Cc: H. Peter Anvin <hpa@...>, Jens Axboe <axboe@...>, Jeff Garzik <jgarzik@...>, Tejun Heo <htejun@...>, Linus Torvalds <torvalds@...>, Andrew Morton <akpm@...>, Linux Kernel <linux-kernel@...>, IDE/ATA development list <linux-ide@...>, linux-scsi <linux-scsi@...>
..
So have we. sysfs is a total nightmare to extract information from
under program / script control. The idea presented in this thread,
is to have it cross-index the contents with a method that actually
makes it easy to access in many common scenarios, without requiring
huge gobs of code in user space. Or in kernel space.
And it's not just a few 10s of lines of code currently,
but rather about 80-100 lines just to find the correct device subdir,
and *then* a few more 10s of lines of code to retrieve the value.
In a bulletproof fashion, that is. Sure it can be slightly smaller
if niceties such as error checking/handling are omitted.
There's no guarantee that udev is present, and even if it were present,
there's no guarantee that the names in /dev/ will match /sysfs/ pathnames,
since udev is very configurable to do otherwise.
So lookups are by dev_t, which sysfs has no simple or even easy way
of accomplishing. O(n) at a minimum.
If we make it easier to access, then more programs will use it
rather than us having to expand our tricky binary ioctl interfaces.
Isn't that part of the idea of sysfs -- to limit the need for new ioctls ?
Cheers
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