- 09 9月, 2013 1 次提交
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由 Linus Torvalds 提交于
This is me being a bit OCD after all the dentry optimization work this merge window: profiles end up showing 'dput()' as a rather expensive operation, and there were two unrelated bad reasons for that. The first reason was reading d_lockref.count for debugging purposes, which touches the lockref cacheline (for reads) before really need to. More importantly, the debugging test in question is _wrong_, and has hidden bugs. It's true that we can only sleep when the count goes down to zero, but the test as-is hides the much more subtle bug that happens if we race with somebody else deleting the file. Anyway we _will_ touch that cacheline, but let's do it for a write and in the right routine (ie in "lockref_put_or_lock()") which annotates the costs better. So remove the misleading debug code. The other was an unnecessary access to the cacheline that contains the d_lru list, just to check whether we already were on the LRU list or not. This is exactly what we have d_flags for, so that we can avoid touching extra cache lines for the common case. So just add another bit for "is this dentry on the LRU". Finally, mark the tests properly likely/unlikely, so that the common fast-paths are dense in the instruction stream. This makes the profiles look much saner. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 08 9月, 2013 2 次提交
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由 Linus Torvalds 提交于
The only actual current lockref user (dcache) uses zero reference counts even for perfectly live dentries, because it's a cache: there may not be any users, but that doesn't mean that we want to throw away the dentry. At the same time, the dentry cache does have a notion of a truly "dead" dentry that we must not even increment the reference count of, because we have pruned it and it is not valid. Currently that distinction is not visible in the lockref itself, and the dentry cache validation uses "lockref_get_or_lock()" to either get a new reference to a dentry that already had existing references (and thus cannot be dead), or get the dentry lock so that we can then verify the dentry and increment the reference count under the lock if that verification was successful. That's all somewhat complicated. This adds the concept of being "dead" to the lockref itself, by simply using a count that is negative. This allows a usage scenario where we can increment the refcount of a dentry without having to validate it, and pushing the special "we killed it" case into the lockref code. The dentry code itself doesn't actually use this yet, and it's probably too late in the merge window to do that code (the dentry_kill() code with its "should I decrement the count" logic really is pretty complex code), but let's introduce the concept at the lockref level now. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
This reverts commits 61e00655, 73f8645d and 8e22ecb6: "Input: introduce BTN/ABS bits for drums and guitars" "HID: wiimote: add support for Guitar-Hero drums" "HID: wiimote: add support for Guitar-Hero guitars" The extra new ABS_xx values resulted in ABS_MAX no longer being a power-of-two, which broke the comparison logic. It also caused the ioctl numbers to overflow into the next byte, causing problems for that. We'll try again for 3.13. Reported-by: NMarkus Trippelsdorf <markus@trippelsdorf.de> Reported-by: NLinus Torvalds <torvalds@linux-foundation.org> Acked-by: NDavid Herrmann <dh.herrmann@gmail.com> Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Benjamin Tissoires <benjamin.tissoires@gmail.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 9月, 2013 3 次提交
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由 Herbert Xu 提交于
This patch reinstates commits 67822649 39761214 0b95a7f8 31d93962 2d31e518 Now that module softdeps are in the kernel we can use that to resolve the boot issue which cause the revert. Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
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由 Andy Adamson 提交于
