bitkeeper revision 1.1159.258.37 (42305f54a6Tlb_891y3QBjoIVcCt3Q)

Fix balloon driver in highmem builds -- must forcibly flush the kmap
cache before relinquishing pages. This requires changes to generic
files highmem.[ch].
Signed-off-by: Keir Fraser <keir.fraser@cl.cam.ac.uk>

6 files changed, 870 insertions, 5 deletions

diff --git a/.rootkeys b/.rootkeys
index d15fe9d75d..f5baebe00f 100644
--- a/.rootkeys
+++ b/.rootkeys
@@ -111,6 +111,7 @@
 3f1056a9L_kqHcFheV00KbKBzv9j5w linux-2.4.29-xen-sparse/include/asm-xen/vga.h
 40659defgWA92arexpMGn8X3QMDj3w linux-2.4.29-xen-sparse/include/asm-xen/xor.h
 3f056927gMHl7mWB89rb73JahbhQIA linux-2.4.29-xen-sparse/include/linux/blk.h
+42305f54mFScQCttpj57EIm60BnxIg linux-2.4.29-xen-sparse/include/linux/highmem.h
 419e0488SBzS3mdUhwgsES5a5e3abA linux-2.4.29-xen-sparse/include/linux/irq.h
 4124f66fPHG6yvB_vXmesjvzrJ3yMg linux-2.4.29-xen-sparse/include/linux/mm.h
 401c0590D_kwJDU59X8NyvqSv_Cl2A linux-2.4.29-xen-sparse/include/linux/sched.h
@@ -247,10 +248,12 @@
 4122466356eIBnC9ot44WSVVIFyhQA linux-2.6.10-xen-sparse/include/asm-xen/queues.h
 3f689063BoW-HWV3auUJ-OqXfcGArw linux-2.6.10-xen-sparse/include/asm-xen/xen_proc.h
 419b4e93z2S0gR17XTy8wg09JEwAhg linux-2.6.10-xen-sparse/include/linux/gfp.h
+42305f545Vc5SLCUewZ2-n-P9JJhEQ linux-2.6.10-xen-sparse/include/linux/highmem.h
 419dfc609zbti8rqL60tL2dHXQ_rvQ linux-2.6.10-xen-sparse/include/linux/irq.h
 4124f66f4NaKNa0xPiGGykn9QaZk3w linux-2.6.10-xen-sparse/include/linux/skbuff.h
 419dfc6awx7w88wk6cG9P3mPidX6LQ linux-2.6.10-xen-sparse/kernel/irq/manage.c
 40f56a0ddHCSs3501MY4hRf22tctOw linux-2.6.10-xen-sparse/mkbuildtree
+42305f54Q6xJ1bXcQJlCQq1m-e2C8g linux-2.6.10-xen-sparse/mm/highmem.c
 412f46c0LJuKAgSPGoC0Z1DEkLfuLA linux-2.6.10-xen-sparse/mm/memory.c
 410a94a4KT6I6X0LVc7djB39tRDp4g linux-2.6.10-xen-sparse/mm/page_alloc.c
 41505c572m-s9ATiO1LiD1GPznTTIg linux-2.6.10-xen-sparse/net/core/skbuff.c
diff --git a/linux-2.4.29-xen-sparse/include/linux/highmem.h b/linux-2.4.29-xen-sparse/include/linux/highmem.h
new file mode 100644
index 0000000000..7dab94f5eb
--- /dev/null
+++ b/linux-2.4.29-xen-sparse/include/linux/highmem.h
@@ -0,0 +1,137 @@
+#ifndef _LINUX_HIGHMEM_H
+#define _LINUX_HIGHMEM_H
+
+#include <linux/config.h>
+#include <asm/pgalloc.h>
+
+#ifdef CONFIG_HIGHMEM
+
+extern struct page *highmem_start_page;
+
+#include <asm/highmem.h>
+
+/* declarations for linux/mm/highmem.c */
+unsigned int nr_free_highpages(void);
+void kmap_flush_unused(void);
+
+extern struct buffer_head *create_bounce(int rw, struct buffer_head * bh_orig);
+
+static inline char *bh_kmap(struct buffer_head *bh)
+{
+	return kmap(bh->b_page) + bh_offset(bh);
+}
+
+static inline void bh_kunmap(struct buffer_head *bh)
+{
+	kunmap(bh->b_page);
+}
+
+/*
+ * remember to add offset! and never ever reenable interrupts between a
+ * bh_kmap_irq and bh_kunmap_irq!!
