BMC/Intel-BMC/linux.git/drivers/hwtracing/stm, branch dev-4.6

stm class: dummy_stm: Add link callback for fault injection

2016-02-20T22:09:14+00:00

STM device's link callback has the power to abort master/channel assignment by returning a negative error code. Use this in dummy stm device to optionally abort assigning certain channel IDs. This is useful as fault injection into the stm class core, for testing purposes. Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman

stm class: Plug stm device's unlink callback

2016-02-20T22:09:14+00:00

STM device's unlink callback is never actually called from anywhere in the stm class code. This patch adds calls to stm driver's unlink method after the unlinking has succeeded. Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman

stm class: Fix a race in unlinking

2016-02-20T22:09:14+00:00

There is a window in stm_source_link_drop(), during which the source's link may change before locks are acquired. When this happens, it throws a warning, since this is not an expected scenario. This patch handles the race in such a way that if the link appears to have changed by the time we took the locks, it will release them and repeat the whole unlinking procedure from the beginning, unless the other contender beat us to it. Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman

stm class: Fix unbalanced module/device refcounting

2016-02-20T22:09:14+00:00

STM code takes references to the stm device and its module for the duration of the character device's existence or the stm_source link. Dropping these references is not well balanced everywhere, which may lead to leaks. This patch balances the acquisition and releasing of these two references and annotates each site so that it's easier to verify correctness by reading the code. Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman

stm class: Guard output assignment against concurrency

2016-02-20T22:09:14+00:00

It is possible to concurrently assign the same output (a character device writer or an stm_source device) to different stm devices, which sets off a strategically placed warning in stm_output_assign(). To avoid this, use a spinlock to serialize (un)assignments between outputs and stm devices. Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman

stm class: Fix unlocking braino in the error path

2016-02-20T22:09:14+00:00

If an illegal attempt is made to unlink stm source device from an stm device, the stm device's link spinlock mistakenly remains locked. While this really shouldn't happen (there's a warning in place), the locking should remain in order so that we can still recover from this situation if it indeed does happen. This patch unifies the unlocking in the exit path of __stm_source_link_drop() to fix this. Reported-by: Laurent Fert Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman

stm class: Add heartbeat stm source device

2016-02-20T22:09:14+00:00

Heartbeat stm source may have multiple instances (for connecting to different stm devices). Each instance will send a periodic test message over its stm device when it is linked. This can be used for testing stm class framework, stm device drivers or as a heartbeat over the stm link. Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman

stm class: dummy_stm: Create multiple devices

2016-02-20T22:09:14+00:00

STM framework should be able to handle multiple STM devices at a time, each one with its own master allocation policy. This patch changes dummy_stm driver to create multiple STM sinks to help testing the framework. Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman

stm class: Support devices with multiple instances

2016-02-20T22:09:14+00:00

By convention, the name of the stm policy directory in configfs consists of the device name to which it applies and the actual policy name, separated by a dot. Now, some devices already have dots in their names that separate name of the actual device from its instance identifier. Such devices will result in two (or more, who can tell) dots in the policy directory name. Existing policy code, however, will treat the first dot as the one that separates device name from policy name, therefore failing the above case. This patch makes the last dot in the directory name be the separator, thus prohibiting dots from being used in policy names. Suggested-by: Chunyan Zhang Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman

stm class: Use driver's packet callback return value

2016-02-20T22:09:14+00:00

STM drivers provide a callback to generate/send individual STP packets; it also tells the stm core how many bytes of payload it has consumed. However, we would also need to use the negative space of this return value to communicate errors that occur during the packet generation, in which case the stm core will have to take appropriate action. For now, we need to account for the possibility that the stm driver may not support certain combinations of packet type/flags, in which case it is expected to signal an error. Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman