On Fri, 3 Aug 2007 19:26:45 +0900 Tejun Heo <[EMAIL PROTECTED]> wrote:
> On Fri, Aug 03, 2007 at 09:58:57AM +0100, Stephen Hemminger wrote: > > On Thu, 2 Aug 2007 15:42:06 -0700 > > Brandon Philips <[EMAIL PROTECTED]> wrote: > > > > > This patch set adds support for devres in the net core and converts the > > > e100 and e1000 drivers to devres. Devres is a simple resource manager > > > for device drivers, see Documentation/driver-model/devres.txt for more > > > information. > > > > > > The use of devres will remain optional for drivers with this patch set. > > > Drivers can be converted when it makes sense. > > > > Just because devres exists is not sufficient motivation to change. > > > > It seems that devres was a band-aid rather than fixing storage drivers > > to have proper DMA lifetimes. > > I don't really get what you mean by "having proper DMA lifetimes" but > please don't write devres off too fast. devres doesn't solve any > problem that you can't fix without it but it does make the 'solving' > much easier. > > IMHO, libata drivers generally have been well maintained and reviewed > but I could still find quite a few bugs (resource leaks or > occasionally double free) in init failure and removal paths. Init > failure paths are especially prone to bugs because they don't get > excercised often. It's just very easy to make a mistake and fail to > notice and low level drivers don't always get sufficient amount of > review or testing. > > Skimming through drivers... via-rhine doesn't disable PCI device on > init failure path but does so on removal. sky2 doesn't free > consistent memory if sky2_init() fails. acenic calls iounmap() with > NULL parameter which I'm not sure whether it's safe or not. natsemi > doesn't disable PCI device on failure or removal. Did you report these to the developers? > Devres makes low level drivers simpler, easier to get right and > maintain. Writing new drivers becomes easier too. So, why not? > > > Network devices seem to work fine thanks, and the resource requirements > > are different. If ain't broke, don't fix it. > > Care to enlighten me on how the resource requirments are different > from ATA drivers? I was thinking of the hot remove (no mod ref counts) and lingering /sys open issues. ATA drivers use ref counts. My take on devres is that it is similar to talloc() for device drivers. Not a bad idea in itself, but the real advantage of hierarchical allocation is that it makes exception handling easier if things are layered deeply. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
