iommu: Flow ERR_PTR out from __iommu_domain_alloc()

Most of the calling code now has error handling that can carry an error
code further up the call chain. Keep the exported interface
iommu_domain_alloc() returning NULL and reflow the internal code to use
ERR_PTR not NULL for domain allocation failure.

Optionally allow drivers to return ERR_PTR from any of the alloc ops. Many
of the new ops (user, sva, etc) already return ERR_PTR, so having two
rules is confusing and hard on drivers. This fixes a bug in DART that was
returning ERR_PTR.

Fixes: 482feb5c6492 ("iommu/dart: Call apple_dart_finalize_domain() as part of alloc_paging()")
Reported-by: Dan Carpenter <[email protected]>
Link: https://lore.kernel.org/linux-iommu/[email protected]/
Signed-off-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Jerry Snitselaar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>

0 files changed, 0 insertions, 0 deletions