Add corrupt_bio_byte feature to simulate corruption by overwriting a byte at a
specified position with a specified value during intervals when the device is
"down".
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

Add 'drop_writes' option to drop writes silently while the
device is 'down'.  Reads are not touched.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

Previous patches in the bad block series extended behavior of
rdev's 'state' interface but lacked documentation update.
Fix it.
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

Previous patch in the bad block series added new sysfs interfaces
([unacknowledged_]bad_blocks) for each rdev without documentation.
Add it.
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

When a kernel BUG or oops occurs, ChromeOS intends to panic and
immediately reboot, with stacktrace and other messages preserved in RAM
across reboot.

But the longer we delay, the more likely the user is to poweroff and
lose the info.

panic_timeout (seconds before rebooting) is set by panic= boot option or
sysctl or /proc/sys/kernel/panic; but 0 means wait forever, so at
present we have to delay at least 1 second.

Let a negative number mean reboot immediately (with the small cosmetic
benefit of suppressing that newline-less "Rebooting in %d seconds.."
message).
Signed-off-by: NHugh Dickins <hughd@chromium.org>
Signed-off-by: NMandeep Singh Baines <msb@chromium.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Olaf Hering <olaf@aepfle.de>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

See: DMA-API.txt, part Id, DMA_FROM_DEVICE description.
Signed-off-by: NMichal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

git grep shows there are no users in tree, so we can remove them safely.
Signed-off-by: NWANG Cong <xiyou.wangcong@gmail.com>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add support for the shm_rmid_forced sysctl.  If set to 1, all shared
memory objects in current ipc namespace will be automatically forced to
use IPC_RMID.

The POSIX way of handling shmem allows one to create shm objects and
call shmdt(), leaving shm object associated with no process, thus
consuming memory not counted via rlimits.

With shm_rmid_forced=1 the shared memory object is counted at least for
one process, so OOM killer may effectively kill the fat process holding
the shared memory.

It obviously breaks POSIX - some programs relying on the feature would
stop working.  So set shm_rmid_forced=1 only if you're sure nobody uses
"orphaned" memory.  Use shm_rmid_forced=0 by default for compatability
reasons.

The feature was previously impemented in -ow as a configure option.

[akpm@linux-foundation.org: fix documentation, per Randy]
[akpm@linux-foundation.org: fix warning]
[akpm@linux-foundation.org: readability/conventionality tweaks]
[akpm@linux-foundation.org: fix shm_rmid_forced/shm_forced_rmid confusion, use standard comment layout]
Signed-off-by: NVasiliy Kulikov <segoon@openwall.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serge.hallyn@canonical.com>
Cc: Daniel Lezcano <daniel.lezcano@free.fr>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Solar Designer <solar@openwall.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The commit log of 0ae5e89c ("memcg: count the soft_limit reclaim
in...") says it adds scanning stats to memory.stat file.  But it doesn't
because we considered we needed to make a concensus for such new APIs.

This patch is a trial to add memory.scan_stat. This shows
  - the number of scanned pages(total, anon, file)
  - the number of rotated pages(total, anon, file)
  - the number of freed pages(total, anon, file)
  - the number of elaplsed time (including sleep/pause time)

  for both of direct/soft reclaim.

The biggest difference with oringinal Ying's one is that this file
can be reset by some write, as

  # echo 0 ...../memory.scan_stat

Example of output is here. This is a result after make -j 6 kernel
under 300M limit.