+ */
+static inline char *bh_kmap_irq(struct buffer_head *bh, unsigned long *flags)
+{
+	unsigned long addr;
+
+	__save_flags(*flags);
+
+	/*
+	 * could be low
+	 */
+	if (!PageHighMem(bh->b_page))
+		return bh->b_data;
+
+	/*
+	 * it's a highmem page
+	 */
+	__cli();
+	addr = (unsigned long) kmap_atomic(bh->b_page, KM_BH_IRQ);
+
+	if (addr & ~PAGE_MASK)
+		BUG();
+
+	return (char *) addr + bh_offset(bh);
+}
+
+static inline void bh_kunmap_irq(char *buffer, unsigned long *flags)
+{
+	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
+
+	kunmap_atomic((void *) ptr, KM_BH_IRQ);
+	__restore_flags(*flags);
+}
+
+#else /* CONFIG_HIGHMEM */
+
+static inline unsigned int nr_free_highpages(void) { return 0; }
+static inline void kmap_flush_unused(void) { }
+
+static inline void *kmap(struct page *page) { return page_address(page); }
+
+#define kunmap(page) do { } while (0)
+
+#define kmap_atomic(page,idx)		kmap(page)
+#define kunmap_atomic(page,idx)		kunmap(page)
+
+#define bh_kmap(bh)			((bh)->b_data)
+#define bh_kunmap(bh)			do { } while (0)
+#define kmap_nonblock(page)            kmap(page)
+#define bh_kmap_irq(bh, flags)		((bh)->b_data)
+#define bh_kunmap_irq(bh, flags)	do { *(flags) = 0; } while (0)
+
+#endif /* CONFIG_HIGHMEM */
+
+/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
+static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
+{
+	void *addr = kmap_atomic(page, KM_USER0);
+	clear_user_page(addr, vaddr);
+	kunmap_atomic(addr, KM_USER0);
+}
+
+static inline void clear_highpage(struct page *page)
+{
+	clear_page(kmap(page));
+	kunmap(page);
+}
+
+/*
+ * Same but also flushes aliased cache contents to RAM.
+ */
+static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
+{
+	char *kaddr;
+
+	if (offset + size > PAGE_SIZE)
+		out_of_line_bug();
+	kaddr = kmap(page);
+	memset(kaddr + offset, 0, size);
+	flush_dcache_page(page);
+	flush_page_to_ram(page);
+	kunmap(page);
+}
+
+static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
+{
+	char *vfrom, *vto;
+
+	vfrom = kmap_atomic(from, KM_USER0);
+	vto = kmap_atomic(to, KM_USER1);
+	copy_user_page(vto, vfrom, vaddr);
+	kunmap_atomic(vfrom, KM_USER0);
+	kunmap_atomic(vto, KM_USER1);
+}
+
+static inline void copy_highpage(struct page *to, struct page *from)
+{
+	char *vfrom, *vto;
+
+	vfrom = kmap_atomic(from, KM_USER0);
+	vto = kmap_atomic(to, KM_USER1);
+	copy_page(vto, vfrom);
+	kunmap_atomic(vfrom, KM_USER0);
+	kunmap_atomic(vto, KM_USER1);
+}
+
+#endif /* _LINUX_HIGHMEM_H */
diff --git a/linux-2.4.29-xen-sparse/mm/highmem.c b/linux-2.4.29-xen-sparse/mm/highmem.c
index 6ff48a0cac..341e6e29a9 100644
--- a/linux-2.4.29-xen-sparse/mm/highmem.c
+++ b/linux-2.4.29-xen-sparse/mm/highmem.c
@@ -130,6 +130,13 @@ start:
 	return vaddr;
 }
 
+void kmap_flush_unused(void)
+{
+	spin_lock(&kmap_lock);
+	flush_all_zero_pkmaps();
+	spin_unlock(&kmap_lock);
+}
+
 void fastcall *kmap_high(struct page *page, int nonblocking)
 {
 	unsigned long vaddr;
diff --git a/linux-2.6.10-xen-sparse/drivers/xen/balloon/balloon.c b/linux-2.6.10-xen-sparse/drivers/xen/balloon/balloon.c
index ad951fa984..9e70f584e0 100644
--- a/linux-2.6.10-xen-sparse/drivers/xen/balloon/balloon.c
+++ b/linux-2.6.10-xen-sparse/drivers/xen/balloon/balloon.c
@@ -92,6 +92,7 @@ static struct timer_list balloon_timer;
 #define UNLIST_PAGE(p)  ( list_del(&p->list) )
 #define pte_offset_kernel pte_offset
 #define subsys_initcall(_fn) __initcall(_fn)
+#define pfn_to_page(_pfn) (mem_map + (_pfn))
 #endif
 
 #define IPRINTK(fmt, args...) \
@@ -245,11 +246,10 @@ static void balloon_process(void *unused)
 
             pfn = page - mem_map;
             mfn_list[i] = phys_to_machine_mapping[pfn];
-            phys_to_machine_mapping[pfn] = INVALID_P2M_ENTRY;
 
             if ( !PageHighMem(page) )
             {
-                v = phys_to_virt((page - mem_map) << PAGE_SHIFT);
+                v = phys_to_virt(pfn << PAGE_SHIFT);
                 scrub_pages(v, 1);
                 queue_l1_entry_update(get_ptep((unsigned long)v), 0);
             }
@@ -260,14 +260,23 @@ static void balloon_process(void *unused)
                 scrub_pages(v, 1);
                 kunmap(page);
             }
-#endif            
-
-            balloon_append(page);
+#endif
         }
 
+        /* Ensure that ballooned highmem pages don't have cached mappings. */
+        kmap_flush_unused();
+
         /* Flush updates through and flush the TLB. */
         xen_tlb_flush();
 
+        /* No more mappings: invalidate pages in P2M and add to balloon. */
+        for ( i = 0; i < debt; i++ )
+        {
+            pfn = mfn_to_pfn(mfn_list[i]);
+            phys_to_machine_mapping[pfn] = INVALID_P2M_ENTRY;
+            balloon_append(pfn_to_page(pfn));
+        }
+
         if ( HYPERVISOR_dom_mem_op(
             MEMOP_decrease_reservation, mfn_list, debt, 0) != debt )
             BUG();
diff --git a/linux-2.6.10-xen-sparse/include/linux/highmem.h b/linux-2.6.10-xen-sparse/include/linux/highmem.h
new file mode 100644
index 0000000000..bbe2ce094e
--- /dev/null
+++ b/linux-2.6.10-xen-sparse/include/linux/highmem.h
@@ -0,0 +1,95 @@
+#ifndef _LINUX_HIGHMEM_H
+#define _LINUX_HIGHMEM_H
+
+#include <linux/config.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include <asm/cacheflush.h>
+
+#ifdef CONFIG_HIGHMEM
+
+extern struct page *highmem_start_page;
+
+#include <asm/highmem.h>
+
+/* declarations for linux/mm/highmem.c */
+unsigned int nr_free_highpages(void);
+void kmap_flush_unused(void);
+
+#else /* CONFIG_HIGHMEM */
+
+static inline unsigned int nr_free_highpages(void) { return 0; }
+static inline void kmap_flush_unused(void) { }
+
+static inline void *kmap(struct page *page)
+{
+	might_sleep();
+	return page_address(page);
+}
+
+#define kunmap(page) do { (void) (page); } while (0)
+
+#define kmap_atomic(page, idx)		page_address(page)
+#define kunmap_atomic(addr, idx)	do { } while (0)
+#define kmap_atomic_to_page(ptr)	virt_to_page(ptr)
+
+#endif /* CONFIG_HIGHMEM */
+
+/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
+static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
+{
+	void *addr = kmap_atomic(page, KM_USER0);
+	clear_user_page(addr, vaddr, page);
+	kunmap_atomic(addr, KM_USER0);
+	/* Make sure this page is cleared on other CPU's too before using it */
+	smp_wmb();
+}
+
+static inline void clear_highpage(struct page *page)
+{
+	void *kaddr = kmap_atomic(page, KM_USER0);
+	clear_page(kaddr);
+	kunmap_atomic(kaddr, KM_USER0);
+}
+
+/*
+ * Same but also flushes aliased cache contents to RAM.
