This patch adds a new subdriver to gspca supporting cams with the stv0680
bridge (replacing the old in kernel v4l1 driver).
Many thanks to Hans Verkuil for providing me with one of the 2 cams used in
testing this new sub driver.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (40 commits)
tracing: Separate raw syscall from syscall tracer
ring-buffer-benchmark: Add parameters to set produce/consumer priorities
tracing, function tracer: Clean up strstrip() usage
ring-buffer benchmark: Run producer/consumer threads at nice +19
tracing: Remove the stale include/trace/power.h
tracing: Only print objcopy version warning once from recordmcount
tracing: Prevent build warning: 'ftrace_graph_buf' defined but not used
ring-buffer: Move access to commit_page up into function used
tracing: do not disable interrupts for trace_clock_local
ring-buffer: Add multiple iterations between benchmark timestamps
kprobes: Sanitize struct kretprobe_instance allocations
tracing: Fix to use __always_unused attribute
compiler: Introduce __always_unused
tracing: Exit with error if a weak function is used in recordmcount.pl
tracing: Move conditional into update_funcs() in recordmcount.pl
tracing: Add regex for weak functions in recordmcount.pl
tracing: Move mcount section search to front of loop in recordmcount.pl
tracing: Fix objcopy revision check in recordmcount.pl
tracing: Check absolute path of input file in recordmcount.pl
tracing: Correct the check for number of arguments in recordmcount.pl
...
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (31 commits)
rcu: Make RCU's CPU-stall detector be default
rcu: Add expedited grace-period support for preemptible RCU
rcu: Enable fourth level of TREE_RCU hierarchy
rcu: Rename "quiet" functions
rcu: Re-arrange code to reduce #ifdef pain
rcu: Eliminate unneeded function wrapping
rcu: Fix grace-period-stall bug on large systems with CPU hotplug
rcu: Eliminate __rcu_pending() false positives
rcu: Further cleanups of use of lastcomp
rcu: Simplify association of forced quiescent states with grace periods
rcu: Accelerate callback processing on CPUs not detecting GP end
rcu: Mark init-time-only rcu_bootup_announce() as __init
rcu: Simplify association of quiescent states with grace periods
rcu: Rename dynticks_completed to completed_fqs
rcu: Enable synchronize_sched_expedited() fastpath
rcu: Remove inline from forward-referenced functions
rcu: Fix note_new_gpnum() uses of ->gpnum
rcu: Fix synchronization for rcu_process_gp_end() uses of ->completed counter
rcu: Prepare for synchronization fixes: clean up for non-NO_HZ handling of ->completed counter
rcu: Cleanup: balance rcu_irq_enter()/rcu_irq_exit() calls
...
* 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ratelimit: Make suppressed output messages more useful
printk: Remove ratelimit.h from kernel.h
ratelimit: Fix/allow use in atomic contexts
ratelimit: Use per ratelimit context locking
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
mutex: Fix missing conditions to build mutex_spin_on_owner()
mutex: Better control mutex adaptive spinning config
locking, task_struct: Reduce size on TRACE_IRQFLAGS and 64bit
locking: Use __[SPIN|RW]_LOCK_UNLOCKED in [spin|rw]_lock_init()
locking: Remove unused prototype
locking: Reduce ifdefs in kernel/spinlock.c
locking: Make inlining decision Kconfig based
* 'core-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits)
x86, Calgary IOMMU quirk: Find nearest matching Calgary while walking up the PCI tree
x86/amd-iommu: Remove amd_iommu_pd_table
x86/amd-iommu: Move reset_iommu_command_buffer out of locked code
x86/amd-iommu: Cleanup DTE flushing code
x86/amd-iommu: Introduce iommu_flush_device() function
x86/amd-iommu: Cleanup attach/detach_device code
x86/amd-iommu: Keep devices per domain in a list
x86/amd-iommu: Add device bind reference counting
x86/amd-iommu: Use dev->arch->iommu to store iommu related information
x86/amd-iommu: Remove support for domain sharing
x86/amd-iommu: Rearrange dma_ops related functions
x86/amd-iommu: Move some pte allocation functions in the right section
x86/amd-iommu: Remove iommu parameter from dma_ops_domain_alloc
x86/amd-iommu: Use get_device_id and check_device where appropriate
x86/amd-iommu: Move find_protection_domain to helper functions
x86/amd-iommu: Simplify get_device_resources()
x86/amd-iommu: Let domain_for_device handle aliases
x86/amd-iommu: Remove iommu specific handling from dma_ops path
x86/amd-iommu: Remove iommu parameter from __(un)map_single
x86/amd-iommu: Make alloc_new_range aware of multiple IOMMUs
...
* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw: (31 commits)
GFS2: Fix glock refcount issues
writeback: remove unused nonblocking and congestion checks (gfs2)
GFS2: drop rindex glock to refresh rindex list
GFS2: Tag all metadata with jid
GFS2: Locking order fix in gfs2_check_blk_state
GFS2: Remove dirent_first() function
GFS2: Display nobarrier option in /proc/mounts
GFS2: add barrier/nobarrier mount options
GFS2: remove division from new statfs code
GFS2: Improve statfs and quota usability
GFS2: Use dquot_send_warning()
VFS: Export dquot_send_warning
GFS2: Add set_xquota support
GFS2: Add get_xquota support
GFS2: Clean up gfs2_adjust_quota() and do_glock()
GFS2: Remove constant argument from qd_get()
GFS2: Remove constant argument from qdsb_get()
GFS2: Add proper error reporting to quota sync via sysfs
GFS2: Add get_xstate quota function
GFS2: Remove obsolete code in quota.c
...
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (30 commits)
TOMOYO: Add recursive directory matching operator support.
remove CONFIG_SECURITY_FILE_CAPABILITIES compile option
SELinux: print denials for buggy kernel with unknown perms
Silence the existing API for capability version compatibility check.
LSM: Move security_path_chmod()/security_path_chown() to after mutex_lock().
SELinux: header generation may hit infinite loop
selinux: Fix warnings
security: report the module name to security_module_request
Config option to set a default LSM
sysctl: require CAP_SYS_RAWIO to set mmap_min_addr
tpm: autoload tpm_tis based on system PnP IDs
tpm_tis: TPM_STS_DATA_EXPECT workaround
define convenient securebits masks for prctl users (v2)
tpm: fix header for modular build
tomoyo: improve hash bucket dispersion
tpm add default function definitions
LSM: imbed ima calls in the security hooks
SELinux: add .gitignore files for dynamic classes
security: remove root_plug
SELinux: fix locking issue introduced with c6d3aaa4e3
...
Starting with version 4.5, GCC has a new built-in function
__builtin_unreachable() that can be used in places like the kernel's
BUG() where inline assembly is used to transfer control flow. This
eliminated the need for an endless loop in these places.
The patch adds a new macro 'unreachable()' that will expand to either
__builtin_unreachable() or an endless loop depending on the compiler
version.
Change from v1: Simplify unreachable() for non-GCC 4.5 case.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are two spare field in the header common to all GFS2
metadata. One is just the right size to fit a journal id
in it, and this patch updates the journal code so that each
time a metadata block is modified, we tag it with the journal
id of the node which is performing the modification.
The reason for this is that it should make it much easier to
debug issues which arise if we can tell which node was the
last to modify a particular metadata block.
Since the field is updated before the block is written into
the journal, each journal should only contain metadata which
is tagged with its own journal id. The one exception to this
is the journal header block, which might have a different node's
id in it, if that journal was recovered by another node in the
cluster.
Thus each journal will contain a record of which nodes recovered
it, via the journal header.
The other field in the metadata header could potentially be
used to hold information about what kind of operation was
performed, but for the time being we just zero it on each
transaction so that if we use it for that in future, we'll
know that the information (where it exists) is reliable.
I did consider using the other field to hold the journal
sequence number, however since in GFS2's journaling we write
the modified data into the journal and not the original
data, this gives no information as to what action caused the
modification, so I think we can probably come up with a better
use for those 64 bits in the future.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Sending a message to userspace in a generic format to warn
of events (e.g. quota exceeded) in the quota subsystem is
a generically useful feature. This patch makes some minor
changes to the send_message function from dquot.c renaming
it quota_send_message, moving it to quota.c and exporting it
for use by filesystems which do not use the dquot code.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This is required for cluster filesystems which want to use
cached ACLs so that they can invalidate the cache when
required.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Alexander Viro <aviro@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Reorder task_struct field for TRACE_IRQFLAGS to remove padding
on 64-bit.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4B135F50.8070302@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There was confusion between the array size and the highest ISEL
value possible.
