The driver assumed it would receive skb packets from MAC80211 which
are not cloned. To guard this assumption an assert was placed in
the transmit routine. As of kernel 2.6.37 it turns out MAC80211 does
pass skb packets that are cloned. The assert is also not needed as
it does not lead to a failure state in our driver when the packet is
cloned. Therefore the assert can safely be removed.
> commit f8a0a78148
> Author: Felix Fietkau <nbd@openwrt.org>
> Date: Sat Dec 18 19:30:50 2010 +0100
>
> mac80211: fix potentially redundant skb data copying
>
> When an skb is shared, it needs to be duplicated, along with its data
> If the skb does not have enough headroom, using skb_copy might cause t
> buffer to be copied twice (once by skb_copy and once by pskb_expand_he
> Fix this by using skb_clone initially and letting ieee80211_skb_resize
> out the rest.
>
> Signed-off-by: Felix Fietkau <nbd@openwrt.org>
> Signed-off-by: John W. Linville <linville@tuxdriver.com>
>
Acked-by: Brett Rudley <brudley@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
iio: Additional fixpoint formatted output bugfixes
Fix some ADC/DAC drivers' _scale interface to correct fixpoint formatted output
This patch adds the fixes to ad7887_core.c and ad5446.c
Signed-off-by: Roland Stigge <stigge@antcom.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The access to pending_port was racy when two devices
were being attached at the same time.
Signed-off-by: Max Vozeler <max@vozeler.com>
Tested-by: Mark Wehby <MWehby@luxotticaRetail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If there is a receive timeout without any active
requests, we can tell the connection was idle and
ignore the timeout.
If there are active requests for which we expect
to receive a reply we close the connection.
This makes it possible to set an upper bound on
the time a usbip device may be unresponsive.
This is a workaround for the lack of heart-beat
messages in the USBIP protocol.
Extending the protocol would break compatibility
with all previous stub versions, so this seems like
the lesser evil.
Signed-off-by: Max Vozeler <max@vozeler.com>
Tested-by: Mark Wehby <MWehby@luxotticaRetail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Also changes the event on connection close to be
VDEV_EVENT_DOWN - no functional change.
Signed-off-by: Max Vozeler <max@vozeler.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
There can be requests to enqueue URBs while we are shutting
down a connection.
Signed-off-by: Max Vozeler <max@vozeler.com>
Tested-by: Mark Wehby <MWehby@luxotticaRetail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If we never received a RET_UNLINK because the TCP
connection broke the pending URBs still need to be
unlinked and given back.
Previously processes would be stuck trying to kill
the URB even after the device was detached.
Signed-off-by: Max Vozeler <max@vozeler.com>
Tested-by: Mark Wehby <MWehby@luxotticaRetail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Lately, mailbox callbacks have been replaced by notifier block
call chains, this needs to be changed in the users of mailbox,
otherwise compilation will break due to missing parameters.
For this new change to work, io_mbox_msg needs to be compatible
with the notifier_call definition.
Reported-by: Hari Kanigeri <h-kanigeri2@ti.com>
Signed-off-by: Omar Ramirez Luna <omar.ramirez@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The ni_labpc driver module only requests a shared IRQ for PCI devices,
requesting a non-shared IRQ for non-PCI devices.
As this module is also used by the ni_labpc_cs module for certain
National Instruments PCMCIA cards, it also needs to request a shared IRQ
for PCMCIA devices, otherwise you get a IRQ mismatch with the CardBus
controller.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The TX queues are allocated inside register_netdev.
It doesn't make any sense to stop the queue before
allocation.
Signed-off-by: Denis Kirjanov <dkirjanov@kernel.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
IVA MMU can manage up to 4GB of address space through its page tables,
given that it's L1 is divided into 1MB sections it requires at least
16KB for its table which represents 4096 entries of 32 bits each.
Previously, only 1GB was being handled by setting the page table size
to 4KB, any virtual address beyond of the L1 size used, would fall
into memory that does not belong to L1 translation tables, leading to
unpredictable results.
So, set the L1 table size to cover the entire MMU range (4GB) whether
is meant to be used or not.
Reported-by: Felipe Contreras <felipe.contreras@nokia.com>
Signed-off-by: Fernando Guzman Lugo <fernando.lugo@ti.com>
Signed-off-by: Felipe Contreras <felipe.contreras@nokia.com>
Signed-off-by: Omar Ramirez Luna <omar.ramirez@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This device was tested with rt2870sta by setting new_id.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Brian Ormond <brian.ormond@oit.edu>
Cc: Stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In the original code the parenthesis are in the wrong position, so the
conditions are always true.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The original code called input_free_device(rmi4_data->input_dev) after
input_unregister_device(rmi4_data->input_dev) and that's a double free.
