drm/nouveau: remove allocations from gart populate() hook

Since some somewhat questionable changes a while back, TTM provides a
completely empty array of struct dma_address that stays around for the
entire lifetime of the TTM object.

Lets use this array, *always*, rather than wasting yet more memory on
another array who's purpose is identical, as well as yet another bool array
of the same size saying *which* of the previous two arrays to use...

This change will also solve the high order allocation failures seen by
some people while using nouveau.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 21 insertions, 45 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_sgdma.c b/drivers/gpu/drm/nouveau/nouveau_sgdma.c
index 2706cb3d871a..b75258a9fe44 100644
--- a/drivers/gpu/drm/nouveau/nouveau_sgdma.c
+++ b/drivers/gpu/drm/nouveau/nouveau_sgdma.c
@@ -12,8 +12,8 @@ struct nouveau_sgdma_be {
         struct drm_device *dev;
 
         dma_addr_t *pages;
-        bool *ttm_alloced;
         unsigned nr_pages;
+        bool unmap_pages;
 
         u64 offset;
         bool bound;
@@ -26,43 +26,28 @@ nouveau_sgdma_populate(struct ttm_backend *be, unsigned long num_pages,
 {
         struct nouveau_sgdma_be *nvbe = (struct nouveau_sgdma_be *)be;
         struct drm_device *dev = nvbe->dev;
+        int i;
 
         NV_DEBUG(nvbe->dev, "num_pages = %ld\n", num_pages);
 
-        if (nvbe->pages)
-                return -EINVAL;
-
-        nvbe->pages = kmalloc(sizeof(dma_addr_t) * num_pages, GFP_KERNEL);
-        if (!nvbe->pages)
-                return -ENOMEM;
+        nvbe->pages = dma_addrs;
+        nvbe->nr_pages = num_pages;
+        nvbe->unmap_pages = true;
 
-        nvbe->ttm_alloced = kmalloc(sizeof(bool) * num_pages, GFP_KERNEL);
-        if (!nvbe->ttm_alloced) {
-                kfree(nvbe->pages);
-                nvbe->pages = NULL;
-                return -ENOMEM;
+        /* this code path isn't called and is incorrect anyways */
+        if (0) { /* dma_addrs[0] != DMA_ERROR_CODE) { */
+                nvbe->unmap_pages = false;
+                return 0;
         }
 
-        nvbe->nr_pages = 0;
-        while (num_pages--) {
-                /* this code path isn't called and is incorrect anyways */
-                if (0) { /*dma_addrs[nvbe->nr_pages] != DMA_ERROR_CODE)*/
-                        nvbe->pages[nvbe->nr_pages] =
-                                        dma_addrs[nvbe->nr_pages];
-                        nvbe->ttm_alloced[nvbe->nr_pages] = true;
-                } else {
-                        nvbe->pages[nvbe->nr_pages] =
-                                pci_map_page(dev->pdev, pages[nvbe->nr_pages], 0,
-                                     PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
-                        if (pci_dma_mapping_error(dev->pdev,
-                                                  nvbe->pages[nvbe->nr_pages])) {
-                                be->func->clear(be);
-                                return -EFAULT;
-                        }
-                        nvbe->ttm_alloced[nvbe->nr_pages] = false;
+        for (i = 0; i < num_pages; i++) {
+                nvbe->pages[i] = pci_map_page(dev->pdev, pages[i], 0,
+                                              PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
+                if (pci_dma_mapping_error(dev->pdev, nvbe->pages[i])) {
+                        nvbe->nr_pages = --i;
+                        be->func->clear(be);
+                        return -EFAULT;
                 }
-
-                nvbe->nr_pages++;
         }
 
         return 0;
@@ -72,25 +57,16 @@ static void
 nouveau_sgdma_clear(struct ttm_backend *be)
 {
         struct nouveau_sgdma_be *nvbe = (struct nouveau_sgdma_be *)be;
-        struct drm_device *dev;
-
-        if (nvbe && nvbe->pages) {
-                dev = nvbe->dev;
-                NV_DEBUG(dev, "\n");
+        struct drm_device *dev = nvbe->dev;
 
-                if (nvbe->bound)
-                        be->func->unbind(be);
+        if (nvbe->bound)
+                be->func->unbind(be);
 
+        if (nvbe->unmap_pages) {
                 while (nvbe->nr_pages--) {
-                        if (!nvbe->ttm_alloced[nvbe->nr_pages])
-                                pci_unmap_page(dev->pdev, nvbe->pages[nvbe->nr_pages],
+                        pci_unmap_page(dev->pdev, nvbe->pages[nvbe->nr_pages],
                                        PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
                 }
-                kfree(nvbe->pages);
-                kfree(nvbe->ttm_alloced);
-                nvbe->pages = NULL;
-                nvbe->ttm_alloced = NULL;
-                nvbe->nr_pages = 0;
         }
 }