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2011-12-16unix_diag: Pending connections IDs NLAPavel Emelyanov1-0/+2
When establishing a unix connection on stream sockets the server end receives an skb with socket in its receive queue. Report who is waiting for these ends to be accepted for listening sockets via NLA. There's a lokcing issue with this -- the unix sk state lock is required to access the peer, and it is taken under the listening sk's queue lock. Strictly speaking the queue lock should be taken inside the state lock, but since in this case these two sockets are different it shouldn't lead to deadlock. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-16unix_diag: Unix peer inode NLAPavel Emelyanov1-0/+2
Report the peer socket inode ID as NLA. With this it's finally possible to find out the other end of an interesting unix connection. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-16unix_diag: Unix inode info NLAPavel Emelyanov1-0/+7
Actually, the socket path if it's not anonymous doesn't give a clue to which file the socket is bound to. Even if the path is absolute, it can be unlinked and then new socket can be bound to it. With this NLA it's possible to check which file a particular socket is really bound to. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-16unix_diag: Unix socket name NLAPavel Emelyanov1-0/+8
Report the sun_path when requested as NLA. With leading '\0' if present but without the leading AF_UNIX bits. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-16unix_diag: Basic module skeletonPavel Emelyanov1-0/+24
Includes basic module_init/_exit functionality, dump/get_exact stubs and declares the basic API structures for request and response. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-16sock_diag: Generalize requests cookies managementsPavel Emelyanov2-1/+3
The sk address is used as a cookie between dump/get_exact calls. It will be required for unix socket sdumping, so move it from inet_diag to sock_diag. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-16sock_diag: Move the SOCK_DIAG_BY_FAMILY cmd declarationPavel Emelyanov2-1/+3
It should belong to sock_diag, not inet_diag. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-16Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds1-3/+0
* 'for-linus' of git://git.kernel.dk/linux-block: block: don't kick empty queue in blk_drain_queue() block/swim3: Locking fixes loop: Fix discard_alignment default setting cfq-iosched: fix cfq_cic_link() race confition cfq-iosched: free cic_index if blkio_alloc_blkg_stats fails cciss: fix flush cache transfer length cciss: Add IRQF_SHARED back in for the non-MSI(X) interrupt handler loop: fix loop block driver discard and encryption comment block: initialize request_queue's numa node during
2011-12-16iommu: Export intel_iommu_enabled to signal when iommu is in useEugeni Dodonov1-0/+2
In i915 driver, we do not enable either rc6 or semaphores on SNB when dmar is enabled. The new 'intel_iommu_enabled' variable signals when the iommu code is in operation. Cc: Ted Phelps <phelps@gnusto.com> Cc: Peter <pab1612@gmail.com> Cc: Lukas Hejtmanek <xhejtman@fi.muni.cz> Cc: Andrew Lutomirski <luto@mit.edu> CC: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Eugeni Dodonov <eugeni.dodonov@intel.com> Signed-off-by: Keith Packard <keithp@keithp.com>
2011-12-15Merge branch 'at91/defconfig' into next/cleanupOlof Johansson15-106/+166
2011-12-15cfg80211: validate nl80211 station handling betterJohannes Berg1-1/+5
The nl80211 station handling code is a bit messy and doesn't do a lot of validation. It seems like this could be an issue for drivers that don't use mac80211 to validate everything. As cfg80211 doesn't keep station state, move the validation of allowing supported_rates to change for TDLS only in station mode to mac80211. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-12-15Move limit definitions outside CONFIG_INETGlauber Costa1-1/+1
They need to be available for other protocols as well, since they are used in sock.c openly Signed-off-by: Glauber Costa <glommer@parallels.com> CC: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com> CC: David S. Miller <davem@davemloft.net> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-15[S390] cputime: add sparse checking and cleanupMartin Schwidefsky1-2/+2
Make cputime_t and cputime64_t nocast to enable sparse checking to detect incorrect use of cputime. Drop the cputime macros for simple scalar operations. The conversion macros are still needed. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-12-15iommu/amd: Add invalidate-context call-backJoerg Roedel1-0/+17
This call-back is invoked when the task that is bound to a pasid is about to exit. The driver can use it to shutdown all context related to that context in a safe way. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
2011-12-15iommu/amd: Add amd_iommu_device_info() functionJoerg Roedel1-0/+26
This function can be used to find out which features necessary for IOMMUv2 usage are available on a given device. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
2011-12-15Merge remote-tracking branch 'pci/pri-changes' into x86/amdJoerg Roedel5-18/+28
2011-12-15sched: Mark parent and real_parent as __rcuKees Cook1-2/+2
