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* rcu: simplify the usage of percpu dataLai Jiangshan2010-08-194-31/+19
| | | | | | | | | | | | | | &percpu_data is compatible with allocated percpu data. And we use it and remove the "->rda[NR_CPUS]" array, saving significant storage on systems with large numbers of CPUs. This does add an additional level of indirection and thus an additional cache line referenced, but because ->rda is not used on the read side, this is OK. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Reviewed-by: Tejun Heo <tj@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* rcutorture: add random preemptionLai Jiangshan2010-08-191-0/+6
| | | | | | | | | | | | | Add random preemption to help we to torture the preemptable rcu. srcu_read_delay() also calls rcu_read_delay() for shorter delays. Added comment to preempt_schedule() call indicating that no quiescent states happen if preemption is disabled. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* rcu: add shiny new debug assists to Documentation/RCU/checklist.txtPaul E. McKenney2010-08-191-0/+23
| | | | | | | | | Add a section describing PROVE_RCU, DEBUG_OBJECTS_RCU_HEAD, and the __rcu sparse checking to the RCU checklist. Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* kvm: add __rcu annotationsArnd Bergmann2010-08-191-1/+1
| | | | | | | | Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Avi Kivity <avi@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* net/netfilter: __rcu annotationsArnd Bergmann2010-08-198-10/+10
| | | | | | | | | Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Patrick McHardy <kaber@trash.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* input: __rcu annotationsArnd Bergmann2010-08-192-2/+2
| | | | | | | | Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Acked-by: Dmitry Torokhov <dtor@mail.ru> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* nfs: __rcu annotationsArnd Bergmann2010-08-192-3/+3
| | | | | | Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* keys: __rcu annotationsArnd Bergmann2010-08-192-2/+3
| | | | | | | Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: David Howells <dhowells@redhat.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* credentials: rcu annotationArnd Bergmann2010-08-191-2/+2
| | | | | | | | | Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* cgroups: __rcu annotationsArnd Bergmann2010-08-193-4/+4
| | | | | | | | Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* rculist: avoid __rcu annotationsArnd Bergmann2010-08-193-25/+46
| | | | | | | | | | | | | | | | This avoids warnings from missing __rcu annotations in the rculist implementation, making it possible to use the same lists in both RCU and non-RCU cases. We can add rculist annotations later, together with lockdep support for rculist, which is missing as well, but that may involve changing all the users. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* rcu: define __rcu address space modifier for sparsePaul E. McKenney2010-08-195-145/+257
| | | | | | | | | | | | | | | | | | | | | | | | This commit provides definitions for the __rcu annotation defined earlier. This annotation permits sparse to check for correct use of RCU-protected pointers. If a pointer that is annotated with __rcu is accessed directly (as opposed to via rcu_dereference(), rcu_assign_pointer(), or one of their variants), sparse can be made to complain. To enable such complaints, use the new default-disabled CONFIG_SPARSE_RCU_POINTER kernel configuration option. Please note that these sparse complaints are intended to be a debugging aid, -not- a code-style-enforcement mechanism. There are special rcu_dereference_protected() and rcu_access_pointer() accessors for use when RCU read-side protection is not required, for example, when no other CPU has access to the data structure in question or while the current CPU hold the update-side lock. This patch also updates a number of docbook comments that were showing their age. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Christopher Li <sparse@chrisli.org> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* net: convert to rcu_dereference_index_check()Paul E. McKenney2010-08-191-1/+2
| | | | | | | | | | | | The task_cls_classid() function applies rcu_dereference() to integers, which does not work with the shiny new sparse-based checking in rcu_dereference(). This commit therefore moves to the new RCU API rcu_dereference_index_check(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
