kernel/drivers/spi/spi.c, branch linux-4.0.y

spi: fix race freeing dummy_tx/rx before it is unmapped

2015-07-21T17:10:13Z

commit 8e76ef88f607174082023f50b87fe12dcdbe5db5 upstream. Fix a race (with some kernel configurations) where a queued master->pump_messages runs and frees dummy_tx/rx before spi_unmap_msg is running (or is finished). This results in the following messages: BUG: Bad page state in process page:db7ba030 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x200(arch_1) page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set ... Reported-by: Noralf Trønnes Suggested-by: Noralf Trønnes Tested-by: Noralf Trønnes Signed-off-by: Martin Sperl Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman

spi: trigger trace event for message-done before mesg->complete

2015-03-18T11:34:10Z

With spidev the mesg->complete callback points to spidev_complete. Calling this unblocks spidev_sync and so spidev_sync_write finishes. As the struct spi_message just read is a local variable in spidev_sync_write and recording the trace event accesses this message the recording is better done first. The same can happen for spidev_sync_read. This fixes an oops observed on a 3.14-rt system with spidev activity after echo 1 > /sys/kernel/debug/tracing/events/spi/enable . Signed-off-by: Uwe Kleine-König Signed-off-by: Mark Brown Cc: stable@vger.kernel.org

Merge remote-tracking branches 'spi/topic/img-spfi', 'spi/topic/imx', 'spi/topic/inline', 'spi/topic/meson' and 'spi/topic/mxs' into spi-next

2015-02-08T03:16:52Z

Merge remote-tracking branches 'spi/topic/falcon', 'spi/topic/fsf', 'spi/topic/fsl', 'spi/topic/fsl-dspi' and 'spi/topic/gpio' into spi-next

2015-02-08T03:16:46Z

spi: match var type to return type of wait_for_completion

2015-02-04T20:52:32Z

return type of wait_for_completion_timeout is unsigned long not int, this patch changes the type of m from int to unsigned long. Signed-off-by: Nicholas Mc Guire Signed-off-by: Mark Brown

spi: Remove FSF mailing addresses

2014-12-22T15:32:42Z

Signed-off-by: Jarkko Nikula Signed-off-by: Mark Brown

Merge tag 'devicetree-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/glikely/linux

2014-12-11T21:06:58Z

Pull devicetree changes from Grant Likely: "Lots of activity in the devicetree code for v3.18. Most of it is related to getting all of the overlay support code in place, but there are other important things in there. Highlights: - OF_RECONFIG notifiers for SPI, I2C and Platform devices. Those subsystems can now respond to live changes to the device tree. - CONFIG_OF_OVERLAY method for applying live changes to the device tree - Removal of the of_allnodes list. This used to be used to iterate over all the nodes in the device tree, but it is unnecessary because the same thing can be done by iterating over the list of child pointers. Getting rid of of_allnodes saves some memory and avoids the possibility of of_allnodes being sorted differently from the child lists. - Support for retrieving original DTB blob via sysfs. Needed by kexec. - More unittests - Documentation and minor bug fixes" * tag 'devicetree-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/glikely/linux: (42 commits) of: Delete unnecessary check before calling "of_node_put()" of: Drop ->next pointer from struct device_node spi: Check for spi_of_notifier when CONFIG_OF_DYNAMIC=y of: support passing console options with stdout-path of: add optional options parameter to of_find_node_by_path() of: Add bindings for chosen node, stdout-path of: Remove unneeded and incorrect MODULE_DEVICE_TABLE ARM: dt: fix up PL011 device tree bindings of: base, fix of_property_read_string_helper kernel-doc of: remove select of non-existant OF_DEVICE config symbol spi/of: Add OF notifier handler spi/of: Create new device registration method and accessors i2c/of: Add OF_RECONFIG notifier handler i2c/of: Factor out Devicetree registration code of/overlay: Add overlay unittests of/overlay: Introduce DT overlay support of/reconfig: Add OF_DYNAMIC notifier for platform_bus_type of/reconfig: Always use the same structure for notifiers of/reconfig: Add debug output for OF_RECONFIG notifiers of/reconfig: Add empty stubs for the of_reconfig methods ...

spi: Only idle the message pump in the worker kthread

2014-12-11T12:25:30Z

In order to avoid the situation where the kthread is waiting for another context to make the hardware idle let the message pump know if it's being called from the worker thread context and if it isn't then defer to the worker thread instead of idling the hardware immediately. This will ensure that if this situation happens we block rather than busy waiting. Signed-off-by: Mark Brown

spi: Pump transfers inside calling context for spi_sync()

2014-12-11T12:23:51Z

If we are using the standard SPI message pump (which all drivers should be transitioning over to) then special case the message enqueue and instead of starting the worker thread to push messages to the hardware do so in the context of the caller if the controller is idle. This avoids a context switch in the common case where the controller has a single user in a single thread, for short PIO transfers there may be no need to context switch away from the calling context to complete the transfer. The code is a bit more complex than is desirable in part due to the need to handle drivers not using the standard queue and in part due to handling the various combinations of bus locking and asynchronous submission in interrupt context. It is still suboptimal since it will still wake the message pump for each transfer in order to schedule idling of the hardware and if multiple contexts are using the controller simultaneously a caller may end up pumping a message for some random other thread rather than for itself, and if the thread ends up deferring due to another context idling the hardware then it will just busy wait. It can, however, have the benefit of aggregating power up and down of the hardware when a caller performs a series of transfers back to back without any need for the use of spi_async(). Signed-off-by: Mark Brown

spi: Check to see if the device is processing a message before we idle

2014-12-11T12:23:23Z

cur_msg is updated under the queue lock and holds the message we are currently processing. Since currently we only ever do removals in the pump kthread it doesn't matter in what order we do things but we want to be able to push things out from the submitting thread so pull the check to see if we're currently handling a message before we check to see if the queue is idle. Signed-off-by: Mark Brown