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* aio: lookup_ioctx can return the wrong value when looking up a bogus contextJeff Moyer2009-03-191-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | The libaio test harness turned up a problem whereby lookup_ioctx on a bogus io context was returning the 1 valid io context from the list (harness/cases/3.p). Because of that, an extra put_iocontext was done, and when the process exited, it hit a BUG_ON in the put_iocontext macro called from exit_aio (since we expect a users count of 1 and instead get 0). The problem was introduced by "aio: make the lookup_ioctx() lockless" (commit abf137dd7712132ee56d5b3143c2ff61a72a5faa). Thanks to Zach for pointing out that hlist_for_each_entry_rcu will not return with a NULL tpos at the end of the loop, even if the entry was not found. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Zach Brown <zach.brown@oracle.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* eventfd: remove fput() call from possible IRQ contextDavide Libenzi2009-03-191-10/+27
| | | | | | | | | | | | | | | | | | | | | Remove a source of fput() call from inside IRQ context. Myself, like Eric, wasn't able to reproduce an fput() call from IRQ context, but Jeff said he was able to, with the attached test program. Independently from this, the bug is conceptually there, so we might be better off fixing it. This patch adds an optimization similar to the one we already do on ->ki_filp, on ->ki_eventfd. Playing with ->f_count directly is not pretty in general, but the alternative here would be to add a brand new delayed fput() infrastructure, that I'm not sure is worth it. Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Cc: Zach Brown <zach.brown@oracle.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [CVE-2009-0029] System call wrappers part 16Heiko Carstens2009-01-141-11/+11
| | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* aio: make the lookup_ioctx() locklessJens Axboe2008-12-291-44/+56
| | | | | | | | | | | | | | The mm->ioctx_list is currently protected by a reader-writer lock, so we always grab that lock on the read side for doing ioctx lookups. As the workload is extremely reader biased, turn this into an rcu hlist so we can make lookup_ioctx() lockless. Get rid of the rwlock and use a spinlock for providing update side exclusion. There's usually only 1 entry on this list, so it doesn't make sense to look into fancier data structures. Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* [PATCH] f_count may wrap aroundAl Viro2008-07-261-3/+3
| | | | | | | make it atomic_long_t; while we are at it, get rid of useless checks in affs, hfs and hpfs - ->open() always has it equal to 1, ->release() - to 0. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* kill PF_BORROWED_MM in favour of PF_KTHREADOleg Nesterov2008-07-251-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kill PF_BORROWED_MM. Change use_mm/unuse_mm to not play with ->flags, and do s/PF_BORROWED_MM/PF_KTHREAD/ for a couple of other users. No functional changes yet. But this allows us to do further fixes/cleanups. oom_kill/ptrace/etc often check "p->mm != NULL" to filter out the kthreads, this is wrong because of use_mm(). The problem with PF_BORROWED_MM is that we need task_lock() to avoid races. With this patch we can check PF_KTHREAD directly, or use a simple lockless helper: /* The result must not be dereferenced !!! */ struct mm_struct *__get_task_mm(struct task_struct *tsk) { if (tsk->flags & PF_KTHREAD) return NULL; return tsk->mm; } Note also ecard_task(). It runs with ->mm != NULL, but it's the kernel thread without PF_BORROWED_MM. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: activate_mm: remove the dead PF_BORROWED_MM checkOleg Nesterov2008-06-061-4/+0
| | | | | | | | | | | | | | use_mm() was changed to use switch_mm() instead of activate_mm(), since then nobody calls (and nobody should call) activate_mm() with PF_BORROWED_MM bit set. As Jeff Dike pointed out, we can also remove the "old != new" check, it is always true. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* debugobjects: add timer specific object debugging codeThomas Gleixner2008-04-301-3/+2
| | | | | | | | | | | | | | Add calls to the generic object debugging infrastructure and provide fixup functions which allow to keep the system alive when recoverable problems have been detected by the object debugging core code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Greg KH <greg@kroah.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* aio: fix misleading commentsJeff Moyer2008-04-291-4/+1
