"This patch corrects what I hope are invalid assumptions about the DMA engine layer: Not only Intel(R) hardware can do DMA, and DMA can be used for other things than memcpy and RAID offloading," Haavard Skinnemoen noted, submitted a small patch against the DMADEVICES Kconfig option. He added, "Don't get me wrong; I think Intel deserves lots of respect for creating this framework. But this is also why I got a bit disappointed when I discovered that it seems to be less generic than I initially hoped." Haavard continued:
"DMA controllers, which may support plain memcpy acceleration in addition to more traditional 'slave DMA', are very common in SoC devices, and I think Linux needs a common framework for it. The existing DMA Engine framework seems to come pretty close already, but I think it needs more input from the embedded crowd before it can be completely usable on a large number of embedded systems."
"It's been NACKed a few times, and just reposting it won't help."
"I'd like to ask you to put a file in Documentation/ somewhere that describes what AppArmor's intended security protection is (it's different from SELinux for sure for example); by having such a document for each LSM user, end users and distros can make a more informed decision which module suits their requirements..." Arjan van de Ven suggested in an attempt to help focus future Linux Security Module discussions on technical issues. He explained, "it also makes it possible to look at the implementation to see if it has gaps to the intent, without getting into a pissing contest about which security model is better; but unless the security goals are explicitly described that's a trap that will keep coming back... so please spend some time on getting a good description going here.." Arjan continued:
"My main concern for now is a description of what it tries to protect against/in what cases you would expect to use it. THe reason for asking this explicitly is simple: Until now the LSM discussions always ended up in a nasty mixed up mess around disagreeing on the theoretical model of what to protect against and the actual implementation of the threat protection. The only way I can think of to get out of this mess is to have the submitter of the security model give a description of what his protection model is (and unless it's silly, not argue about that), and then only focus on how the code manages to achieve this model, to make sure there's no big gaps in it, within its own goals/reference."
"Standards are just papers. Yes, they're important, but they are definitely not more important than anything else, and they are a lot _less_ important than some people seem to think."
Andrew Morton responded favorably to Evgeniy Polyakov's most recent release of his distributed storage subsystem, "I went back and re-read last month's discussion and I'm not seeing any reason why we shouldn't start thinking about merging this." He then asked, "how close is it to that stage? A peek at your development blog indicates that things are still changing at a moderate rate?" Evgeniy replied:
"I completed storage layer development itself, the only remaining todo item is to implement [a] new redundancy algorithm, but I did not see major demand on that, so it will stay for now with low priority. I will use DST as a transport layer for [a] distributed filesystem, and probably that will require additional features, I have no clean design so far, but right now I have nothing in the pipe to commit to DST."
"Sorry, I'm just not going to apply a patch like that. I mean, how the heck is anyone else supposed to understand what you're up to?"
A recent report on the lkml suggested improved IO/writeback performance in the recently released 2.6.24-rc1 kernel compared to the earlier 18.104.22.168 and 22.214.171.124 kernels. Credit was given to some patches by Peter Zijlstra. Ingo Molnar replied, "wow, really nice results! Peter does know how to make stuff fast :) Now lets pick up some of Peter's other, previously discarded patches as well :-)" He pointed to several patches "as a starter", then quipped, "I think the MM should get out of deep-feature-freeze mode - there's tons of room to improve :-/"
Andrew Morton replied, "kidding. We merged about 265 MM patches in 2.6.24-rc1:
482 files changed, 8071 insertions(+), 5142 deletions(-)". He added, "a lot of that was new functionality. That's easier to add than things which change long-standing functionality." Of the patches Ingo pointed to, Peter noted he was currently working on polishing the swap-over-NFS patch, "will post that one again, soonish.... Esp. after Linus professed liking to have swap over NFS." Rik van Riel also replied regarding rewriting the page replacement code, "at the moment I only have the basic 'plumbing' of the split VM working and am fixing some bugs in that. Expect a patch series with that soon, so you guys can review that code and tell me where to beat it into shape some more :)"
"You know, you really are supposed to understand the code you are modifying..."
"This argument seems to start from the assumption that any externally maintained kernel code *can* get into the kernel, which doesn't stand up to reality. Once you admit that there is code which, for very good reasons, won't ever be accepted into the mainline kernel tree, what you are saying amounts to: 'Code that isn't fit to be included in the mainline kernel isn't fit to exist at all'," Tilman Schmidt argued during the ongoing debate about whether or not LSM should support modules.
Greg KH responded, "what kind of code is not accepted into the mainline kernel tree for good reasons? What are these reasons? What specific code are you talking about?" He pointed to a wiki page on the Linux Driver Project website and explained, "I'm trying to compile a list of all known external modules and drivers and work to get them included in the main kernel tree to help prevent these kinds of things."
"... as you probably all have noticed. I've been up all night writing this report for the 'CS Course from Hell' (*), and haven't had time to play with linux. I'll get it done tonight if I can keep awake that long."
"The __deprecated marker is quite useful in highlighting the remnants of old APIs that want removing. However, it is quite normal for one or more years to pass, before the (usually ancient, bitrotten) code in question is either updated or deleted," explained Jeff Garzik, posting a small patch to make it possible to silence "warning: 'foo' is deprecated" type messages.
Andrew Morton wasn't impressed, suggesting, "Sigh. Can't we just fix the dud code? Or mark it BROKEN and see what happens?" Linus Torvalds added, "I think removing __deprecated is the better option. Quite frankly, some people add '__deprecated' *way* too eagerly." Jeff agreed that
__deprecated is over used, "__deprecated has spread to just about every API that people don't consider fresh and up-to-date." He then added ,"like I noted in the patch description, rewriting grotty ISA/MCA/etc. probe code is a thankless, boring task that few are crazy enough to attempt :) As you can see from the patch flood recently I /have/ been working through the dud code, but it will still take years. The changes required for each are on average ~200 LOC changed, if not more."
"We have to rediscover our roots: 'release early, release often'."
"This series kill the old i386 and x86_64 directories. The relevant files are moved and adapted and Kconfig.debug was consolidated (thanks to Randy)," Sam Ravnborg said, describing a set of 6 patches to finish the migration of physical files into the new x86 architecture directory. He described it as "a nice patch series that deletes more lines than it adds," going on to explain:
"I had to modify both the top-level Makefile and the kconfig Makefile to accomplish this. It was done in such a way that it is trivial for other archs to use the same mechanism should they have the need.
"To solve the defconfig issue (i386 and x86_64 cannot share one) the arch/x86/configs/ directory were introduced. This has been used by other archs for some time now but x86 had not had the need until now."
"It's all just too damn subtle and clever. Something like this should not need to be that subtle."
"But hey, don't listen to me - I like C++, and approve of Java."