Commit Graph

210656 Commits

Author SHA1 Message Date
Tejun Heo
4690c4ab56 workqueue: misc/cosmetic updates
Make the following updates in preparation of concurrency managed
workqueue.  None of these changes causes any visible behavior
difference.

* Add comments and adjust indentations to data structures and several
  functions.

* Rename wq_per_cpu() to get_cwq() and swap the position of two
  parameters for consistency.  Convert a direct per_cpu_ptr() access
  to wq->cpu_wq to get_cwq().

* Add work_static() and Update set_wq_data() such that it sets the
  flags part to WORK_STRUCT_PENDING | WORK_STRUCT_STATIC if static |
  @extra_flags.

* Move santiy check on work->entry emptiness from queue_work_on() to
  __queue_work() which all queueing paths share.

* Make __queue_work() take @cpu and @wq instead of @cwq.

* Restructure flush_work() and __create_workqueue_key() to make them
  easier to modify.

Signed-off-by: Tejun Heo <tj@kernel.org>
2010-06-29 10:07:10 +02:00
Tejun Heo
c790bce048 workqueue: kill RT workqueue
With stop_machine() converted to use cpu_stop, RT workqueue doesn't
have any user left.  Kill RT workqueue support.

Signed-off-by: Tejun Heo <tj@kernel.org>
2010-06-29 10:07:09 +02:00
Tejun Heo
8fec62b2d9 acpi: use queue_work_on() instead of binding workqueue worker to cpu0
ACPI works need to be executed on cpu0 and acpi/osl.c achieves this by
creating singlethread workqueue and then binding it to cpu0 from a
work which is quite unorthodox.  Make it create regular workqueues and
use queue_work_on() instead.  This is in preparation of concurrency
managed workqueue and the extra workers won't be a problem after it's
implemented.

Signed-off-by: Tejun Heo <tj@kernel.org>
2010-06-29 10:07:09 +02:00
Tejun Heo
82805ab77d kthread: implement kthread_data()
Implement kthread_data() which takes @task pointing to a kthread and
returns @data specified when creating the kthread.  The caller is
responsible for ensuring the validity of @task when calling this
function.

Signed-off-by: Tejun Heo <tj@kernel.org>
2010-06-29 10:07:09 +02:00
Tejun Heo
7bc465605f ivtv: use kthread_worker instead of workqueue
Upcoming workqueue updates will no longer guarantee fixed workqueue to
worker kthread association, so giving RT priority to the irq worker
won't work.  Use kthread_worker which guarantees specific kthread
association instead.  This also makes setting the priority cleaner.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: ivtv-devel@ivtvdriver.org
Cc: linux-media@vger.kernel.org
2010-06-29 10:07:09 +02:00
Tejun Heo
b56c0d8937 kthread: implement kthread_worker
Implement simple work processor for kthread.  This is to ease using
kthread.  Single thread workqueue used to be used for things like this
but workqueue won't guarantee fixed kthread association anymore to
enable worker sharing.

This can be used in cases where specific kthread association is
necessary, for example, when it should have RT priority or be assigned
to certain cgroup.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
2010-06-29 10:07:09 +02:00
Ben Hutchings
bf988435bd ethtool: Fix potential user buffer overflow for ETHTOOL_{G, S}RXFH
struct ethtool_rxnfc was originally defined in 2.6.27 for the
ETHTOOL_{G,S}RXFH command with only the cmd, flow_type and data
fields.  It was then extended in 2.6.30 to support various additional
commands.  These commands should have been defined to use a new
structure, but it is too late to change that now.

Since user-space may still be using the old structure definition
for the ETHTOOL_{G,S}RXFH commands, and since they do not need the
additional fields, only copy the originally defined fields to and
from user-space.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Cc: stable@kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 01:00:29 -07:00
Ben Hutchings
db048b6903 ethtool: Fix potential kernel buffer overflow in ETHTOOL_GRXCLSRLALL
On a 32-bit machine, info.rule_cnt >= 0x40000000 leads to integer
overflow and the buffer may be smaller than needed.  Since
ETHTOOL_GRXCLSRLALL is unprivileged, this can presumably be used for at
least denial of service.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Cc: stable@kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 01:00:29 -07:00
Choi, David
51f932c487 micrel phy driver - updated(1)
Hello all:

This patch fixes what Ben mentioned, namely duplicated ids.