| | | | | | | | | | | The FIXME comments are inaccurate. The locking comment over lookup_ioctx() is wrong. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Shen Feng <shen@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Remove duplicated unlikely() in IS_ERR()Hirofumi Nakagawa2008-04-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | Some drivers have duplicated unlikely() macros. IS_ERR() already has unlikely() in itself. This patch cleans up such pointless code. Signed-off-by: Hirofumi Nakagawa <hnakagawa@miraclelinux.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Jeff Garzik <jeff@garzik.org> Cc: Paul Clements <paul.clements@steeleye.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: David Brownell <david-b@pacbell.net> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Carsten Otte <cotte@de.ibm.com> Cc: Patrick McHardy <kaber@trash.net> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jaroslav Kysela <perex@perex.cz> Cc: Takashi Iwai <tiwai@suse.de> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/aio.c: make 3 functions staticAdrian Bunk2008-04-291-28/+39
| | | | | | | | | | | | | | | Make the following needlessly global functions static: - __put_ioctx() - lookup_ioctx() - io_submit_one() Signed-off-by: Adrian Bunk <bunk@kernel.org> Cc: Zach Brown <zach.brown@oracle.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* aio: io_getevents() should return if io_destroy() is invokedJeff Moyer2008-04-281-1/+11
| | | | | | | | | | | | | | | | This patch wakes up a thread waiting in io_getevents if another thread destroys the context. This was tested using a small program that spawns a thread to wait in io_getevents while the parent thread destroys the io context and then waits for the getevents thread to exit. Without this patch, the program hangs indefinitely. With the patch, the program exits as expected. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Cc: Zach Brown <zach.brown@oracle.com> Cc: Christopher Smith <x@xman.org> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* eventfd/kaio integration fixDavide Libenzi2008-04-111-8/+9
| | | | | | | | | | | | | | | Jeff Roberson discovered a race when using kaio eventfd based notifications. When it occurs it can lead tomissed wakeups and hung userspace. This patch fixes the race by moving the notification inside the spinlocked section of kaio. The operation is safe since eventfd spinlock and kaio one are unrelated. Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: Zach Brown <zach.brown@oracle.com> Cc: Jeff Roberson <jroberson@chesapeake.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* asmlinkage_protect sys_io_geteventsRoland McGrath2008-04-101-0/+1
| | | | | | | | | | | Use asmlinkage_protect in sys_io_getevents, because GCC for i386 with CONFIG_FRAME_POINTER=n can decide to clobber an argument word on the stack, i.e. the user struct pt_regs. Here the problem is not a tail call, but just the compiler's use of the stack when it inlines and optimizes the body of the called function. This seems to avoid it. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* aio: bad AIO race in aio_complete() leads to process hangQuentin Barnes2008-03-191-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | My group ran into a AIO process hang on a 2.6.24 kernel with the process sleeping indefinitely in io_getevents(2) waiting for the last wakeup to come and it never would. We ran the tests on x86_64 SMP. The hang only occurred on a Xeon box ("Clovertown") but not a Core2Duo ("Conroe"). On the Xeon, the L2 cache isn't shared between all eight processors, but is L2 is shared between between all two processors on the Core2Duo we use. My analysis of the hang is if you go down to the second while-loop in read_events(), what happens on processor #1: 1) add_wait_queue_exclusive() adds thread to ctx->wait 2) aio_read_evt() to check tail 3) if aio_read_evt() returned 0, call [io_]schedule() and sleep In aio_complete() with processor #2: A) info->tail = tail; B) waitqueue_active(&ctx->wait) C) if waitqueue_active() returned non-0, call wake_up() The way the code is written, step 1 must be seen by all other processors before processor 1 checks for pending events in step 2 (that were recorded by step A) and step A by processor 2 must be seen by all other processors (checked in step 2) before step B is done. The race I believed I was seeing is that steps 1 and 2 were effectively