call fails.

Fixes: commit 4c67e2bfc8b7 ("IB/core: Introduce new fast registration API")
Reported-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Sagi Grimberg &lt;sagig@mellanox.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;

Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
On 12/03/2015 01:18 AM, Christoph Hellwig wrote:
&gt; The patch looks good to me, but while we touch this area, how about
&gt; throwing in a few cosmetic fixes as well?

How about the patch below ? In that version of the ib_sg_to_pages() fix
these concerns have been addressed and additionally to more bugs have been fixed.

------------

[PATCH] IB core: Fix ib_sg_to_pages()

Fix the code for detecting gaps. A gap occurs not only if the
second or later scatterlist element is not aligned but also if
any scatterlist element other than the last does not end at a
page boundary.

In the code for coalescing contiguous elements, ensure that
mr-&gt;length is correct and that last_page_addr is up-to-date.

Ensure that this function returns a negative
error code instead of zero if the first set_page() call fails.

Fixes: commit 4c67e2bfc8b7 ("IB/core: Introduce new fast registration API")
Reported-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Sagi Grimberg &lt;sagig@mellanox.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;

Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>IB/sa: Put netlink request into the request list before sending</title>
<updated>2015-12-07T21:43:01+00:00</updated>
<author>
<name>Kaike Wan</name>
<email>kaike.wan@intel.com</email>
</author>
<published>2015-10-30T12:23:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3ebd2fd0d0119a5ac7906bf17be637b527f63d31'/>
<id>3ebd2fd0d0119a5ac7906bf17be637b527f63d31</id>
<content type='text'>
It was found by Saurabh Sengar that the netlink code tried to allocate
memory with GFP_KERNEL while holding a spinlock. While it is possible
to fix the issue by replacing GFP_KERNEL with GFP_ATOMIC, it is better
to get rid of the spinlock while sending the packet. However, in order
to protect against a race condition that a quick response may be received
before the request is put on the request list, we need to put the request
on the list first.

Signed-off-by: Kaike Wan &lt;kaike.wan@intel.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgunthorpe@obsidianresearch.com&gt;
Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Reported-by: Saurabh Sengar &lt;saurabh.truth@gmail.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It was found by Saurabh Sengar that the netlink code tried to allocate
memory with GFP_KERNEL while holding a spinlock. While it is possible
to fix the issue by replacing GFP_KERNEL with GFP_ATOMIC, it is better
to get rid of the spinlock while sending the packet. However, in order
to protect against a race condition that a quick response may be received
before the request is put on the request list, we need to put the request
on the list first.

Signed-off-by: Kaike Wan &lt;kaike.wan@intel.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgunthorpe@obsidianresearch.com&gt;
Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Reported-by: Saurabh Sengar &lt;saurabh.truth@gmail.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>IB/core: use RCU for uverbs id lookup</title>
<updated>2015-12-07T21:39:26+00:00</updated>
<author>
<name>Mike Marciniszyn</name>
<email>mike.marciniszyn@intel.com</email>
</author>
<published>2015-11-02T17:13:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d144da8c6f51f48ec39d891ea9dff80169c45f3b'/>
<id>d144da8c6f51f48ec39d891ea9dff80169c45f3b</id>
<content type='text'>
The current implementation gets a spin_lock, and at any scale with
qib and hfi1 post send, the lock contention grows exponentially
with the number of QPs.

idr_find() is RCU compatibile, so read doesn't need the lock.

Change to use rcu_read_lock() and rcu_read_unlock() in
__idr_get_uobj().

kfree_rcu() is used to insure a grace period between the
idr removal and actual free.

Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Signed-off-by: Mike Marciniszyn &lt;mike.marciniszyn@intel.com&gt;
Reviewed-By: Jason Gunthorpe &lt;jgunthorpe@obsidianresearch.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The current implementation gets a spin_lock, and at any scale with
qib and hfi1 post send, the lock contention grows exponentially
with the number of QPs.

idr_find() is RCU compatibile, so read doesn't need the lock.

Change to use rcu_read_lock() and rcu_read_unlock() in
__idr_get_uobj().

kfree_rcu() is used to insure a grace period between the
idr removal and actual free.

Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Signed-off-by: Mike Marciniszyn &lt;mike.marciniszyn@intel.com&gt;
Reviewed-By: Jason Gunthorpe &lt;jgunthorpe@obsidianresearch.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>IB/core: Fix user mode post wr corruption</title>
<updated>2015-12-07T21:22:14+00:00</updated>
<author>
<name>Mike Marciniszyn</name>
<email>mike.marciniszyn@intel.com</email>
</author>
<published>2015-12-01T15:13:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1d784b890c0101db2556b981e864c2282a3c1b02'/>
<id>1d784b890c0101db2556b981e864c2282a3c1b02</id>
<content type='text'>
Commit e622f2f4ad21 ("IB: split struct ib_send_wr")
introduced a regression for HCAs whose user mode post
sends go through ib_uverbs_post_send().

The code didn't account for the fact that the first sge is
offset by an operation dependent length.  The allocation did,
but the pointer to the destination sge list is computed without
that knowledge.  The sge list copy_from_user() then corrupts
fields in the work request

Store the operation dependent length in a local variable and
compute the sge list copy_from_user() destination using that length.

Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Signed-off-by: Mike Marciniszyn &lt;mike.marciniszyn@intel.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit e622f2f4ad21 ("IB: split struct ib_send_wr")
introduced a regression for HCAs whose user mode post
sends go through ib_uverbs_post_send().

