Not using the return value can in the generic case be racy, so it's
in general good practice to check the return value instead.
This also resolved the warning caused on ARM and other architectures:
fs/direct-io.c: In function 'sb_init_dio_done_wq':
fs/direct-io.c:557:2: warning: value computed is not used [-Wunused-value]
Signed-off-by: Olof Johansson <olof@lixom.net>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: H Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When running the AIM7's short workload, Linus' lockref patch eliminated
most of the spinlock contention. However, there were still some left:
8.46% reaim [kernel.kallsyms] [k] _raw_spin_lock
|--42.21%-- d_path
| proc_pid_readlink
| SyS_readlinkat
| SyS_readlink
| system_call
| __GI___readlink
|
|--40.97%-- sys_getcwd
| system_call
| __getcwd
The big one here is the rename_lock (seqlock) contention in d_path()
and the getcwd system call. This patch will eliminate the need to take
the rename_lock while translating dentries into the full pathnames.
The need to take the rename_lock is to make sure that no rename
operation can be ongoing while the translation is in progress. However,
only one thread can take the rename_lock thus blocking all the other
threads that need it even though the translation process won't make
any change to the dentries.
This patch will replace the writer's write_seqlock/write_sequnlock
sequence of the rename_lock of the callers of the prepend_path() and
__dentry_path() functions with the reader's read_seqbegin/read_seqretry
sequence within these 2 functions. As a result, the code will have to
retry if one or more rename operations had been performed. In addition,
RCU read lock will be taken during the translation process to make sure
that no dentries will go away. To prevent live-lock from happening,
the code will switch back to take the rename_lock if read_seqretry()
fails for three times.
To further reduce spinlock contention, this patch does not take the
dentry's d_lock when copying the filename from the dentries. Instead,
it treats the name pointer and length as unreliable and just copy
the string byte-by-byte over until it hits a null byte or the end of
string as specified by the length. This should avoid stepping into
invalid memory address. The error cases are left to be handled by
the sequence number check.
The following code re-factoring are also made:
1. Move prepend('/') into prepend_name() to remove one conditional
check.
2. Move the global root check in prepend_path() back to the top of
the while loop.
With this patch, the _raw_spin_lock will now account for only 1.2%
of the total CPU cycles for the short workload. This patch also has
the effect of reducing the effect of running perf on its profile
since the perf command itself can be a heavy user of the d_path()
function depending on the complexity of the workload.
When taking the perf profile of the high-systime workload, the amount
of spinlock contention contributed by running perf without this patch
was about 16%. With this patch, the spinlock contention caused by
the running of perf will go away and we will have a more accurate
perf profile.
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull mtd updates from David Woodhouse:
- factor out common code from MTD tests
- nand-gpio cleanup and portability to non-ARM
- m25p80 support for 4-byte addressing chips, other new chips
- pxa3xx cleanup and support for new platforms
- remove obsolete alauda, octagon-5066 drivers
- erase/write support for bcm47xxsflash
- improve detection of ECC requirements for NAND, controller setup
- NFC acceleration support for atmel-nand, read/write via SRAM
- etc
* tag 'for-linus-20130909' of git://git.infradead.org/linux-mtd: (184 commits)
mtd: chips: Add support for PMC SPI Flash chips in m25p80.c
mtd: ofpart: use for_each_child_of_node() macro
mtd: mtdswap: replace strict_strtoul() with kstrtoul()
mtd cs553x_nand: use kzalloc() instead of memset
mtd: atmel_nand: fix error return code in atmel_nand_probe()
mtd: bcm47xxsflash: writing support
mtd: bcm47xxsflash: implement erasing support
mtd: bcm47xxsflash: convert to module_platform_driver instead of init/exit
mtd: bcm47xxsflash: convert kzalloc to avoid invalid access
mtd: remove alauda driver
mtd: nand: mxc_nand: mark 'const' properly
mtd: maps: cfi_flagadm: add missing __iomem annotation
mtd: spear_smi: add missing __iomem annotation
mtd: r852: Staticize local symbols
mtd: nandsim: Staticize local symbols
mtd: impa7: add missing __iomem annotation
mtd: sm_ftl: Staticize local symbols
mtd: m25p80: add support for mr25h10
mtd: m25p80: make CONFIG_M25PXX_USE_FAST_READ safe to enable
mtd: m25p80: Pass flags through CAT25_INFO macro
...
