Commit 79901317ce ("n_tty: Don't flush buffer when closing ldisc"),
first merged in kernel release 3.10, caused the following regression
in the Gigaset M101 driver:
Before that commit, when closing the N_TTY line discipline in
preparation to switching to N_GIGASET_M101, receive_room would be
reset to a non-zero value by the call to n_tty_flush_buffer() in
n_tty's close method. With the removal of that call, receive_room
might be left at zero, blocking data reception on the serial line.
The present patch fixes that regression by setting receive_room
to an appropriate value in the ldisc open method.
Fixes: 79901317ce ("n_tty: Don't flush buffer when closing ldisc")
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
The member (u32) "num_active_agg" of struct qfq_sched has been unused
since its introduction in 462dbc9101
"pkt_sched: QFQ Plus: fair-queueing service at DRR cost" and (AFAICT)
there is no active plan to use it; this removes the member.
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Acked-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is no need to memset memory allocated with vzalloc.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Shahed Shaikh <shahed.shaikh@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixes: 25331d6ce4 ("net: sched: implement qstat helper routines")
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Cong Wang <cwang@twopensource.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently F-RTO may repeatedly send new data packets on non-recurring
timeouts in CA_Loss mode. This is a bug because F-RTO (RFC5682)
should only be used on either new recovery or recurring timeouts.
This exacerbates the recovery progress during frequent timeout &
repair, because we prioritize sending new data packets instead of
repairing the holes when the bandwidth is already scarce.
Fix it by correcting the test of a new recovery episode.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some IP blocks like RTC, needs an additional setting for writing to its
registers. This is to prevent any spurious writes from changing the
register values.
This patch adds optional lock and unlock function pointers to
the IP block's hwmod data. These unlock and lock function pointers
are called by hwmod code before and after writing sysconfig registers.
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
[paul@pwsan.com: fixed indentation level to conform with the rest of the
structure members]
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Since the mdb add/del code was introduced there have been 2 br_mdb_notify
calls when doing br_mdb_add() resulting in 2 notifications on each add.
Example:
Command: bridge mdb add dev br0 port eth1 grp 239.0.0.1 permanent
Before patch:
root@debian:~# bridge monitor all
[MDB]dev br0 port eth1 grp 239.0.0.1 permanent
[MDB]dev br0 port eth1 grp 239.0.0.1 permanent
After patch:
root@debian:~# bridge monitor all
[MDB]dev br0 port eth1 grp 239.0.0.1 permanent
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Fixes: cfd5675435 ("bridge: add support of adding and deleting mdb entries")
Signed-off-by: David S. Miller <davem@davemloft.net>
Claudiu Manoil says:
====================
gianfar: Add Rx S/G
This patch-set introduces scatter/gather support
on the Rx side, addressing Rx path performance
issues in the driver.
Thanks.
As an example, two boards connected back-to-back
were used to measure the throughput, running the
same kernel 4.1, before and after applying these
patches.
The netperf UDP_STREAM results below show that the
bottleneck lies on the Rx side BEFORE applying the
patches, and that the Rx throughput is even lower
with a larger MTU. AFTER applying the patches the
Rx bottleneck is gone (Rx throughput matches the
Tx one) and the RX throughput is not influenced by
MTU size any longer (as expected).