This is described in the comments to input_unregister_device().
The normal way to handle this is to make input_register_device() the
last function in the probe which can fail. That way you can avoid the
call to input_unregister_device() entirely.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Off by one
Signed-off-by: Phillip Simbwa <simbwa at gmail dot com>
Signed-off-by: Vipin Mehta <vmehta@atheros.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Removed the call to netif_stop_queue() in netvsc_probe() as
the queue is not initialized at that point and further call
to it after queue initialization is really not necessary.
This change was prompted after an upstream change went into
2.6.37 (netif_tx_stop_queue) that now checks if netif_stop_queue
is called before register with netdev is done.
This will eliminate the warning message to the log when hv_netvsc
driver starts up.
Signed-off-by: Abhishek Kane <v-abkane@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The channel callbacks are called directly from vmbus_event_dpc
which runs in tasklet context. These callbacks need to use
GFP_ATOMIC.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=16701
Cc: Hank Janssen <hjanssen@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The block device does not create the proper symlink in sysfs because we
forgot to set up the gendisk structure properly. This patch fixes the
issue.
Signed-off-by: K. Y. Srinivasan <ksrinivasan@novell.com>
Cc: Hank Janssen <hjanssen@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
While building latest Linus git, I hit the following:
CC [M] drivers/staging/bcm/Qos.o
drivers/staging/bcm/Qos.c: In function ‘PruneQueue’:
drivers/staging/bcm/Qos.c:367: error: ‘struct netdev_queue’ has no member named ‘tx_dropped’
drivers/staging/bcm/Qos.c: In function ‘flush_all_queues’:
drivers/staging/bcm/Qos.c:416: error: ‘struct netdev_queue’ has no member named ‘tx_dropped’
make[5]: *** [drivers/staging/bcm/Qos.o] Error 1
make[4]: *** [drivers/staging/bcm] Error 2
make[3]: *** [drivers/staging] Error 2
As well as:
CC [M] drivers/staging/bcm/Transmit.o
drivers/staging/bcm/Transmit.c: In function ‘SetupNextSend’:
drivers/staging/bcm/Transmit.c:163: error: ‘struct netdev_queue’ has no member named ‘tx_bytes’
drivers/staging/bcm/Transmit.c:164: error: ‘struct netdev_queue’ has no member named ‘tx_packets’
make[2]: *** [drivers/staging/bcm/Transmit.o] Error 1
tx_dropped/tx_bytes_tx_packets were removed in commit 1ac9ad13. This patch
converts bcm to use net_device_stats instead of netdev_queue.
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Building error for smbfs:
drivers/staging/smbfs/dir.c:286: error: static declaration of 'smbfs_dentry_operations' follows non-static declaration
drivers/staging/smbfs/proto.h:42: error: previous declaration of 'smbfs_dentry_operations' was here
drivers/staging/smbfs/dir.c:294: error: static declaration of 'smbfs_dentry_operations_case' follows non-static declaration
drivers/staging/smbfs/proto.h:41: error: previous declaration of 'smbfs_dentry_operations_case' was here
make[3]: *** [drivers/staging/smbfs/dir.o] Error 1
make[2]: *** [drivers/staging/smbfs] Error 2
make[1]: *** [drivers/staging] Error 2
make[1]: *** Waiting for unfinished jobs....
Fix it by removing static keywords
Signed-off-by: Yang Ruirui <ruirui.r.yang@tieto.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add a dentry op (d_manage) to permit a filesystem to hold a process and make it
sleep when it tries to transit away from one of that filesystem's directories
during a pathwalk. The operation is keyed off a new dentry flag
(DCACHE_MANAGE_TRANSIT).
The filesystem is allowed to be selective about which processes it holds and
which it permits to continue on or prohibits from transiting from each flagged
directory. This will allow autofs to hold up client processes whilst letting
its userspace daemon through to maintain the directory or the stuff behind it
or mounted upon it.
The ->d_manage() dentry operation:
int (*d_manage)(struct path *path, bool mounting_here);
takes a pointer to the directory about to be transited away from and a flag
indicating whether the transit is undertaken by do_add_mount() or
do_move_mount() skipping through a pile of filesystems mounted on a mountpoint.