Pull firewire updates from Stefan Richter:
- Fix a regression since 3.2 inclusive: The subsystem workqueue
deadlocked between transaction completion handling and bus reset
handling if the worker pool could not be increased in time.
- janitorial updates
* tag 'firewire-updates' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
firewire: ohci: Fix deadlock at bus reset
firewire: ohci: Change module_pci_driver to module_init/module_exit
firewire: ohci: beautify some macro definitions
firewire: ohci: change confusing name of a struct member
firewire: core: typecast from gfp_t to bool more safely
firewire: WQ_NON_REENTRANT is meaningless and going away
Pull DMA mapping update from Marek Szyprowski:
"This contains an addition of Device Tree support for reserved memory
regions (Contiguous Memory Allocator is one of the drivers for it) and
changes required by the KVM extensions for PowerPC architectue"
* 'for-v3.12' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
ARM: init: add support for reserved memory defined by device tree
drivers: of: add initialization code for dma reserved memory
drivers: of: add function to scan fdt nodes given by path
drivers: dma-contiguous: clean source code and prepare for device tree
Pull virtio update from Rusty Russell:
"More console fixes; these are the theoretical ones which didn't get
CC:stable. But for that reason, I did a merge with master partway
through to avoid an unnecessary conflict.
Also: a fun lguest bug turns out if you don't clear the TF flag when
trapping Bad Things happen to the guest kernel as the stack
overflows..."
* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
virtio_pci: pm: Use CONFIG_PM_SLEEP instead of CONFIG_PM
lguest: fix GPF in guest when using gdb.
lguest: fix guest kernel stack overflow when TF bit set.
lguest: fix BUG_ON() in invalid guest page table.
virtio: console: prevent use-after-free of port name in port unplug
virtio: console: cleanup an error message
virtio: console: fix locking around send_sigio_to_port()
virtio: console: add locking in port unplug path
virtio: console: add locks around buffer removal in port unplug path
tools/lguest: offer VIRTIO_F_ANY_LAYOUT for net device.
virtio tools: add .gitignore
lguest: Point to the right directory for the lguest launcher
Pull VFIO update from Alex Williamson:
"VFIO updates include safer default file flags for VFIO device fds, an
external user interface exported to allow other modules to hold
references to VFIO groups, a fix to test for extended config space on
PCIe and PCI-x, and new hot reset interfaces for PCI devices which
allows the user to do PCI bus/slot resets when all of the devices
affected by the reset are owned by the user.
For this last feature, the PCI bus reset interface, I depend on
changes already merged from Bjorn's PCI pull request. I therefore
merged my tree up to commit cb3e433, which I think was the correct
action, but as Stephen Rothwell noted, I failed to provide a commit
message indicating why the merge was required. Sorry for that.
Thanks, Alex"
* tag 'vfio-v3.12-rc0' of git://github.com/awilliam/linux-vfio:
vfio: fix documentation
vfio-pci: PCI hot reset interface
vfio-pci: Test for extended config space
vfio-pci: Use fdget() rather than eventfd_fget()
vfio: Add O_CLOEXEC flag to vfio device fd
vfio: use get_unused_fd_flags(0) instead of get_unused_fd()
vfio: add external user support
As we get compile warnings about .init.data being
used by non-init functions.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Pull NFS client updates from Trond Myklebust:
"Highlights include:
- Fix NFSv4 recovery so that it doesn't recover lost locks in cases
such as lease loss due to a network partition, where doing so may
result in data corruption. Add a kernel parameter to control
choice of legacy behaviour or not.
- Performance improvements when 2 processes are writing to the same
file.
- Flush data to disk when an RPCSEC_GSS session timeout is imminent.
- Implement NFSv4.1 SP4_MACH_CRED state protection to prevent other
NFS clients from being able to manipulate our lease and file
locking state.
- Allow sharing of RPCSEC_GSS caches between different rpc clients.
- Fix the broken NFSv4 security auto-negotiation between client and
server.
- Fix rmdir() to wait for outstanding sillyrename unlinks to complete
- Add a tracepoint framework for debugging NFSv4 state recovery
issues.