The parent and real_parent pointers should be considered __rcu, since they should be held under either tasklist_lock or rcu_read_lock. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Link: http://lkml.kernel.org/r/20111214223925.GA27578@www.outflux.net Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-15Merge commit 'v3.2-rc5' into sched/coreIngo Molnar35-146/+210
Merge reason: Pick up the latest fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-15mfd: Declare da9052_regmap_config for the bus driversMark Brown1-0/+2
Fixes build failures. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-12-14edac: convert sysdev_class to a regular subsystemKay Sievers1-4/+4
After all sysdev classes are ported to regular driver core entities, the sysdev implementation will be entirely removed from the kernel. Cc: Doug Thompson <dougthompson@xmission.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Lucas De Marchi <lucas.demarchi@profusion.mobi> Cc: Borislav Petkov <borislav.petkov@amd.com> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-14driver-core: implement 'sysdev' functionality for regular devices and busesKay Sievers1-4/+74
All sysdev classes and sysdev devices will converted to regular devices and buses to properly hook userspace into the event processing. There is no interesting difference between a 'sysdev' and 'device' which would justify to roll an entire own subsystem with different userspace export semantics. Userspace relies on events and generic sysfs subsystem infrastructure from sysdev devices, which are currently not properly available. Every converted sysdev class will create a regular device with the class name in /sys/devices/system and all registered devices will becom a children of theses devices. For compatibility reasons, the sysdev class-wide attributes are created at this parent device. (Do not copy that logic for anything new, subsystem- wide properties belong to the subsystem, not to some fake parent device created in /sys/devices.) Every sysdev driver is implemented as a simple subsystem interface now, and no longer called a driver. After all sysdev classes are ported to regular driver core entities, the sysdev implementation will be entirely removed from the kernel. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-14NFC: Initial LLCP supportSamuel Ortiz1-1/+14
This patch is an initial implementation for the NFC Logical Link Control protocol. It's also known as NFC peer to peer mode. This is a basic implementation as it lacks SDP (services Discovery Protocol), frames aggregation support, and frame rejecion parsing. Follow up patches will implement those missing features. This code has been tested against a Nexus S phone implementing LLCP 1.0. Signed-off-by: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-12-14NFC: Add a DEP link control netlink commandSamuel Ortiz1-0/+14
NFC-DEP (Data Exchange Protocol) is an NFC MAC layer. This command allows to enable and disable the DEP link on to which e.g. LLCP can run. Signed-off-by: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-12-14kref: fix up the kfree build problemsGreg Kroah-Hartman1-5/+10
It turns out that some memory allocators use kobjects, which use krefs, and kref.h was wanting to figure out the address of kfree(), which ended up in a loop. kfree was only being needed for a warning to tell the caller that they were doing something stupid. Now we just move that warning into the comments for the functions, which results in a bit more fun as everyone enjoys digging for people to mock at times of boredom. So, remove the dependancy of slab.h on kref.h, and fix up the other include file as well (we really only need bug.h and atomic.h, not types.h). Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Oliver Neukum <oneukum@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-14Merge branch 'mfd/da9052' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/misc into regmap-nextMark Brown44-150/+1229
2011-12-14MFD: DA9052/53 MFD core moduleAshish Jangam3-0/+918
The DA9052/53 is a highly integrated PMIC subsystem with supply domain flexibility to support wide range of high performance application. It provides voltage regulators, GPIO controller, Touch Screen, RTC, Battery control and other functionality. This patch is functionally tested on Samsung SMDKV6410. Signed-off-by: David Dajun Chen <dchen@diasemi.com> Signed-off-by: Ashish Jangam <ashish.jangam@kpitcummins.com> Acked-by: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-12-14Merge branch 'iommu/page-sizes' into x86/amdJoerg Roedel1-6/+20
Conflicts: drivers/iommu/amd_iommu.c
2011-12-14iommu/amd: Add invalid_ppr callbackJoerg Roedel1-3/+31
This callback can be used to change the PRI response code sent to a device when a PPR fault fails. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
2011-12-14Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcuIngo Molnar6-80/+163
2011-12-13ARM: Orion: Remove address map info from all platform data structuresAndrew Lunn1-3/+0
Signed-off-by: Andrew Lunn <andrew@lunn.ch> Tested-by: Michael Walle <michael@walle.cc> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
2011-12-13ARM: Orion: Get address map from plat-orion instead of via platform_dataAndrew Lunn1-1/+12
Use an getter function in plat-orion/addr-map.c to get the address map structure, rather than pass it to drivers in the platform_data structures. When the drivers are built for none orion platforms, a dummy function is provided instead which returns NULL. Signed-off-by: Andrew Lunn <andrew@lunn.ch> Tested-by: Michael Walle <michael@walle.cc> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