swapped due to the __list_add() being delayed by the L2 cache not shared by some of the other processors. Imagine: proc 2: just before step A proc 1, step 1: adds to ctx->wait, but is not visible by other processors yet proc 1, step 2: checks tail and sees no pending events proc 2, step A: updates tail proc 1, step 3: calls [io_]schedule() and sleeps proc 2, step B: checks ctx->wait, but sees no one waiting, skips wakeup so proc 1 sleeps indefinitely My patch adds a memory barrier between steps A and B. It ensures that the update in step 1 gets seen on processor 2 before continuing. If processor 1 was just before step 1, the memory barrier makes sure that step A (update tail) gets seen by the time processor 1 makes it to step 2 (check tail). Before the patch our AIO process would hang virtually 100% of the time. After the patch, we have yet to see the process ever hang. Signed-off-by: Quentin Barnes <qbarnes+linux@yahoo-inc.com> Reviewed-by: Zach Brown <zach.brown@oracle.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: <stable@kernel.org> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> [ We should probably disallow that "if (waitqueue_active()) wake_up()" coding pattern, because it's so often buggy wrt memory ordering ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* aio: negative offset should return -EINVALRusty Russell2008-02-081-0/+4
| | | | | | | | | | | | An AIO read or write should return -EINVAL if the offset is negative. This check matches the one in pread and pwrite. This was found by the libaio test suite. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* aio: partial write should not return error codeRusty Russell2008-02-081-0/+7
| | | | | | | | | | | | | When an AIO write gets an error after writing some data (eg. ENOSPC), it should return the amount written already, not the error. Just like write() is supposed to. This was found by the libaio test suite. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-By: Zach Brown <zach.brown@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: remove fastcall, it is always emptyHarvey Harrison2008-02-081-9/+8
| | | | | | | [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* core: remove last users of empty FASTCALL macroHarvey Harrison2008-01-301-1/+1
| | | | | | | | FASTCALL is always empty after the x86 removal. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* aio: only account I/O wait time in read_events if there are active requestsJeff Moyer2007-12-051-1/+6
| | | | | | | | | | | | | | | | | On 2.6.24, top started showing 100% iowait on one CPU when a UML instance was running (but completely idle). The UML code sits in io_getevents waiting for an event to be submitted and completed. Fix this by checking ctx->reqs_active before scheduling to determine whether or not we are waiting for I/O. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Cc: Zach Brown <zach.brown@oracle.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Jeff Dike <jdike@addtoit.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Remove struct task_struct::io_waitAlexey Dobriyan2007-10-181-14/+2
| | | | | | | | | | | | Hell knows what happened in commit 63b05203af57e7de4f3bb63b8b81d43bc196d32b during 2.6.9 development. Commit introduced io_wait field which remained write-only than and still remains write-only. Also garbage collect macros which "use" io_wait. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* aio: account I/O wait time properlyJeff Moyer2007-10-171-3/+3
| | | | | | | | | | | | | | | | | | | | | Some months back I proposed changing the schedule() call in read_events to an io_schedule(): http://osdir.com/ml/linux.kernel.aio.general/2006-10/msg00024.html This was rejected as there are AIO operations that do not initiate disk I/O. I've had another look at the problem, and the only AIO operation that will not initiate disk I/O is IOCB_CMD_NOOP. However, this command isn't even wired up! Given that it doesn't work, and hasn't for *years*, I'm going to suggest again that we do proper I/O accounting when using AIO. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Zach Brown <zach.brown@oracle.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Suparna Bhattacharya <suparna@in.ibm.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* AIO: fix cleanup in io_submit_one(...)Yan Zheng2007-10-081-1/+1
