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, 7 insertions, 7 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/vm.c b/drivers/gpu/nvgpu/common/linux/vm.c
index 8b9d6f96..5470d9ee 100644
--- a/drivers/gpu/nvgpu/common/linux/vm.c
+++ b/drivers/gpu/nvgpu/common/linux/vm.c
@@ -20,6 +20,7 @@
 #include <nvgpu/log.h>
 #include <nvgpu/lock.h>
 #include <nvgpu/rbtree.h>
+#include <nvgpu/vm_area.h>
 #include <nvgpu/page_allocator.h>
 
 #include "gk20a/gk20a.h"
@@ -196,7 +197,7 @@ u64 nvgpu_vm_map(struct vm_gk20a *vm,
         struct scatterlist *sgl;
         u64 ctag_map_win_size = 0;
         u32 ctag_map_win_ctagline = 0;
-        struct vm_reserved_va_node *va_node = NULL;
+        struct nvgpu_vm_area *vm_area = NULL;
         u32 ctag_offset;
         enum nvgpu_aperture aperture;
 
@@ -256,9 +257,8 @@ u64 nvgpu_vm_map(struct vm_gk20a *vm,
 
         /* Check if we should use a fixed offset for mapping this buffer */
         if (flags & NVGPU_AS_MAP_BUFFER_FLAGS_FIXED_OFFSET)  {
-                err = validate_fixed_buffer(vm, &bfr,
-                                            offset_align, mapping_size,
-                                            &va_node);
+                err = nvgpu_vm_area_validate_buffer(vm, offset_align, mapping_size,
+                                                    bfr.pgsz_idx, &vm_area);
                 if (err)
                         goto clean_up;
 
@@ -376,10 +376,10 @@ u64 nvgpu_vm_map(struct vm_gk20a *vm,
         if (user_mapped)
                 vm->num_user_mapped_buffers++;
 
-        if (va_node) {
+        if (vm_area) {
                 nvgpu_list_add_tail(&mapped_buffer->buffer_list,
-                              &va_node->buffer_list_head);
-                mapped_buffer->va_node = va_node;
+                              &vm_area->buffer_list_head);
+                mapped_buffer->vm_area = vm_area;
         }
 
         nvgpu_mutex_release(&vm->update_gmmu_lock);