<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/net/core, branch v4.4-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>net/core: revert "net: fix __netdev_update_features return.." and add comment</title>
<updated>2015-11-17T20:25:45+00:00</updated>
<author>
<name>Nikolay Aleksandrov</name>
<email>nikolay@cumulusnetworks.com</email>
</author>
<published>2015-11-17T14:49:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=17b85d29e82cc3c874a497a8bc5764d6a2b043e2'/>
<id>17b85d29e82cc3c874a497a8bc5764d6a2b043e2</id>
<content type='text'>
This reverts commit 00ee59271777 ("net: fix __netdev_update_features return
on ndo_set_features failure")
and adds a comment explaining why it's okay to return a value other than
0 upon error. Some drivers might actually change flags and return an
error so it's better to fire a spurious notification rather than miss
these.

CC: Michał Mirosław &lt;mirq-linux@rere.qmqm.pl&gt;
Signed-off-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 00ee59271777 ("net: fix __netdev_update_features return
on ndo_set_features failure")
and adds a comment explaining why it's okay to return a value other than
0 upon error. Some drivers might actually change flags and return an
error so it's better to fire a spurious notification rather than miss
these.

CC: Michał Mirosław &lt;mirq-linux@rere.qmqm.pl&gt;
Signed-off-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rtnetlink: fix frame size warning in rtnl_fill_ifinfo</title>
<updated>2015-11-17T20:25:44+00:00</updated>
<author>
<name>Hannes Frederic Sowa</name>
<email>hannes@stressinduktion.org</email>
</author>
<published>2015-11-17T13:16:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b22b941b2c253a20e1d000c671594c4f3f0a3858'/>
<id>b22b941b2c253a20e1d000c671594c4f3f0a3858</id>
<content type='text'>
Fix the following warning:

  CC      net/core/rtnetlink.o
net/core/rtnetlink.c: In function ‘rtnl_fill_ifinfo’:
net/core/rtnetlink.c:1308:1: warning: the frame size of 2864 bytes is larger than 2048 bytes [-Wframe-larger-than=]
 }
 ^
by splitting up the huge rtnl_fill_ifinfo into some smaller ones, so we
don't have the huge frame allocations at the same time.

Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix the following warning:

  CC      net/core/rtnetlink.o
net/core/rtnetlink.c: In function ‘rtnl_fill_ifinfo’:
net/core/rtnetlink.c:1308:1: warning: the frame size of 2864 bytes is larger than 2048 bytes [-Wframe-larger-than=]
 }
 ^
by splitting up the huge rtnl_fill_ifinfo into some smaller ones, so we
don't have the huge frame allocations at the same time.

Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: use skb_clone to avoid alloc_pages failure.</title>
<updated>2015-11-17T20:25:44+00:00</updated>
<author>
<name>Martin Zhang</name>
<email>martinbj2008@gmail.com</email>
</author>
<published>2015-11-17T12:49:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=19125c1a4fd873421698876f34a06dbe18d25f17'/>
<id>19125c1a4fd873421698876f34a06dbe18d25f17</id>
<content type='text'>
1. new skb only need dst and ip address(v4 or v6).
2. skb_copy may need high order pages, which is very rare on long running server.

Signed-off-by: Junwei Zhang &lt;linggao.zjw@alibaba-inc.com&gt;
Signed-off-by: Martin Zhang &lt;martinbj2008@gmail.com&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
1. new skb only need dst and ip address(v4 or v6).
2. skb_copy may need high order pages, which is very rare on long running server.

Signed-off-by: Junwei Zhang &lt;linggao.zjw@alibaba-inc.com&gt;
Signed-off-by: Martin Zhang &lt;martinbj2008@gmail.com&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>vlan: Fix untag operations of stacked vlans with REORDER_HEADER off</title>
<updated>2015-11-17T19:38:35+00:00</updated>
<author>
<name>Vlad Yasevich</name>
<email>vyasevich@gmail.com</email>
</author>
<published>2015-11-16T20:43:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a6e18ff111701b4ff6947605bfbe9594ec42a6e8'/>
<id>a6e18ff111701b4ff6947605bfbe9594ec42a6e8</id>
<content type='text'>
When we have multiple stacked vlan devices all of which have
turned off REORDER_HEADER flag, the untag operation does not
locate the ethernet addresses correctly for nested vlans.
The reason is that in case of REORDER_HEADER flag being off,
the outer vlan headers are put back and the mac_len is adjusted
to account for the presense of the header.  Then, the subsequent
untag operation, for the next level vlan, always use VLAN_ETH_HLEN
to locate the begining of the ethernet header and that ends up
being a multiple of 4 bytes short of the actuall beginning
of the mac header (the multiple depending on the how many vlan
encapsulations ethere are).