| | | | | | | | | | | When IOCB_FLAG_RESFD flag is set and iocb->aio_resfd is incorrect, statement 'goto out_put_req' is executed. At label 'out_put_req', aio_put_req(..) is called, which requires 'req->ki_filp' set. Signed-off-by: Yan Zheng<yanzheng@21cn.com> Cc: Zach Brown <zach.brown@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signal/timer/event: KAIO eventfd support exampleDavide Libenzi2007-05-111-2/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is an example about how to add eventfd support to the current KAIO code, in order to enable KAIO to post readiness events to a pollable fd (hence compatible with POSIX select/poll). The KAIO code simply signals the eventfd fd when events are ready, and this triggers a POLLIN in the fd. This patch uses a reserved for future use member of the struct iocb to pass an eventfd file descriptor, that KAIO will use to post events every time a request completes. At that point, an aio_getevents() will return the completed result to a struct io_event. I made a quick test program to verify the patch, and it runs fine here: http://www.xmailserver.org/eventfd-aio-test.c The test program uses poll(2), but it'd, of course, work with select and epoll too. This can allow to schedule both block I/O and other poll-able devices requests, and wait for results using select/poll/epoll. In a typical scenario, an application would submit KAIO request using aio_submit(), and will also use epoll_ctl() on the whole other class of devices (that with the addition of signals, timers and user events, now it's pretty much complete), and then would: epoll_wait(...); for_each_event { if (curr_event_is_kaiofd) { aio_getevents(); dispatch_aio_events(); } else { dispatch_epoll_event(); } } Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* unify flush_work/flush_work_keventd and rename it to cancel_work_syncOleg Nesterov2007-05-091-2/+2
| | | | | | | | | | | | | | | | | | | | flush_work(wq, work) doesn't need the first parameter, we can use cwq->wq (this was possible from the very beginnig, I missed this). So we can unify flush_work_keventd and flush_work. Also, rename flush_work() to cancel_work_sync() and fix all callers. Perhaps this is not the best name, but "flush_work" is really bad. (akpm: this is why the earlier patches bypassed maintainers) Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Jeff Garzik <jeff@garzik.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Tejun Heo <htejun@gmail.com> Cc: Auke Kok <auke-jan.h.kok@intel.com>, Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* aio: use flush_work()Andrew Morton2007-05-091-4/+3
| | | | | | | | | | | | Migrate AIO over to use flush_work(). Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: Zach Brown <zach.brown@oracle.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* KMEM_CACHE(): simplify slab cache creationChristoph Lameter2007-05-071-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch provides a new macro KMEM_CACHE(<struct>, <flags>) to simplify slab creation. KMEM_CACHE creates a slab with the name of the struct, with the size of the struct and with the alignment of the struct. Additional slab flags may be specified if necessary. Example struct test_slab { int a,b,c; struct list_head; } __cacheline_aligned_in_smp; test_slab_cache = KMEM_CACHE(test_slab, SLAB_PANIC) will create a new slab named "test_slab" of the size sizeof(struct test_slab) and aligned to the alignment of test slab. If it fails then we panic. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] aio: remove bare user-triggerable error printkZach Brown2007-03-271-1/+0
| | | | | | | | | | | | The user can generate console output if they cause do_mmap() to fail during sys_io_setup(). This was seen in a regression test that does exactly that by spinning calling mmap() until it gets -ENOMEM before calling io_setup(). We don't need this printk at all, just remove it. Signed-off-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Transform kmem_cache_alloc()+memset(0) -> kmem_cache_zalloc().Robert P. J. Day2007-02-111-2/+1
| | | | | | | | | | | | | | | | | | | | | | Replace appropriate pairs of "kmem_cache_alloc()" + "memset(0)" with the corresponding "kmem_cache_zalloc()" call. Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: Roland McGrath <roland@redhat.com> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Greg KH <greg@kroah.com> Acked-by: Joel Becker <Joel.Becker@oracle.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Jan Kara <jack@ucw.cz> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Remove final references to deprecated "MAP_ANON" page protection flagRobert P. J. Day2007-02-111-1/+1
