ion: Handle the memory mapping correctly on x86

This patch modifies the ion page pool code to address
limitation in x86 PAT. When one physical page is mapped
to multiple virtual pages, the same cache policy
should be used. Add set_memory_wc/uc call to avoid aliases.
If not, all mappings will be cached(write back).

Change-Id: I98ee8902df0c80135dddfa998c4ca4c2bb44e40e
Signed-off-by: Zhebin Jin <zhebin.jin@intel.com>
Signed-off-by: Vinil Cheeramvelil <vinil.cheeramvelil@intel.com>

diff --git a/drivers/staging/android/ion/Kconfig b/drivers/staging/android/ion/Kconfig
index 3452346244922d1211b674087641c1009b2c3e0b..301948cc48bd5f77b90da54b2b46af98d7453884 100644 (file)
--- a/drivers/staging/android/ion/Kconfig
+++ b/drivers/staging/android/ion/Kconfig
@@ -33,3 +33,10 @@ config ION_TEGRA
        help
          Choose this option if you wish to use ion on an nVidia Tegra.
 
+config ION_POOL_CACHE_POLICY
+       bool "Ion set page pool cache policy"
+       depends on ION
+       default y if X86
+       help
+         Choose this option if need to explicity set cache policy of the
+         pages in the page pool.

diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c
index fd7e23e0c06e9bcc47659e4d692819d6b61fe1a5..59ee2f8f67611ec8a92c2be94ec5712881bd2830 100644 (file)
--- a/drivers/staging/android/ion/ion_page_pool.c
+++ b/drivers/staging/android/ion/ion_page_pool.c
@@ -30,6 +30,8 @@ static void *ion_page_pool_alloc_pages(struct ion_page_pool *pool)
 
        if (!page)
                return NULL;
+       ion_page_pool_alloc_set_cache_policy(pool, page);
+
        ion_pages_sync_for_device(NULL, page, PAGE_SIZE << pool->order,
                                                DMA_BIDIRECTIONAL);
        return page;
@@ -38,6 +40,7 @@ static void *ion_page_pool_alloc_pages(struct ion_page_pool *pool)
 static void ion_page_pool_free_pages(struct ion_page_pool *pool,
                                     struct page *page)
 {
+       ion_page_pool_free_set_cache_policy(pool, page);
        __free_pages(page, pool->order);
 }
 
@@ -103,6 +106,11 @@ void ion_page_pool_free(struct ion_page_pool *pool, struct page *page)
                ion_page_pool_free_pages(pool, page);
 }
 
+void ion_page_pool_free_immediate(struct ion_page_pool *pool, struct page *page)
+{
+       ion_page_pool_free_pages(pool, page);
+}
+
 static int ion_page_pool_total(struct ion_page_pool *pool, bool high)
 {
        int count = pool->low_count;

diff --git a/drivers/staging/android/ion/ion_priv.h b/drivers/staging/android/ion/ion_priv.h
index 0239883bffb72a82c0ffb05bc9aaaf0ee52f32aa..6f59a2d36567a5dd64b3761f217f9e894cccd898 100644 (file)
--- a/drivers/staging/android/ion/ion_priv.h
+++ b/drivers/staging/android/ion/ion_priv.h
@@ -26,6 +26,9 @@
 #include <linux/sched.h>
 #include <linux/shrinker.h>
 #include <linux/types.h>
+#ifdef CONFIG_ION_POOL_CACHE_POLICY
+#include <asm/cacheflush.h>
+#endif
 
 #include "ion.h"
 
@@ -381,6 +384,37 @@ struct ion_page_pool *ion_page_pool_create(gfp_t gfp_mask, unsigned int order);
 void ion_page_pool_destroy(struct ion_page_pool *);
 struct page *ion_page_pool_alloc(struct ion_page_pool *);
 void ion_page_pool_free(struct ion_page_pool *, struct page *);
+void ion_page_pool_free_immediate(struct ion_page_pool *, struct page *);
+
+#ifdef CONFIG_ION_POOL_CACHE_POLICY
+static inline void ion_page_pool_alloc_set_cache_policy
+                               (struct ion_page_pool *pool,
+                               struct page *page){
+       void *va = page_address(page);
+
+       if (va)
+               set_memory_wc((unsigned long)va, 1 << pool->order);
+}
+
+static inline void ion_page_pool_free_set_cache_policy
+                               (struct ion_page_pool *pool,
+                               struct page *page){
+       void *va = page_address(page);
+
+       if (va)
+               set_memory_wb((unsigned long)va, 1 << pool->order);
+
+}
+#else
+static inline void ion_page_pool_alloc_set_cache_policy
+                               (struct ion_page_pool *pool,
+                               struct page *page){ }
+
+static inline void ion_page_pool_free_set_cache_policy
+                               (struct ion_page_pool *pool,
+                               struct page *page){ }
+#endif
+
 
 /** ion_page_pool_shrink - shrinks the size of the memory cached in the pool
  * @pool:              the pool

diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
index d4c3e5512dd54dbcf0b3f6d9a927a1e8bbb3fc5a..fa62cc433d488edcf6d6f956164c4324a49be40f 100644 (file)
--- a/drivers/staging/android/ion/ion_system_heap.c
+++ b/drivers/staging/android/ion/ion_system_heap.c
@@ -85,8 +85,10 @@ static void free_buffer_page(struct ion_system_heap *heap,
 
        if (!cached && !(buffer->private_flags & ION_PRIV_FLAG_SHRINKER_FREE)) {
                struct ion_page_pool *pool = heap->pools[order_to_index(order)];
-
-               ion_page_pool_free(pool, page);
+               if (buffer->private_flags & ION_PRIV_FLAG_SHRINKER_FREE)
+                       ion_page_pool_free_immediate(pool, page);
+               else
+                       ion_page_pool_free(pool, page);
        } else {
                __free_pages(page, order);
        }