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 <[email protected]>
Link: https://lore.kernel.org/all/[email protected]
Signed-off-by: Phillip Potter <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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