It should return 0 if successful and to let the process continue on its way;
-EISDIR to prohibit the caller from skipping to overmounted filesystems or
automounting, and to use this directory; or some other error code to return to
the user.
->d_manage() is called with namespace_sem writelocked if mounting_here is true
and no other locks held, so it may sleep. However, if mounting_here is true,
it may not initiate or wait for a mount or unmount upon the parameter
directory, even if the act is actually performed by userspace.
Within fs/namei.c, follow_managed() is extended to check with d_manage() first
on each managed directory, before transiting away from it or attempting to
automount upon it.
follow_down() is renamed follow_down_one() and should only be used where the
filesystem deliberately intends to avoid management steps (e.g. autofs).
A new follow_down() is added that incorporates the loop done by all other
callers of follow_down() (do_add/move_mount(), autofs and NFSD; whilst AFS, NFS
and CIFS do use it, their use is removed by converting them to use
d_automount()). The new follow_down() calls d_manage() as appropriate. It
also takes an extra parameter to indicate if it is being called from mount code
(with namespace_sem writelocked) which it passes to d_manage(). follow_down()
ignores automount points so that it can be used to mount on them.
__follow_mount_rcu() is made to abort rcu-walk mode if it hits a directory with
DCACHE_MANAGE_TRANSIT set on the basis that we're probably going to have to
sleep. It would be possible to enter d_manage() in rcu-walk mode too, and have
that determine whether to abort or not itself. That would allow the autofs
daemon to continue on in rcu-walk mode.
Note that DCACHE_MANAGE_TRANSIT on a directory should be cleared when it isn't
required as every tranist from that directory will cause d_manage() to be
invoked. It can always be set again when necessary.
==========================
WHAT THIS MEANS FOR AUTOFS
==========================
Autofs currently uses the lookup() inode op and the d_revalidate() dentry op to
trigger the automounting of indirect mounts, and both of these can be called
with i_mutex held.
autofs knows that the i_mutex will be held by the caller in lookup(), and so
can drop it before invoking the daemon - but this isn't so for d_revalidate(),
since the lock is only held on _some_ of the code paths that call it. This
means that autofs can't risk dropping i_mutex from its d_revalidate() function
before it calls the daemon.
The bug could manifest itself as, for example, a process that's trying to
validate an automount dentry that gets made to wait because that dentry is
expired and needs cleaning up:
mkdir S ffffffff8014e05a 0 32580 24956
Call Trace:
[<ffffffff885371fd>] :autofs4:autofs4_wait+0x674/0x897
[<ffffffff80127f7d>] avc_has_perm+0x46/0x58
[<ffffffff8009fdcf>] autoremove_wake_function+0x0/0x2e
[<ffffffff88537be6>] :autofs4:autofs4_expire_wait+0x41/0x6b
[<ffffffff88535cfc>] :autofs4:autofs4_revalidate+0x91/0x149
[<ffffffff80036d96>] __lookup_hash+0xa0/0x12f
[<ffffffff80057a2f>] lookup_create+0x46/0x80
[<ffffffff800e6e31>] sys_mkdirat+0x56/0xe4
versus the automount daemon which wants to remove that dentry, but can't
because the normal process is holding the i_mutex lock:
automount D ffffffff8014e05a 0 32581 1 32561
Call Trace:
[<ffffffff80063c3f>] __mutex_lock_slowpath+0x60/0x9b
[<ffffffff8000ccf1>] do_path_lookup+0x2ca/0x2f1
[<ffffffff80063c89>] .text.lock.mutex+0xf/0x14
[<ffffffff800e6d55>] do_rmdir+0x77/0xde
[<ffffffff8005d229>] tracesys+0x71/0xe0
[<ffffffff8005d28d>] tracesys+0xd5/0xe0
which means that the system is deadlocked.
This patch allows autofs to hold up normal processes whilst the daemon goes
ahead and does things to the dentry tree behind the automouter point without
risking a deadlock as almost no locks are held in d_manage() and none in
d_automount().
