dma-remap: separate DMA atomic pools from direct remap code

DMA atomic pools will be needed beyond only CONFIG_DMA_DIRECT_REMAP so
separate them out into their own file.

This also adds a new Kconfig option that can be subsequently used for
options, such as CONFIG_AMD_MEM_ENCRYPT, that will utilize the coherent
pools but do not have a dependency on direct remapping.

For this patch alone, there is no functional change introduced.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Rientjes <rientjes@google.com>
[hch: fixup copyrights and remove unused includes]
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 4c103a2..d006668 100644 (file)
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -79,10 +79,14 @@ config DMA_REMAP
        select DMA_NONCOHERENT_MMAP
        bool
 
-config DMA_DIRECT_REMAP
+config DMA_COHERENT_POOL
        bool
        select DMA_REMAP
 
+config DMA_DIRECT_REMAP
+       bool
+       select DMA_COHERENT_POOL
+
 config DMA_CMA
        bool "DMA Contiguous Memory Allocator"
        depends on HAVE_DMA_CONTIGUOUS && CMA

diff --git a/kernel/dma/Makefile b/kernel/dma/Makefile
index d237cf3..370f633 100644 (file)
--- a/kernel/dma/Makefile
+++ b/kernel/dma/Makefile
@@ -6,4 +6,5 @@ obj-$(CONFIG_DMA_DECLARE_COHERENT)      += coherent.o
 obj-$(CONFIG_DMA_VIRT_OPS)             += virt.o
 obj-$(CONFIG_DMA_API_DEBUG)            += debug.o
 obj-$(CONFIG_SWIOTLB)                  += swiotlb.o
+obj-$(CONFIG_DMA_COHERENT_POOL)                += pool.o
 obj-$(CONFIG_DMA_REMAP)                        += remap.o

diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
new file mode 100644 (file)
index 0000000..3df5d9d
--- /dev/null
+++ b/kernel/dma/pool.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Copyright (C) 2020 Google LLC
+ */
+#include <linux/dma-direct.h>
+#include <linux/dma-noncoherent.h>
+#include <linux/dma-contiguous.h>
+#include <linux/init.h>
+#include <linux/genalloc.h>
+#include <linux/slab.h>
+
+static struct gen_pool *atomic_pool __ro_after_init;
+
+#define DEFAULT_DMA_COHERENT_POOL_SIZE  SZ_256K
+static size_t atomic_pool_size __initdata = DEFAULT_DMA_COHERENT_POOL_SIZE;
+
+static int __init early_coherent_pool(char *p)
+{
+       atomic_pool_size = memparse(p, &p);
+       return 0;
+}
+early_param("coherent_pool", early_coherent_pool);
+
+static gfp_t dma_atomic_pool_gfp(void)
+{
+       if (IS_ENABLED(CONFIG_ZONE_DMA))
+               return GFP_DMA;
+       if (IS_ENABLED(CONFIG_ZONE_DMA32))
+               return GFP_DMA32;
+       return GFP_KERNEL;
+}
+
+static int __init dma_atomic_pool_init(void)
+{
+       unsigned int pool_size_order = get_order(atomic_pool_size);
+       unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT;
+       struct page *page;
+       void *addr;
+       int ret;
+
+       if (dev_get_cma_area(NULL))
+               page = dma_alloc_from_contiguous(NULL, nr_pages,
+                                                pool_size_order, false);
+       else
+               page = alloc_pages(dma_atomic_pool_gfp(), pool_size_order);
+       if (!page)
+               goto out;
+
+       arch_dma_prep_coherent(page, atomic_pool_size);
+
+       atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
+       if (!atomic_pool)
+               goto free_page;
+
+       addr = dma_common_contiguous_remap(page, atomic_pool_size,
+                                          pgprot_dmacoherent(PAGE_KERNEL),
+                                          __builtin_return_address(0));
+       if (!addr)
+               goto destroy_genpool;
+
+       ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr,
+                               page_to_phys(page), atomic_pool_size, -1);
+       if (ret)
+               goto remove_mapping;
+       gen_pool_set_algo(atomic_pool, gen_pool_first_fit_order_align, NULL);
+
+       pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n",
+               atomic_pool_size / 1024);
+       return 0;
+
+remove_mapping:
+       dma_common_free_remap(addr, atomic_pool_size);
+destroy_genpool:
+       gen_pool_destroy(atomic_pool);
+       atomic_pool = NULL;
+free_page:
+       if (!dma_release_from_contiguous(NULL, page, nr_pages))
+               __free_pages(page, pool_size_order);
+out:
+       pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
+               atomic_pool_size / 1024);
+       return -ENOMEM;
+}
+postcore_initcall(dma_atomic_pool_init);
+
+bool dma_in_atomic_pool(void *start, size_t size)
+{
+       if (unlikely(!atomic_pool))
+               return false;
+
+       return gen_pool_has_addr(atomic_pool, (unsigned long)start, size);
+}
+
+void *dma_alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags)
+{
+       unsigned long val;
+       void *ptr = NULL;
+
+       if (!atomic_pool) {
+               WARN(1, "coherent pool not initialised!\n");
+               return NULL;
+       }
+
+       val = gen_pool_alloc(atomic_pool, size);
+       if (val) {
+               phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val);
+
+               *ret_page = pfn_to_page(__phys_to_pfn(phys));
+               ptr = (void *)val;
+               memset(ptr, 0, size);
+       }
+
+       return ptr;
+}
+
+bool dma_free_from_pool(void *start, size_t size)
+{
+       if (!dma_in_atomic_pool(start, size))
+               return false;
+       gen_pool_free(atomic_pool, (unsigned long)start, size);
+       return true;
+}

diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
index d14cbc8..f7b4028 100644 (file)
--- a/kernel/dma/remap.c
+++ b/kernel/dma/remap.c
@@ -1,13 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Copyright (C) 2012 ARM Ltd.
  * Copyright (c) 2014 The Linux Foundation
  */
-#include <linux/dma-direct.h>
-#include <linux/dma-noncoherent.h>
-#include <linux/dma-contiguous.h>
-#include <linux/init.h>
-#include <linux/genalloc.h>
+#include <linux/dma-mapping.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 
@@ -97,117 +92,3 @@ void dma_common_free_remap(void *cpu_addr, size_t size)
        unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
        vunmap(cpu_addr);
 }
-
-#ifdef CONFIG_DMA_DIRECT_REMAP
-static struct gen_pool *atomic_pool __ro_after_init;
-
-#define DEFAULT_DMA_COHERENT_POOL_SIZE  SZ_256K
-static size_t atomic_pool_size __initdata = DEFAULT_DMA_COHERENT_POOL_SIZE;
-
-static int __init early_coherent_pool(char *p)
-{
-       atomic_pool_size = memparse(p, &p);
-       return 0;
-}
-early_param("coherent_pool", early_coherent_pool);
-
-static gfp_t dma_atomic_pool_gfp(void)
-{
-       if (IS_ENABLED(CONFIG_ZONE_DMA))
-               return GFP_DMA;
-       if (IS_ENABLED(CONFIG_ZONE_DMA32))
-               return GFP_DMA32;
-       return GFP_KERNEL;
-}
-
-static int __init dma_atomic_pool_init(void)
-{
-       unsigned int pool_size_order = get_order(atomic_pool_size);
-       unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT;
-       struct page *page;
-       void *addr;
-       int ret;
-
-       if (dev_get_cma_area(NULL))
-               page = dma_alloc_from_contiguous(NULL, nr_pages,
-                                                pool_size_order, false);
-       else
-               page = alloc_pages(dma_atomic_pool_gfp(), pool_size_order);
-       if (!page)
-               goto out;
-
-       arch_dma_prep_coherent(page, atomic_pool_size);
-
-       atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
-       if (!atomic_pool)
-               goto free_page;
-
-       addr = dma_common_contiguous_remap(page, atomic_pool_size,
-                                          pgprot_dmacoherent(PAGE_KERNEL),
-                                          __builtin_return_address(0));
-       if (!addr)
-               goto destroy_genpool;
-
-       ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr,
-                               page_to_phys(page), atomic_pool_size, -1);
-       if (ret)
-               goto remove_mapping;
-       gen_pool_set_algo(atomic_pool, gen_pool_first_fit_order_align, NULL);
-
-       pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n",
-               atomic_pool_size / 1024);
-       return 0;
-
-remove_mapping:
-       dma_common_free_remap(addr, atomic_pool_size);
-destroy_genpool:
-       gen_pool_destroy(atomic_pool);
-       atomic_pool = NULL;
-free_page:
-       if (!dma_release_from_contiguous(NULL, page, nr_pages))
-               __free_pages(page, pool_size_order);
-out:
-       pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
-               atomic_pool_size / 1024);
-       return -ENOMEM;
-}
-postcore_initcall(dma_atomic_pool_init);
-
-bool dma_in_atomic_pool(void *start, size_t size)
-{
-       if (unlikely(!atomic_pool))
-               return false;
-
-       return gen_pool_has_addr(atomic_pool, (unsigned long)start, size);
-}
-
-void *dma_alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags)
-{
-       unsigned long val;
-       void *ptr = NULL;
-
-       if (!atomic_pool) {
-               WARN(1, "coherent pool not initialised!\n");
-               return NULL;
-       }
-
-       val = gen_pool_alloc(atomic_pool, size);
-       if (val) {
-               phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val);
-
-               *ret_page = pfn_to_page(__phys_to_pfn(phys));
-               ptr = (void *)val;
-               memset(ptr, 0, size);
-       }
-
-       return ptr;
-}
-
-bool dma_free_from_pool(void *start, size_t size)
-{
-       if (!dma_in_atomic_pool(start, size))
-               return false;
-       gen_pool_free(atomic_pool, (unsigned long)start, size);
-       return true;
-}
-#endif /* CONFIG_DMA_DIRECT_REMAP */