Hi, On Wed, Mar 25, 2009 at 5:13 PM, Tejun Heo <tj@xxxxxxxxxx> wrote: > Hello, Grant. > > Grant Grundler wrote: >> On Wed, Mar 25, 2009 at 7:17 AM, Tejun Heo <tj@xxxxxxxxxx> wrote: >>> Impact: simpler buffer allocation and handling, fix DMA transfers >> ... >>> + atomic_set(&bh->b_count, bcount); >>> if (atomic_read(&bh->b_count) == bh->b_size) >> ... >> >> I'm failing to see why bh->b_count is an atomic_t. >> I always assumed tapes were exclusive access devices >> and would be serialized at a higher level. > > Beats me. I don't know. The code is generally pretty over-engineered > but, well, it's an ancient piece of code with (probably too) rich > history. Yep, actually the driver was even bigger and it implemented a bunch of fun stuff like command pipelining and those atomics had to protect the pipeline from simultaneous ->open()s through its chrdev interface, IIRC. -- Regards/Gruss, Boris -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