Signed-off-by: David Howells <dhowells@redhat.com>
Was-Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
PCI/PM: Report wakeup events before resuming devices
PCI/PM: Use pm_wakeup_event() directly for reporting wakeup events
PCI: sysfs: Update ROM to include default owner write access
x86/PCI: make Broadcom CNB20LE driver EMBEDDED and EXPERIMENTAL
x86/PCI: don't use native Broadcom CNB20LE driver when ACPI is available
PCI/ACPI: Request _OSC control once for each root bridge (v3)
PCI: enable pci=bfsort by default on future Dell systems
PCI/PCIe: Clear Root PME Status bits early during system resume
PCI: pci-stub: ignore zero-length id parameters
x86/PCI: irq and pci_ids patch for Intel Patsburg
PCI: Skip id checking if no id is passed
PCI: fix __pci_device_probe kernel-doc warning
PCI: make pci_restore_state return void
PCI: Disable ASPM if BIOS asks us to
PCI: Add mask bit definition for MSI-X table
PCI: MSI: Move MSI-X entry definition to pci_regs.h
Fix up trivial conflicts in drivers/net/{skge.c,sky2.c} that had in the
meantime been converted to not use legacy PCI power management, and thus
no longer use pci_restore_state() at all (and that caused trivial
conflicts with the "make pci_restore_state return void" patch)
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (41 commits)
fs: add documentation on fallocate hole punching
Gfs2: fail if we try to use hole punch
Btrfs: fail if we try to use hole punch
Ext4: fail if we try to use hole punch
Ocfs2: handle hole punching via fallocate properly
XFS: handle hole punching via fallocate properly
fs: add hole punching to fallocate
vfs: pass struct file to do_truncate on O_TRUNC opens (try #2)
fix signedness mess in rw_verify_area() on 64bit architectures
fs: fix kernel-doc for dcache::prepend_path
fs: fix kernel-doc for dcache::d_validate
sanitize ecryptfs ->mount()
switch afs
move internal-only parts of ncpfs headers to fs/ncpfs
switch ncpfs
switch 9p
pass default dentry_operations to mount_pseudo()
switch hostfs
switch affs
switch configfs
...
The newer drivers/gpio/cs5535-gpio.c replaces drivers/misc/cs5535_gpio.c.
The new driver has been in the tree for a little while, and has received
some testing; it's time to mark the old one as deprecated. I'm thinking
removal around 2.6.40 would be good, provided we're not missing critical
functionality in the newer driver.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Cc: Daniel Drake <dsd@laptop.org>
Acked-by: Ben Gardner <bgardner@wabtec.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Drop the old geode_gpio crud, as well as the raw outl() calls; instead,
use the Linux GPIO API where possible, and the cs5535_gpio API in other
places.
Note that we don't actually clean up the driver properly yet (once loaded,
it always remains loaded). That'll come later..
This patch is necessary for building the driver.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fix the failure handling in kobjects and the main function so that we
release the virtual keyboard if we exit due to another failure.
Signed-off-by: William Hubbs <w.d.hubbs@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In the vhci_urb_dequeue() function the TCP connection is checked twice.
Each time when the TCP connection is closed the URB is unlinked and given
back. Remove the second attempt of unlinking and giving back of the URB completely.
This patch fixes the bug described at https://bugzilla.kernel.org/show_bug.cgi?id=24872 .
Signed-off-by: Márton Németh <nm127@freemail.hu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (30 commits)
gameport: use this_cpu_read instead of lookup
x86: udelay: Use this_cpu_read to avoid address calculation
x86: Use this_cpu_inc_return for nmi counter
x86: Replace uses of current_cpu_data with this_cpu ops
x86: Use this_cpu_ops to optimize code
vmstat: User per cpu atomics to avoid interrupt disable / enable
irq_work: Use per cpu atomics instead of regular atomics
cpuops: Use cmpxchg for xchg to avoid lock semantics
x86: this_cpu_cmpxchg and this_cpu_xchg operations
percpu: Generic this_cpu_cmpxchg() and this_cpu_xchg support
percpu,x86: relocate this_cpu_add_return() and friends
connector: Use this_cpu operations
xen: Use this_cpu_inc_return
taskstats: Use this_cpu_ops
random: Use this_cpu_inc_return
fs: Use this_cpu_inc_return in buffer.c
highmem: Use this_cpu_xx_return() operations
vmstat: Use this_cpu_inc_return for vm statistics
x86: Support for this_cpu_add, sub, dec, inc_return
percpu: Generic support for this_cpu_add, sub, dec, inc_return
...
Fixed up conflicts: in arch/x86/kernel/{apic/nmi.c, apic/x2apic_uv_x.c, process.c}
as per Tejun.
