Remove pid check in register/unregister
The register/unregister gralloc calls were avoiding
mmapping/munmapping the shared memory region if the buffer was created
by the current process. This is left over from the pmem-based
implementation, where trying to map the same region twice in the same
process would fail, or would reuse a single mapping without
refcounting.
This causes problems if a buffer is
- allocated in process A,
- transferred from A to process B and registered there
- unregistered/freed in A
- transferred back from B to A and re-registered
Process A then has a new handle to the buffer, but since it originally
created the buffer it will not be mmapped, so trying to read or write
the buffer will crash.
With ashmem, mmaping a region twice in the same process creates two
distinct mappings which can be used and munmapped independently. So
we no longer need to avoid mmapping again in the allocating process.
Bug: 8468756
Change-Id: I167bec5ca07e5534c5e2115630fe8386e481388e
2 files changed
