IB/hfi1: Update RMT size calculation

[ Upstream commit 892ede5a77f337831609fb9c248ac60948061894 ]

Fix possible RMT overflow:  Use the correct netdev size.
Don't allow adjusted user contexts to go negative.

Fix QOS calculation: Send kernel context count as an argument since
dd->n_krcv_queues is not yet set up in earliest call.  Do not include
the control context in the QOS calculation.  Use the same sized
variable to find the max of krcvq[] entries.

Update the RMT count explanation to make more sense.

Signed-off-by: Dean Luick <dean.luick@cornelisnetworks.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Link: https://lore.kernel.org/r/167329106946.1472990.18385495251650939054.stgit@awfm-02.cornelisnetworks.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/infiniband/hw/hfi1/chip.c b/drivers/infiniband/hw/hfi1/chip.c
index ebe970f..90b672f 100644 (file)
--- a/drivers/infiniband/hw/hfi1/chip.c
+++ b/drivers/infiniband/hw/hfi1/chip.c
@@ -1056,7 +1056,7 @@ static void read_link_down_reason(struct hfi1_devdata *dd, u8 *ldr);
 static void handle_temp_err(struct hfi1_devdata *dd);
 static void dc_shutdown(struct hfi1_devdata *dd);
 static void dc_start(struct hfi1_devdata *dd);
-static int qos_rmt_entries(struct hfi1_devdata *dd, unsigned int *mp,
+static int qos_rmt_entries(unsigned int n_krcv_queues, unsigned int *mp,
                           unsigned int *np);
 static void clear_full_mgmt_pkey(struct hfi1_pportdata *ppd);
 static int wait_link_transfer_active(struct hfi1_devdata *dd, int wait_ms);
@@ -13362,7 +13362,6 @@ static int set_up_context_variables(struct hfi1_devdata *dd)
        int ret;
        unsigned ngroups;
        int rmt_count;
-       int user_rmt_reduced;
        u32 n_usr_ctxts;
        u32 send_contexts = chip_send_contexts(dd);
        u32 rcv_contexts = chip_rcv_contexts(dd);
@@ -13421,28 +13420,34 @@ static int set_up_context_variables(struct hfi1_devdata *dd)
                                         (num_kernel_contexts + n_usr_ctxts),
                                         &node_affinity.real_cpu_mask);
        /*
-        * The RMT entries are currently allocated as shown below:
-        * 1. QOS (0 to 128 entries);
-        * 2. FECN (num_kernel_context - 1 + num_user_contexts +
-        *    num_netdev_contexts);
-        * 3. netdev (num_netdev_contexts).
-        * It should be noted that FECN oversubscribe num_netdev_contexts
-        * entries of RMT because both netdev and PSM could allocate any receive
-        * context between dd->first_dyn_alloc_text and dd->num_rcv_contexts,
-        * and PSM FECN must reserve an RMT entry for each possible PSM receive
-        * context.
+        * RMT entries are allocated as follows:
+        * 1. QOS (0 to 128 entries)
+        * 2. FECN (num_kernel_context - 1 [a] + num_user_contexts +
+        *          num_netdev_contexts [b])
+        * 3. netdev (NUM_NETDEV_MAP_ENTRIES)
+        *
+        * Notes:
+        * [a] Kernel contexts (except control) are included in FECN if kernel
+        *     TID_RDMA is active.
+        * [b] Netdev and user contexts are randomly allocated from the same
+        *     context pool, so FECN must cover all contexts in the pool.
         */
-       rmt_count = qos_rmt_entries(dd, NULL, NULL) + (num_netdev_contexts * 2);
-       if (HFI1_CAP_IS_KSET(TID_RDMA))
-               rmt_count += num_kernel_contexts - 1;
-       if (rmt_count + n_usr_ctxts > NUM_MAP_ENTRIES) {
-               user_rmt_reduced = NUM_MAP_ENTRIES - rmt_count;
-               dd_dev_err(dd,
-                          "RMT size is reducing the number of user receive contexts from %u to %d\n",
-                          n_usr_ctxts,
-                          user_rmt_reduced);
-               /* recalculate */
-               n_usr_ctxts = user_rmt_reduced;
+       rmt_count = qos_rmt_entries(num_kernel_contexts - 1, NULL, NULL)
+                   + (HFI1_CAP_IS_KSET(TID_RDMA) ? num_kernel_contexts - 1
+                                                 : 0)
+                   + n_usr_ctxts
+                   + num_netdev_contexts
+                   + NUM_NETDEV_MAP_ENTRIES;
+       if (rmt_count > NUM_MAP_ENTRIES) {
+               int over = rmt_count - NUM_MAP_ENTRIES;
+               /* try to squish user contexts, minimum of 1 */
+               if (over >= n_usr_ctxts) {
+                       dd_dev_err(dd, "RMT overflow: reduce the requested number of contexts\n");
+                       return -EINVAL;
+               }
+               dd_dev_err(dd, "RMT overflow: reducing # user contexts from %u to %u\n",
+                          n_usr_ctxts, n_usr_ctxts - over);
+               n_usr_ctxts -= over;
        }
 
        /* the first N are kernel contexts, the rest are user/netdev contexts */
@@ -14299,15 +14304,15 @@ static void clear_rsm_rule(struct hfi1_devdata *dd, u8 rule_index)
 }
 
 /* return the number of RSM map table entries that will be used for QOS */
-static int qos_rmt_entries(struct hfi1_devdata *dd, unsigned int *mp,
+static int qos_rmt_entries(unsigned int n_krcv_queues, unsigned int *mp,
                           unsigned int *np)
 {
        int i;
        unsigned int m, n;
-       u8 max_by_vl = 0;
+       uint max_by_vl = 0;
 
        /* is QOS active at all? */
-       if (dd->n_krcv_queues <= MIN_KERNEL_KCTXTS ||
+       if (n_krcv_queues < MIN_KERNEL_KCTXTS ||
            num_vls == 1 ||
            krcvqsset <= 1)
                goto no_qos;
@@ -14365,7 +14370,7 @@ static void init_qos(struct hfi1_devdata *dd, struct rsm_map_table *rmt)
 
        if (!rmt)
                goto bail;
-       rmt_entries = qos_rmt_entries(dd, &m, &n);
+       rmt_entries = qos_rmt_entries(dd->n_krcv_queues - 1, &m, &n);
        if (rmt_entries == 0)
                goto bail;
        qpns_per_vl = 1 << m;