[PATCH 12/12] dma-mapping: remove dma_assign_coherent_memory

[Christoph Hellwig]

The only useful bit in this function was the already assigned check.
Once that is moved to dma_init_coherent_memory thee rest can easily
be handled in the two callers.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 kernel/dma/coherent.c | 47 +++++++++++++------------------------------
 1 file changed, 14 insertions(+), 33 deletions(-)

diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index d7a27008f228..1e3ce71cd993 100644
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c
@@ -41,6 +41,9 @@ static int dma_init_coherent_memory(phys_addr_t phys_addr,
        int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
        int ret;
 
+       if (*mem)
+               return -EBUSY;
+
        if (!size) {
                ret = -EINVAL;
                goto out;
@@ -88,33 +91,11 @@ static void dma_release_coherent_memory(struct 
dma_coherent_mem *mem)
        kfree(mem);
 }
 
-static int dma_assign_coherent_memory(struct device *dev,
-                                     struct dma_coherent_mem *mem)
-{
-       if (!dev)
-               return -ENODEV;
-
-       if (dev->dma_mem)
-               return -EBUSY;
-
-       dev->dma_mem = mem;
-       return 0;
-}
-
 int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
                                dma_addr_t device_addr, size_t size)
 {
-       struct dma_coherent_mem *mem;
-       int ret;
-
-       ret = dma_init_coherent_memory(phys_addr, device_addr, size, &mem);
-       if (ret)
-               return ret;
-
-       ret = dma_assign_coherent_memory(dev, mem);
-       if (ret)
-               dma_release_coherent_memory(mem);
-       return ret;
+       return dma_init_coherent_memory(phys_addr, device_addr, size,
+                                       &dev->dma_mem);
 }
 EXPORT_SYMBOL(dma_declare_coherent_memory);
 
@@ -238,18 +219,18 @@ static int rmem_dma_device_init(struct reserved_mem 
*rmem, struct device *dev)
        struct dma_coherent_mem *mem = rmem->priv;
        int ret;
 
-       if (!mem) {
-               ret = dma_init_coherent_memory(rmem->base, rmem->base,
-                                              rmem->size, &mem);
-               if (ret) {
-                       pr_err("Reserved memory: failed to init DMA memory pool 
at %pa, size %ld MiB\n",
-                               &rmem->base, (unsigned long)rmem->size / SZ_1M);
-                       return ret;
-               }
+       ret = dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
+                       &mem);
+       if (ret && ret != -EBUSY) {
+               pr_err("Reserved memory: failed to init DMA memory pool at %pa, 
size %ld MiB\n",
+                       &rmem->base, (unsigned long)rmem->size / SZ_1M);
+               return ret;
        }
+
        mem->use_dev_dma_pfn_offset = true;
+       if (dev)
+               dev->dma_mem = mem;
        rmem->priv = mem;
-       dma_assign_coherent_memory(dev, mem);
        return 0;
 }
 
-- 
2.20.1

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