Messages in this thread | | | Date | Thu, 4 May 2017 02:51:34 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH] ata-sff: always map page before data transfer |
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> I don't understand all the factors at play here, so thoughts are definitely > welcome.
I don't fully understand the old code either. One thing that is weird is the "use a bounce buffer comment" which doesn't make any sense.
The other is the local_irq_save, which isn't really needed for kmap_atomic to start with, but maybe that's the reason why the original author didn't want to do it unconditionally?
So based on that:
> + /* FIXME: use a bounce buffer */
drop this comment..
> + local_irq_save(flags);
.. remove the local_irq_save/local_irq_restore ..
> + /* do the actual data transfer */ > + ap->ops->sff_data_xfer(qc, buf + offset, qc->sect_size, > + do_write);
.. and a nice alittle cleanup move the do_write onto the previous line.
> + /* FIXME: use bounce buffer */ > + local_irq_save(flags); > + buf = kmap_atomic(page); > > + /* do the actual data transfer */ > + consumed = ap->ops->sff_data_xfer(qc, buf + offset, > + count, rw);
And same here.
And we should be fine.
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