- Add tracing to the generic NFS layer.
- Add tracing for the SUNRPC socket connection state.
- Clean up the rpc_pipefs mount/umount event management.
- Merge more patches from Chuck in preparation for NFSv4 migration
support"
* tag 'nfs-for-3.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (107 commits)
NFSv4: use mach cred for SECINFO_NO_NAME w/ integrity
NFS: nfs_compare_super shouldn't check the auth flavour unless 'sec=' was set
NFSv4: Allow security autonegotiation for submounts
NFSv4: Disallow security negotiation for lookups when 'sec=' is specified
NFSv4: Fix security auto-negotiation
NFS: Clean up nfs_parse_security_flavors()
NFS: Clean up the auth flavour array mess
NFSv4.1 Use MDS auth flavor for data server connection
NFS: Don't check lock owner compatability unless file is locked (part 2)
NFS: Don't check lock owner compatibility in writes unless file is locked
nfs4: Map NFS4ERR_WRONG_CRED to EPERM
nfs4.1: Add SP4_MACH_CRED write and commit support
nfs4.1: Add SP4_MACH_CRED stateid support
nfs4.1: Add SP4_MACH_CRED secinfo support
nfs4.1: Add SP4_MACH_CRED cleanup support
nfs4.1: Add state protection handler
nfs4.1: Minimal SP4_MACH_CRED implementation
SUNRPC: Replace pointer values with task->tk_pid and rpc_clnt->cl_clid
SUNRPC: Add an identifier for struct rpc_clnt
SUNRPC: Ensure rpc_task->tk_pid is available for tracepoints
...
Pull fuse bugfixes from Miklos Szeredi:
"Just a bunch of bugfixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: use list_for_each_entry() for list traversing
fuse: readdir: check for slash in names
fuse: hotfix truncate_pagecache() issue
fuse: invalidate inode attributes on xattr modification
fuse: postpone end_page_writeback() in fuse_writepage_locked()
Pull GFS2 updates from Steven Whitehouse:
"This is possibly the smallest ever set of GFS2 patches for a merge
window. Also, most of them are bug fixes this time.
Two of my three patches (moving gfs2_sync_meta and merging the two
writepage implementations) are clean ups with the third (taking the
glock ref in examine_bucket) being a fix for a difficult to hit race
condition.
The removal of an unused memory barrier is a clean up from Bob
Peterson, and the "spectator" relates to a rarely used mount option.
Ben Marzinski's patch fixes a corner case where the incorrect inode
flags were being set, resulting in incorrect behaviour on fsync"
* tag 'gfs2-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw:
GFS2: dirty inode correctly in gfs2_write_end
GFS2: Don't flag consistency error if first mounter is a spectator
GFS2: Remove unnecessary memory barrier
GFS2: Merge ordered and writeback writepage
GFS2: Take glock reference in examine_bucket()
GFS2: Move gfs2_sync_meta to lops.c
Pull ceph updates from Sage Weil:
"This includes both the first pile of Ceph patches (which I sent to
torvalds@vger, sigh) and a few new patches that add support for
fscache for Ceph. That includes a few fscache core fixes that David
Howells asked go through the Ceph tree. (Thanks go to Milosz Tanski
for putting this feature together)
This first batch of patches (included here) had (has) several
important RBD bug fixes, hole punch support, several different
cleanups in the page cache interactions, improvements in the truncate
code (new truncate mutex to avoid shenanigans with i_mutex), and a
series of fixes in the synchronous striping read/write code.
On top of that is a random collection of small fixes all across the
tree (error code checks and error path cleanup, obsolete wq flags,
etc)"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (43 commits)
ceph: use d_invalidate() to invalidate aliases
ceph: remove ceph_lookup_inode()
ceph: trivial buildbot warnings fix
ceph: Do not do invalidate if the filesystem is mounted nofsc
ceph: page still marked private_2
ceph: ceph_readpage_to_fscache didn't check if marked
ceph: clean PgPrivate2 on returning from readpages
ceph: use fscache as a local presisent cache
fscache: Netfs function for cleanup post readpages
FS-Cache: Fix heading in documentation
CacheFiles: Implement interface to check cache consistency
FS-Cache: Add interface to check consistency of a cached object
rbd: fix null dereference in dout
rbd: fix buffer size for writes to images with snapshots
libceph: use pg_num_mask instead of pgp_num_mask for pg.seed calc
rbd: fix I/O error propagation for reads
ceph: use vfs __set_page_dirty_nobuffers interface instead of doing it inside filesystem
ceph: allow sync_read/write return partial successed size of read/write.
ceph: fix bugs about handling short-read for sync read mode.
ceph: remove useless variable revoked_rdcache
...
