KVM: MMU: Remove user access when allowing kernel access to gpte.w=0 page

[safe/jmp/linux-2.6] / mm / bounce.c

diff --git a/mm/bounce.c b/mm/bounce.c
index 3b549bf..13b6dad 100644 (file)
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -6,6 +6,7 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/swap.h>
+#include <linux/gfp.h>
 #include <linux/bio.h>
 #include <linux/pagemap.h>
 #include <linux/mempool.h>
@@ -13,9 +14,10 @@
 #include <linux/init.h>
 #include <linux/hash.h>
 #include <linux/highmem.h>
-#include <linux/blktrace_api.h>
 #include <asm/tlbflush.h>
 
+#include <trace/events/block.h>
+
 #define POOL_SIZE      64
 #define ISA_POOL_SIZE  16
 
@@ -189,14 +191,19 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
                /*
                 * is destination page below bounce pfn?
                 */
-               if (page_to_pfn(page) <= q->bounce_pfn)
+               if (page_to_pfn(page) <= queue_bounce_pfn(q))
                        continue;
 
                /*
                 * irk, bounce it
                 */
-               if (!bio)
-                       bio = bio_alloc(GFP_NOIO, (*bio_orig)->bi_vcnt);
+               if (!bio) {
+                       unsigned int cnt = (*bio_orig)->bi_vcnt;
+
+                       bio = bio_alloc(GFP_NOIO, cnt);
+                       memset(bio->bi_io_vec, 0, cnt * sizeof(struct bio_vec));
+               }
+                       
 
                to = bio->bi_io_vec + i;
 
@@ -222,7 +229,7 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
        if (!bio)
                return;
 
-       blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE);
+       trace_block_bio_bounce(q, *bio_orig);
 
        /*
         * at least one page was bounced, fill in possible non-highmem
@@ -265,12 +272,18 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
        mempool_t *pool;
 
        /*
+        * Data-less bio, nothing to bounce
+        */
+       if (!bio_has_data(*bio_orig))
+               return;
+
+       /*
         * for non-isa bounce case, just check if the bounce pfn is equal
         * to or bigger than the highest pfn in the system -- in that case,
         * don't waste time iterating over bio segments
         */
        if (!(q->bounce_gfp & GFP_DMA)) {
-               if (q->bounce_pfn >= blk_max_pfn)
+               if (queue_bounce_pfn(q) >= blk_max_pfn)
                        return;
                pool = page_pool;
        } else {