Commit 4edaa308 "NFS: Use "krb5i" to establish NFSv4 state whenever possible" uses the nfs_client cl_rpcclient for all state management operations, and will use krb5i or auth_sys with no regard to the mount command authflavor choice. The MDS, as any NFSv4.1 mount point, uses the nfs_server rpc client for all non-state management operations with a different nfs_server for each fsid encountered traversing the mount point, each with a potentially different auth flavor. pNFS data servers are not mounted in the normal sense as there is no associated nfs_server structure. Data servers can also export multiple fsids, each with a potentially different auth flavor. Data servers need to use the same authflavor as the MDS server rpc client for non-state management operations. Populate a list of rpc clients with the MDS server rpc client auth flavor for the DS to use. Signed-off-by: NAndy Adamson <andros@netapp.com> Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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由 Florian Fainelli 提交于
Provide a kernel-doc comment documentation for the BQL helpers: - netdev_sent_queue - netdev_completed_queue - netdev_reset_queue Similarly to how it is done for the other functions, the documentation only covers the function operating on struct net_device and not struct netdev_queue. Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com> Acked-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 06 9月, 2013 5 次提交
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由 Milosz Tanski 提交于
Currently the fscache code expect the netfs to call fscache_readpages_or_alloc inside the aops readpages callback. It marks all the pages in the list provided by readahead with PG_private_2. In the cases that the netfs fails to read all the pages (which is legal) it ends up returning to the readahead and triggering a BUG. This happens because the page list still contains marked pages. This patch implements a simple fscache_readpages_cancel function that the netfs should call before returning from readpages. It will revoke the pages from the underlying cache backend and unmark them. The problem was originally worked out in the Ceph devel tree, but it also occurs in CIFS. It appears that NFS, AFS and 9P are okay as read_cache_pages() will clean up the unprocessed pages in the case of an error. This can be used to address the following oops: [12410647.597278] BUG: Bad page state in process petabucket pfn:3d504e [12410647.597292] page:ffffea000f541380 count:0 mapcount:0 mapping: (null) index:0x0 [12410647.597298] page flags: 0x200000000001000(private_2) ... [12410647.597334] Call Trace: [12410647.597345] [<ffffffff815523f2>] dump_stack+0x19/0x1b [12410647.597356] [<ffffffff8111def7>] bad_page+0xc7/0x120 [12410647.597359] [<ffffffff8111e49e>] free_pages_prepare+0x10e/0x120 [12410647.597361] [<ffffffff8111fc80>] free_hot_cold_page+0x40/0x170 [12410647.597363] [<ffffffff81123507>] __put_single_page+0x27/0x30 [12410647.597365] [<ffffffff81123df5>] put_page+0x25/0x40 [12410647.597376] [<ffffffffa02bdcf9>] ceph_readpages+0x2e9/0x6e0 [ceph] [12410647.597379] [<ffffffff81122a8f>] __do_page_cache_readahead+0x1af/0x260 [12410647.597382] [<ffffffff81122ea1>] ra_submit+0x21/0x30 [12410647.597384] [<ffffffff81118f64>] filemap_fault+0x254/0x490 [12410647.597387] [<ffffffff8113a74f>] __do_fault+0x6f/0x4e0 [12410647.597391] [<ffffffff810125bd>] ? __switch_to+0x16d/0x4a0 [12410647.597395] [<ffffffff810865ba>] ? finish_task_switch+0x5a/0xc0 [12410647.597398] [<ffffffff8113d856>] handle_pte_fault+0xf6/0x930 [12410647.597401] [<ffffffff81008c33>] ? pte_mfn_to_pfn+0x93/0x110 [12410647.597403] [<ffffffff81008cce>] ? xen_pmd_val+0xe/0x10 [12410647.597405] [<ffffffff81005469>] ? __raw_callee_save_xen_pmd_val+0x11/0x1e [12410647.597407] [<ffffffff8113f361>] handle_mm_fault+0x251/0x370 [12410647.597411] [<ffffffff812b0ac4>] ? call_rwsem_down_read_failed+0x14/0x30 [12410647.597414] [<ffffffff8155bffa>] __do_page_fault+0x1aa/0x550 [12410647.597418] [<ffffffff8108011d>] ? up_write+0x1d/0x20 [12410647.597422] [<ffffffff8113141c>] ? vm_mmap_pgoff+0xbc/0xe0 [12410647.597425] [<ffffffff81143bb8>] ? SyS_mmap_pgoff+0xd8/0x240 [12410647.597427] [<ffffffff8155c3ae>] do_page_fault+0xe/0x10 [12410647.597431] [<ffffffff81558818>] page_fault+0x28/0x30 Signed-off-by: NMilosz Tanski <milosz@adfin.com> Signed-off-by: NDavid Howells <dhowells@redhat.com>
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由 David Howells 提交于
