ntb_transport: Limit memory windows based on available, scratchpads

[mirror_ubuntu-zesty-kernel.git] / drivers / ntb / ntb_transport.c

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 4eb8adb345084430947ccabdf6962c1099fbb703..9b791cb33c196886cc3ae8071f3ff28762669d10 100644 (file)
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -66,6 +66,7 @@
 #define NTB_TRANSPORT_VER      "4"
 #define NTB_TRANSPORT_NAME     "ntb_transport"
 #define NTB_TRANSPORT_DESC     "Software Queue-Pair Transport over NTB"
+#define NTB_TRANSPORT_MIN_SPADS (MW0_SZ_HIGH + 2)
 
 MODULE_DESCRIPTION(NTB_TRANSPORT_DESC);
 MODULE_VERSION(NTB_TRANSPORT_VER);
@@ -242,9 +243,6 @@ enum {
        NUM_MWS,
        MW0_SZ_HIGH,
        MW0_SZ_LOW,
-       MW1_SZ_HIGH,
-       MW1_SZ_LOW,
-       MAX_SPAD,
 };
 
 #define dev_client_dev(__dev) \
@@ -811,7 +809,7 @@ static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
 {
        struct ntb_transport_qp *qp;
        u64 qp_bitmap_alloc;
-       int i;
+       unsigned int i, count;
 
        qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
 
@@ -831,7 +829,8 @@ static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
         * goes down, blast them now to give them a sane value the next
         * time they are accessed
         */
-       for (i = 0; i < MAX_SPAD; i++)
+       count = ntb_spad_count(nt->ndev);
+       for (i = 0; i < count; i++)
                ntb_spad_write(nt->ndev, i, 0);
 }
 
@@ -1064,17 +1063,12 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
 {
        struct ntb_transport_ctx *nt;
        struct ntb_transport_mw *mw;
-       unsigned int mw_count, qp_count;
+       unsigned int mw_count, qp_count, spad_count, max_mw_count_for_spads;
        u64 qp_bitmap;
        int node;
        int rc, i;
 
        mw_count = ntb_mw_count(ndev);
-       if (ntb_spad_count(ndev) < (NUM_MWS + 1 + mw_count * 2)) {
-               dev_err(&ndev->dev, "Not enough scratch pad registers for %s",
-                       NTB_TRANSPORT_NAME);
-               return -EIO;
-       }
 
        if (ntb_db_is_unsafe(ndev))
                dev_dbg(&ndev->dev,
@@ -1090,8 +1084,18 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
                return -ENOMEM;
 
        nt->ndev = ndev;
+       spad_count = ntb_spad_count(ndev);
+
+       /* Limit the MW's based on the availability of scratchpads */
+
+       if (spad_count < NTB_TRANSPORT_MIN_SPADS) {
+               nt->mw_count = 0;
+               rc = -EINVAL;
+               goto err;
+       }
 
-       nt->mw_count = mw_count;
+       max_mw_count_for_spads = (spad_count - MW0_SZ_HIGH) / 2;
+       nt->mw_count = min(mw_count, max_mw_count_for_spads);
 
        nt->mw_vec = kzalloc_node(mw_count * sizeof(*nt->mw_vec),
                                  GFP_KERNEL, node);