The fix in commit #6a0cc49 requires more than three concurrent instances
of synchronize_sched_expedited() before batching is possible. This
patch uses a ticket-counter-like approach that is also not unrelated to
Lai Jiangshan's Ring RCU to allow sharing of expedited grace periods even
when there are only two concurrent instances of synchronize_sched_expedited().
This commit builds on Tejun's original posting, which may be found at
http://lkml.org/lkml/2010/11/9/204, adding memory barriers, avoiding
overflow of signed integers (other than via atomic_t), and fixing the
detection of batching.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
$ cat << EOF | gcc -Wconversion -xc -S -o/dev/null -
unsigned f(void) {return NLMSG_HDRLEN;}
EOF
<stdin>: In function 'f':
<stdin>:3:26: warning: negative integer implicitly converted to unsigned type
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: David S. Miller <davem@davemloft.net>
This adds arch_remove_reservations(), which an arch can implement if it
needs to protect part of the address space from allocation.
Sometimes that can be done by just putting a region in the resource tree,
but there are cases where that doesn't work well. For example, x86 BIOS
E820 reservations are not related to devices, so they may overlap part of,
all of, or more than a device resource, so they may not end up at the
correct spot in the resource tree.
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
For read operation, we have to set the argument _write_ of get_user_pages
to 1 since we will write data to pages. Also, we need to SetPageDirty before
releasing these pages.
Signed-off-by: Henry C Chang <henry_c_chang@tcloudcomputing.com>
Signed-off-by: Sage Weil <sage@newdream.net>
This new type is a virtual version of snd_soc_dapm_mux. It is used
when a backing register value is not necessary for deciding which
input path to connect. A simple virtual enumeration control e.g.
SOC_DAPM_ENUM_VIRT() can be exposed to userspace which will be used
to choose which path to connect.
The snd_soc_dapm_virt_mux type ensures that during the initial
path setup, the first (which is also the default) input path will
be connected.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
* 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
PM / Runtime: Fix pm_runtime_suspended()
PM / Hibernate: Restore old swap signature to avoid user space breakage
PM / Hibernate: Fix PM_POST_* notification with user-space suspend
- include/linux/percpu.h: this_cpu_add_return() and friends were
located next to __this_cpu_add_return(). However, the overall
organization is to first group by preemption safeness. Relocate
this_cpu_add_return() and friends to preemption-safe area.
- arch/x86/include/asm/percpu.h: Relocate percpu_add_return_op() after
other more basic operations. Relocate [__]this_cpu_add_return_8()
so that they're first grouped by preemption safeness.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Use this_cpu operations to optimize access primitives for highmem.
The main effect is the avoidance of address calculations through the
use of a segment prefix.
V3->V4
- kmap_atomic_idx: Do not return a value.
- Use __this_cpu_dec without HIGHMEM_DEBUG
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Introduce generic support for this_cpu_add_return etc.
The fallback is to realize these operations with simpler __this_cpu_ops.
tj: - Reformatted __cpu_size_call_return2() to make it more consistent
with its neighbors.
- Dropped unnecessary temp variable ret__ from
__this_cpu_generic_add_return().
Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
__get_cpu_var() can be replaced with this_cpu_read and will then use a
single read instruction with implied address calculation to access the
correct per cpu instance.
However, the address of a per cpu variable passed to __this_cpu_read()
cannot be determined (since it's an implied address conversion through
segment prefixes). Therefore apply this only to uses of __get_cpu_var
where the address of the variable is not used.
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Hugh Dickins <hughd@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Use this_cpu ops in various places to optimize per cpu data access.
Cc: Jason Baron <jbaron@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Attempt to minimise audible effects from mixer and mux updates by
implementing the actual register changes between powering down widgets
that have become unused and powering up widgets that are newly used.
This means that we're making the change with the minimum set of widgets
powered, that the input path is connected when we're powering up widgets
(so things like DC offset correction can run with their signal active)
and that we bring things down to cold before switching away. Since
hardware tends to be designed for the power on/off case more than for
dynamic reconfiguration this should minimise pops and clicks during
reconfiguration while active.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Implement blk_limits_max_hw_sectors() and make
blk_queue_max_hw_sectors() a wrapper around it.