  [kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.scan_stat
  [kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.vmscan_stat
  scanned_pages_by_limit 9471864
  scanned_anon_pages_by_limit 6640629
  scanned_file_pages_by_limit 2831235
  rotated_pages_by_limit 4243974
  rotated_anon_pages_by_limit 3971968
  rotated_file_pages_by_limit 272006
  freed_pages_by_limit 2318492
  freed_anon_pages_by_limit 962052
  freed_file_pages_by_limit 1356440
  elapsed_ns_by_limit 351386416101
  scanned_pages_by_system 0
  scanned_anon_pages_by_system 0
  scanned_file_pages_by_system 0
  rotated_pages_by_system 0
  rotated_anon_pages_by_system 0
  rotated_file_pages_by_system 0
  freed_pages_by_system 0
  freed_anon_pages_by_system 0
  freed_file_pages_by_system 0
  elapsed_ns_by_system 0
  scanned_pages_by_limit_under_hierarchy 9471864
  scanned_anon_pages_by_limit_under_hierarchy 6640629
  scanned_file_pages_by_limit_under_hierarchy 2831235
  rotated_pages_by_limit_under_hierarchy 4243974
  rotated_anon_pages_by_limit_under_hierarchy 3971968
  rotated_file_pages_by_limit_under_hierarchy 272006
  freed_pages_by_limit_under_hierarchy 2318492
  freed_anon_pages_by_limit_under_hierarchy 962052
  freed_file_pages_by_limit_under_hierarchy 1356440
  elapsed_ns_by_limit_under_hierarchy 351386416101
  scanned_pages_by_system_under_hierarchy 0
  scanned_anon_pages_by_system_under_hierarchy 0
  scanned_file_pages_by_system_under_hierarchy 0
  rotated_pages_by_system_under_hierarchy 0
  rotated_anon_pages_by_system_under_hierarchy 0
  rotated_file_pages_by_system_under_hierarchy 0
  freed_pages_by_system_under_hierarchy 0
  freed_anon_pages_by_system_under_hierarchy 0
  freed_file_pages_by_system_under_hierarchy 0
  elapsed_ns_by_system_under_hierarchy 0

total_xxxx is for hierarchy management.

This will be useful for further memcg developments and need to be
developped before we do some complicated rework on LRU/softlimit
management.

This patch adds a new struct memcg_scanrecord into scan_control struct.
sc->nr_scanned at el is not designed for exporting information.  For
example, nr_scanned is reset frequentrly and incremented +2 at scanning
mapped pages.

To avoid complexity, I added a new param in scan_control which is for
exporting scanning score.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Andrew Bresticker <abrestic@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Following commits a9049376 and 0c1aa9a9 update the d_splice_alias
desciption.
Signed-off-by: NPhillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

There have been persistent lockdep RCU splats, indicating that submitters
are not testing with CONFIG_PROVE_RCU.  Add this config option to the list
in Documentation/SubmitChecklist.  Also add CONFIG_DEBUG_OBJECTS_RCU_HEAD
for good measure.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The FSA9480 is a USB port accessory detector and switch.  This patch adds
support the FSA9480 USB Switch.

[akpm@linux-foundation.org: make a couple of things static]
Signed-off-by: NDonggeun Kim <dg77.kim@samsung.com>
Signed-off-by: NMinkyu Kang <mk7.kang@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The badness() function in the oom killer was renamed to oom_badness() in
a63d83f4 ("oom: badness heuristic rewrite") since it is a globally
exported function for clarity.

The prototype for the old function still existed in linux/oom.h, so remove
it.  There are no existing users.

Also fixes documentation and comment references to badness() and adjusts
them accordingly.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In commit a2c8990a ("memsw: remove noswapaccount kernel parameter"),
Michal forgot to remove some left pieces of noswapaccount in the tree,
this patch removes them all.
Signed-off-by: NWANG Cong <xiyou.wangcong@gmail.com>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Declare myself the maintainer of the lm78 driver. I still have a
running system with one of these chips.

Also count myself as a co-author of the driver. With 34 commits over
6 years, it seems fair.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Add chassis intrusion detection support for all supported devices,
using the standard interface.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

This patch adds a new driver for SMSC SCH5636 Super I/O chips.
The chips include an embedded microcontroller for hardware monitoring
solutions, allowing motherboard manufacturers to create their own
custom hwmon solution based upon the SCH5636.

Currently the sch5636 driver only supports the Fujitsu Theseus SCH5636
based hwmon solution. The sch5636 driver runs a sanity check on
loading to ensure it is dealing with a Fujitsu Theseus and not with
another custom SCH5636 based hwmon solution.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Replace the ->check_acl method with a ->get_acl method that simply reads an
ACL from disk after having a cache miss.  This means we can replace the ACL
checking boilerplate code with a single implementation in namei.c.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

In Documentation/filesystems/ext3.txt, the section "useful links"
provides two links which link to ibm developerworks articles. While
the second one can be redirected to the latest one, the first one
   http://www.ibm.com/developerworks/library/l-fs7.html
fails to be redirected.