| | | | | | | | | Remove the last vestiges of the long-deprecated "MAP_ANON" page protection flag: use "MAP_ANONYMOUS" instead. Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] aio: fix buggy put_ioctx call in aio_complete - v2Ken Chen2007-02-031-11/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | An AIO bug was reported that sleeping function is being called in softirq context: BUG: warning at kernel/mutex.c:132/__mutex_lock_common() Call Trace: [<a000000100577b00>] __mutex_lock_slowpath+0x640/0x6c0 [<a000000100577ba0>] mutex_lock+0x20/0x40 [<a0000001000a25b0>] flush_workqueue+0xb0/0x1a0 [<a00000010018c0c0>] __put_ioctx+0xc0/0x240 [<a00000010018d470>] aio_complete+0x2f0/0x420 [<a00000010019cc80>] finished_one_bio+0x200/0x2a0 [<a00000010019d1c0>] dio_bio_complete+0x1c0/0x200 [<a00000010019d260>] dio_bio_end_aio+0x60/0x80 [<a00000010014acd0>] bio_endio+0x110/0x1c0 [<a0000001002770e0>] __end_that_request_first+0x180/0xba0 [<a000000100277b90>] end_that_request_chunk+0x30/0x60 [<a0000002073c0c70>] scsi_end_request+0x50/0x300 [scsi_mod] [<a0000002073c1240>] scsi_io_completion+0x200/0x8a0 [scsi_mod] [<a0000002074729b0>] sd_rw_intr+0x330/0x860 [sd_mod] [<a0000002073b3ac0>] scsi_finish_command+0x100/0x1c0 [scsi_mod] [<a0000002073c2910>] scsi_softirq_done+0x230/0x300 [scsi_mod] [<a000000100277d20>] blk_done_softirq+0x160/0x1c0 [<a000000100083e00>] __do_softirq+0x200/0x240 [<a000000100083eb0>] do_softirq+0x70/0xc0 See report: http://marc.theaimsgroup.com/?l=linux-kernel&m=116599593200888&w=2 flush_workqueue() is not allowed to be called in the softirq context. However, aio_complete() called from I/O interrupt can potentially call put_ioctx with last ref count on ioctx and triggers bug. It is simply incorrect to perform ioctx freeing from aio_complete. The bug is trigger-able from a race between io_destroy() and aio_complete(). A possible scenario: cpu0 cpu1 io_destroy aio_complete wait_for_all_aios { __aio_put_req ... ctx->reqs_active--; if (!ctx->reqs_active) return; } ... put_ioctx(ioctx) put_ioctx(ctx); __put_ioctx bam! Bug trigger! The real problem is that the condition check of ctx->reqs_active in wait_for_all_aios() is incorrect that access to reqs_active is not being properly protected by spin lock. This patch adds that protective spin lock, and at the same time removes all duplicate ref counting for each kiocb as reqs_active is already used as a ref count for each active ioctx. This also ensures that buggy call to flush_workqueue() in softirq context is eliminated. Signed-off-by: "Ken Chen" <kenchen@google.com> Cc: Zach Brown <zach.brown@oracle.com> Cc: Suparna Bhattacharya <suparna@in.ibm.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: <stable@kernel.org> Acked-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Fix lock inversion aio_kick_handler()Zach Brown2006-12-301-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | lockdep found a AB BC CA lock inversion in retry-based AIO: 1) The task struct's alloc_lock (A) is acquired in process context with interrupts enabled. An interrupt might arrive and call wake_up() which grabs the wait queue's q->lock (B). 2) When performing retry-based AIO the AIO core registers aio_wake_function() as the wake funtion for iocb->ki_wait. It is called with the wait queue's q->lock (B) held and then tries to add the iocb to the run list after acquiring the ctx_lock (C). 3) aio_kick_handler() holds the ctx_lock (C) while acquiring the alloc_lock (A) via lock_task() and unuse_mm(). Lockdep emits a warning saying that we're trying to connect the irq-safe q->lock to the irq-unsafe alloc_lock via ctx_lock. This fixes the inversion by calling unuse_mm() in the AIO kick handing path after we've released the ctx_lock. As Ben LaHaise pointed out __put_ioctx could set ctx->mm to NULL, so we must only access ctx->mm while we have the lock. Signed-off-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Suparna Bhattacharya <suparna@in.ibm.com> Acked-by: Benjamin LaHaise <bcrl@kvack.org> Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Use activate_mm() in fs/aio.c:use_mm()Jeremy Fitzhardinge2006-12-131-1/+1
| | | | | | | | | | | | | | | | | | | activate_mm() is not the right thing to be using in use_mm(). It should be switch_mm(). On normal x86, they're synonymous, but for the Xen patches I'm adding a hook which assumes that activate_mm is only used the first time a new mm is used after creation (I have another hook for dealing with dup_mm). I think this use of activate_mm() is the only place where it could be used a second time on an mm. >From a quick look at the other architectures I think this is OK (most simply implement one in terms of the other), but some are doing some subtly different stuff between the two. Acked-by: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] aio: remove ki_retried debugging memberBenjamin LaHaise2006-12-071-15/+0
