drm/radeon: Fix memory allocation failures in the preKMS command stream checking.

Allocation of single large block of memory may fail under memory
presure. drm_buffer object can hold one large block of data in
multiple independ pages which preents alloation failures.

This patch converts all access to command stream to use drm_buffer
interface. All direct access to array has to go tough drm_buffer
functions to get correct pointer.

Outputting the command stream to ring buffer needs to be awear of
the split nature of drm_buffer. The output operation requires the
new OUT_RING_DRM_BUFFER.

Signed-off-by: Pauli Nieminen <suokkos@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 31 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_drv.h b/drivers/gpu/drm/radeon/radeon_drv.h
index b058316e311f..f6d20cee5705 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.h
+++ b/drivers/gpu/drm/radeon/radeon_drv.h
@@ -312,9 +312,11 @@ typedef struct drm_radeon_buf_priv {
         u32 age;
 } drm_radeon_buf_priv_t;
 
+struct drm_buffer;
+
 typedef struct drm_radeon_kcmd_buffer {
         int bufsz;
-        char *buf;
+        struct drm_buffer *buffer;
         int nbox;
         struct drm_clip_rect __user *boxes;
 } drm_radeon_kcmd_buffer_t;
@@ -2124,4 +2126,32 @@ extern void radeon_commit_ring(drm_radeon_private_t *dev_priv);
         write &= mask;                                          \
 } while (0)
 
+/**
+ * Copy given number of dwords from drm buffer to the ring buffer.
+ */
+#define OUT_RING_DRM_BUFFER(buf, sz) do {                               \
+        int _size = (sz) * 4;                                           \
+        struct drm_buffer *_buf = (buf);                                \
+        int _part_size;                                                 \
+        while (_size > 0) {                                             \
+                _part_size = _size;                                     \
+                                                                        \
+                if (write + _part_size/4 > mask)                        \
+                        _part_size = ((mask + 1) - write)*4;            \
+                                                                        \
+                if (drm_buffer_index(_buf) + _part_size > PAGE_SIZE)    \
+                        _part_size = PAGE_SIZE - drm_buffer_index(_buf);\
+                                                                        \
+                                                                        \
+                                                                        \
+                memcpy(ring + write, &_buf->data[drm_buffer_page(_buf)] \
+                        [drm_buffer_index(_buf)], _part_size);          \
+                                                                        \
+                _size -= _part_size;                                    \
+                write = (write + _part_size/4) & mask;                  \
+                drm_buffer_advance(_buf, _part_size);                   \
+        }                                                               \
+} while (0)
+
+
 #endif                          /* __RADEON_DRV_H__ */