* Merge branch 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6Linus Torvalds2010-08-1810-24/+68
|\ | | | | | | | | | | | | | | | | | | | | | | | | * 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: NFS: Fix an Oops in the NFSv4 atomic open code NFS: Fix the selection of security flavours in Kconfig NFS: fix the return value of nfs_file_fsync() rpcrdma: Fix SQ size calculation when memreg is FRMR xprtrdma: Do not truncate iova_start values in frmr registrations. nfs: Remove redundant NULL check upon kfree() nfs: Add "lookupcache" to displayed mount options NFS: allow close-to-open cache semantics to apply to root of NFS filesystem SUNRPC: fix NFS client over TCP hangs due to packet loss (Bug 16494)
| * NFS: Fix an Oops in the NFSv4 atomic open codeTrond Myklebust2010-08-182-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adam Lackorzynski reports: with 2.6.35.2 I'm getting this reproducible Oops: [ 110.825396] BUG: unable to handle kernel NULL pointer dereference at (null) [ 110.828638] IP: [<ffffffff811247b7>] encode_attrs+0x1a/0x2a4 [ 110.828638] PGD be89f067 PUD bf18f067 PMD 0 [ 110.828638] Oops: 0000 [#1] SMP [ 110.828638] last sysfs file: /sys/class/net/lo/operstate [ 110.828638] CPU 2 [ 110.828638] Modules linked in: rtc_cmos rtc_core rtc_lib amd64_edac_mod i2c_amd756 edac_core i2c_core dm_mirror dm_region_hash dm_log dm_snapshot sg sr_mod usb_storage ohci_hcd mptspi tg3 mptscsih mptbase usbcore nls_base [last unloaded: scsi_wait_scan] [ 110.828638] [ 110.828638] Pid: 11264, comm: setchecksum Not tainted 2.6.35.2 #1 [ 110.828638] RIP: 0010:[<ffffffff811247b7>] [<ffffffff811247b7>] encode_attrs+0x1a/0x2a4 [ 110.828638] RSP: 0000:ffff88003bf5b878 EFLAGS: 00010296 [ 110.828638] RAX: ffff8800bddb48a8 RBX: ffff88003bf5bb18 RCX: 0000000000000000 [ 110.828638] RDX: ffff8800be258800 RSI: 0000000000000000 RDI: ffff88003bf5b9f8 [ 110.828638] RBP: 0000000000000000 R08: ffff8800bddb48a8 R09: 0000000000000004 [ 110.828638] R10: 0000000000000003 R11: ffff8800be779000 R12: ffff8800be258800 [ 110.828638] R13: ffff88003bf5b9f8 R14: ffff88003bf5bb20 R15: ffff8800be258800 [ 110.828638] FS: 0000000000000000(0000) GS:ffff880041e00000(0063) knlGS:00000000556bd6b0 [ 110.828638] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 110.828638] CR2: 0000000000000000 CR3: 00000000be8ef000 CR4: 00000000000006e0 [ 110.828638] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 110.828638] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 110.828638] Process setchecksum (pid: 11264, threadinfo ffff88003bf5a000, task ffff88003f232210) [ 110.828638] Stack: [ 110.828638] 0000000000000000 ffff8800bfbcf920 0000000000000000 0000000000000ffe [ 110.828638] <0> 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 110.828638] <0> 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 110.828638] Call Trace: [ 110.828638] [<ffffffff81124c1f>] ? nfs4_xdr_enc_setattr+0x90/0xb4 [ 110.828638] [<ffffffff81371161>] ? call_transmit+0x1c3/0x24a [ 110.828638] [<ffffffff813774d9>] ? __rpc_execute+0x78/0x22a [ 110.828638] [<ffffffff81371a91>] ? rpc_run_task+0x21/0x2b [ 110.828638] [<ffffffff81371b7e>] ? rpc_call_sync+0x3d/0x5d [ 110.828638] [<ffffffff8111e284>] ? _nfs4_do_setattr+0x11b/0x147 [ 110.828638] [<ffffffff81109466>] ? nfs_init_locked+0x0/0x32 [ 110.828638] [<ffffffff810ac521>] ? ifind+0x4e/0x90 [ 110.828638] [<ffffffff8111e2fb>] ? nfs4_do_setattr+0x4b/0x6e [ 110.828638] [<ffffffff8111e634>] ? nfs4_do_open+0x291/0x3a6 [ 110.828638] [<ffffffff8111ed81>] ? nfs4_open_revalidate+0x63/0x14a [ 110.828638] [<ffffffff811056c4>] ? nfs_open_revalidate+0xd7/0x161 [ 110.828638] [<ffffffff810a2de4>] ? do_lookup+0x1a4/0x201 [ 110.828638] [<ffffffff810a4733>] ? link_path_walk+0x6a/0x9d5 [ 110.828638] [<ffffffff810a42b6>] ? do_last+0x17b/0x58e [ 110.828638] [<ffffffff810a5fbe>] ? do_filp_open+0x1bd/0x56e [ 110.828638] [<ffffffff811cd5e0>] ? _atomic_dec_and_lock+0x30/0x48 [ 110.828638] [<ffffffff810a9b1b>] ? dput+0x37/0x152 [ 110.828638] [<ffffffff810ae063>] ? alloc_fd+0x69/0x10a [ 110.828638] [<ffffffff81099f39>] ? do_sys_open+0x56/0x100 [ 110.828638] [<ffffffff81027a22>] ? ia32_sysret+0x0/0x5 [ 110.828638] Code: 83 f1 01 e8 f5 ca ff ff 48 83 c4 50 5b 5d 41 5c c3 41 57 41 56 41 55 49 89 