On 05/11/2019 21:54, Jason Gunthorpe wrote:
>> static int qp_mmap_entries_setup(struct efa_qp *qp,
>> struct efa_dev *dev,
>> struct efa_ucontext *ucontext,
>> struct efa_com_create_qp_params *params,
>> struct efa_ibv_create_qp_resp *resp)
>> {
>> - /*
>> - * Once an entry is inserted it might be mmapped, hence cannot be
>> - * cleaned up until dealloc_ucontext.
>> - */
>> - resp->sq_db_mmap_key =
>> - mmap_entry_insert(dev, ucontext, qp,
>> - dev->db_bar_addr + resp->sq_db_offset,
>> - PAGE_SIZE, EFA_MMAP_IO_NC);
>> - if (resp->sq_db_mmap_key == EFA_MMAP_INVALID)
>> + size_t length;
>> + u64 address;
>> +
>> + address = dev->db_bar_addr + resp->sq_db_offset;
>> + qp->sq_db_mmap_entry =
>> + efa_user_mmap_entry_insert(&ucontext->ibucontext,
>> + address,
>> + PAGE_SIZE, EFA_MMAP_IO_NC,
>> + &resp->sq_db_mmap_key);
>
> I'm still confused how this is OK for the lifetime, 'sq_db_offset'
> comes from the device, does the device prevent re-use of the same
> db_offset until the ucontext is closed? If so that deserves a comment
> in here.
The device prevents reuse of the DB offset until the UAR is deallocated (during
ucontext close). Same applies for the RQ DB and LLQ offset.
