gru: add user request to explicitly unload a gru context

Add user function to explicitly unload GRU kernel contexts from the GRU.
Only contexts that are not in-use will be unloaded.

This function is primarily for testing.  It is not expected that this will
be used in normal production systems.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 41 insertions, 28 deletions

diff --git a/drivers/misc/sgi-gru/grufile.c b/drivers/misc/sgi-gru/grufile.c
index bfc88d1b2a5b..e22012db239e 100644
--- a/drivers/misc/sgi-gru/grufile.c
+++ b/drivers/misc/sgi-gru/grufile.c
@@ -287,7 +287,6 @@ static void gru_init_chiplet(struct gru_state *gru, unsigned long paddr,
         gru_dbg(grudev, "bid %d, nid %d, gid %d, vaddr %p (0x%lx)\n",
                 bid, nid, gru->gs_gid, gru->gs_gru_base_vaddr,
                 gru->gs_gru_base_paddr);
-        gru_kservices_init(gru);
 }
 
 static int gru_init_tables(unsigned long gru_base_paddr, void *gru_base_vaddr)
@@ -314,6 +313,7 @@ static int gru_init_tables(unsigned long gru_base_paddr, void *gru_base_vaddr)
                 memset(gru_base[bid], 0, sizeof(struct gru_blade_state));
                 gru_base[bid]->bs_lru_gru = &gru_base[bid]->bs_grus[0];
                 spin_lock_init(&gru_base[bid]->bs_lock);
+                init_rwsem(&gru_base[bid]->bs_kgts_sema);
 
                 dsrbytes = 0;
                 cbrs = 0;
@@ -426,6 +426,7 @@ static int __init gru_init(void)
                 printk(KERN_ERR "%s: init tables failed\n", GRU_DRIVER_ID_STR);
                 goto exit3;
         }
+        gru_kservices_init();
 
         printk(KERN_INFO "%s: v%s\n", GRU_DRIVER_ID_STR,
                GRU_DRIVER_VERSION_STR);
@@ -444,7 +445,7 @@ exit1:
 
 static void __exit gru_exit(void)
 {
-        int i, bid, gid;
+        int i, bid;
         int order = get_order(sizeof(struct gru_state) *
                               GRU_CHIPLETS_PER_BLADE);
 
@@ -453,10 +454,7 @@ static void __exit gru_exit(void)
 
         for (i = 0; i < GRU_CHIPLETS_PER_BLADE; i++)
                 free_irq(IRQ_GRU + i, NULL);
-
-        foreach_gid(gid)
-                gru_kservices_exit(GID_TO_GRU(gid));
-
+        gru_kservices_exit();
         for (bid = 0; bid < GRU_MAX_BLADES; bid++)
                 free_pages((unsigned long)gru_base[bid], order);
 
diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c
index 7586b89fd0d3..5078f57da882 100644
--- a/drivers/misc/sgi-gru/grukservices.c
+++ b/drivers/misc/sgi-gru/grukservices.c
@@ -188,6 +188,34 @@ static void gru_load_kernel_context(struct gru_blade_state *bs, int blade_id)
 }
 
 /*
+ * Free all kernel contexts that are not currently in use.
+ *   Returns 0 if all freed, else number of inuse context.
+ */
+static int gru_free_kernel_contexts(void)
+{
+        struct gru_blade_state *bs;
+        struct gru_thread_state *kgts;
+        int bid, ret = 0;
+
+        for (bid = 0; bid < GRU_MAX_BLADES; bid++) {
+                bs = gru_base[bid];
+                if (!bs)
+                        continue;
+                if (down_write_trylock(&bs->bs_kgts_sema)) {
+                        kgts = bs->bs_kgts;
+                        if (kgts && kgts->ts_gru)
+                                gru_unload_context(kgts, 0);
+                        kfree(kgts);
+                        bs->bs_kgts = NULL;
+                        up_write(&bs->bs_kgts_sema);
+                } else {
+                        ret++;
+                }
+        }
+        return ret;
+}
+
+/*
  * Lock & load the kernel context for the specified blade.
  */
 static struct gru_blade_state *gru_lock_kernel_context(int blade_id)
@@ -1009,35 +1037,22 @@ int gru_ktest(unsigned long arg)
         case 2:
                 ret = quicktest2(arg);
                 break;
+        case 99:
+                ret = gru_free_kernel_contexts();
+                break;
         }
         return ret;
 
 }
 
-int gru_kservices_init(struct gru_state *gru)
+int gru_kservices_init(void)
 {
-        struct gru_blade_state *bs;
-
-        bs = gru->gs_blade;
-        if (gru != &bs->bs_grus[0])
-                return 0;
-
-        init_rwsem(&bs->bs_kgts_sema);
         return 0;
 }
 
-void gru_kservices_exit(struct gru_state *gru)
+void gru_kservices_exit(void)
 {
-        struct gru_blade_state *bs;
-        struct gru_thread_state *kgts;
-
-        bs = gru->gs_blade;
-        if (gru != &bs->bs_grus[0])
-                return;
-
-        kgts = bs->bs_kgts;
-        if (kgts && kgts->ts_gru)
-                gru_unload_context(kgts, 0);
-        kfree(kgts);
+        if (gru_free_kernel_contexts())
+                BUG();
 }
 
diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutables.h
index 665704683ab8..9761bfee8669 100644
--- a/drivers/misc/sgi-gru/grutables.h
+++ b/drivers/misc/sgi-gru/grutables.h
@@ -638,8 +638,8 @@ extern void gru_unload_context(struct gru_thread_state *gts, int savestate);
 extern int gru_update_cch(struct gru_thread_state *gts, int force_unload);
 extern void gts_drop(struct gru_thread_state *gts);
 extern void gru_tgh_flush_init(struct gru_state *gru);
-extern int gru_kservices_init(struct gru_state *gru);
-extern void gru_kservices_exit(struct gru_state *gru);
+extern int gru_kservices_init(void);
+extern void gru_kservices_exit(void);
 extern int gru_dump_chiplet_request(unsigned long arg);
 extern irqreturn_t gru_intr(int irq, void *dev_id);
 extern int gru_handle_user_call_os(unsigned long address);