fd 41 54 49 89 d4 55 48 89 f5 53 48 81 ec 18 01 00 00 <8b> 06 89 c2 83 e2 08 83 fa 01 19 db 83 e3 f8 83 c3 18 a8 01 8d [ 110.828638] RIP [<ffffffff811247b7>] encode_attrs+0x1a/0x2a4 [ 110.828638] RSP <ffff88003bf5b878> [ 110.828638] CR2: 0000000000000000 [ 112.840396] ---[ end trace 95282e83fd77358f ]--- We need to ensure that the O_EXCL flag is turned off if the user doesn't set O_CREAT. Cc: stable@kernel.org Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| * NFS: Fix the selection of security flavours in KconfigTrond Myklebust2010-08-173-6/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Randy Dunlap reports: ERROR: "svc_gss_principal" [fs/nfs/nfs.ko] undefined! because in fs/nfs/Kconfig, NFS_V4 selects RPCSEC_GSS_KRB5 and/or in fs/nfsd/Kconfig, NFSD_V4 selects RPCSEC_GSS_KRB5. RPCSEC_GSS_KRB5 does 5 selects, but none of these is enforced/followed by the fs/nfs[d]/Kconfig configs: select SUNRPC_GSS select CRYPTO select CRYPTO_MD5 select CRYPTO_DES select CRYPTO_CBC Reported-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: J. Bruce Fields <bfields@fieldses.org> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| * NFS: fix the return value of nfs_file_fsync()J. R. Okajima2010-08-111-1/+1
| | | | | | | | | | | | | | | | | | By the commit af7fa16 2010-08-03 NFS: Fix up the fsync code close(2) became returning the non-zero value even if it went well. nfs_file_fsync() should return 0 when "status" is positive. Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| * rpcrdma: Fix SQ size calculation when memreg is FRMRTom Tucker2010-08-112-4/+18
| | | | | | | | | | | | | | | | This patch updates the computation to include the worst case situation where three FRMR are required to map a single RPC REQ. Signed-off-by: Tom Tucker <tom@ogc.us> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| * xprtrdma: Do not truncate iova_start values in frmr registrations.Steve Wise2010-08-111-1/+1
| | | | | | | | | | | | | | | | | | A bad cast causes the iova_start, which in this case is a 64b DMA bus address, to be truncated on 32b systems. This breaks frmrs on 32b systems. No cast is needed. Signed-off-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| * nfs: Remove redundant NULL check upon kfree()Davidlohr Bueso2010-08-111-2/+1
| | | | | | | | | | Signed-off-by: Davidlohr Bueso <dave@gnu.org> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| * nfs: Add "lookupcache" to displayed mount optionsPatrick J. LoPresti2010-08-101-0/+7
| | | | | | | | | | | | | | | | | | | | | | Running "cat /proc/mounts" fails to display the "lookupcache" option. This oversight cost me a bunch of wasted time recently. The following simple patch fixes it. CC: stable <stable@kernel.org> Signed-off-by: Patrick LoPresti <lopresti@gmail.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| * NFS: allow close-to-open cache semantics to apply to root of NFS filesystemNeil Brown2010-08-101-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To obey NFS cache semantics, the client must verify the cached attributes when a file is opened. In most cases this is done by a call to d_validate as one of the last steps in path_walk. However for the root of a filesystem, d_validate is only ever called on the mounted-on filesystem (except when the path ends '.' or '..'). So NFS has no chance to validate the attributes. So, in nfs_opendir, we revalidate the attributes if the opened directory is the mountpoint. This may cause double-validation for "." and ".." lookups, but that is better than missing regular /path/name lookups completely. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| * SUNRPC: fix NFS client over TCP hangs due to packet loss (Bug 16494)Andy Chittenden2010-08-101-6/+22
| | | | | | | | | | | | | | | | | | When reusing a TCP connection, ensure that it's aborted if a previous shutdown attempt has been made on that connection so that the RPC over TCP recovery mechanism succeeds. Signed-off-by: Andy Chittenden <andyc.bluearc@gmail.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* | Merge branch 'for-linus' of ↵Linus Torvalds2010-08-185-6/+20
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid: USB HID: Add ID for eGalax Multitouch used in JooJoo tablet HID: hiddev: fix memory corruption due to invalid intfdata HID: hiddev: protect against disconnect/NULL-dereference race HID: picolcd: correct ordering of framebuffer freeing HID: picolcd: testing the wrong variable