BEFORE:
1) MTU 1500 (default)
root@p1010rdb-pb:~# netperf -l 150 -cC -H 192.85.1.1 -p 12867 -t UDP_STREAM -- -m 512
MIGRATED UDP STREAM TEST from 0.0.0.0 () port 0 AF_INET to 192.85.1.1 () port 0 AF_INET
Socket Message Elapsed Messages CPU Service
Size Size Time Okay Errors Throughput Util Demand
bytes bytes secs # # 10^6bits/sec % SS us/KB
163840 512 150.00 20119124 0 549.4 100.00 14.911
163840 150.00 14057349 383.9 100.00 14.911
root@p1010rdb-pb:~# netperf -l 150 -cC -H 192.85.1.1 -p 12867 -t UDP_STREAM -- -m 64
MIGRATED UDP STREAM TEST from 0.0.0.0 () port 0 AF_INET to 192.85.1.1 () port 0 AF_INET
Socket Message Elapsed Messages CPU Service
Size Size Time Okay Errors Throughput Util Demand
bytes bytes secs # # 10^6bits/sec % SS us/KB
163840 64 150.00 23654013 0 80.7 100.00 101.463
163840 150.00 15875288 54.2 100.00 101.463
2) MTU 8000
root@p1010rdb-pb:~# netperf -l 150 -cC -H 192.85.1.1 -p 12867 -t UDP_STREAM -- -m 512
MIGRATED UDP STREAM TEST from 0.0.0.0 () port 0 AF_INET to 192.85.1.1 () port 0 AF_INET
Socket Message Elapsed Messages CPU Service
Size Size Time Okay Errors Throughput Util Demand
bytes bytes secs # # 10^6bits/sec % SS us/KB
163840 512 150.00 20067232 0 548.0 100.00 14.950
163840 150.00 6113498 166.9 99.95 14.942
root@p1010rdb-pb:~# netperf -l 150 -cC -H 192.85.1.1 -p 12867 -t UDP_STREAM -- -m 64
MIGRATED UDP STREAM TEST from 0.0.0.0 () port 0 AF_INET to 192.85.1.1 () port 0 AF_INET
Socket Message Elapsed Messages CPU Service
Size Size Time Okay Errors Throughput Util Demand
bytes bytes secs # # 10^6bits/sec % SS us/KB
163840 64 150.00 23621279 0 80.6 100.00 101.604
163840 150.00 5868602 20.0 99.96 101.563
AFTER:
(both MTU 1500 and MTU 8000)
root@p1010rdb-pb:~# netperf -l 150 -cC -H 192.85.1.1 -p 12867 -t UDP_STREAM -- -m 512
MIGRATED UDP STREAM TEST from 0.0.0.0 () port 0 AF_INET to 192.85.1.1 () port 0 AF_INET
Socket Message Elapsed Messages CPU Service
Size Size Time Okay Errors Throughput Util Demand
bytes bytes secs # # 10^6bits/sec % SS us/KB
163840 512 150.00 19914969 0 543.8 100.00 15.064
163840 150.00 19914969 543.8 99.35 14.966
root@p1010rdb-pb:~# netperf -l 150 -cC -H 192.85.1.1 -p 12867 -t UDP_STREAM -- -m 64
MIGRATED UDP STREAM TEST from 0.0.0.0 () port 0 AF_INET to 192.85.1.1 () port 0 AF_INET
Socket Message Elapsed Messages CPU Service
Size Size Time Okay Errors Throughput Util Demand
bytes bytes secs # # 10^6bits/sec % SS us/KB
163840 64 150.00 23433989 0 80.0 100.00 102.416
163840 150.00 23433989 80.0 99.62 102.023
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The eTSEC h/w is capable of scatter/gather on the receive side
too if MAXFRM > MRBLR, when the allowed maximum Rx frame size
is set to be greater than the maximum Rx buffer size (MRBLR).
It's about time the driver makes use of this h/w capability,
by supporting fixed buffer sizes and Rx S/G.
The buffer size given to eTSEC for reception is fixed to
1536B (must be multiple of 64), which is the same default
buffer size as before, used to accommodate standard MTU
(1500B) size frames. As before, eTSEC can receive frames of
up to 9600B. Individual Rx buffers are mapped to page halves
(page size for eTSEC systems is 4KB). The skb is built around
the first buffer of a frame (using build_skb()). In case the
frame spans multiple buffers, the trailing buffers are added
as Rx fragments to the skb. The last buffer in frame is marked
by the L status flag. A mechanism is in place to reuse the pages
owned by the driver (for Rx) for subsequent receptions.
Supporting fixed size buffers allows the implementation of Rx S/G,
which in turn removes the memory pressure issues the driver had
before when MTU was set for jumbo frame reception.
Also, in most cases, the Rx path becomes faster due to Rx page
reusal, since the overhead of allocating new rx buffers is removed
from the fast path.
Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use "ndev" instead of "dev", as the rx queue back pointer
to a net_device struct, to avoid name clashing with a
"struct device" reference. This prepares the addition of a
"struct device" back pointer to the rx queue structure.
Remove duplicated rxq registration in the process.
Move napi_gro_receive() outside gfar_process_frame().
Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are several (long standing) problems about how the status
field of the rx buffer descriptor (rxbd) is currently handled on
the error path:
- too many unnecessary 16bit reads of the two halves of the rxbd
status field (32bit), also resulting in overuse of endianness
convesion macros;
- "bdp->status = RXBD_LARGE" makes no sense, since the "large"
flag is read only (only eTSEC can write it), and trying to clear
the other status bits is also error prone in this context
(most of the rx status bits are read only anyway).
This is fixed with a single 32bit read of the "status" field,
and then the appropriate 16bit shifting is applied to access
the various status bits or the rx frame length. Also corrected
the use of the RXBD_LARGE flag.
Additional fix:
"rx_over_errors" stat is incremented instead of "rx_crc_errors"
in case of RXBD_OVERRUN occurrence.
Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use a more common consumer/ producer index design to improve
rx buffer allocation. Instead of allocating a single new buffer
(skb) on each iteration, bundle the allocation of several rx
buffers at a time. This also opens the path for further memory
optimizations.
Remove useless check of rxq->rfbptr, since this patch touches
rx pause frame handling code as well. rxq->rfbptr is always
initialized as part of Rx BD ring init.
Remove redundant (and misleading) 'amount_pull' parameter.
Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A report with INCLUDE/Change_to_include and empty source list should be
treated as a leave, specified by RFC 3376, section 3.1:
"If the requested filter mode is INCLUDE *and* the requested source
list is empty, then the entry corresponding to the requested
interface and multicast address is deleted if present. If no such
entry is present, the request is ignored."
Signed-off-by: Satish Ashok <sashok@cumulusnetworks.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
- Mainly fix-ups for the various 4.2 items
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=N/5G
-----END PGP SIGNATURE-----
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma
Pull rdma fixes from Doug Ledford:
"Mainly fix-ups for the various 4.2 items"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (24 commits)
IB/core: Destroy ocrdma_dev_id IDR on module exit
IB/core: Destroy multcast_idr on module exit
IB/mlx4: Optimize do_slave_init
IB/mlx4: Fix memory leak in do_slave_init
IB/mlx4: Optimize freeing of items on error unwind
IB/mlx4: Fix use of flow-counters for process_mad
IB/ipath: Convert use of __constant_<foo> to <foo>
IB/ipoib: Set MTU to max allowed by mode when mode changes
IB/ipoib: Scatter-Gather support in connected mode
IB/ucm: Fix bitmap wrap when devnum > IB_UCM_MAX_DEVICES
IB/ipoib: Prevent lockdep warning in __ipoib_ib_dev_flush
IB/ucma: Fix lockdep warning in ucma_lock_files
rds: rds_ib_device.refcount overflow
RDMA/nes: Fix for incorrect recording of the MAC address
RDMA/nes: Fix for resolving the neigh
RDMA/core: Fixes for port mapper client registration
IB/IPoIB: Fix bad error flow in ipoib_add_port()
IB/mlx4: Do not attemp to report HCA clock offset on VFs
IB/cm: Do not queue work to a device that's going away
IB/srp: Avoid using uninitialized variable
...
The description and copyright notice of drivers/acpi/power.c is out
of date, so update it as appropriate.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When we calculate the checksum on the recv path, we store the
result in the skb as an optimisation in case we need the checksum
again down the line.
This is in fact bogus for the MSG_PEEK case as this is done without
any locking. So multiple threads can peek and then store the result
to the same skb, potentially resulting in bogus skb states.
This patch fixes this by only storing the result if the skb is not
shared. This preserves the optimisations for the few cases where
it can be done safely due to locking or other reasons, e.g., SIOCINQ.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 6c3e921b18.
commit 6c3e921b18 ("net: fec: Ensure clocks are enabled while using mdio
bus") prevents the kernel to boot on mx6 boards, so let's revert it.
Reported-by: Tyler Baker <tyler.baker@linaro.org>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This may result in a kernel panic. The bug has always existed but
somehow we've run out of luck now and it bites.
Signed-off-by: Richard Stearn <richard@rns-stearn.demon.co.uk>
Cc: stable@vger.kernel.org # all branches
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Shared skbs must not be modified and this is crucial for broadcast
and/or multicast paths where we use it as an optimisation to avoid
unnecessary cloning.
The function skb_recv_datagram breaks this rule by setting peeked
without cloning the skb first. This causes funky races which leads
to double-free.
This patch fixes this by cloning the skb and replacing the skb
in the list when setting skb->peeked.
