On Thu, 14 Jan 2010 12:27:12 GMT bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > http://bugzilla.kernel.org/show_bug.cgi?id=15007 > > > > > > --- Comment #4 from nick cheng <nick.cheng@xxxxxxxxxxxx> 2010-01-14 12:27:11 --- > Sorry, is it a really bug? Yes because if sg entries are larger than 127, they are not continuous. So sg++ doesn't work. We chain sg entries. The last sg entry is a pointer to the next sg list. For example, a command has 128 entries, it has two sg lists. The first sg list has 127 sg entries. The last entry in the first sg list is a pointer to the second sg list. The second sg list has one sg entry. The command has 128 entries in total. My previous mail is partially wrong. As I explained above, if sg entries is 128, this bug leads to bogus 128th sg entry. So I think that you hit this bug. > Does it bug anything? I can't figure it out. > I ever used scsi_for_each_sg() and found the performance is inferior to the > original version. I tracked the source code for scsi_for_each_sg()and there is > no two much difference to each other. I doubt it is compiler issue to make it > worst. > But it is my guess. Do you know why? > Anyway, will you or anybody take care of this issue? -- To unsubscribe from this list: 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