From: David J. Choi <david.choi@micrel.com>

Body of the explanation: This patch has changes as followings;
 -support the interrupt from phy devices from Micrel Inc.
 -support more phy devices, ks8737, ks8721, ks8041, ks8051 from Micrel.
 -remove vsc8201 because this device was used only internal test at Micrel.

Signed-off-by: David J. Choi <david.choi@micrel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 00:58:32 -07:00
Stanislaw Gruszka
deaec0f65b qlcnic: fail when try to setup unsupported features
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 00:53:28 -07:00
Stanislaw Gruszka
ef2519b1dd netxen: fail when try to setup unsupported features
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 00:53:27 -07:00
Stanislaw Gruszka
e0d904ffd0 bnx2x: fail when try to setup unsupported features
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 00:53:27 -07:00
Stanislaw Gruszka
d92be4b166 vmxnet3: fail when try to setup unsupported features
Return EOPNOTSUPP in ethtool_ops->set_flags.

Fix coding style while at it.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 00:53:26 -07:00
Stanislaw Gruszka
52b6dcfe59 e1000e: fail when try to setup unsupported features
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 00:53:25 -07:00
FUJITA Tomonori
f5fa3cb9b7 sparc: remove homegrown L1_CACHE_ALIGN macro
Let's use the standard L1_CACHE_ALIGN macro instead.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 00:38:02 -07:00
Sjur Braendeland
529d6dad5b caif-driver: Add CAIF-SPI Protocol driver.
This patch introduces the CAIF SPI Protocol Driver for
CAIF Link Layer.

This driver implements a platform driver to accommodate for a
platform specific SPI device. A general platform driver is not
possible as there are no SPI Slave side Kernel API defined.
A sample CAIF SPI Platform device can be found in
.../Documentation/networking/caif/spi_porting.txt

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 00:08:21 -07:00
Sjur Braendeland
01eebb53a6 caif: Kconfig and Makefile fixes
Use "depends on" instead of "if" in Kconfig files.
Fixed CAIF debug flag, and removed unnecessary clean-* options.

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-29 00:06:38 -07:00
Casey Leedom
cfc9b16b75 cxgb4vf: Stitch new T4 PCI-E SR-IOV Virtual Function driver into the build
Stitch new T4 PCI-E SR-IOV Virtual Function driver into the build.

Signed-off-by: Casey Leedom
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:59:37 -07:00
Casey Leedom
84c6ade7a7 cxgb4vf: Add new Makefile for T4 PCI-E SR-IOV Virtual Function driver cxgb4vf
Add new Makefile for T4 PCI-E SR-IOV Virtual Function driver "cxgb4vf".

Signed-off-by: Casey Leedom
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:59:37 -07:00
Casey Leedom
be839e3917 cxgb4vf: Add main T4 PCI-E SR-IOV Virtual Function driver for cxgb4vf
Add main T4 PCI-E SR-IOV Virtual Function driver for "cxgb4vf".

Signed-off-by: Casey Leedom
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:59:36 -07:00
Casey Leedom
c6e0d91464 cxgb4vf: Add T4 Virtual Function Scatter-Gather Engine DMA code
Add T4 Virtual Function Scatter-Gather Engine DMA code.

Signed-off-by: Casey Leedom
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:59:36 -07:00
Casey Leedom
16f8bd4be7 cxgb4vf: Add core T4 PCI-E SR-IOV Virtual Function hardware definitions and device communication code
Add core T4 PCI-E SR-IOV Virtual Function hardware definitions and device
communication code.

Signed-off-by: Casey Leedom
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:59:35 -07:00
Casey Leedom
7ee9ff9485 cxgb4vf: Add code to provision T4 PCI-E SR-IOV Virtual Functions with hardware resources
Add code to provision T4 PCI-E SR-IOV Virtual Functions with hardware
resources.

Signed-off-by: Casey Leedom
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:59:35 -07:00
Casey Leedom
17edf2594f cxgb4vf: Add new macros and definitions for hardware constants
Add new macros and definitions for hardware constants.

Signed-off-by: Casey Leedom
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:59:34 -07:00
Casey Leedom
81323b74a8 cxgb4vf: update to latest T4 firmware API file
Update to latest T4 firmware API file.

