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>

2 files changed, 144 insertions, 0 deletions

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;