| | | | | | | | | | | | | | Remove the ki_retried member from struct kiocb. I think the idea was bounced around a while back, but Arnaldo pointed out another reason that we should dig it up when he pointed out that the last cacheline of struct kiocb only contains 4 bytes. By removing the debugging member, we save more than the 8 byte on 64 bit machines. Signed-off-by: Benjamin LaHaise <bcrl@kvack.org> Acked-by: Ken Chen <kenneth.w.chen@intel.com> Acked-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] aio: kill pointless ki_nbytes assignment in aio_setup_single_vectorChen, Kenneth W2006-12-071-1/+0
| | | | | | | | | | | | | io_submit_one assigns ki_left = ki_nbytes = iocb->aio_nbytes, then calls down to aio_setup_iocb, then to aio_setup_single_vector. In there, ki_nbytes is reassigned to the same value it got two call stack above it. There is no need to do so. Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Acked-by: Zach Brown <zach.brown@oracle.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: remove kmem_cache_tChristoph Lameter2006-12-071-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace all uses of kmem_cache_t with struct kmem_cache. The patch was generated using the following script: #!/bin/sh # # Replace one string by another in all the kernel sources. # set -e for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do quilt add $file sed -e "1,\$s/$1/$2/g" $file >/tmp/$$ mv /tmp/$$ $file quilt refresh done The script was run like this sh replace kmem_cache_t "struct kmem_cache" Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge branch 'master' of ↵David Howells2006-12-051-4/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 Conflicts: drivers/infiniband/core/iwcm.c drivers/net/chelsio/cxgb2.c drivers/net/wireless/bcm43xx/bcm43xx_main.c drivers/net/wireless/prism54/islpci_eth.c drivers/usb/core/hub.h drivers/usb/input/hid-core.c net/core/netpoll.c Fix up merge failures with Linus's head and fix new compilation failures. Signed-Off-By: David Howells <dhowells@redhat.com>
| * BUG_ON conversion for fs/aio.cEric Sesterhenn2006-11-301-4/+2
| | | | | | | | | | | | | | | | | | This patch converts a if () BUG(); construct to BUG_ON(); which occupies less space, uses unlikely and is safer when BUG() is disabled. Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* | WorkStruct: Pass the work_struct pointer instead of context dataDavid Howells2006-11-221-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pass the work_struct pointer to the work function rather than context data. The work function can use container_of() to work out the data. For the cases where the container of the work_struct may go away the moment the pending bit is cleared, it is made possible to defer the release of the structure by deferring the clearing of the pending bit. To make this work, an extra flag is introduced into the management side of the work_struct. This governs auto-release of the structure upon execution. Ordinarily, the work queue executor would release the work_struct for further scheduling or deallocation by clearing the pending bit prior to jumping to the work function. This means that, unless the driver makes some guarantee itself that the work_struct won't go away, the work function may not access anything else in the work_struct or its container lest they be deallocated.. This is a problem if the auxiliary data is taken away (as done by the last patch). However, if the pending bit is *not* cleared before jumping to the work function, then the work function *may* access the work_struct and its container with no problems. But then the work function must itself release the work_struct by calling work_release(). In most cases, automatic release is fine, so this is the default. Special initiators exist for the non-auto-release case (ending in _NAR). Signed-Off-By: David Howells <dhowells@redhat.com>
* | WorkStruct: Separate delayable and non-delayable events.David Howells2006-11-221-2/+2