Pull metag architecture changes from James Hogan:
- Device tree updates for TZ1090 GPIO drivers merged via GPIO tree.
- Add driver for ImgTec PDC irqchip as found in TZ1090 SoC.
- Add linux-metag mailing list to MAINTAINERS file.
* tag 'metag-for-v3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag:
irq-imgpdc: add ImgTec PDC irqchip driver
MAINTAINERS: add linux-metag mailing list
metag: tz1090: instantiate gpio-tz1090-pdc
metag: tz1090: select and instantiate gpio-tz1090
metag: tz1090: select and instantiate irq-imgpdc
This reverts commit 70dd4998cb.
Now that the bugs have been resolved we can re-enable the
PV ticketlock implementation under PVHVM Xen guests.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
There is no need to setup this kicker IPI if we are never going
to use the paravirtualized ticketlock mechanism.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Before this patch we would patch all of the pv_lock_ops sites
using alternative assembler. Then later in the bootup cycle
change the unlock_kick and lock_spinning to the Xen specific -
without re patching.
That meant that for the core of the kernel we would be running
with the baremetal version of unlock_kick and lock_spinning while
for modules we would have the proper Xen specific slowpaths.
As most of the module uses some API from the core kernel that ended
up with slowpath lockers waiting forever to be kicked (b/c they
would be using the Xen specific slowpath logic). And the
kick never came b/c the unlock path that was taken was the
baremetal one.
On PV we do not have the problem as we initialise before the
alternative code kicks in.
The fix is to make the updating of the pv_lock_ops function
be done before the alternative code starts patching.
Note that this patch fixes issues discovered by commit
f10cd522c5.
("xen: disable PV spinlocks on HVM") wherein it mentioned
PV spinlocks cannot possibly work with the current code because they are
enabled after pvops patching has already been done, and because PV
spinlocks use a different data structure than native spinlocks so we
cannot switch between them dynamically.
The first problem is solved by this patch.
The second problem has been solved by commit
816434ec4a
(Merge branch 'x86-spinlocks-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip)
P.S.
There is still the commit 70dd4998cb
(xen/spinlock: Disable IRQ spinlock (PV) allocation on PVHVM) to
revert but that can be done later after all other bugs have been
fixed.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
As we are using the generic ticketlock structs and these
old structures are not needed anymore.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
The xen_lock_spinning has a check for the kicker interrupts
and if it is not initialized it will spin normally (not enter
the slowpath).
But for PVHVM case we would initialize the kicker interrupt
before the CPU came online. This meant that if the booting
CPU used a spinlock and went in the slowpath - it would
enter the slowpath and block forever. The forever part because
during bootup: the spinlock would be taken _before_ the CPU
sets itself to be online (more on this further), and we enter
to poll on the event channel forever.
The bootup CPU (see commit fc78d343fa
"xen/smp: initialize IPI vectors before marking CPU online"
for details) and the CPU that started the bootup consult
the cpu_online_mask to determine whether the booting CPU should
get an IPI. The booting CPU has to set itself in this mask via:
set_cpu_online(smp_processor_id(), true);
However, if the spinlock is taken before this (and it is) and
it polls on an event channel - it will never be woken up as
the kernel will never send an IPI to an offline CPU.