DM needs this to avoid setting queue_limits' max_hw_sectors and
max_sectors directly. dm_set_device_limits() now leverages
blk_limits_max_hw_sectors() logic to establish the appropriate
max_hw_sectors minimum (PAGE_SIZE). Fixes issue where DM was
incorrectly setting max_sectors rather than max_hw_sectors (which
caused dm_merge_bvec()'s max_hw_sectors check to be ineffective).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
When stacking devices, a request_queue is not always available. This
forced us to have a no_cluster flag in the queue_limits that could be
used as a carrier until the request_queue had been set up for a
metadevice.
There were several problems with that approach. First of all it was up
to the stacking device to remember to set queue flag after stacking had
completed. Also, the queue flag and the queue limits had to be kept in
sync at all times. We got that wrong, which could lead to us issuing
commands that went beyond the max scatterlist limit set by the driver.
The proper fix is to avoid having two flags for tracking the same thing.
We deprecate QUEUE_FLAG_CLUSTER and use the queue limit directly in the
block layer merging functions. The queue_limit 'no_cluster' is turned
into 'cluster' to avoid double negatives and to ease stacking.
Clustering defaults to being enabled as before. The queue flag logic is
removed from the stacking function, and explicitly setting the cluster
flag is no longer necessary in DM and MD.
Reported-by: Ed Lin <ed.lin@promise.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
tty: add 'active' sysfs attribute to tty0 and console device
Userspace can query the actual virtual console, and the configured
console devices behind /dev/tt0 and /dev/console.
The last entry in the list of devices is the active device, analog
to the console= kernel command line option.
The attribute supports poll(), which is raised when the virtual
console is changed or /dev/console is reconfigured.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
index 0000000..b138b66
* 'for-linus' of git://git.infradead.org/users/eparis/notify:
fanotify: fill in the metadata_len field on struct fanotify_event_metadata
fanotify: split version into version and metadata_len
fanotify: Dont try to open a file descriptor for the overflow event
fanotify: Introduce FAN_NOFD
fanotify: do not leak user reference on allocation failure
inotify: stop kernel memory leak on file creation failure
fanotify: on group destroy allow all waiters to bypass permission check
fanotify: Dont allow a mask of 0 if setting or removing a mark
fanotify: correct broken ref counting in case adding a mark failed
fanotify: if set by user unset FMODE_NONOTIFY before fsnotify_perm() is called
fanotify: remove packed from access response message
fanotify: deny permissions when no event was sent
* 'upstream' of git://git.linux-mips.org/pub/scm/upstream-linus: (28 commits)
MIPS: Add a CONFIG_FORCE_MAX_ZONEORDER Kconfig option.
MIPS: LD/SD o32 macro GAS fix update
MIPS: Alchemy: fix build with SERIAL_8250=n
MIPS: Rename mips_dma_cache_sync back to dma_cache_sync
MIPS: MT: Fix typo in comment.
SSB: Fix nvram_get on BCM47xx platform
MIPS: BCM47xx: Swap serial console if ttyS1 was specified.
MIPS: BCM47xx: Use sscanf for parsing mac address
MIPS: BCM47xx: Fill values for b43 into SSB sprom
MIPS: BCM47xx: Do not read config from CFE
MIPS: FDT size is a be32
MIPS: Fix CP0 COUNTER clockevent race
MIPS: Fix regression on BCM4710 processor detection
MIPS: JZ4740: Fix pcm device name
MIPS: Separate two consecutive loads in memset.S
MIPS: Send proper signal and siginfo on FP emulator faults.
MIPS: AR7: Fix loops per jiffies on TNETD7200 devices
MIPS: AR7: Fix double ar7_gpio_init declaration
MIPS: Rework GENERIC_HARDIRQS Kconfig.
MIPS: Alchemy: Add return value check for strict_strtoul()
...
Introduce skb_checksum_start_offset() to replace repetitive calculation.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Special care is taken inside sk_port_alloc to avoid overwriting
skc_node/skc_nulls_node. We should also avoid overwriting
skc_bind_node/skc_portaddr_node.
