blackfin: use bitmap library functions

The bitmap library provides more efficient functions than accessing
individual bits with bitops.

This uses bitmap_find_next_zero_area() to find a continuing zero area,
and uses bitmap_set()/bitmap_clear() to set/clear specified bit area.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: uclinux-dist-devel@blackfin.uclinux.org
Signed-off-by: Bob Liu <lliubbo@gmail.com>

1 files changed, 7 insertions, 16 deletions

diff --git a/arch/blackfin/kernel/dma-mapping.c b/arch/blackfin/kernel/dma-mapping.c
index e7be6532d6a0..df437e52d9df 100644
--- a/arch/blackfin/kernel/dma-mapping.c
+++ b/arch/blackfin/kernel/dma-mapping.c
@@ -13,6 +13,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/scatterlist.h>
 #include <linux/export.h>
+#include <linux/bitmap.h>
 
 static spinlock_t dma_page_lock;
 static unsigned long *dma_page;
@@ -46,24 +47,17 @@ static inline unsigned int get_pages(size_t size)
 static unsigned long __alloc_dma_pages(unsigned int pages)
 {
         unsigned long ret = 0, flags;
-        int i, count = 0;
+        unsigned long start;
 
         if (dma_initialized == 0)
                 dma_alloc_init(_ramend - DMA_UNCACHED_REGION, _ramend);
 
         spin_lock_irqsave(&dma_page_lock, flags);
 
-        for (i = 0; i < dma_pages;) {
-                if (test_bit(i++, dma_page) == 0) {
-                        if (++count == pages) {
-                                while (count--)
-                                        __set_bit(--i, dma_page);
-
-                                ret = dma_base + (i << PAGE_SHIFT);
-                                break;
-                        }
-                } else
-                        count = 0;
+        start = bitmap_find_next_zero_area(dma_page, dma_pages, 0, pages, 0);
+        if (start < dma_pages) {
+                ret = dma_base + (start << PAGE_SHIFT);
+                bitmap_set(dma_page, start, pages);
         }
         spin_unlock_irqrestore(&dma_page_lock, flags);
         return ret;
@@ -73,7 +67,6 @@ static void __free_dma_pages(unsigned long addr, unsigned int pages)
 {
         unsigned long page = (addr - dma_base) >> PAGE_SHIFT;
         unsigned long flags;
-        int i;
 
         if ((page + pages) > dma_pages) {
                 printk(KERN_ERR "%s: freeing outside range.\n", __func__);
@@ -81,9 +74,7 @@ static void __free_dma_pages(unsigned long addr, unsigned int pages)
         }
 
         spin_lock_irqsave(&dma_page_lock, flags);
-        for (i = page; i < page + pages; i++)
-                __clear_bit(i, dma_page);
-
+        bitmap_clear(dma_page, page, pages);
         spin_unlock_irqrestore(&dma_page_lock, flags);
 }