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2007-05-24Merge branch 'fixes' of git://git.linux-nfs.org/pub/linux/nfs-2.6Linus Torvalds
* 'fixes' of git://git.linux-nfs.org/pub/linux/nfs-2.6: NFS: Fix nfs_direct_dirty_pages() NFS: Fix handful of compiler warnings in direct.c NFS: Avoid a deadlock situation on write
2007-05-24NFS: Fix nfs_direct_dirty_pages()Trond Myklebust
We only need to dirty the pages that were actually read in. Also convert nfs_direct_dirty_pages() to call set_page_dirty() instead of set_page_dirty_lock(). A call to lock_page() is unacceptable in an rpciod callback function. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-24NFS: Fix handful of compiler warnings in direct.cChuck Lever
This patch fixes a couple of signage issues that were causing an Oops when running the LTP diotest4 test. get_user_pages() returns a signed error, hence we need to be careful when comparing with the unsigned number of pages from data->npages. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-24NFS: Avoid a deadlock situation on writeTrond Myklebust
When processes are allowed to attempt to lock a non-contiguous range of nfs write requests, it is possible for generic_writepages to 'wrap round' the address space, and call writepage() on a request that is already locked by the same process. We avoid the deadlock by checking if the page index is contiguous with the list of nfs write requests that is already held in our nfs_pageio_descriptor prior to attempting to lock a new request. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-23eCryptfs: delay writing 0's after llseek until writeMichael Halcrow
Delay writing 0's out in eCryptfs after a seek past the end of the file until data is actually written. http://www.opengroup.org/onlinepubs/009695399/functions/lseek.html ``The lseek() function shall not, by itself, extend the size of a file.'' Without this fix, applications that lseek() past the end of the file without writing will experience unexpected behavior. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-23signalfd: retrieve multiple signals with one read() callDavi Arnaut
Gathering signals in bulk enables server applications to drain a signal queue (almost full of realtime signals) more efficiently by reducing the syscall and file look-up overhead. Very similar to the sigtimedwait4() call described by Niels Provos, Chuck Lever, and Stephen Tweedie in a paper entitled "Analyzing the Overload Behavior of a Simple Web Server". The paper lists more details and advantages. Signed-off-by: Davi E. M. Arnaut <davi@haxent.com.br> Acked-by: Davide Libenzi <davidel@xmailserver.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>
2007-05-23fuse: delete inode on dropMiklos Szeredi
When inode is dropped (no more references) delete it from cache. There's not much point in keeping it cached, when a new lookup will refresh the attributes anyway. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-23fuse: generic_write_checks() for direct_ioMiklos Szeredi
This fixes O_APPEND in direct IO mode. Also checks writes against file size limits, notably rlimits. Reported by Greg Bruno. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-23uselib: add missing MNT_NOEXEC checkChristoph Hellwig
We don't allow loading ELF shared library from noexec points so the same should apply to sys_uselib aswell. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Ulrich Drepper <drepper@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-23Missing 'const' from reiserfs MIN_KEY declaration.David Woodhouse
In stree.c, MIN_KEY is declared const. The extern declaration in dir.c doesn't match... Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-23optimize compat_core_sys_select() by a using stack space for small fd setsBadari Pulavarty
Optimize select by a using stack space for small fd sets. core_sys_select() already has this optimization. This is for compat version. Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-23fuse: fix mknod of regular fileMiklos Szeredi
The wrong lookup flag was tested in ->create() causing havoc (error or Oops) when a regular file was created with mknod() in a fuse filesystem. Thanks to J. Cameijo Cerdeira for the report. Kernels 2.6.18 onward are affected. Please apply to -stable as well. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-22Merge master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh-2.6Linus Torvalds
* master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh-2.6: sh: Fix dreamcast build for IRQ changes. sh: Fix clock multiplier on SH7722. sh: Wire up kdump crash kernel exec in die(). sh: sr.bl toggling around idle sleep. sh: disable genrtc support. fs: Kill sh dependency for binfmt_flat. sh: Disable psw support for R7785RP. sh: Fix page size alignment in __copy_user_page(). sh: Fix up various compile warnings for SE boards. sh: Wire up signalfd/timerfd/eventfd syscalls. sh: revert addition of page fault notifiers spelling fixes: arch/sh/ input: hp680_ts compile fixes. sh: landisk: Header cleanups. sh: landisk: rtc-rs5c313 support. sh: Kill off pmb slab cache destructor. sh: Fix up psw build rules for r7780rp. sh: Shut up compiler warnings in __do_page_fault().