+ */
+static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
+{
+	void *kaddr;
+
+	BUG_ON(offset + size > PAGE_SIZE);
+
+	kaddr = kmap_atomic(page, KM_USER0);
+	memset((char *)kaddr + offset, 0, size);
+	flush_dcache_page(page);
+	kunmap_atomic(kaddr, KM_USER0);
+}
+
+static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
+{
+	char *vfrom, *vto;
+
+	vfrom = kmap_atomic(from, KM_USER0);
+	vto = kmap_atomic(to, KM_USER1);
+	copy_user_page(vto, vfrom, vaddr, to);
+	kunmap_atomic(vfrom, KM_USER0);
+	kunmap_atomic(vto, KM_USER1);
+	/* Make sure this page is cleared on other CPU's too before using it */
+	smp_wmb();
+}
+
+static inline void copy_highpage(struct page *to, struct page *from)
+{
+	char *vfrom, *vto;
+
+	vfrom = kmap_atomic(from, KM_USER0);
+	vto = kmap_atomic(to, KM_USER1);
+	copy_page(vto, vfrom);
+	kunmap_atomic(vfrom, KM_USER0);
+	kunmap_atomic(vto, KM_USER1);
+}
+
+#endif /* _LINUX_HIGHMEM_H */
diff --git a/linux-2.6.10-xen-sparse/mm/highmem.c b/linux-2.6.10-xen-sparse/mm/highmem.c
new file mode 100644
index 0000000000..96e7798983
--- /dev/null
+++ b/linux-2.6.10-xen-sparse/mm/highmem.c
@@ -0,0 +1,614 @@
+/*
+ * High memory handling common code and variables.
+ *
+ * (C) 1999 Andrea Arcangeli, SuSE GmbH, andrea@suse.de
+ *          Gerhard Wichert, Siemens AG, Gerhard.Wichert@pdb.siemens.de
+ *
+ *
+ * Redesigned the x86 32-bit VM architecture to deal with
+ * 64-bit physical space. With current x86 CPUs this
+ * means up to 64 Gigabytes physical RAM.
+ *
+ * Rewrote high memory support to move the page cache into
+ * high memory. Implemented permanent (schedulable) kmaps
+ * based on Linus' idea.
+ *
+ * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/swap.h>
+#include <linux/bio.h>
+#include <linux/pagemap.h>
+#include <linux/mempool.h>
+#include <linux/blkdev.h>
+#include <linux/init.h>
+#include <linux/hash.h>
+#include <linux/highmem.h>
+#include <asm/tlbflush.h>
+
+static mempool_t *page_pool, *isa_page_pool;
+
+static void *page_pool_alloc(int gfp_mask, void *data)
+{
+	int gfp = gfp_mask | (int) (long) data;
+
+	return alloc_page(gfp);
+}
+
+static void page_pool_free(void *page, void *data)
+{
+	__free_page(page);
+}
+
+/*
+ * Virtual_count is not a pure "count".
+ *  0 means that it is not mapped, and has not been mapped
+ *    since a TLB flush - it is usable.
+ *  1 means that there are no users, but it has been mapped
+ *    since the last TLB flush - so we can't use it.
+ *  n means that there are (n-1) current users of it.