The code didn't account for the fact that the first sge is
offset by an operation dependent length.  The allocation did,
but the pointer to the destination sge list is computed without
that knowledge.  The sge list copy_from_user() then corrupts
fields in the work request

Store the operation dependent length in a local variable and
compute the sge list copy_from_user() destination using that length.

Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Signed-off-by: Mike Marciniszyn &lt;mike.marciniszyn@intel.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'akpm' (patches from Andrew)</title>
<updated>2015-11-07T22:32:45+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-11-07T22:32:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ad804a0b2a769a0eed29015c53fe395449c09d13'/>
<id>ad804a0b2a769a0eed29015c53fe395449c09d13</id>
<content type='text'>
Merge second patch-bomb from Andrew Morton:

 - most of the rest of MM

 - procfs

 - lib/ updates

 - printk updates

 - bitops infrastructure tweaks

 - checkpatch updates

 - nilfs2 update

 - signals

 - various other misc bits: coredump, seqfile, kexec, pidns, zlib, ipc,
   dma-debug, dma-mapping, ...

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (102 commits)
  ipc,msg: drop dst nil validation in copy_msg
  include/linux/zutil.h: fix usage example of zlib_adler32()
  panic: release stale console lock to always get the logbuf printed out
  dma-debug: check nents in dma_sync_sg*
  dma-mapping: tidy up dma_parms default handling
  pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode
  kexec: use file name as the output message prefix
  fs, seqfile: always allow oom killer
  seq_file: reuse string_escape_str()
  fs/seq_file: use seq_* helpers in seq_hex_dump()
  coredump: change zap_threads() and zap_process() to use for_each_thread()
  coredump: ensure all coredumping tasks have SIGNAL_GROUP_COREDUMP
  signal: remove jffs2_garbage_collect_thread()-&gt;allow_signal(SIGCONT)
  signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()
  signal: turn dequeue_signal_lock() into kernel_dequeue_signal()
  signals: kill block_all_signals() and unblock_all_signals()
  nilfs2: fix gcc uninitialized-variable warnings in powerpc build
  nilfs2: fix gcc unused-but-set-variable warnings
  MAINTAINERS: nilfs2: add header file for tracing
  nilfs2: add tracepoints for analyzing reading and writing metadata files
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Merge second patch-bomb from Andrew Morton:

 - most of the rest of MM

 - procfs

 - lib/ updates

 - printk updates

 - bitops infrastructure tweaks

 - checkpatch updates

 - nilfs2 update

 - signals

 - various other misc bits: coredump, seqfile, kexec, pidns, zlib, ipc,
   dma-debug, dma-mapping, ...

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (102 commits)
  ipc,msg: drop dst nil validation in copy_msg
  include/linux/zutil.h: fix usage example of zlib_adler32()
  panic: release stale console lock to always get the logbuf printed out
  dma-debug: check nents in dma_sync_sg*
  dma-mapping: tidy up dma_parms default handling
  pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode
  kexec: use file name as the output message prefix
  fs, seqfile: always allow oom killer
  seq_file: reuse string_escape_str()
  fs/seq_file: use seq_* helpers in seq_hex_dump()
  coredump: change zap_threads() and zap_process() to use for_each_thread()
  coredump: ensure all coredumping tasks have SIGNAL_GROUP_COREDUMP
  signal: remove jffs2_garbage_collect_thread()-&gt;allow_signal(SIGCONT)
  signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()
  signal: turn dequeue_signal_lock() into kernel_dequeue_signal()
  signals: kill block_all_signals() and unblock_all_signals()
  nilfs2: fix gcc uninitialized-variable warnings in powerpc build
  nilfs2: fix gcc unused-but-set-variable warnings
  MAINTAINERS: nilfs2: add header file for tracing
  nilfs2: add tracepoints for analyzing reading and writing metadata files
  ...
</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>
<entry>
<title>IB/core, cma: Make __attribute_const__ declarations sparse-friendly</title>
<updated>2015-10-30T21:57:49+00:00</updated>
<author>
<name>Bart Van Assche</name>
<email>bart.vanassche@sandisk.com</email>
</author>
<published>2015-08-03T17:01:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=db7489e07669073970358b6cacf6a9dd8dc9275e'/>
<id>db7489e07669073970358b6cacf6a9dd8dc9275e</id>
<content type='text'>
Move the __attribute_const__ declarations such that sparse understands
that these apply to the function itself and not to the return type.
This avoids that sparse reports error messages like the following:

drivers/infiniband/core/verbs.c:73:12: error: symbol 'ib_event_msg' redeclared with different type (originally declared at include/rdma/ib_verbs.h:470) - different modifiers

Fixes: 2b1b5b601230 ("IB/core, cma: Nice log-friendly string helpers")
Signed-off-by: Bart Van Assche &lt;bart.vanassche@sandisk.com&gt;
Cc: Sagi Grimberg &lt;sagig@mellanox.com&gt;
Reviewed-by: Sagi Grimberg &lt;sagig@mellanox.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Move the __attribute_const__ declarations such that sparse understands
that these apply to the function itself and not to the return type.
This avoids that sparse reports error messages like the following:

drivers/infiniband/core/verbs.c:73:12: error: symbol 'ib_event_msg' redeclared with different type (originally declared at include/rdma/ib_verbs.h:470) - different modifiers

Fixes: 2b1b5b601230 ("IB/core, cma: Nice log-friendly string helpers")
Signed-off-by: Bart Van Assche &lt;bart.vanassche@sandisk.com&gt;
Cc: Sagi Grimberg &lt;sagig@mellanox.com&gt;
Reviewed-by: Sagi Grimberg &lt;sagig@mellanox.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