Update the 2 links to the latest ones.
Signed-off-by: NWang Sheng-Hui <shhuiw@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>

The video= parameter of the DRM drivers supports some additional flags that
the normal fb drivers do not have. They also allow to limit these flags to
specific outputs. Both things were previously undocumented.

Also the parsing of the line had some oddities:
-A lot of misplaced options were silently ignored or partly rejected instead
 of stopping the parsing immediately
-The 'R' option is documented to follow the 'M' option if specified. It is not
 documented that 'M' is needed to specify 'R' (also this is the case for normal
 fb drivers). In fact the code is correct for normal fb drivers but wrong for
 DRM ones.
 The old code allowed 'R' only _before_ 'M' (since it parses backwards) and only
 if 'M' is given at all which is not needed for the DRM drivers.
-the margins option ('m') was parsed but later ignored even if the later
 functions support it.
-specifying multiple enable options at the same time did not lead to an error.
-specifying something bogus for horizontal resolution (i.e. other things as
 digits) did not lead to an error but an invalid resolution was used.

If any errors are encountered the position of the faulting string is now
printed to the user and the complete mode is ignored. This gives much
more consistent error behaviour.

I also removed some useless assignments and changed the local flag variables
to be bool.
Signed-off-by: NRolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Current documentation referred to the old method of handling augmented
trees.  Update documentation to correspond with the changes done in
commit b945d6b2 ("rbtree: Undo augmented trees performance damage
and regression").

Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NSasha Levin <levinsasha928@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The idea is from Avi:
| Maybe it's time to kill off bypass_guest_pf=1.  It's not as effective as
| it used to be, since unsync pages always use shadow_trap_nonpresent_pte,
| and since we convert between the two nonpresent_ptes during sync and unsync.
Signed-off-by: NXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

This patch implements the kvm bits of the steal time infrastructure.
The most important part of it, is the steal time clock. It is an
continuous clock that shows the accumulated amount of steal time
since vcpu creation. It is supposed to survive cpu offlining/onlining.

[marcelo: fix build with CONFIG_KVM_GUEST=n]
Signed-off-by: NGlauber Costa <glommer@redhat.com>
Acked-by: NRik van Riel <riel@redhat.com>
Tested-by: NEric B Munson <emunson@mgebm.net>
CC: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Avi Kivity <avi@redhat.com>
CC: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

After git commit 66ceed5a removed
the tape block device driver, remove its documentation as well.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Some systems benefit from completions always being steered to the strict
requester cpu rather than the looser "per-socket" steering that
blk_cpu_to_group() attempts by default. This is because the first
CPU in the group mask ends up being completely overloaded with work,
while the others (including the original submitter) has power left
to spare.

Allow the strict mode to be set by writing '2' to the sysfs control
file. This is identical to the scheme used for the nomerges file,
where '2' is a more aggressive setting than just being turned on.

echo 2 > /sys/block/<bdev>/queue/rq_affinity

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Roland Dreier <roland@purestorage.com>
Tested-by: NDave Jiang <dave.jiang@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Refresh sysctl/kernel.txt.  More specifically,

 - drop stale index entries
 - sync and sort index and entries
 - reflow sticking out paragraphs to colwidth 72
 - correct typos
 - cleanup whitespace
Signed-off-by: NBorislav Petkov <bp@alien8.de>
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Only the root cpuset has cpuset.memory_pressure_enabled flag,
but not the only one.
Signed-off-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Must echo a task id to the cgroups' tasks file, but not to a directory.
Signed-off-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Also removes a long-unused #define and an extraneous semicolon.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

We used to notify the Host every time we updated a device's status.  However,
it only really needs to know when we're resetting the device, or failed to
initialize it, or when we've finished our feature negotiation.