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-fscache: (31 commits)
FS-Cache: Provide nop fscache_stat_d() if CONFIG_FSCACHE_STATS=n
SLOW_WORK: Fix GFS2 to #include <linux/module.h> before using THIS_MODULE
SLOW_WORK: Fix CIFS to pass THIS_MODULE to slow_work_register_user()
CacheFiles: Don't log lookup/create failing with ENOBUFS
CacheFiles: Catch an overly long wait for an old active object
CacheFiles: Better showing of debugging information in active object problems
CacheFiles: Mark parent directory locks as I_MUTEX_PARENT to keep lockdep happy
CacheFiles: Handle truncate unlocking the page we're reading
CacheFiles: Don't write a full page if there's only a partial page to cache
FS-Cache: Actually requeue an object when requested
FS-Cache: Start processing an object's operations on that object's death
FS-Cache: Make sure FSCACHE_COOKIE_LOOKING_UP cleared on lookup failure
FS-Cache: Add a retirement stat counter
FS-Cache: Handle pages pending storage that get evicted under OOM conditions
FS-Cache: Handle read request vs lookup, creation or other cache failure
FS-Cache: Don't delete pending pages from the page-store tracking tree
FS-Cache: Fix lock misorder in fscache_write_op()
FS-Cache: The object-available state can't rely on the cookie to be available
FS-Cache: Permit cache retrieval ops to be interrupted in the initial wait phase
FS-Cache: Use radix tree preload correctly in tracking of pages to be stored
...
SPIN_LOCK_UNLOCKED and RW_LOCK_UNLOCKED are deprecated. Replace them
with the __*_LOCK_UNLOCKED variants.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
commit 910067d1(remove generic__raw_read_trylock()) removed the
implementation but left the prototype around. Remove it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
As far as I know, all distros currently ship kernels with default
CONFIG_SECURITY_FILE_CAPABILITIES=y. Since having the option on
leaves a 'no_file_caps' option to boot without file capabilities,
the main reason to keep the option is that turning it off saves
you (on my s390x partition) 5k. In particular, vmlinux sizes
came to:
without patch fscaps=n: 53598392
without patch fscaps=y: 53603406
with this patch applied: 53603342
with the security-next tree.
Against this we must weigh the fact that there is no simple way for
userspace to figure out whether file capabilities are supported,
while things like per-process securebits, capability bounding
sets, and adding bits to pI if CAP_SETPCAP is in pE are not supported
with SECURITY_FILE_CAPABILITIES=n, leaving a bit of a problem for
applications wanting to know whether they can use them and/or why
something failed.
It also adds another subtly different set of semantics which we must
maintain at the risk of severe security regressions.
So this patch removes the SECURITY_FILE_CAPABILITIES compile
option. It drops the kernel size by about 50k over the stock
SECURITY_FILE_CAPABILITIES=y kernel, by removing the
cap_limit_ptraced_target() function.
Changelog:
Nov 20: remove cap_limit_ptraced_target() as it's logic
was ifndef'ed.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: Andrew G. Morgan" <morgan@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
As this struct is exposed to user space and the API was added for this
release it's a bit of a pain for the C++ world and we still have time to
fix it. Rename the fields before we end up with that pain in an actual
release.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Reported-by: Olivier Goffart
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Catch an overly long wait for an old, dying active object when we want to
replace it with a new one. The probability is that all the slow-work threads
are hogged, and the delete can't get a look in.
What we do instead is:
(1) if there's nothing in the slow work queue, we sleep until either the dying
object has finished dying or there is something in the slow work queue
behind which we can queue our object.
(2) if there is something in the slow work queue, we return ETIMEDOUT to
fscache_lookup_object(), which then puts us back on the slow work queue,
presumably behind the deletion that we're blocked by. We are then
deferred for a while until we work our way back through the queue -
without blocking a slow-work thread unnecessarily.
