drm/radeon/kms: don't require up to 64k allocations. (v2)

This avoids needing to do a kmalloc > PAGE_SIZE for the main
indirect buffer chunk, it adds an accessor for all reads from
the chunk and caches a single page at a time for subsequent
reads.

changes since v1:
Use a two page pool which should be the most common case
a single packet spanning > PAGE_SIZE will be hit, but I'm
having trouble seeing anywhere we currently generate anything like that.
hopefully proper short page copying at end
added parser_error flag to set deep errors instead of having to test
every ib value fetch.
fixed bug in patch that went to list.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 96 insertions, 9 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c
index 12f5990c2d2a..dea8acf88865 100644
--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -142,15 +142,31 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)
                 }
 
                 p->chunks[i].length_dw = user_chunk.length_dw;
-                cdata = (uint32_t *)(unsigned long)user_chunk.chunk_data;
+                p->chunks[i].user_ptr = (void __user *)(unsigned long)user_chunk.chunk_data;
 
-                size = p->chunks[i].length_dw * sizeof(uint32_t);
-                p->chunks[i].kdata = kmalloc(size, GFP_KERNEL);
-                if (p->chunks[i].kdata == NULL) {
-                        return -ENOMEM;
-                }
-                if (DRM_COPY_FROM_USER(p->chunks[i].kdata, cdata, size)) {
-                        return -EFAULT;
+                cdata = (uint32_t *)(unsigned long)user_chunk.chunk_data;
+                if (p->chunks[i].chunk_id != RADEON_CHUNK_ID_IB) {
+                        size = p->chunks[i].length_dw * sizeof(uint32_t);
+                        p->chunks[i].kdata = kmalloc(size, GFP_KERNEL);
+                        if (p->chunks[i].kdata == NULL) {
+                                return -ENOMEM;
+                        }
+                        if (DRM_COPY_FROM_USER(p->chunks[i].kdata,
+                                               p->chunks[i].user_ptr, size)) {
+                                return -EFAULT;
+                        }
+                } else {
+                        p->chunks[i].kpage[0] = kmalloc(PAGE_SIZE, GFP_KERNEL);
+                        p->chunks[i].kpage[1] = kmalloc(PAGE_SIZE, GFP_KERNEL);
+                        if (p->chunks[i].kpage[0] == NULL || p->chunks[i].kpage[1] == NULL) {
+                                kfree(p->chunks[i].kpage[0]);
+                                kfree(p->chunks[i].kpage[1]);
+                                return -ENOMEM;
+                        }
+                        p->chunks[i].kpage_idx[0] = -1;
+                        p->chunks[i].kpage_idx[1] = -1;
+                        p->chunks[i].last_copied_page = -1;
+                        p->chunks[i].last_page_index = ((p->chunks[i].length_dw * 4) - 1) / PAGE_SIZE;
                 }
         }
         if (p->chunks[p->chunk_ib_idx].length_dw > (16 * 1024)) {
@@ -190,6 +206,8 @@ static void radeon_cs_parser_fini(struct radeon_cs_parser *parser, int error)
         kfree(parser->relocs_ptr);
         for (i = 0; i < parser->nchunks; i++) {
                 kfree(parser->chunks[i].kdata);
+                kfree(parser->chunks[i].kpage[0]);
+                kfree(parser->chunks[i].kpage[1]);
         }
         kfree(parser->chunks);
         kfree(parser->chunks_array);
@@ -238,8 +256,14 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
          * uncached). */
         ib_chunk = &parser.chunks[parser.chunk_ib_idx];
         parser.ib->length_dw = ib_chunk->length_dw;
-        memcpy((void *)parser.ib->ptr, ib_chunk->kdata, ib_chunk->length_dw*4);
         r = radeon_cs_parse(&parser);
+        if (r || parser.parser_error) {
+                DRM_ERROR("Invalid command stream !\n");
+                radeon_cs_parser_fini(&parser, r);
+                mutex_unlock(&rdev->cs_mutex);
+                return r;
+        }
+        r = radeon_cs_finish_pages(&parser);
         if (r) {
                 DRM_ERROR("Invalid command stream !\n");
                 radeon_cs_parser_fini(&parser, r);
@@ -254,3 +278,66 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
         mutex_unlock(&rdev->cs_mutex);
         return r;
 }
+
+int radeon_cs_finish_pages(struct radeon_cs_parser *p)
+{
+        struct radeon_cs_chunk *ibc = &p->chunks[p->chunk_ib_idx];
+        int i;
+        int size = PAGE_SIZE;
+
+        for (i = ibc->last_copied_page + 1; i <= ibc->last_page_index; i++) {
+                if (i == ibc->last_page_index) {
+                        size = (ibc->length_dw * 4) % PAGE_SIZE;
+                        if (size == 0)
+                                size = PAGE_SIZE;
+                }
+                
+                if (DRM_COPY_FROM_USER(p->ib->ptr + (i * (PAGE_SIZE/4)),
+                                       ibc->user_ptr + (i * PAGE_SIZE),
+                                       size))
+                        return -EFAULT;
+        }
+        return 0;
+}
+
+int radeon_cs_update_pages(struct radeon_cs_parser *p, int pg_idx)
+{
+        int new_page;
+        int num_extra_pages;
+        struct radeon_cs_chunk *ibc = &p->chunks[p->chunk_ib_idx];
+        int i;
+        int size = PAGE_SIZE;
+
+        num_extra_pages = (pg_idx - ibc->last_copied_page - 1);
+        for (i = ibc->last_copied_page + 1; i < ibc->last_copied_page + num_extra_pages; i++) {
+                if (DRM_COPY_FROM_USER(p->ib->ptr + (i * (PAGE_SIZE/4)),
+                                       ibc->user_ptr + (i * PAGE_SIZE),
+                                       PAGE_SIZE)) {
+                        p->parser_error = -EFAULT;
+                        return 0;
+                }
+        }
+
+        new_page = ibc->kpage_idx[0] < ibc->kpage_idx[1] ? 0 : 1;
+
+        if (pg_idx == ibc->last_page_index) {
+                size = (ibc->length_dw * 4) % PAGE_SIZE;
+                        if (size == 0)
+                                size = PAGE_SIZE;
+        }
+
+        if (DRM_COPY_FROM_USER(ibc->kpage[new_page],
+                               ibc->user_ptr + (pg_idx * PAGE_SIZE),
+                               size)) {
+                p->parser_error = -EFAULT;
+                return 0;
+        }
+
+        /* copy to IB here */
+        memcpy((void *)(p->ib->ptr+(pg_idx*(PAGE_SIZE/4))), ibc->kpage[new_page], size);
+
+        ibc->last_copied_page = pg_idx;
+        ibc->kpage_idx[new_page] = pg_idx;
+
+        return new_page;
+}