2011-12-14block, cfq: move icq creation and rq->elv.icq association to block coreTejun Heo2-4/+63
Now block layer knows everything necessary to create and associate icq's with requests. Move ioc_create_icq() to blk-ioc.c and update get_request() such that, if elevator_type->icq_size is set, requests are automatically associated with their matching icq's before elv_set_request(). io_context reference is also managed by block core on request alloc/free. * Only ioprio/cgroup changed handling remains from cfq_get_cic(). Collapsed into cfq_set_request(). * This removes queue kicking on icq allocation failure (for now). As icq allocation failure is rare and the only effect of queue kicking achieved was possibily accelerating queue processing, this change shouldn't be noticeable. There is a larger underlying problem. Unlike request allocation, icq allocation is not guaranteed to succeed eventually after retries. The number of icq is unbound and thus mempool can't be the solution either. This effectively adds allocation dependency on memory free path and thus possibility of deadlock. This usually wouldn't happen because icq allocation is not a hot path and, even when the condition triggers, it's highly unlikely that none of the writeback workers already has icq. However, this is still possible especially if elevator is being switched under high memory pressure, so we better get it fixed. Probably the only solution is just bypassing elevator and appending to dispatch queue on any elevator allocation failure. * Comment added to explain how icq's are managed and synchronized. This completes cleanup of io_context interface. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: restructure io_cq creation path for io_context interface cleanupTejun Heo1-0/+2
Add elevator_ops->elevator_init_icq_fn() and restructure cfq_create_cic() and rename it to ioc_create_icq(). The new function expects its caller to pass in io_context, uses elevator_type->icq_cache, handles generic init, calls the new elevator operation for elevator specific initialization, and returns pointer to created or looked up icq. This leaves cfq_icq_pool variable without any user. Removed. This prepares for io_context interface cleanup and doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: move io_cq exit/release to blk-ioc.cTejun Heo2-6/+19
With kmem_cache managed by blk-ioc, io_cq exit/release can be moved to blk-ioc too. The odd ->io_cq->exit/release() callbacks are replaced with elevator_ops->elevator_exit_icq_fn() with unlinking from both ioc and q, and freeing automatically handled by blk-ioc. The elevator operation only need to perform exit operation specific to the elevator - in cfq's case, exiting the cfqq's. Also, clearing of io_cq's on q detach is moved to block core and automatically performed on elevator switch and q release. Because the q io_cq points to might be freed before RCU callback for the io_cq runs, blk-ioc code should remember to which cache the io_cq needs to be freed when the io_cq is released. New field io_cq->__rcu_icq_cache is added for this purpose. As both the new field and rcu_head are used only after io_cq is released and the q/ioc_node fields aren't, they are put into unions. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: move icq cache management to block coreTejun Heo1-1/+10
Let elevators set ->icq_size and ->icq_align in elevator_type and elv_register() and elv_unregister() respectively create and destroy kmem_cache for icq. * elv_register() now can return failure. All callers updated. * icq caches are automatically named "ELVNAME_io_cq". * cfq_slab_setup/kill() are collapsed into cfq_init/exit(). * While at it, minor indentation change for iosched_cfq.elevator_name for consistency. This will help moving icq management to block core. This doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: move cfqd->icq_list to request_queue and add request->elv.icqTejun Heo1-2/+8
Most of icq management is about to be moved out of cfq into blk-ioc. This patch prepares for it. * Move cfqd->icq_list to request_queue->icq_list * Make request explicitly point to icq instead of through elevator private data. ->elevator_private[3] is replaced with sub struct elv which contains icq pointer and priv[2]. cfq is updated accordingly. * Meaningless clearing of ->elevator_private[0] removed from elv_set_request(). At that point in code, the field was guaranteed to be %NULL anyway. This patch doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: reorganize cfq_io_context into generic and cfq specific partsTejun Heo1-29/+14
Currently io_context and cfq logics are mixed without clear boundary. Most of io_context is independent from cfq but cfq_io_context handling logic is dispersed between generic ioc code and cfq. cfq_io_context represents association between an io_context and a request_queue, which is a concept useful outside of cfq, but it also contains fields which are useful only to cfq. This patch takes out generic part and put it into io_cq (io context-queue) and the rest into cfq_io_cq (cic moniker remains the same) which contains io_cq. The following changes are made together. * cfq_ttime and cfq_io_cq now live in cfq-iosched.c. * All related fields, functions and constants are renamed accordingly. * ioc->ioc_data is now "struct io_cq *" instead of "void *" and renamed to icq_hint. This prepares for io_context API cleanup. Documentation is currently sparse. It will be added later. Changes in this patch are mechanical and don't cause functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block: remove elevator_queue->opsTejun Heo1-3/+2
elevator_queue->ops points to the same ops struct ->elevator_type.ops is pointing to. The only effect of caching it in elevator_queue is shorter notation - it doesn't save any indirect derefence. Relocate elevator_type->list which used only during module init/exit to the end of the structure, rename elevator_queue->elevator_type to ->type, and replace elevator_queue->ops with elevator_queue->type.ops. This doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: kill cic->keyTejun Heo1-1/+0
Now that lazy paths are removed, cfqd_dead_key() is meaningless and cic->q can be used whereever cic->key is used. Kill cic->key. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: kill ioc_goneTejun Heo1-17/+0
Now that cic's are immediately unlinked under both locks, there's no need to count and drain cic's before module unload. RCU callback completion is waited with rcu_barrier(). While at it, remove residual RCU operations on cic_list. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: remove delayed unlinkTejun Heo1-1/+0
Now that all cic's are immediately unlinked from both ioc and queue, lazy dropping from lookup path and trimming on elevator unregister are unnecessary. Kill them and remove now unused elevator_ops->trim(). This also leaves call_for_each_cic() without any user. Removed. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: unlink cfq_io_context's immediatelyTejun Heo2-4/+11
cic is association between io_context and request_queue. A cic is linked from both ioc and q and should be destroyed when either one goes away. As ioc and q both have their own locks, locking becomes a bit complex - both orders work for removal from one but not from the other. Currently, cfq tries to circumvent this locking order issue with RCU. ioc->lock nests inside queue_lock but the radix tree and cic's are also protected by RCU allowing either side to walk their lists without grabbing lock. This rather unconventional use of RCU quickly devolves into extremely fragile convolution. e.g. The following is from cfqd going away too soon after ioc and q exits raced. general protection fault: 0000 [#1] PREEMPT SMP CPU 2 Modules linked in: [ 88.503444] Pid: 599, comm: hexdump Not tainted 3.1.0-rc10-work+ #158 Bochs Bochs RIP: 0010:[<ffffffff81397628>] [<ffffffff81397628>] cfq_exit_single_io_context+0x58/0xf0 ... Call Trace: [<ffffffff81395a4a>] call_for_each_cic+0x5a/0x90 [<ffffffff81395ab5>] cfq_exit_io_context+0x15/0x20 [<ffffffff81389130>] exit_io_context+0x100/0x140 [<ffffffff81098a29>] do_exit+0x579/0x850 [<ffffffff81098d5b>] do_group_exit+0x5b/0xd0 [<ffffffff81098de7>] sys_exit_group+0x17/0x20 [<ffffffff81b02f2b>] system_call_fastpath+0x16/0x1b The only real hot path here is cic lookup during request initialization and avoiding extra locking requires very confined use of RCU. This patch makes cic removal from both ioc and request_queue perform double-locking and unlink immediately. * From q side, the change is almost trivial as ioc->lock nests inside queue_lock. It just needs to grab each ioc->lock as it walks cic_list and unlink it. * From ioc side, it's a bit more difficult because of inversed lock order. ioc needs its lock to walk its cic_list but can't grab the matching queue_lock and needs to perform unlock-relock dancing. Unlinking is now wholly done from put_io_context() and fast path is optimized by using the queue_lock the caller already holds, which is by far the most common case. If the ioc accessed multiple devices, it tries with trylock. In unlikely cases of fast path failure, it falls back to full double-locking dance from workqueue. Double-locking isn't the prettiest thing in the world but it's *far* simpler and more understandable than RCU trick without adding any meaningful overhead. This still leaves a lot of now unnecessary RCU logics. Future patches will trim them. -v2: Vivek pointed out that cic->q was being dereferenced after cic->release() was called. Updated to use local variable @this_q instead. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: move ioc ioprio/cgroup changed handling to cicTejun Heo1-5/+9
ioprio/cgroup change was handled by marking the changed state in ioc and, on the following access to the ioc, performing RCU-protected iteration through all cic's grabbing the matching queue_lock. This patch moves the changed state to each cic. When ioprio or cgroup changes, the respective bit is set on all cic's of the ioc and when each of those cic (not ioc) is accessed, change is applied for that specific ioc-queue pair. This also fixes the following two race conditions between setting and clearing of changed states. * Missing barrier between assign/load of ioprio and ioprio_changed allowed applying old ioprio. * Change requests could happen between application of change and clearing of changed variables. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: misc updates to cfq_io_contextTejun Heo1-0/+1