As a reslult, if there are multiple levles of vlan devices
with REODER_HEADER being off, the recevied packets end up
being dropped.

To solve this, we use skb-&gt;mac_len as the offset.  The value
is always set on receive path and starts out as a ETH_HLEN.
The value is also updated when the vlan header manupations occur
so we know it will be correct.

Signed-off-by: Vladislav Yasevich &lt;vyasevic@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When we have multiple stacked vlan devices all of which have
turned off REORDER_HEADER flag, the untag operation does not
locate the ethernet addresses correctly for nested vlans.
The reason is that in case of REORDER_HEADER flag being off,
the outer vlan headers are put back and the mac_len is adjusted
to account for the presense of the header.  Then, the subsequent
untag operation, for the next level vlan, always use VLAN_ETH_HLEN
to locate the begining of the ethernet header and that ends up
being a multiple of 4 bytes short of the actuall beginning
of the mac header (the multiple depending on the how many vlan
encapsulations ethere are).

As a reslult, if there are multiple levles of vlan devices
with REODER_HEADER being off, the recevied packets end up
being dropped.

To solve this, we use skb-&gt;mac_len as the offset.  The value
is always set on receive path and starts out as a ETH_HLEN.
The value is also updated when the vlan header manupations occur
so we know it will be correct.

Signed-off-by: Vladislav Yasevich &lt;vyasevic@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net/core: use netdev name in warning if no parent</title>
<updated>2015-11-16T21:21:48+00:00</updated>
<author>
<name>Bjørn Mork</name>
<email>bjorn@mork.no</email>
</author>
<published>2015-11-16T18:16:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=88ad4175b201ae24be5e9b7752cf33c1306b64e4'/>
<id>88ad4175b201ae24be5e9b7752cf33c1306b64e4</id>
<content type='text'>
A recent flaw in the netdev feature setting resulted in warnings
like this one from VLAN interfaces:

 WARNING: CPU: 1 PID: 4975 at net/core/dev.c:2419 skb_warn_bad_offload+0xbc/0xcb()
 : caps=(0x00000000001b5820, 0x00000000001b5829) len=2782 data_len=0 gso_size=1348 gso_type=16 ip_summed=3

The ":" is supposed to be preceded by a driver name, but in this
case it is an empty string since the device has no parent.

There are many types of network devices without a parent. The
anonymous warnings for these devices can be hard to debug.  Log
the network device name instead in these cases to assist further
debugging.

This is mostly similar to how __netdev_printk() handles orphan
devices.

Signed-off-by: Bjørn Mork &lt;bjorn@mork.no&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
A recent flaw in the netdev feature setting resulted in warnings
like this one from VLAN interfaces:

 WARNING: CPU: 1 PID: 4975 at net/core/dev.c:2419 skb_warn_bad_offload+0xbc/0xcb()
 : caps=(0x00000000001b5820, 0x00000000001b5829) len=2782 data_len=0 gso_size=1348 gso_type=16 ip_summed=3

The ":" is supposed to be preceded by a driver name, but in this
case it is an empty string since the device has no parent.

There are many types of network devices without a parent. The
anonymous warnings for these devices can be hard to debug.  Log
the network device name instead in these cases to assist further
debugging.

This is mostly similar to how __netdev_printk() handles orphan
devices.

Signed-off-by: Bjørn Mork &lt;bjorn@mork.no&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: fix __netdev_update_features return on ndo_set_features failure</title>
<updated>2015-11-16T19:56:03+00:00</updated>
<author>
<name>Nikolay Aleksandrov</name>
<email>nikolay@cumulusnetworks.com</email>
</author>
<published>2015-11-13T14:20:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=00ee5927177792a6e139d50b6b7564d35705556a'/>
<id>00ee5927177792a6e139d50b6b7564d35705556a</id>
<content type='text'>
If ndo_set_features fails __netdev_update_features() will return -1 but
this is wrong because it is expected to return 0 if no features were
changed (see netdev_update_features()), which will cause a netdev
notifier to be called without any actual changes. Fix this by returning
0 if ndo_set_features fails.

Fixes: 6cb6a27c45ce ("net: Call netdev_features_change() from netdev_update_features()")
CC: Michał Mirosław &lt;mirq-linux@rere.qmqm.pl&gt;
Signed-off-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If ndo_set_features fails __netdev_update_features() will return -1 but
this is wrong because it is expected to return 0 if no features were
changed (see netdev_update_features()), which will cause a netdev
notifier to be called without any actual changes. Fix this by returning
0 if ndo_set_features fails.

