gpu: nvgpu: Split vm_area management into vm code

The vm_reserve_va_node struct is essentially a special VM area that
can be used for sparse mappings and fixed mappings. The name of this
struct is somewhat confusing (as node is typically used for list
items). Though this struct is a part of a list it doesn't really
make sense to call this a list item since it's much more. Based on
that the struct has been renamed to nvgpu_vm_area to capture the
actual use of the struct more accurately.

This also moves all of the management code of vm areas to a new file
devoted solely to vm_area management.

Also add a brief overview of the VM architecture. This should help
other people follow along the hierachy of ownership and lifetimes in
the rather complex MM code.

JIRA NVGPU-12
JIRA NVGPU-30

Change-Id: If85e1cf868031d0dc265e7bed50b58a2aed2602e
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/1477744
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 8 insertions, 7 deletions

diff --git a/drivers/gpu/nvgpu/vgpu/mm_vgpu.c b/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
index f4004f42..b42fbcb3 100644
--- a/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
+++ b/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
@@ -18,6 +18,7 @@
 #include <nvgpu/kmem.h>
 #include <nvgpu/dma.h>
 #include <nvgpu/bug.h>
+#include <nvgpu/vm_area.h>
 
 #include "vgpu/vgpu.h"
 #include "gk20a/mm_gk20a.h"
@@ -203,7 +204,7 @@ static void vgpu_vm_remove_support(struct vm_gk20a *vm)
 {
         struct gk20a *g = vm->mm->g;
         struct nvgpu_mapped_buf *mapped_buffer;
-        struct vm_reserved_va_node *va_node, *va_node_tmp;
+        struct nvgpu_vm_area *vm_area, *vm_area_tmp;
         struct tegra_vgpu_cmd_msg msg;
         struct tegra_vgpu_as_share_params *p = &msg.params.as_share;
         struct nvgpu_rbtree_node *node = NULL;
@@ -223,11 +224,11 @@ static void vgpu_vm_remove_support(struct vm_gk20a *vm)
         }
 
         /* destroy remaining reserved memory areas */
-        nvgpu_list_for_each_entry_safe(va_node, va_node_tmp,
-                        &vm->reserved_va_list,
-                        vm_reserved_va_node, reserved_va_list) {
-                nvgpu_list_del(&va_node->reserved_va_list);
-                nvgpu_kfree(g, va_node);
+        nvgpu_list_for_each_entry_safe(vm_area, vm_area_tmp,
+                        &vm->vm_area_list,
+                        nvgpu_vm_area, vm_area_list) {
+                nvgpu_list_del(&vm_area->vm_area_list);
+                nvgpu_kfree(g, vm_area);
         }
 
         msg.cmd = TEGRA_VGPU_CMD_AS_FREE_SHARE;
@@ -413,7 +414,7 @@ static int vgpu_vm_alloc_share(struct gk20a_as_share *as_share,
 
         nvgpu_mutex_init(&vm->update_gmmu_lock);
         kref_init(&vm->ref);
-        nvgpu_init_list_node(&vm->reserved_va_list);
+        nvgpu_init_list_node(&vm->vm_area_list);
 
         vm->enable_ctag = true;