|/ | | | | | | | | | | | Separate delayable work items from non-delayable work items be splitting them into a separate structure (delayed_work), which incorporates a work_struct and the timer_list removed from work_struct. The work_struct struct is huge, and this limits it's usefulness. On a 64-bit architecture it's nearly 100 bytes in size. This reduces that by half for the non-delayable type of event. Signed-Off-By: David Howells <dhowells@redhat.com>
* [PATCH] pr_debug: aio: use size_t length modifier in pr_debug format argumentsZach Brown2006-10-031-2/+2
| | | | | | | | aio: use size_t length modifier in pr_debug format arguments Signed-off-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Add vector AIO supportBadari Pulavarty2006-10-011-54/+117
| | | | | | | | | | | | | | | This work is initially done by Zach Brown to add support for vectored aio. These are the core changes for AIO to support IOCB_CMD_PREADV/IOCB_CMD_PWRITEV. [akpm@osdl.org: huge build fix] Signed-off-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Acked-by: Benjamin LaHaise <bcrl@kvack.org> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Vectorize aio_read/aio_write fileop methodsBadari Pulavarty2006-10-011-4/+11
| | | | | | | | | | | | This patch vectorizes aio_read() and aio_write() methods to prepare for collapsing all aio & vectored operations into one interface - which is aio_read()/aio_write(). Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Michael Holzheu <HOLZHEU@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* spelling fixesAndreas Mohr2006-06-261-1/+1
| | | | | | | | | | | | acquired (aquired) contiguous (contigious) successful (succesful, succesfull) surprise (suprise) whether (weather) some other misspellings Signed-off-by: Andreas Mohr <andi@lisas.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] list: use list_replace_init() instead of list_splice_init()Oleg Nesterov2006-06-231-2/+2
| | | | | | | | | | list_splice_init(list, head) does unneeded job if it is known that list_empty(head) == 1. We can use list_replace_init() instead. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] use kzalloc and kcalloc in core fs codeOliver Neukum2006-03-251-2/+1
| | | | | | Signed-off-by: Oliver Neukum <oliver@neukum.name> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] rcu file: use atomic primitivesNick Piggin2006-01-081-2/+1
| | | | | | | | | Use atomic_inc_not_zero for rcu files instead of special case rcuref. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] aio: replace locking comments with assert_spin_locked()Zach Brown2005-11-131-5/+12
| | | | | | | | | aio: replace locking comments with assert_spin_locked() Signed-off-by: Zach Brown <zach.brown@oracle.com> Acked-by: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] aio: remove kioctx from mm_structZach Brown2005-11-131-18/+9
| | | | | | | | | | | | | | | | | | | | | | Sync iocbs have a life cycle that don't need a kioctx. Their retrying, if any, is done in the context of their owner who has allocated them on the stack. The sole user of a sync iocb's ctx reference was aio_complete() checking for an elevated iocb ref count that could never happen. No path which grabs an iocb ref has access to sync iocbs. If we were to implement sync iocb cancelation it would be done by the owner of the iocb using its on-stack reference. Removing this chunk from aio_complete allows us to remove the entire kioctx instance from mm_struct, reducing its size by a third. On a i386 testing box the slab size went from 768 to 504 bytes and from 5 to 8 per page. Signed-off-by: Zach Brown <zach.brown@oracle.com> Acked-by: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] aio: remove aio_max_nr accounting raceZach Brown2005-11-071-10/+21
| | | | | | | | | | | | | | | | | | | | | AIO was adding a new context's max requests to the global total before testing if that resulting total was over the global limit. This let innocent tasks get their new limit tested along with a racing guilty task that was crossing the limit. This serializes the _nr accounting with a spinlock It also switches to using unsigned long for the global totals. Individual contexts are still limited to an unsigned int's worth of requests by the syscall interface. The problem and fix were verified with a simple program that spun creating and destroying a context while holding on to another long lived context. Before the patch a task creating a tiny context could get a spurious EAGAIN if it raced with a task creating a very large context that overran the limit. Signed-off-by: Zach Brown <zach.brown@oracle.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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