Signed-off-by: Casey Leedom
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:58:55 -07:00
Casey Leedom
1704d74894 cxgb4vf: small changes to message processing structures/macros
Split cpl_tx_pkt_lso into core message structure and encapsulated message,
make RSPD_LEN macro match other response descriptor macros.

Signed-off-by: Casey Leedom
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:58:54 -07:00
David Daney
a71e832917 netdev: mdio-octeon: Fix section mismatch errors.
We started getting:

WARNING: vmlinux.o(.data+0x20bd0): Section mismatch in reference from
the variable octeon_mdiobus_driver to the function
.init.text:octeon_mdiobus_probe()

This fixes it.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:58:54 -07:00
David Daney
d30b181bd6 netdev: octeon_mgmt: Fix section mismatch errors.
We started getting:

WARNING: drivers/net/built-in.o(.data+0x10f0): Section mismatch in
reference from the variable octeon_mgmt_driver to the function
.init.text:octeon_mgmt_probe()

This fixes it.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:58:53 -07:00
Andy Gospodarek
c22d7ac844 bonding: prevent netpoll over bonded interfaces
Support for netpoll over bonded interfaces was added here:

	commit f6dc31a85c
	Author: WANG Cong <amwang@redhat.com>
	Date:   Thu May 6 00:48:51 2010 -0700

	    bonding: make bonding support netpoll

but it is bad enough that we should probably just disable netpoll over
bonding until some of the locking logic in the bonding driver is changed
or converted completely to RCU.  Simple actions like changing the active
slave in active-backup mode will hang the box if a high enough printk
debugging level is enabled.

Keeping the old code around will be good for anyone that wants to work
on it (and for after the RCU conversion), so I propose this small patch
rather than ripping it all out.

Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:54:10 -07:00
Changli Gao
210d6de78c act_mirred: don't clone skb when skb isn't shared
don't clone skb when skb isn't shared

When the tcf_action is TC_ACT_STOLEN, and the skb isn't shared, we don't need
to clone a new skb. As the skb will be freed after this function returns, we
can use it freely once we get a reference to it.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
----
 include/net/sch_generic.h |   11 +++++++++--
 net/sched/act_mirred.c    |    6 +++---
 2 files changed, 12 insertions(+), 5 deletions(-)
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:24:32 -07:00
Eric Dumazet
c4ead4c595 tcp: tso_fragment() might avoid GFP_ATOMIC
We can pass a gfp argument to tso_fragment() and avoid GFP_ATOMIC
allocations sometimes.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:24:31 -07:00
Eric Dumazet
9618e2ffd7 vlan: 64 bit rx counters
Use u64_stats_sync infrastructure to implement 64bit rx stats.

(tx stats are addressed later)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:24:31 -07:00
Eric Dumazet
bc66154efe macvlan: 64 bit rx counters
Use u64_stats_sync infrastructure to implement 64bit stats.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:24:30 -07:00
Eric Dumazet
33d91f00c7 net: u64_stats_fetch_begin_bh() and u64_stats_fetch_retry_bh()
- Must disable preemption in case of 32bit UP in u64_stats_fetch_begin()
and u64_stats_fetch_retry()

- Add new u64_stats_fetch_begin_bh() and u64_stats_fetch_retry_bh() for
network usage, disabling BH on 32bit UP only.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:24:30 -07:00
Eric Dumazet
7a9b2d5950 net: use this_cpu_ptr()
use this_cpu_ptr(p) instead of per_cpu_ptr(p, smp_processor_id())

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:24:29 -07:00
Eric Dumazet
b6b3ecc71a net: u64_stats_sync improvements
- Add a comment about interrupts:

6) If counter might be written by an interrupt, readers should block
interrupts.

- Fix a typo in sample of use.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:24:29 -07:00
Ben Hutchings
a095cfc40e 3c59x: Specify window explicitly for access to windowed registers
Currently much of the code assumes that a specific window has been
selected, while a few functions save and restore the window.  This
makes it impossible to introduce fine-grained locking.

Make those assumptions explicit by introducing wrapper functions
to set the window and read/write a register.  Use these everywhere
except vortex_interrupt(), vortex_start_xmit() and vortex_rx().
These set the window just once, or not at all in the case of
vortex_rx() as it should always be called from vortex_interrupt().