Fixes: 6cb6a27c45ce ("net: Call netdev_features_change() from netdev_update_features()")
CC: Michał Mirosław &lt;mirq-linux@rere.qmqm.pl&gt;
Signed-off-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: fix feature changes on devices without ndo_set_features</title>
<updated>2015-11-16T19:56:03+00:00</updated>
<author>
<name>Nikolay Aleksandrov</name>
<email>nikolay@cumulusnetworks.com</email>
</author>
<published>2015-11-13T13:54:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5f8dc33e8ee7e59bee3bc6dc2088807a384b285a'/>
<id>5f8dc33e8ee7e59bee3bc6dc2088807a384b285a</id>
<content type='text'>
When __netdev_update_features() was updated to ensure some features are
disabled on new lower devices, an error was introduced for devices which
don't have the ndo_set_features() method set. Before we'll just set the
new features, but now we return an error and don't set them. Fix this by
returning the old behaviour and setting err to 0 when ndo_set_features
is not present.

Fixes: e7868a85e1b2 ("net/core: ensure features get disabled on new lower devs")
CC: Jarod Wilson &lt;jarod@redhat.com&gt;
CC: Jiri Pirko &lt;jiri@resnulli.us&gt;
CC: Ido Schimmel &lt;idosch@mellanox.com&gt;
CC: Sander Eikelenboom &lt;linux@eikelenboom.it&gt;
CC: Andy Gospodarek &lt;gospo@cumulusnetworks.com&gt;
CC: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Signed-off-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Reviewed-by: Jiri Pirko &lt;jiri@mellanox.com&gt;
Reviewed-by: Andy Gospodarek &lt;gospo@cumulusnetworks.com&gt;
Reviewed-by: Jarod Wilson &lt;jarod@redhat.com&gt;
Tested-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Tested-by: Dave Young &lt;dyoung@redhat.com&gt;
Tested-by: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When __netdev_update_features() was updated to ensure some features are
disabled on new lower devices, an error was introduced for devices which
don't have the ndo_set_features() method set. Before we'll just set the
new features, but now we return an error and don't set them. Fix this by
returning the old behaviour and setting err to 0 when ndo_set_features
is not present.

Fixes: e7868a85e1b2 ("net/core: ensure features get disabled on new lower devs")
CC: Jarod Wilson &lt;jarod@redhat.com&gt;
CC: Jiri Pirko &lt;jiri@resnulli.us&gt;
CC: Ido Schimmel &lt;idosch@mellanox.com&gt;
CC: Sander Eikelenboom &lt;linux@eikelenboom.it&gt;
CC: Andy Gospodarek &lt;gospo@cumulusnetworks.com&gt;
CC: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Signed-off-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Reviewed-by: Jiri Pirko &lt;jiri@mellanox.com&gt;
Reviewed-by: Andy Gospodarek &lt;gospo@cumulusnetworks.com&gt;
Reviewed-by: Jarod Wilson &lt;jarod@redhat.com&gt;
Tested-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Tested-by: Dave Young &lt;dyoung@redhat.com&gt;
Tested-by: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net</title>
<updated>2015-11-11T02:11:41+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-11-11T02:11:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2df4ee78d042ee3d17cbebd51e31b300286549dc'/>
<id>2df4ee78d042ee3d17cbebd51e31b300286549dc</id>
<content type='text'>
Pull networking fixes from David Miller:

 1) Fix null deref in xt_TEE netfilter module, from Eric Dumazet.

 2) Several spots need to get to the original listner for SYN-ACK
    packets, most spots got this ok but some were not.  Whilst covering
    the remaining cases, create a helper to do this.  From Eric Dumazet.

 3) Missiing check of return value from alloc_netdev() in CAIF SPI code,
    from Rasmus Villemoes.

 4) Don't sleep while != TASK_RUNNING in macvtap, from Vlad Yasevich.

 5) Use after free in mvneta driver, from Justin Maggard.

 6) Fix race on dst-&gt;flags access in dst_release(), from Eric Dumazet.

 7) Add missing ZLIB_INFLATE dependency for new qed driver.  From Arnd
    Bergmann.

 8) Fix multicast getsockopt deadlock, from WANG Cong.

 9) Fix deadlock in btusb, from Kuba Pawlak.

10) Some ipv6_add_dev() failure paths were not cleaning up the SNMP6
    counter state.  From Sabrina Dubroca.

11) Fix packet_bind() race, which can cause lost notifications, from
    Francesco Ruggeri.

12) Fix MAC restoration in qlcnic driver during bonding mode changes,
    from Jarod Wilson.