Extend the fscache netfs API so that the netfs can ask as to whether a cache object is up to date with respect to its corresponding netfs object: int fscache_check_consistency(struct fscache_cookie *cookie) This will call back to the netfs to check whether the auxiliary data associated with a cookie is correct. It returns 0 if it is and -ESTALE if it isn't; it may also return -ENOMEM and -ERESTARTSYS. The backends now have to implement a mandatory operation pointer: int (*check_consistency)(struct fscache_object *object) that corresponds to the above API call. FS-Cache takes care of pinning the object and the cookie in memory and managing this call with respect to the object state. Original-author: Hongyi Jia <jiayisuse@gmail.com> Signed-off-by: NDavid Howells <dhowells@redhat.com> cc: Hongyi Jia <jiayisuse@gmail.com> cc: Milosz Tanski <milosz@adfin.com>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Miklos Szeredi 提交于
We check submounts before doing d_drop() on a non-empty directory dentry in NFS (have_submounts()), but we do not exclude a racing mount. Process A: have_submounts() -> returns false Process B: mount() -> success Process A: d_drop() This patch prepares the ground for the fix by doing the following operations all under the same rename lock: have_submounts() shrink_dcache_parent() d_drop() This is actually an optimization since have_submounts() and shrink_dcache_parent() both traverse the same dentry tree separately. Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> CC: David Howells <dhowells@redhat.com> CC: Steven Whitehouse <swhiteho@redhat.com> CC: Trond Myklebust <Trond.Myklebust@netapp.com> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Joseph Gasparakis 提交于
This patch adds two more ndo ops: ndo_add_rx_vxlan_port() and ndo_del_rx_vxlan_port(). Drivers can get notifications through the above functions about changes of the UDP listening port of VXLAN. Also, when physical ports come up, now they can call vxlan_get_rx_port() in order to obtain the port number(s) of the existing VXLAN interface in case they already up before them. This information about the listening UDP port would be used for VXLAN related offloads. A big thank you to John Fastabend (john.r.fastabend@intel.com) for his input and his suggestions on this patch set. CC: John Fastabend <john.r.fastabend@intel.com> CC: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: NJoseph Gasparakis <joseph.gasparakis@intel.com> Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 05 9月, 2013 8 次提交
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由 Weston Andros Adamson 提交于
WRITE and COMMIT can use the machine credential. If WRITE is supported and COMMIT is not, make all (mach cred) writes FILE_SYNC4. Signed-off-by: NWeston Andros Adamson <dros@netapp.com> Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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由 Weston Andros Adamson 提交于
TEST_STATEID and FREE_STATEID can use the machine credential. Signed-off-by: NWeston Andros Adamson <dros@netapp.com> Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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由 Weston Andros Adamson 提交于
SECINFO and SECINFO_NONAME can use the machine credential. Signed-off-by: NWeston Andros Adamson <dros@netapp.com> Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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由 Weston Andros Adamson 提交于
CLOSE and LOCKU can use the machine credential. Signed-off-by: NWeston Andros Adamson <dros@netapp.com> Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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由 Weston Andros Adamson 提交于
This is a minimal client side implementation of SP4_MACH_CRED. It will attempt to negotiate SP4_MACH_CRED iff the EXCHANGE_ID is using krb5i or krb5p auth. SP4_MACH_CRED will be used if the server supports the minimal operations: BIND_CONN_TO_SESSION EXCHANGE_ID CREATE_SESSION DESTROY_SESSION DESTROY_CLIENTID This patch only includes the EXCHANGE_ID negotiation code because the client will already use the machine cred for these operations. If the server doesn't support SP4_MACH_CRED or doesn't support the minimal operations, the exchange id will be resent with SP4_NONE. Signed-off-by: NWeston Andros Adamson <dros@netapp.com> Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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由 Trond Myklebust 提交于
Add an identifier in order to aid debugging. Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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由 Trond Myklebust 提交于
