diff options
| author | Roland Dreier <rolandd@cisco.com> | 2008-05-16 14:58:44 -0700 |
|---|---|---|
| committer | Roland Dreier <rolandd@cisco.com> | 2008-05-16 14:58:44 -0700 |
| commit | 12103dca52e79e23afe2fbcaf3d9e7fc9ceb6b18 (patch) | |
| tree | 91c8f6f489e8e47a926c0bf6337660894b6a2e50 | |
| parent | 21609ae3efa42f4118ce741f7e55d66d716cb17c (diff) | |
IB/mthca: Fix max_sge value returned by query_device
The mthca driver returns the maximum number of scatter/gather entries
returned by the firmware as the max_sge value when device properties
are queried. However, the firmware also reports a limit on the
maximum descriptor size allowed, and because mthca takes into account
the worst case send request overhead when checking whether to allow a
QP to be created, the largest number of scatter/gather entries that
can be used with mthca may be limited by the maximum descriptor size
rather than just by the actual s/g entry limit.
This means that applications cannot actually create QPs with
max_send_sge equal to the limit returned by ib_query_device(). Fix
this by checking if the maximum descriptor size imposes a lower limit
and if so returning that lower limit.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
| -rw-r--r-- | drivers/infiniband/hw/mthca/mthca_main.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/infiniband/hw/mthca/mthca_main.c b/drivers/infiniband/hw/mthca/mthca_main.c index 9ebadd6e0cf..200cf13fc9b 100644 --- a/drivers/infiniband/hw/mthca/mthca_main.c +++ b/drivers/infiniband/hw/mthca/mthca_main.c @@ -45,6 +45,7 @@ #include "mthca_cmd.h" #include "mthca_profile.h" #include "mthca_memfree.h" +#include "mthca_wqe.h" MODULE_AUTHOR("Roland Dreier"); MODULE_DESCRIPTION("Mellanox InfiniBand HCA low-level driver"); @@ -200,7 +201,18 @@ static int mthca_dev_lim(struct mthca_dev *mdev, struct mthca_dev_lim *dev_lim) mdev->limits.gid_table_len = dev_lim->max_gids; mdev->limits.pkey_table_len = dev_lim->max_pkeys; mdev->limits.local_ca_ack_delay = dev_lim->local_ca_ack_delay; - mdev->limits.max_sg = dev_lim->max_sg; + /* + * Need to allow for worst case send WQE overhead and check + * whether max_desc_sz imposes a lower limit than max_sg; UD + * send has the biggest overhead. + */ + mdev->limits.max_sg = min_t(int, dev_lim->max_sg, + (dev_lim->max_desc_sz - + sizeof (struct mthca_next_seg) - + (mthca_is_memfree(mdev) ? + sizeof (struct mthca_arbel_ud_seg) : + sizeof (struct mthca_tavor_ud_seg))) / + sizeof (struct mthca_data_seg)); mdev->limits.max_wqes = dev_lim->max_qp_sz; mdev->limits.max_qp_init_rdma = dev_lim->max_requester_per_qp; mdev->limits.reserved_qps = dev_lim->reserved_qps; |