13) Revert bridging forward delay change which broke libvirt and other
    userspace things, from Vlad Yasevich.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (65 commits)
  Revert "bridge: Allow forward delay to be cfgd when STP enabled"
  bpf_trace: Make dependent on PERF_EVENTS
  qed: select ZLIB_INFLATE
  net: fix a race in dst_release()
  net: mvneta: Fix memory use after free.
  net: Documentation: Fix default value tcp_limit_output_bytes
  macvtap: Resolve possible __might_sleep warning in macvtap_do_read()
  mvneta: add FIXED_PHY dependency
  net: caif: check return value of alloc_netdev
  net: hisilicon: NET_VENDOR_HISILICON should depend on HAS_DMA
  drivers: net: xgene: fix RGMII 10/100Mb mode
  netfilter: nft_meta: use skb_to_full_sk() helper
  net_sched: em_meta: use skb_to_full_sk() helper
  sched: cls_flow: use skb_to_full_sk() helper
  netfilter: xt_owner: use skb_to_full_sk() helper
  smack: use skb_to_full_sk() helper
  net: add skb_to_full_sk() helper and use it in selinux_netlbl_skbuff_setsid()
  bpf: doc: correct arch list for supported eBPF JIT
  dwc_eth_qos: Delete an unnecessary check before the function call "of_node_put"
  bonding: fix panic on non-ARPHRD_ETHER enslave failure
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking fixes from David Miller:

 1) Fix null deref in xt_TEE netfilter module, from Eric Dumazet.

 2) Several spots need to get to the original listner for SYN-ACK
    packets, most spots got this ok but some were not.  Whilst covering
    the remaining cases, create a helper to do this.  From Eric Dumazet.

 3) Missiing check of return value from alloc_netdev() in CAIF SPI code,
    from Rasmus Villemoes.

 4) Don't sleep while != TASK_RUNNING in macvtap, from Vlad Yasevich.

 5) Use after free in mvneta driver, from Justin Maggard.

 6) Fix race on dst-&gt;flags access in dst_release(), from Eric Dumazet.

 7) Add missing ZLIB_INFLATE dependency for new qed driver.  From Arnd
    Bergmann.

 8) Fix multicast getsockopt deadlock, from WANG Cong.

 9) Fix deadlock in btusb, from Kuba Pawlak.

10) Some ipv6_add_dev() failure paths were not cleaning up the SNMP6
    counter state.  From Sabrina Dubroca.

11) Fix packet_bind() race, which can cause lost notifications, from
    Francesco Ruggeri.

12) Fix MAC restoration in qlcnic driver during bonding mode changes,
    from Jarod Wilson.

13) Revert bridging forward delay change which broke libvirt and other
    userspace things, from Vlad Yasevich.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (65 commits)
  Revert "bridge: Allow forward delay to be cfgd when STP enabled"
  bpf_trace: Make dependent on PERF_EVENTS
  qed: select ZLIB_INFLATE
  net: fix a race in dst_release()
  net: mvneta: Fix memory use after free.
  net: Documentation: Fix default value tcp_limit_output_bytes
  macvtap: Resolve possible __might_sleep warning in macvtap_do_read()
  mvneta: add FIXED_PHY dependency
  net: caif: check return value of alloc_netdev
  net: hisilicon: NET_VENDOR_HISILICON should depend on HAS_DMA
  drivers: net: xgene: fix RGMII 10/100Mb mode
  netfilter: nft_meta: use skb_to_full_sk() helper
  net_sched: em_meta: use skb_to_full_sk() helper
  sched: cls_flow: use skb_to_full_sk() helper
  netfilter: xt_owner: use skb_to_full_sk() helper
  smack: use skb_to_full_sk() helper
  net: add skb_to_full_sk() helper and use it in selinux_netlbl_skbuff_setsid()
  bpf: doc: correct arch list for supported eBPF JIT
  dwc_eth_qos: Delete an unnecessary check before the function call "of_node_put"
  bonding: fix panic on non-ARPHRD_ETHER enslave failure
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>net: fix a race in dst_release()</title>
<updated>2015-11-10T02:55:48+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2015-11-10T01:51:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d69bbf88c8d0b367cf3e3a052f6daadf630ee566'/>
<id>d69bbf88c8d0b367cf3e3a052f6daadf630ee566</id>
<content type='text'>
Only cpu seeing dst refcount going to 0 can safely
dereference dst-&gt;flags.

Otherwise an other cpu might already have freed the dst.

Fixes: 27b75c95f10d ("net: avoid RCU for NOCACHE dst")
Reported-by: Greg Thelen &lt;gthelen@google.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Only cpu seeing dst refcount going to 0 can safely
dereference dst-&gt;flags.

Otherwise an other cpu might already have freed the dst.

Fixes: 27b75c95f10d ("net: avoid RCU for NOCACHE dst")
Reported-by: Greg Thelen &lt;gthelen@google.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</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.tavy.me/linux.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>
</feed>