+ */
+#ifdef CONFIG_HIGHMEM
+static int pkmap_count[LAST_PKMAP];
+static unsigned int last_pkmap_nr;
+static spinlock_t kmap_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
+
+pte_t * pkmap_page_table;
+
+static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait);
+
+static void flush_all_zero_pkmaps(void)
+{
+	int i;
+
+	flush_cache_kmaps();
+
+	for (i = 0; i < LAST_PKMAP; i++) {
+		struct page *page;
+
+		/*
+		 * zero means we don't have anything to do,
+		 * >1 means that it is still in use. Only
+		 * a count of 1 means that it is free but
+		 * needs to be unmapped
+		 */
+		if (pkmap_count[i] != 1)
+			continue;
+		pkmap_count[i] = 0;
+
+		/* sanity check */
+		if (pte_none(pkmap_page_table[i]))
+			BUG();
+
+		/*
+		 * Don't need an atomic fetch-and-clear op here;
+		 * no-one has the page mapped, and cannot get at
+		 * its virtual address (and hence PTE) without first
+		 * getting the kmap_lock (which is held here).
+		 * So no dangers, even with speculative execution.
+		 */
+		page = pte_page(pkmap_page_table[i]);
+		pte_clear(&pkmap_page_table[i]);
+
+		set_page_address(page, NULL);
+	}
+	flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
+}
+
+static inline unsigned long map_new_virtual(struct page *page)
+{
+	unsigned long vaddr;
+	int count;
+
+start:
+	count = LAST_PKMAP;
+	/* Find an empty entry */
+	for (;;) {
+		last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK;
+		if (!last_pkmap_nr) {
+			flush_all_zero_pkmaps();
+			count = LAST_PKMAP;
+		}
+		if (!pkmap_count[last_pkmap_nr])
+			break;	/* Found a usable entry */
+		if (--count)
+			continue;
+
+		/*
+		 * Sleep for somebody else to unmap their entries
+		 */
+		{
+			DECLARE_WAITQUEUE(wait, current);
+
+			__set_current_state(TASK_UNINTERRUPTIBLE);
+			add_wait_queue(&pkmap_map_wait, &wait);
+			spin_unlock(&kmap_lock);
+			schedule();
+			remove_wait_queue(&pkmap_map_wait, &wait);
+			spin_lock(&kmap_lock);
+
+			/* Somebody else might have mapped it while we slept */
+			if (page_address(page))
+				return (unsigned long)page_address(page);
+
+			/* Re-start */
+			goto start;
+		}
+	}
+	vaddr = PKMAP_ADDR(last_pkmap_nr);
+	set_pte(&(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot));
+
+	pkmap_count[last_pkmap_nr] = 1;
+	set_page_address(page, (void *)vaddr);
+
+	return vaddr;
+}
+
+void kmap_flush_unused(void)
+{
+	spin_lock(&kmap_lock);
+	flush_all_zero_pkmaps();
+	spin_unlock(&kmap_lock);
+}
+
+EXPORT_SYMBOL(kmap_flush_unused);
+
+void fastcall *kmap_high(struct page *page)
+{
+	unsigned long vaddr;
+
+	/*
+	 * For highmem pages, we can't trust "virtual" until
+	 * after we have the lock.
+	 *
+	 * We cannot call this from interrupts, as it may block
+	 */
+	spin_lock(&kmap_lock);
+	vaddr = (unsigned long)page_address(page);
+	if (!vaddr)
+		vaddr = map_new_virtual(page);
+	pkmap_count[PKMAP_NR(vaddr)]++;
+	if (pkmap_count[PKMAP_NR(vaddr)] < 2)
+		BUG();
+	spin_unlock(&kmap_lock);
+	return (void*) vaddr;
+}
+
+EXPORT_SYMBOL(kmap_high);
+
+void fastcall kunmap_high(struct page *page)
+{
+	unsigned long vaddr;
+	unsigned long nr;
+	int need_wakeup;
+
+	spin_lock(&kmap_lock);
+	vaddr = (unsigned long)page_address(page);
+	if (!vaddr)
+		BUG();
+	nr = PKMAP_NR(vaddr);
+
+	/*
+	 * A count must never go down to zero
+	 * without a TLB flush!
+	 */
+	need_wakeup = 0;
+	switch (--pkmap_count[nr]) {
+	case 0:
+		BUG();
+	case 1:
+		/*
+		 * Avoid an unnecessary wake_up() function call.
