[ Upstream commit fe51f6254d81f5a69c31df16353d6539b2b51630 ]
When allocating MTT hem, for each hop level of each hem that is being
allocated, the driver iterates the hem list to find out whether the
bt page has been allocated in this hop level. If not, allocate a new
one and splice it to the list. The time complexity is O(n^2) in worst
cases.
Currently the allocation for-loop uses 'unit' as the step size. This
actually has taken into account the reuse of last-hop-level MTT bt
pages by multiple buffer pages. Thus pages of last hop level will
never have been allocated, so there is no need to iterate the hem list
in last hop level.
Removing this unnecessary iteration can reduce the time complexity to
O(n).
Fixes: 38389eaa4db1 ("RDMA/hns: Add mtr support for mixed multihop addressing")
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://patch.msgid.link/20240906093444.3571619-9-huangjunxian6@hisilicon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d586628b169d14bbf36be64d2b3ec9d9d2fe0432 ]
The max value of 'unit' and 'hop_num' is 2^24 and 2, so the value of
'step' may exceed the range of u32. Change the type of 'step' to u64.
Fixes: 38389eaa4db1 ("RDMA/hns: Add mtr support for mixed multihop addressing")
Signed-off-by: wenglianfa <wenglianfa@huawei.com>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://patch.msgid.link/20240906093444.3571619-5-huangjunxian6@hisilicon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1f704d8cc07269f31daf9bdafe84882ad7596a2c ]
Split the hem_list_alloc_root_bt() into serval small functions to make the
code flow more clear.
Link: https://lore.kernel.org/r/1621589395-2435-3-git-send-email-liweihang@huawei.com
Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Stable-dep-of: d586628b169d ("RDMA/hns: Fix the overflow risk of hem_list_calc_ba_range()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
