On Sat, 4 Feb 2006, Kai Makisara wrote: > On Fri, 3 Feb 2006, Hugh Dickins wrote: > > > > Very interesting. James can confirm, but I think that means everybody > > can ignore my drivers/scsi/st.c patch for 2.6.16-rc, and the unposted > > sg.c patches for the same issue that I was going to send Doug. > > > The patch st is not necessary now but I don't think it would be a bad idea > to include it anyway. My reasoning is based on that the patch is very > inexpensive, it basically moves freeing of an array to another place. > The reasons for inclusion are: > - someone reviewing the code may wonder why the change to 2.6.15.x is > not in 2.6.x >= 16; 2.6.16 would need at least a comment about this > - it does decouple st from any dependencies about what happens to > the s/g array at the lower levels > - if the s/g array will at some future time be again passed directly to > dma mapping, we would not face the problem again > > I don't have any firm opinion either way. Fair points, I don't have a firm opinion either, it's entirely up to you as maintainer. But I'd be less keen to force the equivalent changes into 2.6.16's sg.c. Saving sg_pages from get_user_pages fits in quite unobtrusively in st.c, and its enlarge_buffer/normalize_buffer pages are already safely isolated from the scatterlist by the separate frp_segs array. But sg.c presently uses the scatterlist for the latter case too, so would need more change: except that, thanks to Mike, we find it doesn't need changing now. Your suggestion of a comment would be most appropriate there. (I've not forgotten our outstanding SetPageDirty to set_page_dirty_lock issue, but still striving to avoid too much nuisance in sg.c's case.) 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
