On 11/11/06, Luben Tuikov <ltuikov@xxxxxxxxx> wrote:
--- Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > On Fri, Nov 10, 2006 at 12:08:15PM -0800, Luben Tuikov wrote: > > P.S. I'd love to see SG_DXFER_TO_FROM_DEV completely ripped out > > of sg.c, for obvious reasons. Can you not duplicate the resid "fix" > > it provides into "FROM_DEV" -- do apps really rely on it? > > At the beginning of this thread it was mentioned cdparanio uses it. > But in general we can't just rip out userland interfaces, we pretend > to have a stable userspace abi (and except for the big sysfs mess that > actually comes very close to the truth). The more reason to think things thorougly when introducing new code and architecture into a kernel.
It was introduced for a good reason, and that reason is still relevant today. Cdparanoia is not using it gratuitously. The only problem is that the implementation had a bug (well, at least two bugs) and only sg ever implemented it correctly. Had block and sata implemente dit correctly, we'd not be having this discussion. Or you can blame a lower level layer for having no way to inform mid-level drivers that DMA only completed a partial transfer. "but anyway"... This lockup was happening using SATA through the block layer, or does SATA implement its own version of the ioctl? Back when I was testing my probing code, the buggy kernel would reject the request, not lock up-- did a change make it inot 2.6.18 or later that causes a lockup instead? (I never tested with SATA cdroms, as I don't have any. I tested with IDE and SCSI and saw correct or detectable behavior) Monty - 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