Note that the PVHVM logic in sending IPIs is using the HVM
path which has numerous checks using the cpu_online_mask
and cpu_active_mask. See above mention git commit for details.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Linux 3.11-rc7
As we need the git commit 28817e9de4f039a1a8c1fe1df2fa2df524626b9e
Author: Chuck Anderson <chuck.anderson@oracle.com>
Date: Tue Aug 6 15:12:19 2013 -0700
xen/smp: initialize IPI vectors before marking CPU online
* tag 'v3.11-rc7': (443 commits)
Linux 3.11-rc7
ARC: [lib] strchr breakage in Big-endian configuration
VFS: collect_mounts() should return an ERR_PTR
bfs: iget_locked() doesn't return an ERR_PTR
efs: iget_locked() doesn't return an ERR_PTR()
proc: kill the extra proc_readfd_common()->dir_emit_dots()
cope with potentially long ->d_dname() output for shmem/hugetlb
usb: phy: fix build breakage
USB: OHCI: add missing PCI PM callbacks to ohci-pci.c
staging: comedi: bug-fix NULL pointer dereference on failed attach
lib/lz4: correct the LZ4 license
memcg: get rid of swapaccount leftovers
nilfs2: fix issue with counting number of bio requests for BIO_EOPNOTSUPP error detection
nilfs2: remove double bio_put() in nilfs_end_bio_write() for BIO_EOPNOTSUPP error
drivers/platform/olpc/olpc-ec.c: initialise earlier
ipv4: expose IPV4_DEVCONF
ipv6: handle Redirect ICMP Message with no Redirected Header option
be2net: fix disabling TX in be_close()
Revert "ACPI / video: Always call acpi_video_init_brightness() on init"
Revert "genetlink: fix family dump race"
...
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Add error reporting to of_amba_device_create() so the user knows
when (and why) some device tree nodes fail to initialize.
[ The issue was spotted on Universal C210 board (using revision 0 of
ARM Exynos4210 SoC) on which initialization was silently failing
for PL330 MDMA1 device tree node (it was using the wrong addres
resulting in amba_device_add() returning -ENODEV). ]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>
Pull m68knommu fixes from Greg Ungerer:
"Just a small collection of cleanups and fixes this time, no big
changes. The most interresting are to make the m68k and m68knommu
consistently use CONFIG_IOMAP, clean out some unused board config
options and flush the cache on signal stack creation"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
m68k: remove 16 unused boards in Kconfig.machine
m68k: define 'VM_DATA_DEFAULT_FLAGS' no matter whether has 'NOMMU' or not
m68knommu: user generic iomap to support ioread*/iowrite*
m68k/coldfire: flush cache when creating the signal stack frame
m68knommu: Mark functions only called from setup_arch() __init
Pull UML updates from Richard Weinberger:
"This pile contains mostly fixes and improvements for issues identified
by Richard W M Jones while adding UML as backend to libguestfs"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: Add irq chip um/mask handlers
um: prctl: Do not include linux/ptrace.h
um: Run UML in it's own session.
um: Cleanup SIGTERM handling
um: ubd: Introduce submit_request()
um: ubd: Add REQ_FLUSH suppport
um: Implement probe_kernel_read()
um: hostfs: Fix writeback
* 'x86/spinlocks' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/kvm/guest: Fix sparse warning: "symbol 'klock_waiting' was not declared as static"
kvm: Paravirtual ticketlocks support for linux guests running on KVM hypervisor
kvm guest: Add configuration support to enable debug information for KVM Guests
kvm uapi: Add KICK_CPU and PV_UNHALT definition to uapi
xen, pvticketlock: Allow interrupts to be enabled while blocking
x86, ticketlock: Add slowpath logic
jump_label: Split jumplabel ratelimit
x86, pvticketlock: When paravirtualizing ticket locks, increment by 2
x86, pvticketlock: Use callee-save for lock_spinning
xen, pvticketlocks: Add xen_nopvspin parameter to disable xen pv ticketlocks
xen, pvticketlock: Xen implementation for PV ticket locks
xen: Defer spinlock setup until boot CPU setup
x86, ticketlock: Collapse a layer of functions
x86, ticketlock: Don't inline _spin_unlock when using paravirt spinlocks
x86, spinlock: Replace pv spinlocks with pv ticketlocks
When linux is running as dom0, Xen doesn't show the physical cpu but a
virtual CPU.
On some ARM SOC (for instance the exynos 5250), linux registers callbacks
for cpuidle and cpufreq. When these callbacks are called, they will modify
directly the physical cpu not the virtual one. It can impact the whole board
instead of only dom0.
