PCI: epf-test: Simplify DMA support checks

There is no need to have each read, write and copy test functions check
for the FLAG_USE_DMA flag against the DMA support status indicated by
epf_test->dma_supported. Move this test to the command handler function
pci_epf_test_cmd_handler() to check once for all cases.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Damien Le Moal <[email protected]>
Signed-off-by: Lorenzo Pieralisi <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Manivannan Sadhasivam <[email protected]>

Author: damien-lemoal

drivers/pci/endpoint/functions/pci-epf-test.c

@@ -329,7 +329,6 @@ static void pci_epf_test_copy(struct pci_epf_test *epf_test,
 			      struct pci_epf_test_reg *reg)
 {
 	int ret;
-	bool use_dma;
 	void __iomem *src_addr;
 	void __iomem *dst_addr;
 	phys_addr_t src_phys_addr;
@@ -372,14 +371,7 @@ static void pci_epf_test_copy(struct pci_epf_test *epf_test,
 	}
 
 	ktime_get_ts64(&start);
-	use_dma = !!(reg->flags & FLAG_USE_DMA);
-	if (use_dma) {
-		if (!epf_test->dma_supported) {
-			dev_err(dev, "Cannot transfer data using DMA\n");
-			ret = -EINVAL;
-			goto err_map_addr;
-		}
-
+	if (reg->flags & FLAG_USE_DMA) {
 		if (epf_test->dma_private) {
 			dev_err(dev, "Cannot transfer data using DMA\n");
 			ret = -EINVAL;
@@ -405,7 +397,8 @@ static void pci_epf_test_copy(struct pci_epf_test *epf_test,
 		kfree(buf);
 	}
 	ktime_get_ts64(&end);
-	pci_epf_test_print_rate("COPY", reg->size, &start, &end, use_dma);
+	pci_epf_test_print_rate("COPY", reg->size, &start, &end,
+				reg->flags & FLAG_USE_DMA);
 
 err_map_addr:
 	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, dst_phys_addr);
@@ -433,7 +426,6 @@ static void pci_epf_test_read(struct pci_epf_test *epf_test,
 	void __iomem *src_addr;
 	void *buf;
 	u32 crc32;
-	bool use_dma;
 	phys_addr_t phys_addr;
 	phys_addr_t dst_phys_addr;
 	struct timespec64 start, end;
@@ -464,14 +456,7 @@ static void pci_epf_test_read(struct pci_epf_test *epf_test,
 		goto err_map_addr;
 	}
 
-	use_dma = !!(reg->flags & FLAG_USE_DMA);
-	if (use_dma) {
-		if (!epf_test->dma_supported) {
-			dev_err(dev, "Cannot transfer data using DMA\n");
-			ret = -EINVAL;
-			goto err_dma_map;
-		}
-
+	if (reg->flags & FLAG_USE_DMA) {
 		dst_phys_addr = dma_map_single(dma_dev, buf, reg->size,
 					       DMA_FROM_DEVICE);
 		if (dma_mapping_error(dma_dev, dst_phys_addr)) {
@@ -496,7 +481,8 @@ static void pci_epf_test_read(struct pci_epf_test *epf_test,
 		ktime_get_ts64(&end);
 	}
 
-	pci_epf_test_print_rate("READ", reg->size, &start, &end, use_dma);
+	pci_epf_test_print_rate("READ", reg->size, &start, &end,
+				reg->flags & FLAG_USE_DMA);
 
 	crc32 = crc32_le(~0, buf, reg->size);
 	if (crc32 != reg->checksum)
@@ -524,7 +510,6 @@ static void pci_epf_test_write(struct pci_epf_test *epf_test,
 	int ret;
 	void __iomem *dst_addr;
 	void *buf;
-	bool use_dma;
 	phys_addr_t phys_addr;
 	phys_addr_t src_phys_addr;
 	struct timespec64 start, end;
@@ -558,14 +543,7 @@ static void pci_epf_test_write(struct pci_epf_test *epf_test,
 	get_random_bytes(buf, reg->size);
 	reg->checksum = crc32_le(~0, buf, reg->size);
 
-	use_dma = !!(reg->flags & FLAG_USE_DMA);
-	if (use_dma) {
-		if (!epf_test->dma_supported) {
-			dev_err(dev, "Cannot transfer data using DMA\n");
-			ret = -EINVAL;
-			goto err_dma_map;
-		}
-
+	if (reg->flags & FLAG_USE_DMA) {
 		src_phys_addr = dma_map_single(dma_dev, buf, reg->size,
 					       DMA_TO_DEVICE);
 		if (dma_mapping_error(dma_dev, src_phys_addr)) {
@@ -592,7 +570,8 @@ static void pci_epf_test_write(struct pci_epf_test *epf_test,
 		ktime_get_ts64(&end);
 	}
 
-	pci_epf_test_print_rate("WRITE", reg->size, &start, &end, use_dma);
+	pci_epf_test_print_rate("WRITE", reg->size, &start, &end,
+				reg->flags & FLAG_USE_DMA);
 
 	/*
 	 * wait 1ms inorder for the write to complete. Without this delay L3
@@ -679,6 +658,12 @@ static void pci_epf_test_cmd_handler(struct work_struct *work)
 	WRITE_ONCE(reg->command, 0);
 	WRITE_ONCE(reg->status, 0);
 
+	if ((READ_ONCE(reg->flags) & FLAG_USE_DMA) &&
+	    !epf_test->dma_supported) {
+		dev_err(dev, "Cannot transfer data using DMA\n");
+		goto reset_handler;
+	}
+
 	if (reg->irq_type > IRQ_TYPE_MSIX) {
 		dev_err(dev, "Failed to detect IRQ type\n");
 		goto reset_handler;