https://bugzilla.kernel.org/show_bug.cgi?id=204243 Thomas Schmitt (scdbackup@xxxxxxx) changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |scdbackup@xxxxxxx --- Comment #2 from Thomas Schmitt (scdbackup@xxxxxxx) --- Hi, the lock in sr_block_open() is a nuisance since it was introduced by a daring mass change nine years ago: https://lkml.org/lkml/2010/9/14/338 It has a history of complaints about slowing down concurrent use of ioctl(SG_IO) on different sr drives: https://marc.info/?l=linux-scsi&m=135705061804384&w=2 As developer of libburn i had to develop workarounds in userspace: http://libburnia-project.org/wiki/ConcurrentLinuxSr None of them is really satisfying. Since 3 years i use /dev/sg* instead of /dev/sr* for burning. The older readers will remember the relief when we could use hd and sr and thus had proper coordination with mount(8). This is gone, at least for systems where more than one optical drive shall be used concurrently. So, as did others before, i propose to remove the mutex_lock()/mutex_unlock() pair in sr_block_ioctl(). (Actually the other mutex_lock()/mutex_unlock() pairs introduced by https://lkml.org/lkml/2010/9/14/338 should be examined whether they are appropriate replacements of the previously existing BKLs. They don't have this long lasting impact on multi-drive operation, though.) Have a nice day :) Thomas -- You are receiving this mail because: You are the assignee for the bug.