A backtrace similar to the following may appear in the log without this patch:
INFO: task kslowd004:5711 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kslowd004 D 0000000000000000 0 5711 2 0x00000080
ffff88000340bb80 0000000000000046 ffff88002550d000 0000000000000000
ffff88002550d000 0000000000000007 ffff88000340bfd8 ffff88002550d2a8
000000000000ddf0 00000000000118c0 00000000000118c0 ffff88002550d2a8
Call Trace:
[<ffffffff81058e21>] ? trace_hardirqs_on+0xd/0xf
[<ffffffffa011c4d8>] ? cachefiles_wait_bit+0x0/0xd [cachefiles]
[<ffffffffa011c4e1>] cachefiles_wait_bit+0x9/0xd [cachefiles]
[<ffffffff81353153>] __wait_on_bit+0x43/0x76
[<ffffffff8111ae39>] ? ext3_xattr_get+0x1ec/0x270
[<ffffffff813531ef>] out_of_line_wait_on_bit+0x69/0x74
[<ffffffffa011c4d8>] ? cachefiles_wait_bit+0x0/0xd [cachefiles]
[<ffffffff8104c125>] ? wake_bit_function+0x0/0x2e
[<ffffffffa011bc79>] cachefiles_mark_object_active+0x203/0x23b [cachefiles]
[<ffffffffa011c209>] cachefiles_walk_to_object+0x558/0x827 [cachefiles]
[<ffffffffa011a429>] cachefiles_lookup_object+0xac/0x12a [cachefiles]
[<ffffffffa00aa1e9>] fscache_lookup_object+0x1c7/0x214 [fscache]
[<ffffffffa00aafc5>] fscache_object_state_machine+0xa5/0x52d [fscache]
[<ffffffffa00ab4ac>] fscache_object_slow_work_execute+0x5f/0xa0 [fscache]
[<ffffffff81082093>] slow_work_execute+0x18f/0x2d1
[<ffffffff8108239a>] slow_work_thread+0x1c5/0x308
[<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
[<ffffffff810821d5>] ? slow_work_thread+0x0/0x308
[<ffffffff8104be91>] kthread+0x7a/0x82
[<ffffffff8100beda>] child_rip+0xa/0x20
[<ffffffff8100b87c>] ? restore_args+0x0/0x30
[<ffffffff8104be17>] ? kthread+0x0/0x82
[<ffffffff8100bed0>] ? child_rip+0x0/0x20
1 lock held by kslowd004/5711:
#0: (&sb->s_type->i_mutex_key#7/1){+.+.+.}, at: [<ffffffffa011be64>] cachefiles_walk_to_object+0x1b3/0x827 [cachefiles]
Signed-off-by: David Howells <dhowells@redhat.com>
cachefiles_write_page() writes a full page to the backing file for the last
page of the netfs file, even if the netfs file's last page is only a partial
page.
This causes the EOF on the backing file to be extended beyond the EOF of the
netfs, and thus the backing file will be truncated by cachefiles_attr_changed()
called from cachefiles_lookup_object().
So we need to limit the write we make to the backing file on that last page
such that it doesn't push the EOF too far.
Also, if a backing file that has a partial page at the end is expanded, we
discard the partial page and refetch it on the basis that we then have a hole
in the file with invalid data, and should the power go out... A better way to
deal with this could be to record a note that the partial page contains invalid
data until the correct data is written into it.
This isn't a problem for netfs's that discard the whole backing file if the
file size changes (such as NFS).
Signed-off-by: David Howells <dhowells@redhat.com>
Start processing an object's operations when that object moves into the DYING
state as the object cannot be destroyed until all its outstanding operations
have completed.
Furthermore, make sure that read and allocation operations handle being woken
up on a dead object. Such events are recorded in the Allocs.abt and
Retrvls.abt statistics as viewable through /proc/fs/fscache/stats.
The code for waiting for object activation for the read and allocation
operations is also extracted into its own function as it is much the same in
all cases, differing only in the stats incremented.
Signed-off-by: David Howells <dhowells@redhat.com>
Handle netfs pages that the vmscan algorithm wants to evict from the pagecache
under OOM conditions, but that are waiting for write to the cache. Under these
conditions, vmscan calls the releasepage() function of the netfs, asking if a
page can be discarded.