+		 * The common case is pkmap_count[] == 1, but
+		 * no waiters.
+		 * The tasks queued in the wait-queue are guarded
+		 * by both the lock in the wait-queue-head and by
+		 * the kmap_lock.  As the kmap_lock is held here,
+		 * no need for the wait-queue-head's lock.  Simply
+		 * test if the queue is empty.
+		 */
+		need_wakeup = waitqueue_active(&pkmap_map_wait);
+	}
+	spin_unlock(&kmap_lock);
+
+	/* do wake-up, if needed, race-free outside of the spin lock */
+	if (need_wakeup)
+		wake_up(&pkmap_map_wait);
+}
+
+EXPORT_SYMBOL(kunmap_high);
+
+#define POOL_SIZE	64
+
+static __init int init_emergency_pool(void)
+{
+	struct sysinfo i;
+	si_meminfo(&i);
+	si_swapinfo(&i);
+        
+	if (!i.totalhigh)
+		return 0;
+
+	page_pool = mempool_create(POOL_SIZE, page_pool_alloc, page_pool_free, NULL);
+	if (!page_pool)
+		BUG();
+	printk("highmem bounce pool size: %d pages\n", POOL_SIZE);
+
+	return 0;
+}
+
+__initcall(init_emergency_pool);
+
+/*
+ * highmem version, map in to vec
+ */
+static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
+{
+	unsigned long flags;
+	unsigned char *vto;
+
+	local_irq_save(flags);
+	vto = kmap_atomic(to->bv_page, KM_BOUNCE_READ);
+	memcpy(vto + to->bv_offset, vfrom, to->bv_len);
+	kunmap_atomic(vto, KM_BOUNCE_READ);
+	local_irq_restore(flags);
+}
+
+#else /* CONFIG_HIGHMEM */
+
+#define bounce_copy_vec(to, vfrom)	\
+	memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
+
+#endif
+
+#define ISA_POOL_SIZE	16
+
+/*
+ * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
+ * as the max address, so check if the pool has already been created.
+ */
+int init_emergency_isa_pool(void)
+{
+	if (isa_page_pool)
+		return 0;
+
+	isa_page_pool = mempool_create(ISA_POOL_SIZE, page_pool_alloc, page_pool_free, (void *) __GFP_DMA);
+	if (!isa_page_pool)
+		BUG();
+
+	printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE);
+	return 0;
+}
+
+/*
+ * Simple bounce buffer support for highmem pages. Depending on the
+ * queue gfp mask set, *to may or may not be a highmem page. kmap it
+ * always, it will do the Right Thing
+ */
+static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
+{
+	unsigned char *vfrom;
+	struct bio_vec *tovec, *fromvec;
+	int i;
+
+	__bio_for_each_segment(tovec, to, i, 0) {
+		fromvec = from->bi_io_vec + i;
+
+		/*
+		 * not bounced
+		 */
+		if (tovec->bv_page == fromvec->bv_page)
+			continue;
+
+		/*
+		 * fromvec->bv_offset and fromvec->bv_len might have been
+		 * modified by the block layer, so use the original copy,
+		 * bounce_copy_vec already uses tovec->bv_len
+		 */
+		vfrom = page_address(fromvec->bv_page) + tovec->bv_offset;
+
+		flush_dcache_page(tovec->bv_page);
+		bounce_copy_vec(tovec, vfrom);
+	}
+}
+
+static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
+{
+	struct bio *bio_orig = bio->bi_private;
+	struct bio_vec *bvec, *org_vec;
+	int i;
+
+	if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
+		set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);
+
+	/*
+	 * free up bounce indirect pages used
+	 */
+	__bio_for_each_segment(bvec, bio, i, 0) {
+		org_vec = bio_orig->bi_io_vec + i;
+		if (bvec->bv_page == org_vec->bv_page)
+			continue;
+
+		mempool_free(bvec->bv_page, pool);	
+	}
+
+	bio_endio(bio_orig, bio_orig->bi_size, err);
+	bio_put(bio);
+}
+
+static int bounce_end_io_write(struct bio *bio, unsigned int bytes_done,int err)
+{