| * | USB HID: Add ID for eGalax Multitouch used in JooJoo tabletChris Ball2010-08-163-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The JooJoo tablet (http://thejoojoo.com/) contains an "eGalax Inc. USB TouchController", and this patch hooks it up to the egalax-touch driver. Without the patch we don't get any cursor motion, since it comes through Z/RX rather than X/Y. (The egalax-touch driver does not yet generate a correct event sequence for the "serial" protocol used by this device, though -- see the note added to the code, which comes from research by Stéphane Chatty.) Cc: Jiri Kosina <jkosina@suse.cz> Cc: Stéphane Chatty <chatty@enac.fr> Signed-off-by: Chris Ball <cjb@laptop.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| * | HID: hiddev: fix memory corruption due to invalid intfdataJiri Kosina2010-08-131-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit bd25f4dd6972755579d0 ("HID: hiddev: use usb_find_interface, get rid of BKL") introduced using of private intfdata in hiddev for purpose of storing hiddev pointer. This is a problem, because intf pointer is already being set to struct hid_device pointer by HID core. This obviously lead to memory corruptions at device disconnect time, such as WARNING: at lib/kobject.c:595 kobject_put+0x37/0x4b() kobject: '(null)' (ffff88011e9cd898): is not initialized, yet kobject_put() is being called. Convert hiddev into accessing hiddev through struct hid_device which is in intfdata already. Reported-and-tested-by: Markus Trippelsdorf <markus@trippelsdorf.de> Reported-and-tested-by: Heinz Diehl <htd@fritha.org> Reported-and-tested-by: Alan Ott <alan@signal11.us> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| * | HID: hiddev: protect against disconnect/NULL-dereference raceChris Ball2010-08-131-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One of our users reports consistently hitting a NULL dereference that resolves to the "hid_to_usb_dev(hid);" call in hiddev_ioctl(), when disconnecting a Lego WeDo USB HID device from an OLPC XO running Scratch software. There's a FIXME comment and a guard against the dereference, but that happens farther down the function than the initial dereference does. This patch moves the call to be below the guard, and the user reports that it fixes the problem for him. OLPC bug report: http://dev.laptop.org/ticket/10174 Signed-off-by: Chris Ball <cjb@laptop.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| * | HID: picolcd: correct ordering of framebuffer freeingBruno Prémont2010-08-061-1/+1
| | | | | | | | | | | | | | | | | | | | | Fix the free() ordering (which was never reached due to wrong check). Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| * | HID: picolcd: testing the wrong variableDan Carpenter2010-08-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | "ref_cnt" is a point to the reference count and it's non-null. We really want to test the reference count itself. Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* | | Merge branch 'release' of ↵Linus Torvalds2010-08-181-2/+0
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6 * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6: [IA64] Fix build error: conflicting types for ‘sys_execve’
| * | | [IA64] Fix build error: conflicting types for ‘sys_execve’Tony Luck2010-08-181-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | arch/ia64/kernel/process.c:636: error: conflicting types for ‘sys_execve’ commit d7627467b7a8dd6944885290a03a07ceb28c10eb Make do_execve() take a const filename pointer Missed the declaration of sys_execve in the ia64 asm/unistd.h (perhaps because there is no reason for it to be there ... it might be a left over from the COMPAT code?). Just delete the conflicting version. Signed-off-by: Tony Luck <tony.luck@intel.com>
* | | | Fix the declaration of sys_execve() in asm-generic/syscalls.hDavid Howells2010-08-181-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix the declaration of sys_execve() in asm-generic/syscalls.h to have various consts applied to its pointers. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | Merge branch 'for-linus' of ↵Linus Torvalds2010-08-1843-450/+797