Fixes: a59322be07 ("[UDP]: Only increment counter on first peek/recv")
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similarly as in commit 4f7d2cdfdd ("rtnetlink: verify IFLA_VF_INFO
attributes before passing them to driver"), we have a double nesting
of netlink attributes, i.e. IFLA_VF_PORTS only contains IFLA_VF_PORT
that is nested itself. While IFLA_VF_PORTS is a verified attribute
from ifla_policy[], we only check if the IFLA_VF_PORTS container has
IFLA_VF_PORT attributes and then pass the attribute's content itself
via nla_parse_nested(). It would be more correct to reject inner types
other than IFLA_VF_PORT instead of continuing parsing and also similarly
as in commit 4f7d2cdfdd, to check for a minimum of NLA_HDRLEN.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Cc: Scott Feldman <sfeldma@gmail.com>
Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
GPMC smart idle is not really broken but it does not support
smart idle with wakeup.
Fixes: 556708fe87 ("ARM: OMAP: DRA7: hwmod: Make gpmc software supervised as the smart idle is broken")
Signed-off-by: Roger Quadros <rogerq@ti.com>
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
If a failure occurs during probe, brcmstb_gpio_remove() is called. In
remove, we call platform_get_drvdata(), but at the time of failure in
the probe the driver data hadn't yet been set which leads to a NULL
ptr dereference in the remove's list_for_each. Call
platform_set_drvdata() and set up list head right after allocating the
priv struct to both avoid the null pointer dereference that could
occur today. To guard against potential future changes, check for
null pointer in remove.
Reported-by: Tim Ross <tross@broadcom.com>
Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The variable "desc" is only used for storing the return value at the
end of the function. It is unneeded.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The driver gpio-mvebu.c does not depend on gpio-generic.c at all.
Drop unneeded "select GPIO_GENERIC".
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This driver calls of_mm_gpiochip_add() to add a memory mapped gpio
chip. So, of_mm_gpiochip_remove() should be used when removing it.
The direct call of gpiochip_remove() misses unmapping the register
and freeing the label.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Tien Hock Loh <thloh@altera.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The driver gpio-altera.c does not depend on gpio-generic.c at all.
Drop unneeded "select GPIO_GENERIC".
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Tien Hock Loh <thloh@altera.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This driver is tristate, so it should be cleanable.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Some brcmstb GPIO controllers can be used to wake from suspend, so use
the de facto standard property 'wakeup-source' to mark the nodes of
controllers with that capability.
Also document interrupts-extended, which will be used for wakeup
handling because the interrupt parent for the wake IRQ is different
from the regular IRQ.
While we're at it, a few more fixes: We don't actually use the
"interrupt-names" property, so remove it from the listed optional
properties and from the examples. And since we're modifying the
examples, also follow Brian's suggestions to:
- change #gpio-cells, #interrupt-cells, and brcm,gpio-bank-widths from
hex to dec
- use phandles
Reviewed-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
gpiochip_add_pingroup_range() has a pctldev argument, not pinctrl.
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Allow to determine the current direction configuration by
reading back from the direction register.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Currently none of the RCU-tasks scenarios enables lockdep-RCU, which
causes bugs to be missed. This commit therefore enables lockdep-RCU
on TASKS01.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Although RCU-tasks isn't really designed to support rcu_dereference()
and list manipulation, that is how rcutorture tests it. Which means
that lockdep-RCU complains about the rcu_dereference_check() invocations
because RCU-tasks doesn't have read-side markers. This commit therefore
creates a torturing_tasks() to silence the lockdep-RCU complaints from
rcu_dereference_check() when RCU-tasks is being tortured.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_torture_cbflood() function correctly checks for flavors of
RCU that lack analogs to call_rcu() and rcu_barrier(), but in that
case it fails to terminate correctly. In fact, it terminates so
incorrectly that segfaults can result. This commit therefore causes
rcu_torture_cbflood() to do the proper wait-for-stop procedure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Specifying a negative rcutorture.shuffle_interval value will cause a
negative value to be used as a sleep time. This commit therefore
refuses to start shuffling unless the rcutorture.shuffle_interval
value is greater than zero.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, a negative value for rcutorture.nfakewriters= can cause
rcutorture to pass a negative size to the memory allocator, which
is not really a particularly good thing to do. This commit therefore
adds bounds checking to this parameter, so that values that are less
than or equal to zero disable fake writing.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
A negative value for rcutorture.n_barrier_cbs can pass a negative value
to the memory allocator, so this commit instead causes rcu_barrier()
testing to be disabled in this case.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This update makes arithmetic to calculate number of RCU nodes
more straight and easy to read.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Although a number of RCU levels may be less than the current
maximum of four, some static data associated with each level
are allocated for all four levels. As result, the extra data
never get accessed and just wast memory. This update limits
count of allocated items to the number of used RCU levels.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Members rcu_state::levelcnt[] and rcu_state::levelspread[]
are only used at init. There is no reason to keep them
afterwards.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Number of items in rcu_capacity[] array is defined by macro
MAX_RCU_LVLS. However, that array is never accessed beyond
RCU_NUM_LVLS index. Therefore, we can limit the array to
RCU_NUM_LVLS items and eliminate MAX_RCU_LVLS. As result,
in most cases the memory is conserved.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Variable rcu_num_lvls is limited by RCU_NUM_LVLS macro.