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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由 NeilBrown 提交于
When an NFSv4 client loses contact with the server it can lose any locks that it holds. Currently when it reconnects to the server it simply tries to reclaim those locks. This might succeed even though some other client has held and released a lock in the mean time. So the first client might think the file is unchanged, but it isn't. This isn't good. If, when recovery happens, the locks cannot be claimed because some other client still holds the lock, then we get a message in the kernel logs, but the client can still write. So two clients can both think they have a lock and can both write at the same time. This is equally not good. There was a patch a while ago http://comments.gmane.org/gmane.linux.nfs/41917 which tried to address some of this, but it didn't seem to go anywhere. That patch would also send a signal to the process. That might be useful but for now this patch just causes writes to fail. For NFSv4 (unlike v2/v3) there is a strong link between the lock and the write request so we can fairly easily fail any IO of the lock is gone. While some applications might not expect this, it is still safer than allowing the write to succeed. Because this is a fairly big change in behaviour a module parameter, "recover_locks", is introduced which defaults to true (the current behaviour) but can be set to "false" to tell the client not to try to recover things that were lost. Signed-off-by: NNeilBrown <neilb@suse.de> Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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- 04 9月, 2013 18 次提交
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由 Christoph Hellwig 提交于
Add support to the core direct-io code to defer AIO completions to user context using a workqueue. This replaces opencoded and less efficient code in XFS and ext4 (we save a memory allocation for each direct IO) and will be needed to properly support O_(D)SYNC for AIO. The communication between the filesystem and the direct I/O code requires a new buffer head flag, which is a bit ugly but not avoidable until the direct I/O code stops abusing the buffer_head structure for communicating with the filesystems. Currently this creates a per-superblock unbound workqueue for these completions, which is taken from an earlier patch by Jan Kara. I'm not really convinced about this use and would prefer a "normal" global workqueue with a high concurrency limit, but this needs further discussion. JK: Fixed ext4 part, dynamic allocation of the workqueue. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJan Kara <jack@suse.cz> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 David Herrmann 提交于
HID_REPORT_TYPES defines the number of available report-types. Move it closer to the actualy definition of the report-types so we can see the relation more clearly (and hopefully will never forget to update it). Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com> Signed-off-by: NJiri Kosina <jkosina@suse.cz>
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由 David Herrmann 提交于
There are a bunch of guitar and drums devices out there that all report similar data. To avoid reporting this as BTN_MISC or ABS_MISC, we allocate some proper namespace for them. Note that most of these devices are toys and we cannot report any sophisticated physics via this API. I did some google-images research and tried to provide definitions that work with all common devices. That's why I went with 4 toms, 4 cymbals, one bass, one hi-hat. I haven't seen other drums and I doubt that we need any additions to that. Anyway, the naming-scheme is intentionally done in an extensible way. For guitars, we support 5 frets (normally aligned vertically, compared to the real horizontal layouts), a single strum-bar with up/down directions, an optional fret-board and a whammy-bar. Most of the devices provide pressure values so I went with ABS_* bits. If we ever support devices which only provide digital input, we have to decide whether to emulate pressure data or add additional BTN_* bits. If someone is not familiar with these devices, here are two pictures which provide almost all introduced interfaces (or try the given keywords with a google-image search): Guitar: ("guitar hero world tour guitar") http://images1.wikia.nocookie.net/__cb20120911023442/applezone/es/images/f/f9/Wii_Guitar.jpg Drums: ("guitar hero drums") http://oyster.ignimgs.com/franchises/images/03/55/35526_band-hero-drum-set-hands-on-20090929040735768.jpgSigned-off-by: NDavid Herrmann <dh.herrmann@gmail.com> Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: NJiri Kosina <jkosina@suse.cz>