The problem is typified by the following trace of a stuck process:
kslowd005 D 0000000000000000 0 4253 2 0x00000080
ffff88001b14f370 0000000000000046 ffff880020d0d000 0000000000000007
0000000000000006 0000000000000001 ffff88001b14ffd8 ffff880020d0d2a8
000000000000ddf0 00000000000118c0 00000000000118c0 ffff880020d0d2a8
Call Trace:
[<ffffffffa00782d8>] __fscache_wait_on_page_write+0x8b/0xa7 [fscache]
[<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
[<ffffffffa0078240>] ? __fscache_check_page_write+0x63/0x70 [fscache]
[<ffffffffa00b671d>] nfs_fscache_release_page+0x4e/0xc4 [nfs]
[<ffffffffa00927f0>] nfs_release_page+0x3c/0x41 [nfs]
[<ffffffff810885d3>] try_to_release_page+0x32/0x3b
[<ffffffff81093203>] shrink_page_list+0x316/0x4ac
[<ffffffff8109372b>] shrink_inactive_list+0x392/0x67c
[<ffffffff813532fa>] ? __mutex_unlock_slowpath+0x100/0x10b
[<ffffffff81058df0>] ? trace_hardirqs_on_caller+0x10c/0x130
[<ffffffff8135330e>] ? mutex_unlock+0x9/0xb
[<ffffffff81093aa2>] shrink_list+0x8d/0x8f
[<ffffffff81093d1c>] shrink_zone+0x278/0x33c
[<ffffffff81052d6c>] ? ktime_get_ts+0xad/0xba
[<ffffffff81094b13>] try_to_free_pages+0x22e/0x392
[<ffffffff81091e24>] ? isolate_pages_global+0x0/0x212
[<ffffffff8108e743>] __alloc_pages_nodemask+0x3dc/0x5cf
[<ffffffff81089529>] grab_cache_page_write_begin+0x65/0xaa
[<ffffffff8110f8c0>] ext3_write_begin+0x78/0x1eb
[<ffffffff81089ec5>] generic_file_buffered_write+0x109/0x28c
[<ffffffff8103cb69>] ? current_fs_time+0x22/0x29
[<ffffffff8108a509>] __generic_file_aio_write+0x350/0x385
[<ffffffff8108a588>] ? generic_file_aio_write+0x4a/0xae
[<ffffffff8108a59e>] generic_file_aio_write+0x60/0xae
[<ffffffff810b2e82>] do_sync_write+0xe3/0x120
[<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
[<ffffffff810b18e1>] ? __dentry_open+0x1a5/0x2b8
[<ffffffff810b1a76>] ? dentry_open+0x82/0x89
[<ffffffffa00e693c>] cachefiles_write_page+0x298/0x335 [cachefiles]
[<ffffffffa0077147>] fscache_write_op+0x178/0x2c2 [fscache]
[<ffffffffa0075656>] fscache_op_execute+0x7a/0xd1 [fscache]
[<ffffffff81082093>] slow_work_execute+0x18f/0x2d1
[<ffffffff8108239a>] slow_work_thread+0x1c5/0x308
[<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
[<ffffffff810821d5>] ? slow_work_thread+0x0/0x308
[<ffffffff8104be91>] kthread+0x7a/0x82
[<ffffffff8100beda>] child_rip+0xa/0x20
[<ffffffff8100b87c>] ? restore_args+0x0/0x30
[<ffffffff8102ef83>] ? tg_shares_up+0x171/0x227
[<ffffffff8104be17>] ? kthread+0x0/0x82
[<ffffffff8100bed0>] ? child_rip+0x0/0x20
In the above backtrace, the following is happening:
(1) A page storage operation is being executed by a slow-work thread
(fscache_write_op()).
(2) FS-Cache farms the operation out to the cache to perform
(cachefiles_write_page()).
(3) CacheFiles is then calling Ext3 to perform the actual write, using Ext3's
standard write (do_sync_write()) under KERNEL_DS directly from the netfs
page.
(4) However, for Ext3 to perform the write, it must allocate some memory, in
particular, it must allocate at least one page cache page into which it
can copy the data from the netfs page.
(5) Under OOM conditions, the memory allocator can't immediately come up with
a page, so it uses vmscan to find something to discard
(try_to_free_pages()).
(6) vmscan finds a clean netfs page it might be able to discard (possibly the
one it's trying to write out).
(7) The netfs is called to throw the page away (nfs_release_page()) - but it's
called with __GFP_WAIT, so the netfs decides to wait for the store to
complete (__fscache_wait_on_page_write()).
(8) This blocks a slow-work processing thread - possibly against itself.
