Thread (64 messages) 64 messages, 8 authors, 2017-06-26

[PATCH 03/44] dmaengine: ioat: don't use DMA_ERROR_CODE

From: Alexander Duyck <hidden>
Date: 2017-06-16 20:40:30
Also in: dri-devel, linux-iommu, linux-mips, linux-s390, linux-samsung-soc, linux-sh, linux-tegra, linuxppc-dev, lkml, netdev, sparclinux

On Fri, Jun 16, 2017 at 11:10 AM, Christoph Hellwig [off-list ref] wrote:
quoted hunk ↗ jump to hunk
DMA_ERROR_CODE is not a public API and will go away.  Instead properly
unwind based on the loop counter.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Acked-By: Vinod Koul <redacted>
---
 drivers/dma/ioat/init.c | 24 +++++++-----------------
 1 file changed, 7 insertions(+), 17 deletions(-)
diff --git a/drivers/dma/ioat/init.c b/drivers/dma/ioat/init.c
index 6ad4384b3fa8..ed8ed1192775 100644
--- a/drivers/dma/ioat/init.c
+++ b/drivers/dma/ioat/init.c
@@ -839,8 +839,6 @@ static int ioat_xor_val_self_test(struct ioatdma_device *ioat_dma)
                goto free_resources;
        }

-       for (i = 0; i < IOAT_NUM_SRC_TEST; i++)
-               dma_srcs[i] = DMA_ERROR_CODE;
        for (i = 0; i < IOAT_NUM_SRC_TEST; i++) {
                dma_srcs[i] = dma_map_page(dev, xor_srcs[i], 0, PAGE_SIZE,
                                           DMA_TO_DEVICE);
@@ -910,8 +908,6 @@ static int ioat_xor_val_self_test(struct ioatdma_device *ioat_dma)

        xor_val_result = 1;

-       for (i = 0; i < IOAT_NUM_SRC_TEST + 1; i++)
-               dma_srcs[i] = DMA_ERROR_CODE;
        for (i = 0; i < IOAT_NUM_SRC_TEST + 1; i++) {
                dma_srcs[i] = dma_map_page(dev, xor_val_srcs[i], 0, PAGE_SIZE,
                                           DMA_TO_DEVICE);
@@ -965,8 +961,6 @@ static int ioat_xor_val_self_test(struct ioatdma_device *ioat_dma)
        op = IOAT_OP_XOR_VAL;

        xor_val_result = 0;
-       for (i = 0; i < IOAT_NUM_SRC_TEST + 1; i++)
-               dma_srcs[i] = DMA_ERROR_CODE;
        for (i = 0; i < IOAT_NUM_SRC_TEST + 1; i++) {
                dma_srcs[i] = dma_map_page(dev, xor_val_srcs[i], 0, PAGE_SIZE,
                                           DMA_TO_DEVICE);
@@ -1017,18 +1011,14 @@ static int ioat_xor_val_self_test(struct ioatdma_device *ioat_dma)
        goto free_resources;
 dma_unmap:
        if (op == IOAT_OP_XOR) {
-               if (dest_dma != DMA_ERROR_CODE)
-                       dma_unmap_page(dev, dest_dma, PAGE_SIZE,
-                                      DMA_FROM_DEVICE);
-               for (i = 0; i < IOAT_NUM_SRC_TEST; i++)
-                       if (dma_srcs[i] != DMA_ERROR_CODE)
-                               dma_unmap_page(dev, dma_srcs[i], PAGE_SIZE,
-                                              DMA_TO_DEVICE);
+               while (--i >= 0)
+                       dma_unmap_page(dev, dma_srcs[i], PAGE_SIZE,
+                                      DMA_TO_DEVICE);
+               dma_unmap_page(dev, dest_dma, PAGE_SIZE, DMA_FROM_DEVICE);
        } else if (op == IOAT_OP_XOR_VAL) {
-               for (i = 0; i < IOAT_NUM_SRC_TEST + 1; i++)
-                       if (dma_srcs[i] != DMA_ERROR_CODE)
-                               dma_unmap_page(dev, dma_srcs[i], PAGE_SIZE,
-                                              DMA_TO_DEVICE);
+               while (--i >= 0)
+                       dma_unmap_page(dev, dma_srcs[i], PAGE_SIZE,
+                                      DMA_TO_DEVICE);
Wouldn't it make more sense to pull out the while loop and just call
dma_unmap_page on dest_dma if "op == IOAT_OP_XOR"? Odds are it is what
the compiler is already generating and will save a few lines of code
so what you end up with is something like:
    while (--i >= 0)
        dma_unmap_page(dev, dma_srcs[i], PAGE_SIZE, DMA_TO_DEVICE);
    if (op == IOAT_OP_XOR)
        dma_unmap_page(dev, dest_dma, PAGE_SIZE, DMA_FROM_DEVICE);
        }
 free_resources:
        dma->device_free_chan_resources(dma_chan);
--
2.11.0
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