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: fs: brlock vfsmount_lock fs: scale files_lock lglock: introduce special lglock and brlock spin locks tty: fix fu_list abuse fs: cleanup files_lock locking fs: remove extra lookup in __lookup_hash fs: fs_struct rwlock to spinlock apparmor: use task path helpers fs: dentry allocation consolidation fs: fix do_lookup false negative mbcache: Limit the maximum number of cache entries hostfs ->follow_link() braino hostfs: dumb (and usually harmless) tpyo - strncpy instead of strlcpy remove SWRITE* I/O types kill BH_Ordered flag vfs: update ctime when changing the file's permission by setfacl cramfs: only unlock new inodes fix reiserfs_evict_inode end_writeback second call
| * | | | fs: brlock vfsmount_lockNick Piggin2010-08-185-77/+134
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fs: brlock vfsmount_lock Use a brlock for the vfsmount lock. It must be taken for write whenever modifying the mount hash or associated fields, and may be taken for read when performing mount hash lookups. A new lock is added for the mnt-id allocator, so it doesn't need to take the heavy vfsmount write-lock. The number of atomics should remain the same for fastpath rlock cases, though code would be slightly slower due to per-cpu access. Scalability is not not be much improved in common cases yet, due to other locks (ie. dcache_lock) getting in the way. However path lookups crossing mountpoints should be one case where scalability is improved (currently requiring the global lock). The slowpath is slower due to use of brlock. On a 64 core, 64 socket, 32 node Altix system (high latency to remote nodes), a simple umount microbenchmark (mount --bind mnt mnt2 ; umount mnt2 loop 1000 times), before this patch it took 6.8s, afterwards took 7.1s, about 5% slower. Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | fs: scale files_lockNick Piggin2010-08-183-18/+115
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fs: scale files_lock Improve scalability of files_lock by adding per-cpu, per-sb files lists, protected with an lglock. The lglock provides fast access to the per-cpu lists to add and remove files. It also provides a snapshot of all the per-cpu lists (although this is very slow). One difficulty with this approach is that a file can be removed from the list by another CPU. We must track which per-cpu list the file is on with a new variale in the file struct (packed into a hole on 64-bit archs). Scalability could suffer if files are frequently removed from different cpu's list. However loads with frequent removal of files imply short interval between adding and removing the files, and the scheduler attempts to avoid moving processes too far away. Also, even in the case of cross-CPU removal, the hardware has much more opportunity to parallelise cacheline transfers with N cachelines than with 1. A worst-case test of 1 CPU allocating files subsequently being freed by N CPUs degenerates to contending on a single lock, which is no worse than before. When more than one CPU are allocating files, even if they are always freed by different CPUs, there will be more parallelism than the single-lock case. Testing results: On a 2 socket, 8 core opteron, I measure the number of times the lock is taken to remove the file, the number of times it is removed by the same CPU that added it, and the number of times it is removed by the same node that added it. Booting: locks= 25049 cpu-hits= 23174 (92.5%) node-hits= 23945 (95.6%) kbuild -j16 locks=2281913 cpu-hits=2208126 (96.8%) node-hits=2252674 (98.7%) dbench 64 locks=4306582 cpu-hits=4287247 (99.6%) node-hits=4299527 (99.8%) So a file is removed from the same CPU it was added by over 90% of the time. It remains within the same node 95% of the time. Tim Chen ran some numbers for a 64 thread Nehalem system performing a compile. throughput 2.6.34-rc2 24.5 +patch 24.9 us sys idle IO wait (in %) 2.6.34-rc2 51.25 28.25 17.25 3.25 +patch 53.75 18.5 19 8.75 So significantly less CPU time spent in kernel code, higher idle time and slightly higher throughput. Single threaded performance difference was within the noise of microbenchmarks. That is not to say penalty does not exist, the code is larger and more memory accesses required so it will be slightly slower. Cc: linux-kernel@vger.kernel.org Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | lglock: introduce special lglock and brlock spin locksNick Piggin2010-08-181-0/+172