In particular, we used to wait for VIRTIO_CONFIG_S_DRIVER_OK in the
status byte before starting the device service threads.  But this
corresponds to the successful finish of device initialization, which
might (like virtio_blk's partition scanning) use the device.  So we
had a hack, if they used the device before we expected we started the
threads anyway.

Now we hook into the finalize_features hook in the Guest: at that
point we tell the Launcher that it can rely on the features we have
acked.  On the Launcher side, we look at the status at that point, and
start servicing the device.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Do not exit on some non-fatal errors:

- writev() fails in net_output(). The result is a lost packet or packets.
- writev() fails in console_output(). The result is partially lost console
output.
- readv() fails in net_input(). The result is a lost packet or packets.

Rather than bringing the guest down, this patch ignores e.g. an allocation
failure on the host side. Example:

lguest: page allocation failure. order:4, mode:0x4d0
Pid: 4045, comm: lguest Tainted: G        W   2.6.36 #1
Call Trace:
 [<c138d614>] ? printk+0x18/0x1c
 [<c106a4e2>] __alloc_pages_nodemask+0x4d2/0x570
 [<c1087954>] cache_alloc_refill+0x2a4/0x4d0
 [<c1305149>] ? __netif_receive_skb+0x189/0x270
 [<c1087c5a>] __kmalloc+0xda/0xf0
 [<c12fffa5>] __alloc_skb+0x55/0x100
 [<c1305519>] ? net_rx_action+0x79/0x100
 [<c12fafed>] sock_alloc_send_pskb+0x18d/0x280
 [<c11fda25>] ? _copy_from_user+0x35/0x130
 [<c13010b6>] ? memcpy_fromiovecend+0x56/0x80
 [<c12a74dc>] tun_chr_aio_write+0x1cc/0x500
 [<c108a125>] do_sync_readv_writev+0x95/0xd0
 [<c11fda25>] ? _copy_from_user+0x35/0x130
 [<c1089fa8>] ? rw_copy_check_uvector+0x58/0x100
 [<c108a7bc>] do_readv_writev+0x9c/0x1d0
 [<c12a7310>] ? tun_chr_aio_write+0x0/0x500
 [<c108a93a>] vfs_writev+0x4a/0x60
 [<c108aa21>] sys_writev+0x41/0x80
 [<c138f061>] syscall_call+0x7/0xb
Mem-Info:
DMA per-cpu:
CPU    0: hi:    0, btch:   1 usd:   0
Normal per-cpu:
CPU    0: hi:  186, btch:  31 usd:   0
HighMem per-cpu:
CPU    0: hi:  186, btch:  31 usd:   0
active_anon:134651 inactive_anon:50543 isolated_anon:0
 active_file:96881 inactive_file:132007 isolated_file:0
 unevictable:0 dirty:3 writeback:0 unstable:0
 free:91374 slab_reclaimable:6300 slab_unreclaimable:2802
 mapped:2281 shmem:9 pagetables:330 bounce:0
DMA free:3524kB min:64kB low:80kB high:96kB active_anon:0kB inactive_anon:8kB active_file:8760kB inactive_file:2760kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15868kB mlocked:0kB dirty:0kB writeback:0kB mapped:16kB shmem:0kB slab_reclaimable:88kB slab_unreclaimable:148kB kernel_stack:40kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 865 2016 2016
Normal free:150100kB min:3728kB low:4660kB high:5592kB active_anon:6224kB inactive_anon:15772kB active_file:324084kB inactive_file:325944kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:885944kB mlocked:0kB dirty:12kB writeback:0kB mapped:1520kB shmem:0kB slab_reclaimable:25112kB slab_unreclaimable:11060kB kernel_stack:1888kB pagetables:1320kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 9207 9207
HighMem free:211872kB min:512kB low:1752kB high:2992kB active_anon:532380kB inactive_anon:186392kB active_file:54680kB inactive_file:199324kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:1178504kB mlocked:0kB dirty:0kB writeback:0kB mapped:7588kB shmem:36kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0
DMA: 3*4kB 65*8kB 35*16kB 18*32kB 11*64kB 9*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 3524kB
Normal: 35981*4kB 344*8kB 158*16kB 28*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 150100kB
HighMem: 5732*4kB 5462*8kB 2826*16kB 1598*32kB 84*64kB 10*128kB 7*256kB 1*512kB 1*1024kB 1*2048kB 9*4096kB = 211872kB
231237 total pagecache pages
2340 pages in swap cache
Swap cache stats: add 160060, delete 157720, find 189017/194106
Free swap  = 4179840kB
Total swap = 4194300kB
524271 pages RAM
296946 pages HighMem
5668 pages reserved
867664 pages shared
82155 pages non-shared
Signed-off-by: NSakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Signed-off-by: NPhillip Lougher <phillip@squashfs.org.uk>

