1 files changed, 40 insertions, 15 deletions

diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c
index 0c7bd384f0cf..3398e54a762b 100644
--- a/drivers/misc/sgi-gru/grumain.c
+++ b/drivers/misc/sgi-gru/grumain.c
@@ -96,7 +96,7 @@ static int gru_reset_asid_limit(struct gru_state *gru, int asid)
         gid = gru->gs_gid;
 again:
         for (i = 0; i < GRU_NUM_CCH; i++) {
-                if (!gru->gs_gts[i])
+                if (!gru->gs_gts[i] || is_kernel_context(gru->gs_gts[i]))
                         continue;
                 inuse_asid = gru->gs_gts[i]->ts_gms->ms_asids[gid].mt_asid;
                 gru_dbg(grudev, "gid %d, gts %p, gms %p, inuse 0x%x, cxt %d\n",
@@ -506,7 +506,8 @@ void gru_unload_context(struct gru_thread_state *gts, int savestate)
         struct gru_context_configuration_handle *cch;
         int ctxnum = gts->ts_ctxnum;
 
-        zap_vma_ptes(gts->ts_vma, UGRUADDR(gts), GRU_GSEG_PAGESIZE);
+        if (!is_kernel_context(gts))
+                zap_vma_ptes(gts->ts_vma, UGRUADDR(gts), GRU_GSEG_PAGESIZE);
         cch = get_cch(gru->gs_gru_base_vaddr, ctxnum);
 
         gru_dbg(grudev, "gts %p\n", gts);
@@ -514,7 +515,8 @@ void gru_unload_context(struct gru_thread_state *gts, int savestate)
         if (cch_interrupt_sync(cch))
                 BUG();
 
-        gru_unload_mm_tracker(gru, gts);
+        if (!is_kernel_context(gts))
+                gru_unload_mm_tracker(gru, gts);
         if (savestate)
                 gru_unload_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr,
                                         ctxnum, gts->ts_cbr_map,
@@ -526,7 +528,6 @@ void gru_unload_context(struct gru_thread_state *gts, int savestate)
         unlock_cch_handle(cch);
 
         gru_free_gru_context(gts);
-        STAT(unload_context);
 }
 
 /*
@@ -554,11 +555,16 @@ void gru_load_context(struct gru_thread_state *gts)
         cch->tfm_done_bit_enable = 0;
         cch->dsr_allocation_map = gts->ts_dsr_map;
         cch->cbr_allocation_map = gts->ts_cbr_map;
-        asid = gru_load_mm_tracker(gru, gts);
-        cch->unmap_enable = 0;
-        for (i = 0; i < 8; i++) {
-                cch->asid[i] = asid + i;
-                cch->sizeavail[i] = gts->ts_sizeavail;
+
+        if (is_kernel_context(gts)) {
+                cch->unmap_enable = 1;
+        } else {
+                cch->unmap_enable = 0;
+                asid = gru_load_mm_tracker(gru, gts);
+                for (i = 0; i < 8; i++) {
+                        cch->asid[i] = asid + i;
+                        cch->sizeavail[i] = gts->ts_sizeavail;
+                }
         }
 
         err = cch_allocate(cch);
@@ -575,8 +581,6 @@ void gru_load_context(struct gru_thread_state *gts)
         if (cch_start(cch))
                 BUG();
         unlock_cch_handle(cch);
-
-        STAT(load_context);
 }
 
 /*
@@ -652,6 +656,27 @@ static int gru_retarget_intr(struct gru_thread_state *gts)
 #define next_gru(b, g)  (((g) < &(b)->bs_grus[GRU_CHIPLETS_PER_BLADE - 1]) ?  \
                                  ((g)+1) : &(b)->bs_grus[0])
 
+static int is_gts_stealable(struct gru_thread_state *gts,
+                struct gru_blade_state *bs)
+{
+        if (is_kernel_context(gts))
+                return down_write_trylock(&bs->bs_kgts_sema);
+        else
+                return mutex_trylock(&gts->ts_ctxlock);
+}
+
+static void gts_stolen(struct gru_thread_state *gts,
+                struct gru_blade_state *bs)
+{
+        if (is_kernel_context(gts)) {
+                up_write(&bs->bs_kgts_sema);
+                STAT(steal_kernel_context);
+        } else {
+                mutex_unlock(&gts->ts_ctxlock);
+                STAT(steal_user_context);
+        }
+}
+
 void gru_steal_context(struct gru_thread_state *gts, int blade_id)
 {
         struct gru_blade_state *blade;
@@ -685,7 +710,7 @@ void gru_steal_context(struct gru_thread_state *gts, int blade_id)
                          * success are high. If trylock fails, try to steal a
                          * different GSEG.
                          */
-                        if (ngts && mutex_trylock(&ngts->ts_ctxlock))
+                        if (ngts && is_gts_stealable(ngts, blade))
                                 break;
                         ngts = NULL;
                         flag = 1;
@@ -701,10 +726,9 @@ void gru_steal_context(struct gru_thread_state *gts, int blade_id)
         spin_unlock(&blade->bs_lock);
 
         if (ngts) {
-                STAT(steal_context);
                 ngts->ts_steal_jiffies = jiffies;
-                gru_unload_context(ngts, 1);
-                mutex_unlock(&ngts->ts_ctxlock);
+                gru_unload_context(ngts, is_kernel_context(ngts) ? 0 : 1);
+                gts_stolen(ngts, blade);
         } else {
                 STAT(steal_context_failed);
         }
@@ -810,6 +834,7 @@ again:
         }
 
         if (!gts->ts_gru) {
+                STAT(load_user_context);
                 if (!gru_assign_gru_context(gts, blade_id)) {
                         preempt_enable();
                         mutex_unlock(&gts->ts_ctxlock);