The patch fixes the following crash:
BUG: unable to handle kernel paging request at fffffffffffffff0
IP: [<ffffffff812ec6dd>] udp4_lib_lookup2+0xad/0x370
[<ffffffff812ecc22>] __udp4_lib_lookup+0x282/0x360
[<ffffffff812ed63e>] __udp4_lib_rcv+0x31e/0x700
[<ffffffff812bba45>] ? ip_local_deliver_finish+0x65/0x190
[<ffffffff812bbbf8>] ? ip_local_deliver+0x88/0xa0
[<ffffffff812eda35>] udp_rcv+0x15/0x20
[<ffffffff812bba45>] ip_local_deliver_finish+0x65/0x190
[<ffffffff812bbbf8>] ip_local_deliver+0x88/0xa0
[<ffffffff812bb2cd>] ip_rcv_finish+0x32d/0x6f0
[<ffffffff8128c14c>] ? netif_receive_skb+0x99c/0x11c0
[<ffffffff812bb94b>] ip_rcv+0x2bb/0x350
[<ffffffff8128c14c>] netif_receive_skb+0x99c/0x11c0
Signed-off-by: Leonard Crestez <lcrestez@ixiacom.com>
Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some windows versions have wrong RFC1323 implementations, with SYN and
SYNACKS messages containing zero tcp timestamps.
We relaxed in commit fc1ad92dfc the passive connection case
(Windows connects to a linux machine), but the reverse case (linux
connects to a Windows machine) has an analogue problem when tsvals from
windows machine are 'negative' (high order bit set) : PAWS triggers and
we drops incoming messages.
Fix this by making zero ts_recent value special, allowing frame to be
processed.
Based on a report and initial patch from Dmitiy Balakin
Bugzilla reference : https://bugzilla.kernel.org/show_bug.cgi?id=24842
Reported-by: dmitriy.balakin@nicneiron.ru
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add dev_close_many and dev_deactivate_many to factorize another
sync-rcu operation on the netdevice unregister path.
$ modprobe dummy numdummies=10000
$ ip link set dev dummy* up
$ time rmmod dummy
Without the patch With the patch
real 0m 24.63s real 0m 5.15s
user 0m 0.00s user 0m 0.00s
sys 0m 6.05s sys 0m 5.14s
Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move the calcualation of the Tx hash for a given hash range into a separate
function and define the skb_tx_hash(), which calculates a Tx hash for a
[0; dev->real_num_tx_queues - 1] hash values range, using this
function (__skb_tx_hash()).
Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
To avoid unbalanced IRQ wake disable, ensure that wakeups are disabled
only when wakeups have been successfully enabled.
Tested on OMAP3630SDP/ZOOM3.
Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Reported-by: Paul Walmsley <paul@pwsan.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix various typos and other errors in comments of tty_driver.h. The most
significant is the wrong name of a function for the description of
TTY_DRIVER_DYNAMIC_DEV.
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add a new notification to indicate that a received, unprotected
Deauthentication or Disassociation frame was dropped due to
management frame protection being in use. This notification is
needed to allow user space (e.g., wpa_supplicant) to implement
SA Query procedure to recover from association state mismatch
between an AP and STA.
This is needed to avoid getting stuck in non-working state when MFP
(IEEE 802.11w) is used and a protected Deauthentication or
Disassociation frame is dropped for any reason. After that, the
station would silently discard any unprotected Deauthentication or
Disassociation frame that could be indicating that the AP does not
have association for the STA (when the Reason Code would be 6 or 7).
IEEE Std 802.11w-2009, 11.13 describes this recovery mechanism.
Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The nvram_get function was never in the mainline kernel, it only existed in
an external OpenWrt patch. Use nvram_getenv function, which is in mainline
and use an include instead of an extra function declaration. et0macaddr
contains the mac address in text from like 00:11:22:33:44:55. We have to
parse it before adding it into macaddr.