2007-05-21partitions/LDM: build fixJeff Garzik
This from a "tested" patch... Signed-off-by: Jeff Garzik <jeff@garzik.org> Cc: Anton Altaparmakov <aia21@cantab.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-21LDM: Fix for Windows Vista dynamic disksAnton Altaparmakov
This fixes the LDM driver so that it works with Windows Vista dynamic disks which are subtly different to Windows 2000/XP ones. The patch was needed to get a Vista formatted dynamic disk to be recognized and parsed successfully. Thanks go to Chris Teachworth for the report and testing. Cc: Richard Russon <ldm@flatcap.org> Signed-off-by: Anton Altaparmakov <aia21@cantab.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-21Detach sched.h from mm.hAlexey Dobriyan
First thing mm.h does is including sched.h solely for can_do_mlock() inline function which has "current" dereference inside. By dealing with can_do_mlock() mm.h can be detached from sched.h which is good. See below, why. This patch a) removes unconditional inclusion of sched.h from mm.h b) makes can_do_mlock() normal function in mm/mlock.c c) exports can_do_mlock() to not break compilation d) adds sched.h inclusions back to files that were getting it indirectly. e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were getting them indirectly Net result is: a) mm.h users would get less code to open, read, preprocess, parse, ... if they don't need sched.h b) sched.h stops being dependency for significant number of files: on x86_64 allmodconfig touching sched.h results in recompile of 4083 files, after patch it's only 3744 (-8.3%). Cross-compile tested on all arm defconfigs, all mips defconfigs, all powerpc defconfigs, alpha alpha-up arm i386 i386-up i386-defconfig i386-allnoconfig ia64 ia64-up m68k mips parisc parisc-up powerpc powerpc-up s390 s390-up sparc sparc-up sparc64 sparc64-up um-x86_64 x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig as well as my two usual configs. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-21Fix "fs: convert core functions to zero_user_page"OGAWA Hirofumi
The bug was introduced by 01f2705daf5a36208e69d7cf95db9c330f843af6. It misses to convert the first argument, it should be "new_page". This became a cause of fatfs corruption. Cc: Nate Diller <nate.diller@gmail.com> Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-21fs: Kill sh dependency for binfmt_flat.Paul Mundt
Not really sure where this bogosity came from, but there's certainly nothing special about sh that lets us use flat files with the MMU on. Kill the dependency, and leave it as !MMU, like it is for all of the other nommu-wielding ports. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-05-18timerfd use waitqueue lock ...Davide Libenzi
The timerfd was using the unlocked waitqueue operations, but it was using a different lock, so poll_wait() would race with it. This makes timerfd directly use the waitqueue lock. Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-18eventfd use waitqueue lock ...Davide Libenzi
The eventfd was using the unlocked waitqueue operations, but it was using a different lock, so poll_wait() would race with it. This makes eventfd directly use the waitqueue lock. Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17Merge branch 'master' of /home/trondmy/repositories/git/linux-2.6/Trond Myklebust
2007-05-17Fix page allocation flags in grow_dev_page()Christoph Lameter
grow_dev_page() simply passes GFP_NOFS to find_or_create_page. This means the allocation of radix tree nodes is done with GFP_NOFS and the allocation of a new page is done using GFP_NOFS. The mapping has a flags field that contains the necessary allocation flags for the page cache allocation. These need to be consulted in order to get DMA and HIGHMEM allocations etc right. And yes a blockdev could be allowing Highmem allocations if its a ramdisk. Cc: Hugh Dickins <hugh@veritas.com> 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>
2007-05-17circular locking dependency found in QUOTA OFFJan Kara
i_mutex on quota files is special. Unlike i_mutexes for other inodes it is acquired under dqonoff_mutex. Tell lockdep about this lock ranking. Also comment and code in quota_sync_sb() seem to be bogus (as i_mutex for quota file can be acquired under dqonoff_mutex). Move truncate_inode_pages() call under dqonoff_mutex and save some problems with races... Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17ecryptfs: use zero_user_pageNate Diller
Use zero_user_page() instead of open-coding it. Signed-off-by: Nate Diller <nate.diller@gmail.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17make sysctl/kernel/core_pattern and fs/exec.c agree on maximum core filename ↵Dan Aloni
size Make sysctl/kernel/core_pattern and fs/exec.c agree on maximum core filename size and change it to 128, so that extensive patterns such as '/local/cores/%e-%h-%s-%t-%p.core' won't result in truncated filename generation. Signed-off-by: Dan Aloni <da-x@monatomic.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17Merge branch 'master' of /home/trondmy/repositories/git/linux-2.6/Trond Myklebust