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | lglock: introduce special lglock and brlock spin locks This patch introduces "local-global" locks (lglocks). These can be used to: - Provide fast exclusive access to per-CPU data, with exclusive access to another CPU's data allowed but possibly subject to contention, and to provide very slow exclusive access to all per-CPU data. - Or to provide very fast and scalable read serialisation, and to provide very slow exclusive serialisation of data (not necessarily per-CPU data). Brlocks are also implemented as a short-hand notation for the latter use case. Thanks to Paul for local/global naming convention. Cc: linux-kernel@vger.kernel.org Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | tty: fix fu_list abuseNick Piggin2010-08-186-38/+69
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tty: fix fu_list abuse tty code abuses fu_list, which causes a bug in remount,ro handling. If a tty device node is opened on a filesystem, then the last link to the inode removed, the filesystem will be allowed to be remounted readonly. This is because fs_may_remount_ro does not find the 0 link tty inode on the file sb list (because the tty code incorrectly removed it to use for its own purpose). This can result in a filesystem with errors after it is marked "clean". Taking idea from Christoph's initial patch, allocate a tty private struct at file->private_data and put our required list fields in there, linking file and tty. This makes tty nodes behave the same way as other device nodes and avoid meddling with the vfs, and avoids this bug. The error handling is not trivial in the tty code, so for this bugfix, I take the simple approach of using __GFP_NOFAIL and don't worry about memory errors. This is not a problem because our allocator doesn't fail small allocs as a rule anyway. So proper error handling is left as an exercise for tty hackers. [ Arguably filesystem's device inode would ideally be divorced from the driver's pseudo inode when it is opened, but in practice it's not clear whether that will ever be worth implementing. ] Cc: linux-kernel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | fs: cleanup files_lock lockingNick Piggin2010-08-187-42/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fs: cleanup files_lock locking Lock tty_files with a new spinlock, tty_files_lock; provide helpers to manipulate the per-sb files list; unexport the files_lock spinlock. Cc: linux-kernel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | fs: remove extra lookup in __lookup_hashNick Piggin2010-08-182-41/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fs: remove extra lookup in __lookup_hash Optimize lookup for create operations, where no dentry should often be common-case. In cases where it is not, such as unlink, the added overhead is much smaller than the removed. Also, move comments about __d_lookup racyness to the __d_lookup call site. d_lookup is intuitive; __d_lookup is what needs commenting. So in that same vein, add kerneldoc comments to __d_lookup and clean up some of the comments: - We are interested in how the RCU lookup works here, particularly with renames. Make that explicit, and point to the document where it is explained in more detail. - RCU is pretty standard now, and macros make implementations pretty mindless. If we want to know about RCU barrier details, we look in RCU code. - Delete some boring legacy comments because we don't care much about how the code used to work, more about the interesting parts of how it works now. So comments about lazy LRU may be interesting, but would better be done in the LRU or refcount management code. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | fs: fs_struct rwlock to spinlockNick Piggin2010-08-185-34/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fs: fs_struct rwlock to spinlock struct fs_struct.lock is an rwlock with the read-side used to protect root and pwd members while taking references to them. Taking a reference to a path typically requires just 2 atomic ops, so the critical section is very small. Parallel read-side operations would have cacheline contention on the lock, the dentry, and the vfsmount cachelines, so the rwlock is unlikely to ever give a real parallelism increase. Replace it with a spinlock to avoid one or two atomic operations in typical path lookup fastpath. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | apparmor: use task path helpersNick Piggin2010-08-181-7/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | apparmor: use task path helpers Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | fs: dentry allocation consolidationNick Piggin2010-08-181-37/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fs: dentry allocation consolidation There are 2 duplicate copies of code in dentry allocation in path lookup. Consolidate them into a single function. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | fs: fix do_lookup false negativeNick Piggin2010-08-181-8/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fs: fix do_lookup false negative In do_lookup, if we initially find no dentry, we take the directory i_mutex and re-check the lookup. If we find a dentry there, then we revalidate it if needed. However if that revalidate asks for the dentry to be invalidated, we return -ENOENT from do_lookup. What should happen instead is an attempt to allocate and lookup a new dentry. This is probably not noticed because it is rare. It is only reached if a concurrent create races in first (in which case, the dentry probably won't be invalidated anyway), or if the racy __d_lookup has failed due to a false-negative (which is very rare). Fix this by removing code and have it use the normal reval path. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | mbcache: Limit the maximum number of cache entriesAndreas Gruenbacher2010-08-181-6/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Limit the maximum number of mb_cache entries depending on the number of hash buckets: if the only limit to the number of cache entries is the available memory the hash chains can grow very long, taking a long time to search. At least partially solves https://bugzilla.lustre.org/show_bug.cgi?id=22771. Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | hostfs ->follow_link() brainoAl Viro2010-08-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | we want the assignment to err done inside the if () to be visible after it, so (re)declaring err inside if () body is wrong. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | hostfs: dumb (and usually harmless) tpyo - strncpy instead of strlcpyAl Viro2010-08-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... not harmless in this case - we have a string in the end of buffer already. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | remove SWRITE* I/O typesChristoph Hellwig2010-08-1816-94/+73
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These flags aren't real I/O types, but tell ll_rw_block to always lock the buffer instead of giving up on a failed trylock. Instead add a new write_dirty_buffer helper that implements this semantic and use it from the existing SWRITE* callers. Note that the ll_rw_block code had a bug where it didn't promote WRITE_SYNC_PLUG properly, which this patch fixes. In the ufs code clean up the helper that used to call ll_rw_block to mirror sync_dirty_buffer, which is the function it implements for compound buffers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | kill BH_Ordered flagChristoph Hellwig2010-08-185-73/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of abusing a buffer_head flag just add a variant of sync_dirty_buffer which allows passing the exact type of write flag required. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | vfs: update ctime when changing the file's permission by setfaclJan Kara2010-08-181-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | generic_acl_set didn't update the ctime of the file when its permission was changed. Steps to reproduce: # touch aaa # stat -c %Z aaa 1275289822 # setfacl -m 'u::x,g::x,o::x' aaa # stat -c %Z aaa 1275289822 <- unchanged But, according to the spec of the ctime, vfs must update it. Port of ext3 patch by Miao Xie <miaox@cn.fujitsu.com>. CC: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | cramfs: only unlock new inodesAlexander Shishkin2010-08-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 77b8a75f5bb introduced a warning at fs/inode.c:692 unlock_new_inode(), caused by unlock_new_inode() being called on existing inodes as well. This patch changes setup_inode() to only call unlock_new_inode() for I_NEW inodes. Signed-off-by: Alexander Shishkin <virtuoso@slind.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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