1 files changed, 22 insertions, 6 deletions

diff --git a/drivers/misc/cxl/fault.c b/drivers/misc/cxl/fault.c
index cb4f3231b451..c99e896604ee 100644
--- a/drivers/misc/cxl/fault.c
+++ b/drivers/misc/cxl/fault.c
@@ -21,11 +21,20 @@
 
 #include "cxl.h"
 
-/* This finds a free SSTE for the given SLB */
+static bool sste_matches(struct cxl_sste *sste, struct copro_slb *slb)
+{
+        return ((sste->vsid_data == cpu_to_be64(slb->vsid)) &&
+                (sste->esid_data == cpu_to_be64(slb->esid)));
+}
+
+/*
+ * This finds a free SSTE for the given SLB, or returns NULL if it's already in
+ * the segment table.
+ */
 static struct cxl_sste* find_free_sste(struct cxl_context *ctx,
                                        struct copro_slb *slb)
 {
-        struct cxl_sste *primary, *sste;
+        struct cxl_sste *primary, *sste, *ret = NULL;
         unsigned int mask = (ctx->sst_size >> 7) - 1; /* SSTP0[SegTableSize] */
         unsigned int entry;
         unsigned int hash;
@@ -38,15 +47,19 @@ static struct cxl_sste* find_free_sste(struct cxl_context *ctx,
         primary = ctx->sstp + (hash << 3);
 
         for (entry = 0, sste = primary; entry < 8; entry++, sste++) {
-                if (!(be64_to_cpu(sste->esid_data) & SLB_ESID_V))
-                        return sste;
+                if (!ret && !(be64_to_cpu(sste->esid_data) & SLB_ESID_V))
+                        ret = sste;
+                if (sste_matches(sste, slb))
+                        return NULL;
         }
+        if (ret)
+                return ret;
 
         /* Nothing free, select an entry to cast out */
-        sste = primary + ctx->sst_lru;
+        ret = primary + ctx->sst_lru;
         ctx->sst_lru = (ctx->sst_lru + 1) & 0x7;
 
-        return sste;
+        return ret;
 }
 
 static void cxl_load_segment(struct cxl_context *ctx, struct copro_slb *slb)
@@ -57,12 +70,15 @@ static void cxl_load_segment(struct cxl_context *ctx, struct copro_slb *slb)
 
         spin_lock_irqsave(&ctx->sste_lock, flags);
         sste = find_free_sste(ctx, slb);
+        if (!sste)
+                goto out_unlock;
 
         pr_devel("CXL Populating SST[%li]: %#llx %#llx\n",
                         sste - ctx->sstp, slb->vsid, slb->esid);
 
         sste->vsid_data = cpu_to_be64(slb->vsid);
         sste->esid_data = cpu_to_be64(slb->esid);
+out_unlock:
         spin_unlock_irqrestore(&ctx->sste_lock, flags);
 }