Lukas Prediger 67f1e027c2 drivers/cdrom: improved ioctl for media change detection ... The current implementation of the CDROM_MEDIA_CHANGED ioctl relies on global state, meaning that only one process can detect a disc change while the ioctl call will return 0 for other calling processes afterwards (see bug 213267). This introduces a new cdrom ioctl, CDROM_TIMED_MEDIA_CHANGE, that works by maintaining a timestamp of the last detected disc change instead of a boolean flag: Processes calling this ioctl command can provide a timestamp of the last disc change known to them and receive an indication whether the disc was changed since then and the updated timestamp. I considered fixing the buggy behavior in the original CDROM_MEDIA_CHANGED ioctl but that would require maintaining state for each calling process in the kernel, which seems like a worse solution than introducing this new ioctl. Signed-off-by: Lukas Prediger <lumip@lumip.de> Link: https://lore.kernel.org/all/20210912191207.74449-1-lumip@lumip.de Signed-off-by: Phillip Potter <phil@philpotter.co.uk> Link: https://lore.kernel.org/r/20210913230942.1188-1-phil@philpotter.co.uk Signed-off-by: Jens Axboe <axboe@kernel.dk>		2021-09-14 20:05:26 -06:00
..
cdrom-standard.rst	drivers/cdrom: improved ioctl for media change detection	2021-09-14 20:05:26 -06:00
ide-cd.rst	docs: ide: convert docs to ReST and rename to *.rst	2019-06-14 14:21:18 -06:00
index.rst	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
packet-writing.rst	docs: cdrom: convert docs to ReST and rename to *.rst	2019-06-14 14:20:46 -06:00