2007-05-17simplify compat_sys_timerfdHeiko Carstens
Just thought this is easier to read. Acked-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17Remove SLAB_CTOR_CONSTRUCTORChristoph Lameter
SLAB_CTOR_CONSTRUCTOR is always specified. No point in checking it. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: David Howells <dhowells@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven French <sfrench@us.ibm.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@ucw.cz> Cc: David Chinner <dgc@sgi.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-16AFS: Fix afs_prepare_write()David Howells
afs_prepare_write() should not mark a page up to date if it only partially fills it in, in expectation of the caller filling in the rest prior to calling commit_write(). commit_write(), however, should mark the page up to date. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-16AFS: write back dirty data on unmountDavid Howells
Fix AFS to write back dirty on unmounting. This didn't happen because afs_super_ops.drop_inode was pointing to generic_delete_inode. Now this pointer is left set to NULL so that the default behaviour occurs instead. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-15Merge branch 'origin'Trond Myklebust
2007-05-15epoll: move kfree inside ep_freeDavide Libenzi
Move the kfree() call inside the ep_free() function. 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>
2007-05-15epoll: fix some commentsDavide Libenzi
Fixes some epoll code comments. 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>
2007-05-15epoll locks changes and cleanupsDavide Libenzi
Changes the rwlock to a spinlock, and drops the use-count variable. Operations are always bound by the mutex now, so the use-count is no more needed. For the same reason, the rwlock can become a simple spinlock. 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>
2007-05-15fix epoll single pass code and add wait-exclusive flagDavide Libenzi
Fixes the epoll single pass code. During the unlocked event delivery (to userspace) code, the poll callback can re-issue new events, and we must receive them correctly. Since we loop in a lockless fashion, we want to be O(nready), and we don't want to flash on/off the spinlock for every event, we have the poll callback to use a secondary list to queue events while we're inside the event delivery loop. The rw_semaphore has been turned into a mutex. This patch also adds the wait-exclusive flag, as suggested by Davi Arnaut. 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>
2007-05-14NLM: Fix sparse warningsTrond Myklebust
- fs/lockd/xdr4.c:140:27: warning: incorrect type in argument 2 (different explicit signedness) - fs/lockd/xdr4.c:141:27: warning: incorrect type in argument 2 (different explicit signedness) - fs/lockd/xdr4.c:432:28: warning: incorrect type in argument 2 (different explicit signedness) - fs/lockd/xdr4.c:433:28: warning: incorrect type in argument 2 (different explicit signedness) - fs/lockd/xdr4.c:587:20: warning: symbol 'nlm_version4' was not declared. Should it be static? Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-14NFS: Fix more sparse warningsTrond Myklebust
- fs/nfs/nfs4xdr.c:2499:42: warning: incorrect type in argument 2 (different signedness) - fs/nfs/nfs4xdr.c:2658:49: warning: incorrect type in argument 4 (different explicit signedness) - fs/nfs/nfs4xdr.c:2683:50: warning: incorrect type in argument 4 (different explicit signedness) - fs/nfs/nfs4xdr.c:3063:68: warning: incorrect type in argument 4 (different explicit signedness) - fs/nfs/nfs4xdr.c:3065:68: warning: incorrect type in argument 4 (different explicit signedness) - fs/nfs/callback_xdr.c:138:31: warning: incorrect type in argument 2 (different signedness) Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-14NFS: Fix some 'sparse' warnings...Trond Myklebust
- fs/nfs/dir.c:610:8: warning: symbol 'nfs_llseek_dir' was not declared. Should it be static? - fs/nfs/dir.c:636:5: warning: symbol 'nfs_fsync_dir' was not declared. Should it be static? - fs/nfs/write.c:925:19: warning: symbol 'req' shadows an earlier one - fs/nfs/write.c:61:6: warning: symbol 'nfs_commit_rcu_free' was not declared. Should it be static? - fs/nfs/nfs4proc.c:793:5: warning: symbol 'nfs4_recover_expired_lease' was not declared. Should it be static? Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-14NFS4: Fix incorrect use of sizeof() in fs/nfs/nfs4xdr.cTrond Myklebust
The XDR code should not depend on the physical allocation size of structures like nfs4_stateid and nfs4_verifier since those may have to change at some future date. We therefore replace all uses of sizeof() with constants like NFS4_VERIFIER_SIZE and NFS4_STATEID_SIZE. This also has the side-effect of fixing some warnings of the type format ‘%u’ expects type ‘unsigned int’, but argument X has type ‘long unsigned int’ on 64-bit systems Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-14NFS: use zero_user_pageNate Diller
Use zero_user_page() instead of the newly deprecated memclear_highpage_flush(). Signed-off-by: Nate Diller <nate.diller@gmail.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-14NLM: don't use CLONE_SIGHAND in nlmclnt_recoveryOleg Nesterov
reclaimer() calls allow_signal() which plays with parent process's ->sighand. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-14NLM: Fix locking client timeouts...Trond Myklebust
nlmsvc_timeout is already in units of HZ... Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-12ntfs: use zero_user_pageNate Diller
Use zero_user_page() instead of open-coding it. [akpm@linux-foundation.org: kmap-type fixes] Signed-off-by: Nate Diller <nate.diller@gmail.com> Acked-by: Anton Altaparmakov <aia21@cantab.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11Merge branch 'audit.b38' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current * 'audit.b38' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current: [PATCH] Abnormal End of Processes [PATCH] match audit name data [PATCH] complete message queue auditing [PATCH] audit inode for all xattr syscalls [PATCH] initialize name osid [PATCH] audit signal recipients [PATCH] add SIGNAL syscall class (v3) [PATCH] auditing ptrace
2007-05-11epoll cleanups: epoll remove static pre-declarations and akpm-ize the codeDavide Libenzi
Re-arrange epoll code to avoid static functions pre-declarations, and apply akpm-filter on it. 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>
2007-05-11epoll cleanups: epoll no moduleDavide Libenzi
Epoll is either compiled it, or not (if EMBEDDED). Remove the module code and use fs_initcall(). 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>
2007-05-11epoll: use anonymous inodesDavide Libenzi
Cut out lots of code from epoll, by reusing the anonymous inode source patch (fs/anon_inodes.c). 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>
2007-05-11signal/timer/event: KAIO eventfd support exampleDavide Libenzi
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>
2007-05-11signal/timer/event: eventfd coreDavide Libenzi
This is a very simple and light file descriptor, that can be used as event wait/dispatch by userspace (both wait and dispatch) and by the kernel (dispatch only). It can be used instead of pipe(2) in all cases where those would simply be used to signal events. Their kernel overhead is much lower than pipes, and they do not consume two fds. When used in the kernel, it can offer an fd-bridge to enable, for example, functionalities like KAIO or syslets/threadlets to signal to an fd the completion of certain operations. But more in general, an eventfd can be used by the kernel to signal readiness, in a POSIX poll/select way, of interfaces that would otherwise be incompatible with it. The API is: int eventfd(unsigned int count); The eventfd API accepts an initial "count" parameter, and returns an eventfd fd. It supports poll(2) (POLLIN, POLLOUT, POLLERR), read(2) and write(2). The POLLIN flag is raised when the internal counter is greater than zero. The POLLOUT flag is raised when at least a value of "1" can be written to the internal counter. The POLLERR flag is raised when an overflow in the counter value is detected. The write(2) operation can never overflow the counter, since it blocks (unless O_NONBLOCK is set, in which case -EAGAIN is returned). But the eventfd_signal() function can do it, since it's supposed to not sleep during its operation. The read(2) function reads the __u64 counter value, and reset the internal value to zero. If the value read is equal to (__u64) -1, an overflow happened on the internal counter (due to 2^64 eventfd_signal() posts that has never been retired - unlickely, but possible). The write(2) call writes an __u64 count value, and adds it to the current counter. The eventfd fd supports O_NONBLOCK also. On the kernel side, we have: struct file *eventfd_fget(int fd); int eventfd_signal(struct file *file, unsigned int n); The eventfd_fget() should be called to get a struct file* from an eventfd fd (this is an fget() + check of f_op being an eventfd fops pointer). The kernel can then call eventfd_signal() every time it wants to post an event to userspace. The eventfd_signal() function can be called from any context. An eventfd() simple test and bench is available here: http://www.xmailserver.org/eventfd-bench.c This is the eventfd-based version of pipetest-4 (pipe(2) based): http://www.xmailserver.org/pipetest-4.c Not that performance matters much in the eventfd case, but eventfd-bench shows almost as double as performance than pipetest-4. [akpm@linux-foundation.org: fix i386 build] [akpm@linux-foundation.org: add sys_eventfd to sys_ni.c] 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>
2007-05-11signal/timer/event: timerfd compat codeDavide Libenzi
This patch implements the necessary compat code for the timerfd system call. 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>
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