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Subject[PATCH] PowerPC consistent_free() didn't free physical, just virtual (fixed)
consistent_free() was only freeing the virtual addresses before.
This actually frees the virtual address and physical pages now.
The hacked "track" array allows us to keep track of the
address/order tuple so consistent_free() knows how large the area
was without passing it in (and changing the arity of the function).

I discovered this by using consistent_alloc() and consistent_free() several
times. Eventually, there was no RAM was left and instead of returning an
error consistent_alloc() panics.


diff -Nru a/arch/ppc/mm/cachemap.c b/arch/ppc/mm/cachemap.c
--- a/arch/ppc/mm/cachemap.c Sat Aug 16 14:31:27 2003
+++ b/arch/ppc/mm/cachemap.c Sat Aug 16 14:31:27 2003
@@ -60,6 +60,18 @@
* portions of the kernel with single large page TLB entries, and
* still get unique uncached pages for consistent DMA.
*/
+
+/*
+ * consistent_free() was only freeing the virtual addresses before.
+ * This actually frees the virtual address and physical pages now.
+ * The hacked "track" array allows us to keep track of the
+ * address/order tuple so consistent_free() knows how large the area
+ * was without passing it in (and changing the arity of the function).
+ * -- Cort <cort@fsmlabs.com>
+ */
+#define TRACK_SZ 100
+static unsigned long track[TRACK_SZ][3];
+
void *consistent_alloc(int gfp, size_t size, dma_addr_t *dma_handle)
{
int order, err, i;
@@ -125,6 +137,21 @@
return NULL;
}

+ {
+ int i;
+
+ for ( i = 0; i < TRACK_SZ ; i++ ) {
+ if ( track[i][0] == 0 ) {
+ break;
+ }
+ }
+ if ( i >= TRACK_SZ )
+ panic("ran out of space\n");
+ track[i][0] = ret;
+ track[i][1] = page;
+ track[i][2] = order;
+ }
+
return ret;
}

@@ -135,7 +162,26 @@
{
if (in_interrupt())
BUG();
- vfree(vaddr);
+
+ {
+ int i;
+
+ for ( i = 0; i < TRACK_SZ ; i++ ) {
+ if ( track[i][0] == vaddr ) {
+ break;
+ }
+ }
+ if ( i >= TRACK_SZ )
+ panic("couldn't find vaddr\n");
+
+ free_pages(track[i][1], track[i][2]);
+
+ track[i][0] = 0;
+ track[i][1] = 0;
+ track[i][2] = 0;
+
+ }
+
}

/*
-
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