Hi,
In a design of ALSA control core, each set of elements have data of
Type-Length-Value shape. This is called as TLV data. In ALSA control
interface, applications can three types of requests to elements about
TLV data; read, write and command.
In current implementation of ALSA control core, these three requests
are handled with read lock of a counting semaphore. However, this has an
issue of concurrent access because in theory write/command requests have
sub-effects to change state of the set of elements in a point of TLV data.
Read requests and write/command requests are handled exclusively as well
as each write/command requests.
This patchset is for this purpose. Additionally, this applies code
refactoring to TLV ioctl handler and TLV handler for user-defined element
set so that they get better shape for readers.
Takashi Sakamoto (5):
ALSA: control: queue events within locking of controls_rwsem for TLV
operation
ALSA: control: use counting semaphore as write lock for TLV
write/command operations
ALSA: control: obsolete user_ctl_lock
ALSA: control: code refactoring TLV ioctl handler
ALSA: control: code refactoring for TLV request handler to user
element set
include/sound/core.h | 2 -
sound/core/control.c | 252 +++++++++++++++++++++++++++++++--------------------
sound/core/init.c | 1 -
3 files changed, 155 insertions(+), 100 deletions(-)
--
2.11.0
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