Signed-off-by: Julien Grall <julien.grall@linaro.org>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
m2p_remove_override() calls get_balloon_scratch_page() in
MULTI_update_va_mapping() even though it already has pointer to this page from
the earlier call (in scratch_page). This second call doesn't have a matching
put_balloon_scratch_page() thus not restoring preempt count back. (Also, there
is no put_balloon_scratch_page() in the error path.)
In addition, the second multicall uses __xen_mc_entry() which does not disable
interrupts. Rearrange xen_mc_* calls to keep interrupts off while performing
multicalls.
This commit fixes a regression introduced by:
commit ee0726407f
Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Date: Tue Jul 23 17:23:54 2013 +0000
xen/m2p: use GNTTABOP_unmap_and_replace to reinstate the original mapping
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
xen_pm_init was unconditionally setting pm_power_off and arm_pm_restart
function pointers. This breaks multi-platform kernels. Make this
conditional on running as a Xen guest and make it a late_initcall to
ensure it is setup after platform code for Dom0.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
CC: stable@vger.kernel.org
Change the hash algorithm a bit so it produces only values in the
range of 0..31.
This allows to reduce the size of the external interrupt handler hash
array even further while making sure that each of the known interrupt
sources keeps its unique hash with the slightly modified algorithm:
0x1004 --> 12
0x1201 --> 10
0x1202 --> 11
0x1406 --> 16
0x1407 --> 17
0x2401 --> 19
0x2603 --> 22
0x4000 --> 0
This also means that the entire array now fits into exactly one cache
line; so add a proper align statement as well.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
When reconnecting to automounts at startup an autofs ioctl is used
to find the device and inode of existing mounts so they can be used
to open a file descriptor of possibly covered mounts.
At this time the the caller might not yet "own" the mount so it can
trigger calling ->d_automount(). This causes automount to hang when
trying to reconnect to direct or offset mount types.
Consequently kern_path() can't be used but kern_path_mountpoint() can be.
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This is the fix that the last two commits indirectly led up to - making
sure that we don't call dput() in a bad context on the dentries we've
looked up in RCU mode after the sequence count validation fails.
This basically expands d_rcu_to_refcount() into the callers, and then
fixes the callers to delay the dput() in the failure case until _after_
we've dropped all locks and are no longer in an RCU-locked region.
The case of 'complete_walk()' was trivial, since its failure case did
the unlock_rcu_walk() directly after the call to d_rcu_to_refcount(),
and as such that is just a pure expansion of the function with a trivial
movement of the resulting dput() to after 'unlock_rcu_walk()'.
In contrast, the unlazy_walk() case was much more complicated, because
not only does convert two different dentries from RCU to be reference
counted, but it used to not call unlock_rcu_walk() at all, and instead
just returned an error and let the caller clean everything up in
"terminate_walk()".
Happily, one of the dentries in question (called "parent" inside
unlazy_walk()) is the dentry of "nd->path", which terminate_walk() wants
a refcount to anyway for the non-RCU case.
So what the new and improved unlazy_walk() does is to first turn that
dentry into a refcounted one, and once that is set up, the error cases
can continue to use the terminate_walk() helper for cleanup, but for the
non-RCU case. Which makes it possible to drop out of RCU mode if we
actually hit the sequence number failure case.
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The virtio_pci_freeze/restore are defined under CONFIG_PM but is used
by SET_SYSTEM_SLEEP_PM_OPS macro, which is defined under
CONFIG_PM_SLEEP. So if CONFIG_PM_SLEEP is not cofigured but
CONFIG_PM_RUNTIME is, the following warning message appeared:
drivers/virtio/virtio_pci.c:770:12: warning: ‘virtio_pci_freeze’ defined but not used [-Wunused-function]
static int virtio_pci_freeze(struct device *dev)
^
drivers/virtio/virtio_pci.c:790:12: warning: ‘virtio_pci_restore’ defined but not used [-Wunused-function]
static int virtio_pci_restore(struct device *dev)
^
Fix it by changing CONFIG_PM to CONFIG_PM_SLEEP.
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This simplifies the RCU to refcounting code in particular.
I was originally intending to leave this for later, but walking through
all the dput() logic (see previous commit), I realized that the dput()
"might_sleep()" check was misleadingly weak. And I removed it as
misleading, both for performance profiling and for debugging.
However, the might_sleep() debugging case is actually true: the final
dput() can indeed sleep, if the inode of the dentry that you are
releasing ends up sleeping at iput time (see dentry_iput()). So the
problem with the might_sleep() in dput() wasn't that it wasn't true, it
was that it wasn't actually testing and triggering on the interesting
case.
In particular, just about *any* dput() can indeed sleep, if you happen
to race with another thread deleting the file in question, and you then
lose the race to the be the last dput() for that file. But because it's
a very rare race, the debugging code would never trigger it in practice.
Why is this problematic? The new d_rcu_to_refcount() (see commit
15570086b5: "vfs: reimplement d_rcu_to_refcount() using
lockref_get_or_lock()") does a dput() for the failure case, and it does
it under the RCU lock. So potentially sleeping really is a bug.
But there's no way I'm going to fix this with the previous complicated
"lockref_get_or_lock()" interface. And rather than revert to the old
and crufty nested dentry locking code (which did get this right by
delaying the reference count updates until they were verified to be
safe), let's make forward progress.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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: Linus Torvalds <torvalds@linux-foundation.org>
Pull NVM Express driver update from Matthew Wilcox.
* git://git.infradead.org/users/willy/linux-nvme:
NVMe: Merge issue on character device bring-up
NVMe: Handle ioremap failure
NVMe: Add pci suspend/resume driver callbacks
NVMe: Use normal shutdown
NVMe: Separate controller init from disk discovery
NVMe: Separate queue alloc/free from create/delete
NVMe: Group pci related actions in functions
NVMe: Disk stats for read/write commands only
NVMe: Bring up cdev on set feature failure
NVMe: Fix checkpatch issues
NVMe: Namespace IDs are unsigned
NVMe: Update nvme_id_power_state with latest spec
NVMe: Split header file into user-visible and kernel-visible pieces
NVMe: Call nvme_process_cq from submission path
NVMe: Remove "process_cq did something" message
NVMe: Return correct value from interrupt handler
NVMe: Disk IO statistics
NVMe: Restructure MSI / MSI-X setup
NVMe: Use kzalloc instead of kmalloc+memset
Pull NTB (non-transparent bridge) updates from Jon Mason:
"NTB driver bug fixes to address issues in NTB-RP enablement, spad,
debugfs, and USD/DSD identification.
Add a workaround on Xeon NTB devices for b2bdoorbell errata. Also,
add new NTB driver features to support 32bit x86, DMA engine support,
and NTB-RP support.
Finally, a few clean-ups and update to MAINTAINERS for the NTB git
tree and wiki location"
* tag 'ntb-3.12' of git://github.com/jonmason/ntb:
ntb: clean up unnecessary MSI/MSI-X capability find
MAINTAINERS: Add Website and Git Tree for NTB
NTB: Update Version
NTB: Comment Fix
NTB: Remove unused variable
NTB: Remove References of non-B2B BWD HW
NTB: NTB-RP support
NTB: Rename Variables for NTB-RP
NTB: Use DMA Engine to Transmit and Receive
NTB: Enable 32bit Support
NTB: Update Device IDs
NTB: BWD Link Recovery
NTB: Xeon Errata Workaround
NTB: Correct debugfs to work with more than 1 NTB Device
NTB: Correct USD/DSD Identification
NTB: Correct Number of Scratch Pad Registers
NTB: Add Error Handling in ntb_device_setup
Pull MFD (multi-function device) updates from Samuel Ortiz:
"For the 3.12 merge window we have one new driver for the DA9063 PMIC
from Dialog Semiconductor.
Besides that driver we also have:
- Device tree support for the s2mps11 driver
- More devm_* conversion for the pm8921, max89xx, menelaus, tps65010,
wl1273 and pcf50633-adc drivers.
- A conversion to threaded IRQ and IRQ domain for the twl6030 driver.
- A fairly big update for the rtsx driver: Better power saving
support, better vendor settings handling, and a few fixes.
- Support for a couple more boards (COMe-bHL6 and COMe-cTH6) for the
Kontron driver.
- A conversion to the dev_get_platdata() API for all MFD drivers.
- A removal of non-DT (legacy) support for the twl6040 driver.
- A few fixes and additions (Mic detect level) to the wm5110 register
tables.
- Regmap support for the davinci_voicecodec driver.