+	if (bio->bi_size)
+		return 1;
+
+	bounce_end_io(bio, page_pool, err);
+	return 0;
+}
+
+static int bounce_end_io_write_isa(struct bio *bio, unsigned int bytes_done, int err)
+{
+	if (bio->bi_size)
+		return 1;
+
+	bounce_end_io(bio, isa_page_pool, err);
+	return 0;
+}
+
+static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
+{
+	struct bio *bio_orig = bio->bi_private;
+
+	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
+		copy_to_high_bio_irq(bio_orig, bio);
+
+	bounce_end_io(bio, pool, err);
+}
+
+static int bounce_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
+{
+	if (bio->bi_size)
+		return 1;
+
+	__bounce_end_io_read(bio, page_pool, err);
+	return 0;
+}
+
+static int bounce_end_io_read_isa(struct bio *bio, unsigned int bytes_done, int err)
+{
+	if (bio->bi_size)
+		return 1;
+
+	__bounce_end_io_read(bio, isa_page_pool, err);
+	return 0;
+}
+
+static void __blk_queue_bounce(request_queue_t *q, struct bio **bio_orig,
+			mempool_t *pool)
+{
+	struct page *page;
+	struct bio *bio = NULL;
+	int i, rw = bio_data_dir(*bio_orig);
+	struct bio_vec *to, *from;
+
+	bio_for_each_segment(from, *bio_orig, i) {
+		page = from->bv_page;
+
+		/*
+		 * is destination page below bounce pfn?
+		 */
+		if (page_to_pfn(page) < q->bounce_pfn)
+			continue;
+
+		/*
+		 * irk, bounce it
+		 */
+		if (!bio)
+			bio = bio_alloc(GFP_NOIO, (*bio_orig)->bi_vcnt);
+
+		to = bio->bi_io_vec + i;
+
+		to->bv_page = mempool_alloc(pool, q->bounce_gfp);
+		to->bv_len = from->bv_len;
+		to->bv_offset = from->bv_offset;
+
+		if (rw == WRITE) {
+			char *vto, *vfrom;
+
+			flush_dcache_page(from->bv_page);
+			vto = page_address(to->bv_page) + to->bv_offset;
+			vfrom = kmap(from->bv_page) + from->bv_offset;
+			memcpy(vto, vfrom, to->bv_len);
+			kunmap(from->bv_page);
+		}
+	}
+
+	/*
+	 * no pages bounced
+	 */
+	if (!bio)
+		return;
+
+	/*
+	 * at least one page was bounced, fill in possible non-highmem
+	 * pages
+	 */
+	bio_for_each_segment(from, *bio_orig, i) {
+		to = bio_iovec_idx(bio, i);
+		if (!to->bv_page) {
+			to->bv_page = from->bv_page;
+			to->bv_len = from->bv_len;
+			to->bv_offset = from->bv_offset;
+		}
+	}
+
+	bio->bi_bdev = (*bio_orig)->bi_bdev;
+	bio->bi_flags |= (1 << BIO_BOUNCED);
+	bio->bi_sector = (*bio_orig)->bi_sector;
+	bio->bi_rw = (*bio_orig)->bi_rw;
+
+	bio->bi_vcnt = (*bio_orig)->bi_vcnt;
+	bio->bi_idx = (*bio_orig)->bi_idx;
+	bio->bi_size = (*bio_orig)->bi_size;
+
+	if (pool == page_pool) {
+		bio->bi_end_io = bounce_end_io_write;
+		if (rw == READ)
+			bio->bi_end_io = bounce_end_io_read;
+	} else {
+		bio->bi_end_io = bounce_end_io_write_isa;
+		if (rw == READ)
+			bio->bi_end_io = bounce_end_io_read_isa;
+	}
+
+	bio->bi_private = *bio_orig;
+	*bio_orig = bio;
+}
+
+void blk_queue_bounce(request_queue_t *q, struct bio **bio_orig)
+{
+	mempool_t *pool;
+
+	/*
+	 * 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)
+			return;
+		pool = page_pool;
+	} else {
+		BUG_ON(!isa_page_pool);
+		pool = isa_page_pool;
+	}
+
+	/*
+	 * slow path
+	 */
+	__blk_queue_bounce(q, bio_orig, pool);
+}
+
+EXPORT_SYMBOL(blk_queue_bounce);
+
+#if defined(HASHED_PAGE_VIRTUAL)
+
+#define PA_HASH_ORDER	7
+
+/*
+ * Describes one page->virtual association
+ */
+struct page_address_map {
+	struct page *page;
+	void *virtual;
+	struct list_head list;
+};
+
+/*
+ * page_address_map freelist, allocated from page_address_maps.