This patch adds new information for the driver
especially about its platform structure fields.
Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation about the background and the design of mmc non-blocking.
Host driver guidelines to minimize request preparation overhead.
Signed-off-by: NPer Forlin <per.forlin@linaro.org>
Acked-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NChris Ball <cjb@laptop.org>

All these are instances of
  #define NAME value;
or
  #define NAME(params_opt) value;

These of course fail to build when used in contexts like
  if(foo $OP NAME)
  while(bar $OP NAME)
and may silently generate the wrong code in contexts such as
  foo = NAME + 1;    /* foo = value; + 1; */
  bar = NAME - 1;    /* bar = value; - 1; */
  baz = NAME & quux; /* baz = value; & quux; */

Reported on comp.lang.c,
Message-ID: <ab0d55fe-25e5-482b-811e-c475aa6065c3@c29g2000yqd.googlegroups.com>
Initial analysis of the dangers provided by Keith Thompson in that thread.

There are many more instances of more complicated macros having unnecessary
trailing semicolons, but this pile seems to be all of the cases of simple
values suffering from the problem. (Thus things that are likely to be found
in one of the contexts above, more complicated ones aren't.)
Signed-off-by: NPhil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Btrfs needs to be able to control how filemap_write_and_wait_range() is called
in fsync to make it less of a painful operation, so push down taking i_mutex and
the calling of filemap_write_and_wait() down into the ->fsync() handlers.  Some
file systems can drop taking the i_mutex altogether it seems, like ext3 and
ocfs2.  For correctness sake I just pushed everything down in all cases to make
sure that we keep the current behavior the same for everybody, and then each
individual fs maintainer can make up their mind about what to do from there.
Thanks,
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This just gets us ready to support the SEEK_HOLE and SEEK_DATA flags.  Turns out
using fiemap in things like cp cause more problems than it solves, so lets try
and give userspace an interface that doesn't suck.  We need to match solaris
here, and the definitions are

*o* If /whence/ is SEEK_HOLE, the offset of the start of the
next hole greater than or equal to the supplied offset
is returned. The definition of a hole is provided near
the end of the DESCRIPTION.

*o* If /whence/ is SEEK_DATA, the file pointer is set to the
start of the next non-hole file region greater than or
equal to the supplied offset.

So in the generic case the entire file is data and there is a virtual hole at
the end.  That means we will just return i_size for SEEK_HOLE and will return
the same offset for SEEK_DATA.  This is how Solaris does it so we have to do it
the same way.

Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Now that the per-sb shrinker is responsible for shrinking 2 or more
caches, increase the batch size to keep econmies of scale for
shrinking each cache.  Increase the shrinker batch size to 1024
objects.

To allow for a large increase in batch size, add a conditional
reschedule to prune_icache_sb() so that we don't hold the LRU spin
lock for too long. This mirrors the behaviour of the
__shrink_dcache_sb(), and allows us to increase the batch size
without needing to worry about problems caused by long lock hold
times.

To ensure that filesystems using the per-sb shrinker callouts don't
cause problems, document that the object freeing method must
reschedule appropriately inside loops.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Now we have a per-superblock shrinker implementation, we can add a
filesystem specific callout to it to allow filesystem internal
caches to be shrunk by the superblock shrinker.

Rather than perpetuate the multipurpose shrinker callback API (i.e.
nr_to_scan == 0 meaning "tell me how many objects freeable in the
cache), two operations will be added. The first will return the
number of objects that are freeable, the second is the actual
shrinker call.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>