[Intel-gfx] [PATCH v2] drm/i915: Propagate errors on failed PPGTT

[Ben Widawsky]

Clean up the return values/error handling so it's obvious what is going
on. This was tripped over in the PPGTT branch where code was added to do
a ret = foo() near the top, and this ended up bypassing some error cases
later.

These errors shouldn't exist with today's code, but a future patch
will add a ret = ..., and this the value of ret needs to be set
explicitly.

v2: Missed an error in alloc_page for gen6

Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index e63ae52..866b23e 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -361,7 +361,7 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
 static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
 {
 	struct page *pt_pages;
-	int i, j, ret = -ENOMEM;
+	int i, j, ret;
 	const int max_pdp = DIV_ROUND_UP(size, 1 << 30);
 	const int num_pt_pages = GEN8_PDES_PER_PAGE * max_pdp;
 
@@ -407,14 +407,17 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
 		temp = pci_map_page(ppgtt->base.dev->pdev,
 				    &ppgtt->pd_pages[i], 0,
 				    PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
-		if (pci_dma_mapping_error(ppgtt->base.dev->pdev, temp))
+		ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, temp);
+		if (ret)
 			goto err_out;
 
 		ppgtt->pd_dma_addr[i] = temp;
 
 		ppgtt->gen8_pt_dma_addr[i] = kmalloc(sizeof(dma_addr_t) * GEN8_PDES_PER_PAGE, GFP_KERNEL);
-		if (!ppgtt->gen8_pt_dma_addr[i])
+		if (!ppgtt->gen8_pt_dma_addr[i]) {
+			ret = -ENOMEM;
 			goto err_out;
+		}
 
 		for (j = 0; j < GEN8_PDES_PER_PAGE; j++) {
 			struct page *p = &pt_pages[i * GEN8_PDES_PER_PAGE + j];
@@ -422,7 +425,8 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
 					    p, 0, PAGE_SIZE,
 					    PCI_DMA_BIDIRECTIONAL);
 
-			if (pci_dma_mapping_error(ppgtt->base.dev->pdev, temp))
+			ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, temp);
+			if (ret)
 				goto err_out;
 
 			ppgtt->gen8_pt_dma_addr[i][j] = temp;
@@ -849,7 +853,7 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
 	struct drm_device *dev = ppgtt->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	bool retried = false;
-	int i, ret = -ENOMEM;
+	int i, ret;
 
 	/* PPGTT PDEs reside in the GGTT and consists of 512 entries. The
 	 * allocator works in address space sizes, so it's multiplied by page
@@ -904,14 +908,18 @@ alloc:
 
 	for (i = 0; i < ppgtt->num_pd_entries; i++) {
 		ppgtt->pt_pages[i] = alloc_page(GFP_KERNEL);
-		if (!ppgtt->pt_pages[i])
+		if (!ppgtt->pt_pages[i]) {
+			ret = -ENOMEM;
 			goto err_pt_alloc;
+		}
 	}
 
 	ppgtt->pt_dma_addr = kcalloc(ppgtt->num_pd_entries, sizeof(dma_addr_t),
 				     GFP_KERNEL);
-	if (!ppgtt->pt_dma_addr)
+	if (!ppgtt->pt_dma_addr) {
+		ret = -ENOMEM;
 		goto err_pt_alloc;
+	}
 
 	for (i = 0; i < ppgtt->num_pd_entries; i++) {
 		dma_addr_t pt_addr;
-- 
1.8.4.2