nvram_parse_macaddr will be merged into asm/mach-bcm47xx/nvram.h through
the MIPS git tree and will be available soon. It will not build now without
nvram_parse_macaddr, but it hasn't before either.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
To: linux-mips@linux-mips.org
Cc: mb@bu3sch.de
Cc: netdev@vger.kernel.org
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Michael Buesch <mb@bu3sch.de>
Patchwork: https://patchwork.linux-mips.org/patch/1849/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* usb-next: (132 commits)
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
usb: gadget: f_ncm.c added
usb: gadget: u_ether: prepare for NCM
usb: pch_udc: Fix setup transfers with data out
usb: pch_udc: Fix compile error, warnings and checkpatch warnings
usb: add ab8500 usb transceiver driver
USB: gadget: Implement runtime PM for MSM bus glue driver
USB: gadget: Implement runtime PM for ci13xxx gadget
USB: gadget: Add USB controller driver for MSM SoC
USB: gadget: Introduce ci13xxx_udc_driver struct
USB: gadget: Initialize ci13xxx gadget device's coherent DMA mask
USB: gadget: Fix "scheduling while atomic" bugs in ci13xxx_udc
USB: gadget: Separate out PCI bus code from ci13xxx_udc
...
Clean up.
Change nlmsvc_lookup_host() to be purpose-built for server-side
nlm_host management. This replaces the generic nlm_lookup_host()
helper function, just like on the client side. The lookup logic is
specialized for server host lookups.
The server side cache also gets its own specialized equivalent of the
nlm_release_host() function.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS clients don't need the garbage collection processing that is
performed on nlm_host structures. The client picks up an nlm_host at
mount time and holds a reference to it until the file system is
unmounted.
Servers, on the other hand, don't have a precise way to tell when an
nlm_host is no longer being used, so zero refcount nlm_host entries
are left to expire in the cache after a time.
Basically there's nothing holding a reference to an nlm_host between
individual server-side NLM requests, but we can't afford the expense
of recreating them for every new NLM request from a client. The
nlm_host cache adds some lifetime hysteresis to entries in the cache
so the next time a particular nlm_host is needed, it's likely to be
discovered by a lookup rather than created from whole cloth.
With the new implementation, client nlm_host cache items are no longer
garbage collected, and are destroyed directly by a new release
function specialized for client entries, nlmclnt_release_host(). They
are cached in their own data structure, and have their own lookup
logic, simplified and specialized for client nlm_host entries.
However, the client nlm_host cache still shares reboot recovery logic
with the server nlm_host cache. The NSM "peer rebooted" downcall for
clients and servers still come through the same RPC call. This is a
legacy formal API that would be difficult to alter, and besides, the
user space NSM implementation can't tell the difference between peers
that are clients or servers.
For this reason, the client cache continues to share the
nlm_host_mutex (and reboot recovery logic) with the server cache.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The nlm_release_call() function is invoked from both the server and
the client side. We're about to introduce a distinct server- and
client-side nlm_release_host(), so nlm_release_call() must first be
split into a client-side and a server-side version.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Now that all client-side XDR decoder routines use xdr_streams, there
should be no need to support the legacy calling sequence [rpc_rqst *,
__be32 *, RPC res *] anywhere. We can construct an xdr_stream in the
generic RPC code, instead of in each decoder function.
This is a refactoring change. It should not cause different behavior.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Now that all client-side XDR encoder routines use xdr_streams, there
should be no need to support the legacy calling sequence [rpc_rqst *,
__be32 *, RPC arg *] anywhere. We can construct an xdr_stream in the
generic RPC code, instead of in each encoder function.
Also, all the client-side encoder functions return 0 now, making a
return value superfluous. Take this opportunity to convert them to
return void instead.
This is a refactoring change. It should not cause different behavior.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Clean up.
The pointer returned by ->decode_dirent() is no longer used as a
pointer. The only call site (xdr_decode() in fs/nfs/dir.c) simply
extracts the errno value encoded in the pointer. Replace the
returned pointer with a standard integer errno return value.
Also, pass the "server" argument as part of the nfs_entry instead of
as a separate parameter. It's faster to derive "server" in
nfs_readdir_xdr_to_array() since we already have the directory's inode
handy. "server" ought to be invariant for a set of entries in the
same directory, right?
The legacy versions of decode_dirent() don't use "server" anyway, so
it's wasted work for them to derive and pass "server" for each entry.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Clean up. nlmdbg_cookie2a() is used only in svclock.c.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We'd like to prevent local buffer overflows caused by malicious or
broken servers. New xdr_stream style decoders can do that.
For efficiency, we also eventually want to be able to pass xdr_streams
from call_decode() to all XDR decoding functions, rather than building
an xdr_stream in every XDR decoding function in the kernel.