+ */
+static struct list_head page_address_pool;	/* freelist */
+static spinlock_t pool_lock;			/* protects page_address_pool */
+
+/*
+ * Hash table bucket
+ */
+static struct page_address_slot {
+	struct list_head lh;			/* List of page_address_maps */
+	spinlock_t lock;			/* Protect this bucket's list */
+} ____cacheline_aligned_in_smp page_address_htable[1<<PA_HASH_ORDER];
+
+static struct page_address_slot *page_slot(struct page *page)
+{
+	return &page_address_htable[hash_ptr(page, PA_HASH_ORDER)];
+}
+
+void *page_address(struct page *page)
+{
+	unsigned long flags;
+	void *ret;
+	struct page_address_slot *pas;
+
+	if (!PageHighMem(page))
+		return lowmem_page_address(page);
+
+	pas = page_slot(page);
+	ret = NULL;
+	spin_lock_irqsave(&pas->lock, flags);
+	if (!list_empty(&pas->lh)) {
+		struct page_address_map *pam;
+
+		list_for_each_entry(pam, &pas->lh, list) {
+			if (pam->page == page) {
+				ret = pam->virtual;
+				goto done;
+			}
+		}
+	}
+done:
+	spin_unlock_irqrestore(&pas->lock, flags);
+	return ret;
+}
+
+EXPORT_SYMBOL(page_address);
+
+void set_page_address(struct page *page, void *virtual)
+{
+	unsigned long flags;
+	struct page_address_slot *pas;
+	struct page_address_map *pam;
+
+	BUG_ON(!PageHighMem(page));
+
+	pas = page_slot(page);
+	if (virtual) {		/* Add */
+		BUG_ON(list_empty(&page_address_pool));
+
+		spin_lock_irqsave(&pool_lock, flags);
+		pam = list_entry(page_address_pool.next,
+				struct page_address_map, list);
+		list_del(&pam->list);
+		spin_unlock_irqrestore(&pool_lock, flags);
+
+		pam->page = page;
+		pam->virtual = virtual;
+
+		spin_lock_irqsave(&pas->lock, flags);
+		list_add_tail(&pam->list, &pas->lh);
+		spin_unlock_irqrestore(&pas->lock, flags);
+	} else {		/* Remove */
+		spin_lock_irqsave(&pas->lock, flags);
+		list_for_each_entry(pam, &pas->lh, list) {
+			if (pam->page == page) {
+				list_del(&pam->list);
+				spin_unlock_irqrestore(&pas->lock, flags);
+				spin_lock_irqsave(&pool_lock, flags);
+				list_add_tail(&pam->list, &page_address_pool);
+				spin_unlock_irqrestore(&pool_lock, flags);
+				goto done;
+			}
+		}
+		spin_unlock_irqrestore(&pas->lock, flags);
+	}
+done:
+	return;
+}
+
+static struct page_address_map page_address_maps[LAST_PKMAP];
+
+void __init page_address_init(void)
+{
+	int i;
+
+	INIT_LIST_HEAD(&page_address_pool);
+	for (i = 0; i < ARRAY_SIZE(page_address_maps); i++)
+		list_add(&page_address_maps[i].list, &page_address_pool);
+	for (i = 0; i < ARRAY_SIZE(page_address_htable); i++) {
+		INIT_LIST_HEAD(&page_address_htable[i].lh);
+		spin_lock_init(&page_address_htable[i].lock);
+	}
+	spin_lock_init(&pool_lock);
+}
+
+#endif	/* defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL) */