http://bugzilla.kernel.org/show_bug.cgi?id=15565 --- Comment #4 from Mike Hayward <mh-linux-kernel@xxxxxxxx> 2010-03-18 17:21:05 --- Hi Boaz, > I have fixed that for bsg long ago. There is a flag > that you put: > sg.flags = BSG_FLAG_Q_AT_TAIL; > Which will do the by order, queue at tail. Zero was kept compatible > to sg meaning "queue at head" i.e. jump the line. > > It could be added to sg as well if needed I think that would be a huge improvement for disk drives. Isn't BSG driven with a blocking ioctl? Maybe I'm using old docs, but from the HOWTO's I've read, I was under the impression it would issue one SCSI command at a time and block until it completed. Queueing would effectively only be possible then with multiple threads, right? Since sg allows multiple (only 16 right now) ios to be queued nonblocking to a block device from a single threaded process, an SG_FLAG_Q_AT_TAIL flag would seem particularly relevant. Nonblocking behavior is the primary reason why I am using sg... it seems really inefficient and complex to use dozens of threads and ipc just to try to submit a queue of ios to the kernel and hence a device. If bsg actually allowed tasks to be queued nonblocking like sg, I'd switch in a heart beat since having two filesystem names for the same device introduces locking problems, name translation complexity, and confusion in general for administrators. - Mike -- Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