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由 Nicolas Dichtel 提交于
This function was only used when a packet was sent to another netns. Now, it can also be used after tunnel encapsulation or decapsulation. Only skb_orphan() should not be done when a packet is not crossing netns. Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
same story as with oprofilefs_mkdir() Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
it's always equal to ->d_sb of the second argument (parent dentry), due to either being literally that, or ->d_sb of parent's parent. Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Jeff Layton 提交于
Christopher reported a regression where he was unable to unmount a NFS filesystem where the root had gone stale. The problem is that d_revalidate handles the root of the filesystem differently from other dentries, but d_weak_revalidate does not. We could simply fix this by making d_weak_revalidate return success on IS_ROOT dentries, but there are cases where we do want to revalidate the root of the fs. A umount is really a special case. We generally aren't interested in anything but the dentry and vfsmount that's attached at that point. If the inode turns out to be stale we just don't care since the intent is to stop using it anyway. Try to handle this situation better by treating umount as a special case in the lookup code. Have it resolve the parent using normal means, and then do a lookup of the final dentry without revalidating it. In most cases, the final lookup will come out of the dcache, but the case where there's a trailing symlink or !LAST_NORM entry on the end complicates things a bit. Cc: Neil Brown <neilb@suse.de> Reported-by: NChristopher T Vogan <cvogan@us.ibm.com> Signed-off-by: NJeff Layton <jlayton@redhat.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Florian Fainelli 提交于
The name of the function in the comment is __skb_alloc_page() while we are actually commenting __skb_alloc_pages(). Fix this typo and make it a valid kernel doc comment. Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Bjørn Mork 提交于
Some etherdevices inherit their address from a parent or master device. The addr_assign_type should be updated along with the address in these cases. Adding a helper function to simplify this. Signed-off-by: NBjørn Mork <bjorn@mork.no> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Keith Busch 提交于
The NVMe spec recommends using the shutdown normal sequence when safely taking the controller offline instead of hitting CC.EN on the next start-up to reset the controller. The spec recommends a minimum of 1 second for the shutdown complete. This patch waits 2 seconds to be on the safe side. Signed-off-by: NKeith Busch <keith.busch@intel.com> Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>
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由 Matthew Wilcox 提交于
The 'Number of Namespaces' read from the device was being treated as signed, which would cause us to not scan any namespaces for a device with more than 2 billion namespaces. That led to noticing that the namespace ID was also being treated as signed, which could lead to the result from NVME_IOCTL_ID being treated as an error code. Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>
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由 Matthew Wilcox 提交于
To build user programs that call the NVMe ioctls, we need to have a user header file. Catch up to the new way of doing that by splitting the header file into kernel and uapi portions. Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>
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由 Chuck Lever 提交于
Anchor an nfs4_slot_table in the nfs_client for use with NFSv4.0 transport blocking. It is initialized only for NFSv4.0 nfs_client's. Introduce appropriate minor version ops to handle nfs_client initialization and shutdown requirements that differ for each minor version. Signed-off-by: NChuck Lever <chuck.lever@oracle.com> Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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由 Trond Myklebust 提交于