The system ends up stuck because it can't write out any netfs pages to the
cache without allocating more memory.
To avoid this, we make FS-Cache cancel some writes that aren't in the middle of
actually being performed. This means that some data won't make it into the
cache this time. To support this, a new FS-Cache function is added
fscache_maybe_release_page() that replaces what the netfs releasepage()
functions used to do with respect to the cache.
The decisions fscache_maybe_release_page() makes are counted and displayed
through /proc/fs/fscache/stats on a line labelled "VmScan". There are four
counters provided: "nos=N" - pages that weren't pending storage; "gon=N" -
pages that were pending storage when we first looked, but weren't by the time
we got the object lock; "bsy=N" - pages that we ignored as they were actively
being written when we looked; and "can=N" - pages that we cancelled the storage
of.
What I'd really like to do is alter the behaviour of the cancellation
heuristics, depending on how necessary it is to expel pages. If there are
plenty of other pages that aren't waiting to be written to the cache that
could be ejected first, then it would be nice to hold up on immediate
cancellation of cache writes - but I don't see a way of doing that.
Signed-off-by: David Howells <dhowells@redhat.com>
FS-Cache has two structs internally for keeping track of the internal state of
a cached file: the fscache_cookie struct, which represents the netfs's state,
and fscache_object struct, which represents the cache's state. Each has a
pointer that points to the other (when both are in existence), and each has a
spinlock for pointer maintenance.
Since netfs operations approach these structures from the cookie side, they get
the cookie lock first, then the object lock. Cache operations, on the other
hand, approach from the object side, and get the object lock first. It is not
then permitted for a cache operation to get the cookie lock whilst it is
holding the object lock lest deadlock occur; instead, it must do one of two
things:
(1) increment the cookie usage counter, drop the object lock and then get both
locks in order, or
(2) simply hold the object lock as certain parts of the cookie may not be
altered whilst the object lock is held.
It is also not permitted to follow either pointer without holding the lock at
the end you start with. To break the pointers between the cookie and the
object, both locks must be held.
fscache_write_op(), however, violates the locking rules: It attempts to get the
cookie lock without (a) checking that the cookie pointer is a valid pointer,
and (b) holding the object lock to protect the cookie pointer whilst it follows
it. This is so that it can access the pending page store tree without
interference from __fscache_write_page().
This is fixed by splitting the cookie lock, such that the page store tracking
tree is protected by its own lock, and checking that the cookie pointer is
non-NULL before we attempt to follow it whilst holding the object lock.
The new lock is subordinate to both the cookie lock and the object lock, and so
should be taken after those.
Signed-off-by: David Howells <dhowells@redhat.com>
Allow the current state of all fscache objects to be dumped by doing:
cat /proc/fs/fscache/objects
By default, all objects and all fields will be shown. This can be restricted
by adding a suitable key to one of the caller's keyrings (such as the session
keyring):
keyctl add user fscache:objlist "<restrictions>" @s
The <restrictions> are:
K Show hexdump of object key (don't show if not given)
A Show hexdump of object aux data (don't show if not given)
And paired restrictions:
C Show objects that have a cookie
c Show objects that don't have a cookie
B Show objects that are busy
b Show objects that aren't busy
W Show objects that have pending writes
w Show objects that don't have pending writes
R Show objects that have outstanding reads
r Show objects that don't have outstanding reads
S Show objects that have slow work queued
s Show objects that don't have slow work queued
If neither side of a restriction pair is given, then both are implied. For
example:
keyctl add user fscache:objlist KB @s
shows objects that are busy, and lists their object keys, but does not dump
their auxiliary data. It also implies "CcWwRrSs", but as 'B' is given, 'b' is
not implied.
Signed-off-by: David Howells <dhowells@redhat.com>
Annotate slow-work runqueue proc lines for FS-Cache work items. Objects
include the object ID and the state. Operations include the object ID, the
operation ID and the operation type and state.
Signed-off-by: David Howells <dhowells@redhat.com>
Add a function to allow a requeueable work item to sleep till the thread
processing it is needed by the slow-work facility to perform other work.
Sometimes a work item can't progress immediately, but must wait for the
completion of another work item that's currently being processed by another
slow-work thread.
In some circumstances, the waiting item could instead - theoretically - put
itself back on the queue and yield its thread back to the slow-work facility,
thus waiting till it gets processing time again before attempting to progress.