- The usual bunch of minor cleanups and janitorial fixes"
* tag 'mfd-3.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-next: (81 commits)
mfd: ucb1x00-core: Rewrite ucb1x00_add_dev()
mfd: ab8500-debugfs: Apply a check for -ENOMEM after allocating memory for event name
mfd: ab8500-debugfs: Apply a check for -ENOMEM after allocating memory for sysfs
mfd: timberdale: Use module_pci_driver
mfd: timberdale: Remove redundant break
mfd: timberdale: Staticize local variables
mfd: ab8500-debugfs: Staticize local variables
mfd: db8500-prcmu: Staticize clk_mgt
mfd: db8500-prcmu: Use ANSI function declaration
mfd: omap-usb-host: Staticize usbhs_driver_name
mfd: 88pm805: Fix potential NULL pdata dereference
mfd: 88pm800: Fix potential NULL pdata dereference
mfd: twl6040: Use regmap for register cache
mfd: davinci_voicecodec: Provide a regmap for register I/O
mfd: davinci_voicecodec: Remove unused read and write functions
mmc: memstick: rtsx: Modify copyright comments
mmc: rtsx: Clear SD_CLK toggle enable bit if switching voltage fail
mfd: mmc: rtsx: Change default tx phase
mfd: pcf50633-adc: Use devm_*() functions
mfd: rtsx: Copyright modifications
...
Pull misc kbuild updates from Michal Marek:
"In the kbuild misc branch, I have:
- make rpm-pkg updates, most importantly the rpm package now calls
/sbin/installkernel
- make deb-pkg: debuginfo split, correct kernel image path for
parisc, mips and powerpc and a couple more minor fixes
- New coccinelle check"
* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
scripts/checkkconfigsymbols.sh: replace echo -e with printf
Provide version number for Debian firmware package
coccinelle: replace 0/1 with false/true in functions returning bool
deb-pkg: add a hook argument to match debian hooks parameters
deb-pkg: fix installed image path on parisc, mips and powerpc
deb-pkg: split debug symbols in their own package
deb-pkg: use KCONFIG_CONFIG instead of .config file directly
rpm-pkg: add generation of kernel-devel
rpm-pkg: install firmware files in kernel relative directory
rpm-pkg: add %post section to create initramfs and grub hooks
Pull kbuild update from Michal Marek:
"Only these two commits are in the kbuild branch this time:
- Using filechk for include/config/kernel.release
- Cleanup in scripts/sortextable.c"
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
kbuild: Do not overwrite include/config/kernel.release needlessly
scripts: remove unused function in sortextable.c
kernel/cgroup.c is the only place in the tree that relies on eventfd.h
pulling file.h; move that include there. Switch from eventfd_fget()/fput()
to fdget()/fdput(), while we are at it - eventfd_ctx_fileget() will fail
on non-eventfd descriptors just fine, no need to do that check twice...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
On some filesystems it's impossible even with fs corruption, but we'd
better not rely on that, what with memcpy() into on-stack array we
are doing there.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
No dentry can get to directory modification methods without
having passed either ->lookup() or ->atomic_open(); if name is
rejected by those two (or by ->d_hash()) with an error, it won't
be seen by anything else.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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: Linus Torvalds <torvalds@linux-foundation.org>
Commit 97431204ea introduced a regression
that causes SECINFO_NO_NAME to fail without sending an RPC if:
1) the nfs_client's rpc_client is using krb5i/p (now tried by default)
2) the current user doesn't have valid kerberos credentials
This situation is quite common - as of now a sec=sys mount would use
krb5i for the nfs_client's rpc_client and a user would hardly be faulted
for not having run kinit.
The solution is to use the machine cred when trying to use an integrity
protected auth flavor for SECINFO_NO_NAME.
Older servers may not support using the machine cred or an integrity
protected auth flavor for SECINFO_NO_NAME in every circumstance, so we fall
back to using the user's cred and the filesystem's auth flavor in this case.
We run into another problem when running against linux nfs servers -
they return NFS4ERR_WRONGSEC when using integrity auth flavor (unless the
mount is also that flavor) even though that is not a valid error for
SECINFO*. Even though it's against spec, handle WRONGSEC errors on
SECINFO_NO_NAME by falling back to using the user cred and the
filesystem's auth flavor.
Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
