On Wed, Nov 25, 2020 at 07:03:34PM +0800, Yong Wu wrote:
> On Tue, 2020-11-24 at 11:05 +0000, Will Deacon wrote:
> > On Tue, Nov 24, 2020 at 05:24:44PM +0800, Yong Wu wrote:
> > > On Mon, 2020-11-23 at 12:32 +0000, Will Deacon wrote:
> > That said, maybe we could simplify this further by changing the loop bounds
> > to be:
> >
> > for (addr = start; addr <= end; addr += pg_size)
> >
> > and checking:
> >
> > if (!phys_addr && addr != end) {
> > map_size += pg_size;
> > continue;
> > }
> >
> > does that work?
>
> It works but I think we can not check iommu_iova_to_phys(domain, end).
> We should add a "if", like:
>
> for (addr = start; addr <= end; addr += pg_size) {
> ...
> if (addr < end) {
> phys_addr = iommu_iova_to_phys(domain, addr);
> if (!phys_addr) {
> map_size += pg_size;
> continue;
> }
> }
> ...
>
Oh yes, you're right.
> If you don't like this "if (addr < end)", then we have to add a "goto".
> like this:
>
>
> for (addr = start; addr <= end; addr += pg_size) {
> phys_addr_t phys_addr;
>
> if (addr == end)
> goto map_last;
>
> phys_addr = iommu_iova_to_phys(domain, addr);
> if (!phys_addr) {
> map_size += pg_size;
> continue;
> }
>
> map_last:
> if (!map_size)
> continue;
> ret = iommu_map(domain, addr - map_size,
> addr - map_size, map_size, entry->prot);
I think it's cleared to invert this as you had before:
if (map_size)
ret = iommu_map(...);
> Which one is better?
The second one is easier to read. I'll stop making suggestions now, thanks.
Will
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