Make the following changes to prepare for ioc/cic management cleanup. * Add cic->q so that ioc can determine the associated queue without querying cfq. This will eventually replace ->key. * Factor out cfq_release_cic() from cic_free_func(). This function assumes that the caller handled locking. * Rename __cfq_exit_single_io_context() to cfq_exit_cic() and make it take only @cic. * Restructure cfq_cic_link() for future updates. This patch doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block: misc updates to blk_get_queue()Tejun Heo1-1/+1
* blk_get_queue() is peculiar in that it returns 0 on success and 1 on failure instead of 0 / -errno or boolean. Update it such that it returns %true on success and %false on failure. * Make sure the caller checks for the return value. * Separate out __blk_get_queue() which doesn't check whether @q is dead and put it in blk.h. This will be used later. This patch doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block: make ioc get/put interface more conventional and fix race on alloctionTejun Heo1-2/+2
Ignoring copy_io() during fork, io_context can be allocated from two places - current_io_context() and set_task_ioprio(). The former is always called from local task while the latter can be called from different task. The synchornization between them are peculiar and dubious. * current_io_context() doesn't grab task_lock() and assumes that if it saw %NULL ->io_context, it would stay that way until allocation and assignment is complete. It has smp_wmb() between alloc/init and assignment. * set_task_ioprio() grabs task_lock() for assignment and does smp_read_barrier_depends() between "ioc = task->io_context" and "if (ioc)". Unfortunately, this doesn't achieve anything - the latter is not a dependent load of the former. ie, if ioc itself were being dereferenced "ioc->xxx", it would mean something (not sure what tho) but as the code currently stands, the dependent read barrier is noop. As only one of the the two test-assignment sequences is task_lock() protected, the task_lock() can't do much about race between the two. Nothing prevents current_io_context() and set_task_ioprio() allocating its own ioc for the same task and overwriting the other's. Also, set_task_ioprio() can race with exiting task and create a new ioc after exit_io_context() is finished. ioc get/put doesn't have any reason to be complex. The only hot path is accessing the existing ioc of %current, which is simple to achieve given that ->io_context is never destroyed as long as the task is alive. All other paths can happily go through task_lock() like all other task sub structures without impacting anything. This patch updates ioc get/put so that it becomes more conventional. * alloc_io_context() is replaced with get_task_io_context(). This is the only interface which can acquire access to ioc of another task. On return, the caller has an explicit reference to the object which should be put using put_io_context() afterwards. * The functionality of current_io_context() remains the same but when creating a new ioc, it shares the code path with get_task_io_context() and always goes through task_lock(). * get_io_context() now means incrementing ref on an ioc which the caller already has access to (be that an explicit refcnt or implicit %current one). * PF_EXITING inhibits creation of new io_context and once exit_io_context() is finished, it's guaranteed that both ioc acquisition functions return %NULL. * All users are updated. Most are trivial but smp_read_barrier_depends() removal from cfq_get_io_context() needs a bit of explanation. I suppose the original intention was to ensure ioc->ioprio is visible when set_task_ioprio() allocates new io_context and installs it; however, this wouldn't have worked because set_task_ioprio() doesn't have wmb between init and install. There are other problems with this which will be fixed in another patch. * While at it, use NUMA_NO_NODE instead of -1 for wildcard node specification. -v2: Vivek spotted contamination from debug patch. Removed. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block: misc ioc cleanupsTejun Heo1-9/+3
* int return from put_io_context() wasn't used by anybody. Make it return void like other put functions and docbook-fy the function comment. * Reorder dummy declarations for !CONFIG_BLOCK case a bit. * Make alloc_ioc_context() use __GFP_ZERO allocation, take init out of if block and drop 0'ing. * Docbook-fy current_io_context() comment. This patch doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, cfq: move cfqd->cic_index to q->idTejun Heo1-0/+6
cfq allocates per-queue id using ida and uses it to index cic radix tree from io_context. Move it to q->id and allocate on queue init and free on queue release. This simplifies cfq a bit and will allow for further improvements of io context life-cycle management. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block: add blk_queue_dead()Tejun Heo1-0/+1
There are a number of QUEUE_FLAG_DEAD tests. Add blk_queue_dead() macro and use it. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14block, sx8: kill blk_insert_request()Tejun Heo1-1/+0
The only user left for blk_insert_request() is sx8 and it can be trivially switched to use blk_execute_rq_nowait() - special requests aren't included in io stat and sx8 doesn't use block layer tagging. Switch sx8 and kill blk_insert_requeset(). This patch doesn't introduce any functional difference. Only compile tested. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Jeff Garzik <jgarzik@pobox.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>