Cache the current window in struct vortex_private to avoid
unnecessary hardware writes.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Tested-by: Arne Nordmark <nordmark@mech.kth.se> [against 2.6.32]
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:19:18 -07:00
Amerigo Wang
d2ef859034 mlx4: add dynamic LRO disable support
This patch adds dynamic LRO diable support for mlx4 net driver.
It also fixes a bug of mlx4, which checks NETIF_F_LRO flag in rx
path without rtnl lock.

(I don't have mlx4 card, so only did compiling test. Anyone who wants
to test this is more than welcome.)

This is based on Neil's initial work too, and heavily modified based
on Stanislaw's suggestions.

Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Neil Horman <nhorman@redhat.com>
Acked-by: Neil Horman <nhorman@redhat.com>
Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:04:10 -07:00
Jon Mason
958de1931c s2io: add dynamic LRO disable support
This patch adds dynamic LRO disable support for s2io net driver,
enables LRO by default, increases the driver version number, and
corrects the name of the LRO modparm.

This is mostly Wang's patch based on Neil's initial work, heavily
modified based on Ramkrishna's suggestions.  This has been tested on
a Neterion Xframe adapter and verified via adapter LRO statistics.

Signed-off-by: Jon Mason <jon.mason@exar.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Neil Horman <nhorman@redhat.com>
Acked-by: Neil Horman <nhorman@redhat.com>
Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Ramkrishna Vepa <Ramkrishna.Vepa@exar.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-28 23:04:10 -07:00
Kanigeri, Hari
1fd7f46712 omap iommu: update ducati mmu irq define name
2.6.34-rc6 kernel has the Ducati mmu irq define name changed, which is
resulting in compilation error.

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
2010-06-29 07:55:08 +03:00
Hiroshi DOYU
0bbc6fcff6 omap iommu: Make omap-iommu.o built-in
This is a platform device registration.

Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
2010-06-29 07:55:07 +03:00
Hiroshi DOYU
37b298100f omap iommu: move iommu_disable at fault to the above layer
The function prefix "omap2_iommu_" indicates that the prefixed
function belongs to "omap2_iommu_ops" to provide iommu basic
functionalities for the above layers. It's better to avoid the
prefixed function called in the same prefixed ones internally, like
nested here. Now "iommu_disable" is called just after fault_isr() in
the above layer. This is a little bit more sensible to keep the
consistency of module layers.

Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
2010-06-29 07:55:07 +03:00
Kanigeri, Hari
ddfa975a8c omap iommu: add functionality to get TLB miss interrupt
In order to enable TLB miss interrupt, the TWL should be
disabled. This patch provides the functionality to get the
MMU fault interrupt for a TLB miss in the cases where the
users are working with the locked TLB entries and with TWL
disabled.
New interface is added to select twl and to enable TLB miss
interrupt.

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
Signed-off-by: Ramesh Gupta <grgupta@ti.com>
Signed-off-by: Hiroshi Doyu <Hiroshi.DOYU@nokia.com>
2010-06-29 07:55:07 +03:00
Kanigeri, Hari
993dd17e32 omap iommu: update irq mask to be specific about twl and tlb
Revise the IRQ mask definitions to handle the  MMU faults related
to TWL fault as well as TLB miss fault.

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
Signed-off-by: Hiroshi Doyu <Hiroshi.DOYU@nokia.com>
2010-06-29 07:55:06 +03:00
Hiroshi DOYU
124933599a omap iommu: Rename iopte_[p,v]addr -> iopte_page_[p,v]addr
Follow Linux pagetable accessor name convention.

Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
2010-06-29 07:55:05 +03:00
Hiroshi DOYU
a1a54456d0 omap iommu: Introduce iopgd_is_table MACRO
A bit more strict comparison.

Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
2010-06-29 07:55:04 +03:00
Steven Rostedt
a1d0ce8213 tracing: Use class->reg() for all registering of events
Because kprobes and syscalls need special processing to register
events, the class->reg() method was created to handle the differences.

But instead of creating a default ->reg for perf and ftrace events,
the code was scattered with:

	if (class->reg)
		class->reg();
	else
		default_reg();

This is messy and can also lead to bugs.

