On Thu, 1 Dec 2005, Kai Makisara wrote: > On Thu, 1 Dec 2005, James Bottomley wrote: > > > > On a side note, I have Kai's patch in the scsi-rc-fixes tree which I'm > > getting ready to push. Can we get a consensus on whether it should be > > removed before I merge upwards? I too need to decide whether to base my little sg.c,st.c patchset on top of Kai's (as I see in 2.6.15-rc3-mm1, I presume) or on top of 2.6.15-rc4. > I think it should be removed because it is based partly on a wrong > assumption: asynchronous writes are _not_ done together with direct i/o. > (I have also experimentally verified that this does not happen.) I'm assuming from this that I'd best base on 2.6.15-rc4; but by all means overrule me if you've changed your mind. > The patch includes the patch I sent sent to linux-scsi on Nov 21. Nobody > has commented it and I don't know if the user pages have to be explicitly > marked dirty after the HBA has read data there. If they have to, then this > earlier patch is valid. What I see in 2.6.15-rc3-mm1 looks like three patches. One to do with resetting sg_segs to 0 at various points: I've no appreciation of that patch at all. If it would help you for me to add that into my little set, please send me a comment for it. One to add an "is_read" argument to release_buffering. Yes, that's a part of my set too, though in my case called "dirtied" (and I believe that the call at the end of st_read can say 0, because that's just for an error path: when it's really dirtied user memory, it'll be read_tape that does the release_buffering). sg.c was always saying dirtied, even when writing from memory; st.c was always saying not dirtied, even when reading into memory. Usually the latter is okay, get_user_pages has said dirty in advance; but under pressure there's a window whereby it's not good enough. And SetPageDirty can be counter-productive these days, so your patch is incomplete in that regard: I'll explain more in mine. One to move around where release_buffering is called from: that's the part you've decided was wrong, or at least unnecessary. > If not, I will send a patch for 2.6.16 to remove the latent code. I didn't understand that bit, but I probably don't need to. Hugh - : 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
