RE: [RFC 1/1] swiotlb: Reduce calls to swiotlb_find_pool()

[Michael Kelley <mhklinux@xxxxxxxxxxx>]

From: hch@xxxxxx <hch@xxxxxx> Sent: Saturday, June 29, 2024 10:56 PM
> 
> On Sat, Jun 29, 2024 at 03:55:58PM +0000, Michael Kelley wrote:
> > Unless there is further discussion on this point, I'll just keep the 
> > original
> > "is_swiotlb_buffer()" in v2.
> 
> That is the wrong name for something that returns the pool as pointed
> out before.

OK. Since any new name could cause confusion with the existing
swiotlb_find_pool(), here's my proposal:

1) Rename is_swiotlb_buffer() to swiotlb_find_pool(), since it
now returns a pool.  A NULL return value indicates that the
paddr is not an swiotlb buffer.

2) Similarly, rename is_xen_swiotlb_buffer() to
xen_swiotlb_find_pool()

3) The existing swiotlb_find_pool() has the same function signature,
but it is used only where the paddr is known to be an swiotlb buffer
and hence always succeeds. Rename it to __swiotlb_find_pool() as
the "internal" version of swiotlb_find_pool().

4) Do you still want is_swiotlb_buffer() as a trivial wrapper around
the new swiotlb_find_pool(), for use solely in dma_direct_need_sync()
where only a Boolean is needed and not the pool?

Thanks,

Michael