Static helper functions are left without the "inline" directive. This
allows the compiler to choose automatically how to optimize these for
size or speed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We're interested in taking advantage of the safety benefits of
xdr_streams. These data structures allow more careful checking for
buffer overflow while encoding. More careful type checking is also
introduced in the new functions.
For efficiency, we also eventually want to be able to pass xdr_streams
from call_encode() to all XDR encoding functions, rather than building
an xdr_stream in every XDR encoding function in the kernel. To do
this means all encoders must be ready to handle a passed-in
xdr_stream.
The new encoders follow the modern paradigm for XDR encoders: BUG on
error, and always return a zero status code.
Static helper functions are left without the "inline" directive. This
allows the compiler to choose automatically how to optimize these for
size or speed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Replace sr_media_change() with sr_check_events(). It normally only
uses GET_EVENT_STATUS_NOTIFICATION to check both media change and
eject request. If @clearing includes DISK_EVENT_MEDIA_CHANGE, it
issues TUR and compares whether media presence has changed. The SCSI
specific media change uevent is kept for compatibility.
sr_media_change() was doing both media change check and revalidation.
The revalidation part is split into sr_block_revalidate_disk().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
In principle, cdrom just needs to pass through ->check_events() but
CDROM_MEDIA_CHANGED ioctl makes things a bit more complex. Just as
with ->media_changed() support, cdrom code needs to buffer the events
and serve them to ioctl and vfs as requested.
As the code has to deal with both ->check_events() and
->media_changed(), and vfs and ioctl event buffering, this patch adds
check_events caching on top of the existing cdi->mc_flags buffering.
It may be a good idea to deprecate CDROM_MEDIA_CHANGED ioctl and
remove all this mess.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Currently, media presence polling for removeable block devices is done
from userland. There are several issues with this.
* Polling is done by periodically opening the device. For SCSI
devices, the command sequence generated by such action involves a
few different commands including TEST_UNIT_READY. This behavior,
while perfectly legal, is different from Windows which only issues
single command, GET_EVENT_STATUS_NOTIFICATION. Unfortunately, some
ATAPI devices lock up after being periodically queried such command
sequences.
* There is no reliable and unintrusive way for a userland program to
tell whether the target device is safe for media presence polling.
For example, polling for media presence during an on-going burning
session can make it fail. The polling program can avoid this by
opening the device with O_EXCL but then it risks making a valid
exclusive user of the device fail w/ -EBUSY.
* Userland polling is unnecessarily heavy and in-kernel implementation
is lighter and better coordinated (workqueue, timer slack).
This patch implements framework for in-kernel disk event handling,
which includes media presence polling.
* bdops->check_events() is added, which supercedes ->media_changed().
It should check whether there's any pending event and return if so.
Currently, two events are defined - DISK_EVENT_MEDIA_CHANGE and
DISK_EVENT_EJECT_REQUEST. ->check_events() is guaranteed not to be
called parallelly.
* gendisk->events and ->async_events are added. These should be
initialized by block driver before passing the device to add_disk().
The former contains the mask of all supported events and the latter
the mask of all events which the device can report without polling.
/sys/block/*/events[_async] export these to userland.
* Kernel parameter block.events_dfl_poll_msecs controls the system
polling interval (default is 0 which means disable) and
/sys/block/*/events_poll_msecs control polling intervals for
individual devices (default is -1 meaning use system setting). Note
that if a device can report all supported events asynchronously and
its polling interval isn't explicitly set, the device won't be
polled regardless of the system polling interval.
* If a device is opened exclusively with write access, event checking
is automatically disabled until all write exclusive accesses are
released.
* There are event 'clearing' events. For example, both of currently
defined events are cleared after the device has been successfully
opened. This information is passed to ->check_events() callback
using @clearing argument as a hint.
* Event checking is always performed from system_nrt_wq and timer
slack is set to 25% for polling.
* Nothing changes for drivers which implement ->media_changed() but
not ->check_events(). Going forward, all drivers will be converted
to ->check_events() and ->media_change() will be dropped.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
There's no reason for register_disk() and del_gendisk() to be in
fs/partitions/check.c. Move both to genhd.c. While at it, collapse
unlink_gendisk(), which was artificially in a separate function due to
genhd.c / check.c split, into del_gendisk().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