If an NFS client does mkdir("dir"); fd = open("dir/file"); unlink("dir/file"); close(fd); rmdir("dir"); then the asynchronous nature of the sillyrename operation means that we can end up getting EBUSY for the rmdir() in the above test. Fix that by ensuring that we wait for any in-progress sillyrenames before sending the rmdir() to the server. Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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由 Andy Adamson 提交于
This patch provides the RPC layer helper functions to allow NFS to manage data in the face of expired credentials - such as avoiding buffered WRITEs and COMMITs when the gss context will expire before the WRITEs are flushed and COMMITs are sent. These helper functions enable checking the expiration of an underlying credential key for a generic rpc credential, e.g. the gss_cred gss context gc_expiry which for Kerberos is set to the remaining TGT lifetime. A new rpc_authops key_timeout is only defined for the generic auth. A new rpc_credops crkey_to_expire is only defined for the generic cred. A new rpc_credops crkey_timeout is only defined for the gss cred. Set a credential key expiry watermark, RPC_KEY_EXPIRE_TIMEO set to 240 seconds as a default and can be set via a module parameter as we need to ensure there is time for any dirty data to be flushed. If key_timeout is called on a credential with an underlying credential key that will expire within watermark seconds, we set the RPC_CRED_KEY_EXPIRE_SOON flag in the generic_cred acred so that the NFS layer can clean up prior to key expiration. Checking a generic credential's underlying credential involves a cred lookup. To avoid this lookup in the normal case when the underlying credential has a key that is valid (before the watermark), a notify flag is set in the generic credential the first time the key_timeout is called. The generic credential then stops checking the underlying credential key expiry, and the underlying credential (gss_cred) match routine then checks the key expiration upon each normal use and sets a flag in the associated generic credential only when the key expiration is within the watermark. This in turn signals the generic credential key_timeout to perform the extra credential lookup thereafter. Signed-off-by: NAndy Adamson <andros@netapp.com> Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
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- 03 9月, 2013 3 次提交
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由 Li Zhong 提交于
DEBUG_KOBJECT_RELEASE helps to find the issue attached below. After some investigation, it seems the reason is: The mod->mkobj.kobj(ffffffffa01600d0 below) is freed together with mod itself in free_module(). However, its children still hold references to it, as the delay caused by DEBUG_KOBJECT_RELEASE. So when the child(holders below) tries to decrease the reference count to its parent in kobject_del(), BUG happens as it tries to access already freed memory. This patch tries to fix it by waiting for the mod->mkobj.kobj to be really released in the module removing process (and some error code paths). [ 1844.175287] kobject: 'holders' (ffff88007c1f1600): kobject_release, parent ffffffffa01600d0 (delayed) [ 1844.178991] kobject: 'notes' (ffff8800370b2a00): kobject_release, parent ffffffffa01600d0 (delayed) [ 1845.180118] kobject: 'holders' (ffff88007c1f1600): kobject_cleanup, parent ffffffffa01600d0 [ 1845.182130] kobject: 'holders' (ffff88007c1f1600): auto cleanup kobject_del [ 1845.184120] BUG: unable to handle kernel paging request at ffffffffa01601d0 [ 1845.185026] IP: [<ffffffff812cda81>] kobject_put+0x11/0x60 [ 1845.185026] PGD 1a13067 PUD 1a14063 PMD 7bd30067 PTE 0 [ 1845.185026] Oops: 0000 [#1] PREEMPT [ 1845.185026] Modules linked in: xfs libcrc32c [last unloaded: kprobe_example] [ 1845.185026] CPU: 0 PID: 18 Comm: kworker/0:1 Tainted: G O 3.11.0-rc6-next-20130819+ #1 [ 1845.185026] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 1845.185026] Workqueue: events kobject_delayed_cleanup [ 1845.185026] task: ffff88007ca51f00 ti: ffff88007ca5c000 task.ti: ffff88007ca5c000 [ 1845.185026] RIP: 0010:[<ffffffff812cda81>] [<ffffffff812cda81>] kobject_put+0x11/0x60 [ 1845.185026] RSP: 0018:ffff88007ca5dd08 EFLAGS: 00010282 [ 1845.185026] RAX: 0000000000002000 RBX: ffffffffa01600d0 RCX: ffffffff8177d638 [ 1845.185026] RDX: ffff88007ca5dc18 RSI: 0000000000000000 RDI: ffffffffa01600d0 [ 1845.185026] RBP: ffff88007ca5dd18 R08: ffffffff824e9810 R09: ffffffffffffffff [ 1845.185026] R10: ffff8800ffffffff R11: dead4ead00000001 R12: ffffffff81a95040 [ 1845.185026] R13: ffff88007b27a960 R14: ffff88007c1f1600 R15: 0000000000000000 [ 1845.185026] FS: 0000000000000000(0000) GS:ffffffff81a23000(0000) knlGS:0000000000000000 [ 1845.185026] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 1845.185026] CR2: ffffffffa01601d0 CR3: 0000000037207000 CR4: 00000000000006b0 [ 1845.185026] Stack: [ 1845.185026] ffff88007c1f1600 ffff88007c1f1600 ffff88007ca5dd38 ffffffff812cdb7e [ 1845.185026] 0000000000000000 ffff88007c1f1640 ffff88007ca5dd68 ffffffff812cdbfe [ 1845.185026] ffff88007c974800 ffff88007c1f1640 ffff88007ff61a00 0000000000000000 [ 1845.185026] Call Trace: [ 1845.185026] [<ffffffff812cdb7e>] kobject_del+0x2e/0x40 [ 1845.185026] [<ffffffff812cdbfe>] kobject_delayed_cleanup+0x6e/0x1d0 [ 1845.185026] [<ffffffff81063a45>] process_one_work+0x1e5/0x670 [ 1845.185026] [<ffffffff810639e3>] ? process_one_work+0x183/0x670 [ 1845.185026] [<ffffffff810642b3>] worker_thread+0x113/0x370 [ 1845.185026] [<ffffffff810641a0>] ? rescuer_thread+0x290/0x290 [ 1845.185026] [<ffffffff8106bfba>] kthread+0xda/0xe0 [ 1845.185026] [<ffffffff814ff0f0>] ? _raw_spin_unlock_irq+0x30/0x60 [ 1845.185026] [<ffffffff8106bee0>] ? kthread_create_on_node+0x130/0x130 [ 1845.185026] [<ffffffff8150751a>] ret_from_fork+0x7a/0xb0 [ 1845.185026] [<ffffffff8106bee0>] ? kthread_create_on_node+0x130/0x130 [ 1845.185026] Code: 81 48 c7 c7 28 95 ad 81 31 c0 e8 9b da 01 00 e9 4f ff ff ff 66 0f 1f 44 00 00 55 48 89 e5 53 48 89 fb 48 83 ec 08 48 85 ff 74 1d <f6> 87 00 01 00 00 01 74 1e 48 8d 7b 38 83 6b 38 01 0f 94 c0 84 [ 1845.185026] RIP [<ffffffff812cda81>] kobject_put+0x11/0x60 [ 1845.185026] RSP <ffff88007ca5dd08> [ 1845.185026] CR2: ffffffffa01601d0 [ 1845.185026] ---[ end trace 49a70afd109f5653 ]--- Signed-off-by: NLi Zhong <zhong@linux.vnet.ibm.com> Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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由 Linus Torvalds 提交于
Instead of taking the spinlock, the lockless versions atomically check that the lock is not taken, and do the reference count update using a cmpxchg() loop. This is semantically identical to doing the reference count update protected by the lock, but avoids the "wait for lock" contention that you get when accesses to the reference count are contended. Note that a "lockref" is absolutely _not_ equivalent to an atomic_t. Even when the lockref reference counts are updated atomically with cmpxchg, the fact that they also verify the state of the spinlock means that the lockless updates can never happen while somebody else holds the spinlock. So while "lockref_put_or_lock()" looks a lot like just another name for "atomic_dec_and_lock()", and both optimize to lockless updates, they are fundamentally different: the decrement done by atomic_dec_and_lock() is truly independent of any lock (as long as it doesn't decrement to zero), so a locked region can still see the count change. The lockref structure, in contrast, really is a *locked* reference count. If you hold the spinlock, the reference count will be stable and you can modify the reference count without using atomics, because even the lockless updates will see and respect the state of the lock. In order to enable the cmpxchg lockless code, the architecture needs to do three things: (1) Make sure that the "arch_spinlock_t" and an "unsigned int" can fit in an aligned u64, and have a "cmpxchg()" implementation that works on such a u64 data type. (2) define a helper function to test for a spinlock being unlocked ("arch_spin_value_unlocked()") (3) select the "ARCH_USE_CMPXCHG_LOCKREF" config variable in its Kconfig file. This enables it for x86-64 (but not 32-bit, we'd need to make sure cmpxchg() turns into the proper cmpxchg8b in order to enable it for 32-bit mode). Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
They aren't very good to inline, since they already call external functions (the spinlock code), and we're going to create rather more complicated versions of them that can do the reference count updates locklessly. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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