In turn, rcu_state::levelcnt[] array is never accessed
beyond rcu_num_lvls. Thus, rcu_state::levelcnt[] is safe
to limit to RCU_NUM_LVLS items.
Since rcu_num_lvls could be changed during boot (as result
of rcutree.rcu_fanout_leaf kernel parameter update) one might
assume a new value could overflow the value of RCU_NUM_LVLS.
However, that is not the case, since leaf-level fanout is only
permitted to increase, resulting in rcu_num_lvls possibly to
decrease.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Current code suggests that introducing the extra level to
rcu_capacity[] array makes some of the arithmetic easier.
Well, in fact it appears rather confusing and unnecessary.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This update simplifies rcu_init_geometry() code flow
and makes calculation of the total number of rcu_node
structures more easy to read.
The update relies on the fact num_rcu_lvl[] is never
accessed beyond rcu_num_lvls index by the rest of the
code. Therefore, there is no need initialize the whole
num_rcu_lvl[].
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Local variable 'n' mimics 'nr_cpu_ids' while the both are
used within one function. There is no reason for 'n' to
exist whatsoever.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently a condition when RCU tree is unable to accommodate
the configured number of CPUs is not permitted and causes
a fall back to compile-time values. However, the code has no
means to exceed the RCU tree capacity neither at compile-time
nor in run-time. Therefore, if the condition is met in run-
time then it indicates a serios problem elsewhere and should
be handled with a panic.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Type-checking coccinelle spatches are being used to locate type mismatches
between function signatures and return values in this case this produced:
./kernel/rcu/srcu.c:271 WARNING: return of wrong type
int != unsigned long,
srcu_readers_active() returns an int that is the sum of per_cpu unsigned
long but the only user is cleanup_srcu_struct() which is using it as a
boolean (condition) to see if there is any readers rather than actually
using the approximate number of readers. The theoretically possible
unsigned long overflow case does not need to be handled explicitly - if
we had 4G++ readers then something else went wrong a long time ago.
proposal: change the return type to boolean. The function name is left
unchanged as it fits the naming expectation for a boolean.
patch was compile tested for x86_64_defconfig (implies CONFIG_SRCU=y)
patch is against 4.1-rc5 (localversion-next is -next-20150525)
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
DEBUG_LOCK_ALLOC=y is not a production setting, but it is
not very unusual either. Many developers routinely
use kernels built with it enabled.
Apart from being selected by hand, it is also auto-selected by
PROVE_LOCKING "Lock debugging: prove locking correctness" and
LOCK_STAT "Lock usage statistics" config options.
LOCK STAT is necessary for "perf lock" to work.
I wouldn't spend too much time optimizing it, but this particular
function has a very large cost in code size: when it is deinlined,
code size decreases by 830,000 bytes:
text data bss dec hex filename
85674192 22294776 20627456 128596424 7aa39c8 vmlinux.before
84837612 22294424 20627456 127759492 79d7484 vmlinux
(with this config: http://busybox.net/~vda/kernel_config)
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Lai Jiangshan <laijs@cn.fujitsu.com>
CC: Tejun Heo <tj@kernel.org>
CC: Oleg Nesterov <oleg@redhat.com>
CC: linux-kernel@vger.kernel.org
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