This would allow other work items processing time on that thread.
However, this only works if there is something on the queue for it to queue
behind - otherwise it will just get a thread again immediately, and will end
up cycling between the queue and the thread, eating up valuable CPU time.
So, slow_work_sleep_till_thread_needed() is provided such that an item can put
itself on a wait queue that will wake it up when the event it is actually
interested in occurs, then call this function in lieu of calling schedule().
This function will then sleep until either the item's event occurs or another
work item appears on the queue. If another work item is queued, but the
item's event hasn't occurred, then the work item should requeue itself and
yield the thread back to the slow-work facility by returning.
This can be used by CacheFiles for an object that is being created on one
thread to wait for an object being deleted on another thread where there is
nothing on the queue for the creation to go and wait behind. As soon as an
item appears on the queue that could be given thread time instead, CacheFiles
can stick the creating object back on the queue and return to the slow-work
facility - assuming the object deletion didn't also complete.
Signed-off-by: David Howells <dhowells@redhat.com>
Add a function (slow_work_is_queued()) to permit the owner of a work item to
determine if the item is queued or not.
The work item is counted as being queued if it is actually on the queue, not
just if it is pending. If it is executing and pending, then it is not on the
queue, but will rather be put back on the queue when execution finishes.
This permits a caller to quickly work out if it may be able to put another,
dependent work item on the queue behind it, or whether it will have to wait
till that is finished.
This can be used by CacheFiles to work out whether the creation a new object
can be immediately deferred when it has to wait for an old object to be
deleted, or whether a wait must take place. If a wait is necessary, then the
slow-work thread can otherwise get blocked, preventing the deletion from
taking place.
Signed-off-by: David Howells <dhowells@redhat.com>
This adds support for starting slow work with a delay, similar
to the functionality we have for workqueues.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Add support for cancellation of queued slow work and delayed slow work items.
The cancellation functions will wait for items that are pending or undergoing
execution to be discarded by the slow work facility.
Attempting to enqueue work that is in the process of being cancelled will
result in ECANCELED.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Wait for outstanding slow work items belonging to a module to clear when
unregistering that module as a user of the facility. This prevents the put_ref
code of a work item from being taken away before it returns.
Signed-off-by: David Howells <dhowells@redhat.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (42 commits)
cxgb3: fix premature page unmap
ibm_newemac: Fix EMACx_TRTR[TRT] bit shifts
vlan: Fix register_vlan_dev() error path
gro: Fix illegal merging of trailer trash
sungem: Fix Serdes detection.
net: fix mdio section mismatch warning
ppp: fix BUG on non-linear SKB (multilink receive)
ixgbe: Fixing EEH handler to handle more than one error
net: Fix the rollback test in dev_change_name()
Revert "isdn: isdn_ppp: Use SKB list facilities instead of home-grown implementation."
TI Davinci EMAC : Fix Console Hang when bringing the interface down
smsc911x: Fix Console Hang when bringing the interface down.
mISDN: fix error return in HFCmulti_init()
forcedeth: mac address fix
r6040: fix version printing
Bluetooth: Fix regression with L2CAP configuration in Basic Mode
Bluetooth: Select Basic Mode as default for SOCK_SEQPACKET
Bluetooth: Set general bonding security for ACL by default
r8169: Fix receive buffer length when MTU is between 1515 and 1536
can: add the missing netlink get_xstats_size callback
...
Andrew points out that acpi-cpufreq uses cpumask_any, when it really
would prefer to use the same CPU if possible (to avoid an IPI). In
general, this seems a good idea to offer.
[ tglx: Documented selection preference and Inlined the UP case to
avoid the copy of smp_call_function_single() and the extra
EXPORT ]
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Zhao Yakui <yakui.zhao@intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Allow memory hotplug and hibernation in the same kernel
Memory hotplug and hibernation were exclusive in Kconfig. This is
obviously a problem for distribution kernels who want to support both in
the same image.
After some discussions with Rafael and others the only problem is with
parallel memory hotadd or removal while a hibernation operation is in
process. It was also working for s390 before.
This patch removes the Kconfig level exclusion, and simply makes the
memory add / remove functions grab the pm_mutex to exclude against
hibernation.
Fixes a regression - old kernels didn't exclude memory hotadd and
hibernation.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