* 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (33 commits)
usb: don't use flush_scheduled_work()
speedtch: don't abuse struct delayed_work
media/video: don't use flush_scheduled_work()
media/video: explicitly flush request_module work
ioc4: use static work_struct for ioc4_load_modules()
init: don't call flush_scheduled_work() from do_initcalls()
s390: don't use flush_scheduled_work()
rtc: don't use flush_scheduled_work()
mmc: update workqueue usages
mfd: update workqueue usages
dvb: don't use flush_scheduled_work()
leds-wm8350: don't use flush_scheduled_work()
mISDN: don't use flush_scheduled_work()
macintosh/ams: don't use flush_scheduled_work()
vmwgfx: don't use flush_scheduled_work()
tpm: don't use flush_scheduled_work()
sonypi: don't use flush_scheduled_work()
hvsi: don't use flush_scheduled_work()
xen: don't use flush_scheduled_work()
gdrom: don't use flush_scheduled_work()
...
Fixed up trivial conflict in drivers/media/video/bt8xx/bttv-input.c
as per Tejun.
* 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (144 commits)
USB: add support for Dream Cheeky DL100B Webmail Notifier (1d34:0004)
USB: serial: ftdi_sio: add support for TIOCSERGETLSR
USB: ehci-mxc: Setup portsc register prior to accessing OTG viewport
USB: atmel_usba_udc: fix freeing irq in usba_udc_remove()
usb: ehci-omap: fix tll channel enable mask
usb: ohci-omap3: fix trivial typo
USB: gadget: ci13xxx: don't assume that PAGE_SIZE is 4096
USB: gadget: ci13xxx: fix complete() callback for no_interrupt rq's
USB: gadget: update ci13xxx to work with g_ether
USB: gadgets: ci13xxx: fix probing of compiled-in gadget drivers
Revert "USB: musb: pm: don't rely fully on clock support"
Revert "USB: musb: blackfin: pm: make it work"
USB: uas: Use GFP_NOIO instead of GFP_KERNEL in I/O submission path
USB: uas: Ensure we only bind to a UAS interface
USB: uas: Rename sense pipe and sense urb to status pipe and status urb
USB: uas: Use kzalloc instead of kmalloc
USB: uas: Fix up the Sense IU
usb: musb: core: kill unneeded #include's
DA8xx: assign name to MUSB IRQ resource
usb: gadget: g_ncm added
...
Manually fix up trivial conflicts in USB Kconfig changes in:
arch/arm/mach-omap2/Kconfig
arch/sh/Kconfig
drivers/usb/Kconfig
drivers/usb/host/ehci-hcd.c
and annoying chip clock data conflicts in:
arch/arm/mach-omap2/clock3xxx_data.c
arch/arm/mach-omap2/clock44xx_data.c
Require filesystems be aware of .d_revalidate being called in rcu-walk
mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning
-ECHILD from all implementations.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry->d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.
Patched with:
git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
RCU free the struct inode. This will allow:
- Subsequent store-free path walking patch. The inode must be consulted for
permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
to take i_lock no longer need to take sb_inode_list_lock to walk the list in
the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
page lock to follow page->mapping.
The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.
In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.
The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
dget_locked was a shortcut to avoid the lazy lru manipulation when we already
held dcache_lock (lru manipulation was relatively cheap at that point).
However, how that the lru lock is an innermost one, we never hold it at any
caller, so the lock cost can now be avoided. We already have well working lazy
dcache LRU, so it should be fine to defer LRU manipulations to scan time.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
The remaining usages for dcache_lock is to allow atomic, multi-step read-side
operations over the directory tree by excluding modifications to the tree.
Also, to walk in the leaf->root direction in the tree where we don't have
a natural d_lock ordering.
This could be accomplished by taking every d_lock, but this would mean a
huge number of locks and actually gets very tricky.
Solve this instead by using the rename seqlock for multi-step read-side
operations, retry in case of a rename so we don't walk up the wrong parent.
Concurrent dentry insertions are not serialised against. Concurrent deletes
are tricky when walking up the directory: our parent might have been deleted
when dropping locks so also need to check and retry for that.
We can also use the rename lock in cases where livelock is a worry (and it
is introduced in subsequent patch).
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Protect d_subdirs and d_child with d_lock, except in filesystems that aren't
using dcache_lock for these anyway (eg. using i_mutex).
Note: if we change the locking rule in future so that ->d_child protection is
provided only with ->d_parent->d_lock, it may allow us to reduce some locking.
But it would be an exception to an otherwise regular locking scheme, so we'd
have to see some good results. Probably not worthwhile.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Change d_hash so it may be called from lock-free RCU lookups. See similar
patch for d_compare for details.
For in-tree filesystems, this is just a mechanical change.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
