From: Gioh Kim <gi-oh.kim@xxxxxxxxxxxxxxx> [ Upstream commit 3a98ea7041b7d18ac356da64823c2ba2f8391b3e ] Max IB immediate data size is 2^28 (MAX_IMM_PAYL_BITS) and the minimum chunk size is 4096 (2^12). Therefore the maximum sess_queue_depth is 65536 (2^16). Link: https://lore.kernel.org/r/20210528113018.52290-6-jinpu.wang@xxxxxxxxx Signed-off-by: Gioh Kim <gi-oh.kim@xxxxxxxxx> Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxx> Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/infiniband/ulp/rtrs/rtrs-pri.h | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/infiniband/ulp/rtrs/rtrs-pri.h b/drivers/infiniband/ulp/rtrs/rtrs-pri.h index 8caad0a2322b..51c60f542876 100644 --- a/drivers/infiniband/ulp/rtrs/rtrs-pri.h +++ b/drivers/infiniband/ulp/rtrs/rtrs-pri.h @@ -47,12 +47,15 @@ enum { MAX_PATHS_NUM = 128, /* - * With the size of struct rtrs_permit allocated on the client, 4K - * is the maximum number of rtrs_permits we can allocate. This number is - * also used on the client to allocate the IU for the user connection - * to receive the RDMA addresses from the server. + * Max IB immediate data size is 2^28 (MAX_IMM_PAYL_BITS) + * and the minimum chunk size is 4096 (2^12). + * So the maximum sess_queue_depth is 65536 (2^16) in theory. + * But mempool_create, create_qp and ib_post_send fail with + * "cannot allocate memory" error if sess_queue_depth is too big. + * Therefore the pratical max value of sess_queue_depth is + * somewhere between 1 and 65536 and it depends on the system. */ - MAX_SESS_QUEUE_DEPTH = 4096, + MAX_SESS_QUEUE_DEPTH = 65536, RTRS_HB_INTERVAL_MS = 5000, RTRS_HB_MISSED_MAX = 5, -- 2.30.2