This patch cleans up this code and creates a default reg() entry for
the events allowing for the code to directly call the class->reg()
without the condition.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-28 21:13:14 -04:00
Chase Douglas
d62f85d1e2 tracing/function-graph: Use correct string size for snprintf
The nsecs_str string is a local variable defined as:

char nsecs_str[5];

It is possible for the snprintf call to use a size value larger than the
size of the string. This should not cause a buffer overrun as it is
written now due to the value for the string format "%03lu" can not be
larger than 1000. However, this change makes it correct. By making the
size correct we guard against potential future changes that could actually
cause a buffer overrun.

Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
LKML-Reference: <1276619355-18116-1-git-send-email-chase.douglas@canonical.com>

[ added 'UL' to number 8 to fix gcc warning comparing it to sizeof() ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-28 21:11:39 -04:00
Len Brown
3d695839a1 ACPI: handle systems which asynchoronously enable ACPI mode
Folklore suggested that such systems existed
in the pre-history of ACPI.

However, we removed the SCI_EN polling loop from
acpi_hw_set_mode() in b430acbd7c
because it delayed resume by 3 seconds on boxes
that refused to set SCI_EN.

Matthew removed the call to acpi_enable() from
the suspend resume path.

James found a modern system that still needs to be polled
upon boot.

So here we restore the workaround, except that we
put it in acpi_enable() rather than the low level
acpi_hw_set_mode().

https://bugzilla.kernel.org/show_bug.cgi?id=16271

Signed-off-by: Len Brown <len.brown@intel.com>
2010-06-28 20:55:01 -04:00
Ernst Schwab
cf32b71e98 spi/mmc_spi: SPI bus locking API, using mutex
SPI bus locking API to allow exclusive access to the SPI bus, especially, but
not limited to, for the mmc_spi driver.

Coded according to an outline from Grant Likely; here is his
specification (accidentally swapped function names corrected):

It requires 3 things to be added to struct spi_master.
- 1 Mutex
- 1 spin lock
- 1 flag.

The mutex protects spi_sync, and provides sleeping "for free"
The spinlock protects the atomic spi_async call.
The flag is set when the lock is obtained, and checked while holding
the spinlock in spi_async().  If the flag is checked, then spi_async()
must fail immediately.

The current runtime API looks like this:
spi_async(struct spi_device*, struct spi_message*);
spi_sync(struct spi_device*, struct spi_message*);

The API needs to be extended to this:
spi_async(struct spi_device*, struct spi_message*)
spi_sync(struct spi_device*, struct spi_message*)
spi_bus_lock(struct spi_master*)  /* although struct spi_device* might
be easier */
spi_bus_unlock(struct spi_master*)
spi_async_locked(struct spi_device*, struct spi_message*)
spi_sync_locked(struct spi_device*, struct spi_message*)

Drivers can only call the last two if they already hold the spi_master_lock().

spi_bus_lock() obtains the mutex, obtains the spin lock, sets the
flag, and releases the spin lock before returning.  It doesn't even
need to sleep while waiting for "in-flight" spi_transactions to
complete because its purpose is to guarantee no additional
transactions are added.  It does not guarantee that the bus is idle.

spi_bus_unlock() clears the flag and releases the mutex, which will
wake up any waiters.

The difference between spi_async() and spi_async_locked() is that the
locked version bypasses the check of the lock flag.  Both versions
need to obtain the spinlock.

The difference between spi_sync() and spi_sync_locked() is that
spi_sync() must hold the mutex while enqueuing a new transfer.
spi_sync_locked() doesn't because the mutex is already held.  Note
however that spi_sync must *not* continue to hold the mutex while
waiting for the transfer to complete, otherwise only one transfer
could be queued up at a time!

Almost no code needs to be written.  The current spi_async() and
spi_sync() can probably be renamed to __spi_async() and __spi_sync()
so that spi_async(), spi_sync(), spi_async_locked() and
spi_sync_locked() can just become wrappers around the common code.

spi_sync() is protected by a mutex because it can sleep
spi_async() needs to be protected with a flag and a spinlock because
it can be called atomically and must not sleep

Signed-off-by: Ernst Schwab <eschwab@online.de>
[grant.likely@secretlab.ca: use spin_lock_irqsave()]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Matt Fleming <matt@console-pimps.org>
Tested-by: Antonio Ospite <ospite@studenti.unina.it>
2010-06-28 17:49:29 -07:00