On Thursday 31 July 2008 18:52, Benjamin Herrenschmidt wrote:
> On Thu, 2008-07-31 at 18:48 +1000, Nick Piggin wrote:
> > > If we do this then corresponding changes should be made to the powerpc
> > > patch upon which Ben presently sits.
> >
> > Powerpc will still use the CONFIG symbol for the moment because 32-bit
> > TLB flushing has not been verified to work, so we don't want to pull in
> > the 64-bit gup. There is some discussion going on, but they probably need
> > at least to implement pte_special, and then also do RCU freeing of page
> > tables.
>
> It's just a matter of building gup.c or not .. as long as it's
> in the makefile as obj-$(CONFIG_PPC64) (as I put it in the merged
> version of the patch), the weak symbol should work.
I see. Here we are, then.
Out of line get_user_pages_fast fallback implementation, make it a weak
symbol, get rid of CONFIG_HAVE_GET_USER_PAGES_FAST.
Export the symbol to modules so lguest can use it.
Signed-off-by: Nick Piggin <[EMAIL PROTECTED]>
---
Index: linux-2.6/include/linux/mm.h
===================================================================
--- linux-2.6.orig/include/linux/mm.h 2008-07-31 18:45:19.000000000 +1000
+++ linux-2.6/include/linux/mm.h 2008-07-31 18:53:43.000000000 +1000
@@ -834,7 +834,6 @@ extern int mprotect_fixup(struct vm_area
struct vm_area_struct **pprev, unsigned long start,
unsigned long end, unsigned long newflags);
-#ifdef CONFIG_HAVE_GET_USER_PAGES_FAST
/*
* get_user_pages_fast provides equivalent functionality to get_user_pages,
* operating on current and current->mm (force=0 and doesn't return any vmas).
@@ -848,25 +847,6 @@ extern int mprotect_fixup(struct vm_area
int get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages);
-#else
-/*
- * Should probably be moved to asm-generic, and architectures can include it if
- * they don't implement their own get_user_pages_fast.
- */
-#define get_user_pages_fast(start, nr_pages, write, pages) \
-({ \
- struct mm_struct *mm = current->mm; \
- int ret; \
- \
- down_read(&mm->mmap_sem); \
- ret = get_user_pages(current, mm, start, nr_pages, \
- write, 0, pages, NULL); \
- up_read(&mm->mmap_sem); \
- \
- ret; \
-})
-#endif
-
/*
* A callback you can register to apply pressure to ageable caches.
*
Index: linux-2.6/mm/memory.c
===================================================================
--- linux-2.6.orig/mm/memory.c 2008-07-31 18:45:19.000000000 +1000
+++ linux-2.6/mm/memory.c 2008-07-31 18:53:43.000000000 +1000
@@ -1270,6 +1270,21 @@ int get_user_pages(struct task_struct *t
}
EXPORT_SYMBOL(get_user_pages);
+int __attribute__((weak)) get_user_pages_fast(unsigned long start,
+ int nr_pages, int write, struct page **pages)
+{
+ struct mm_struct *mm = current->mm;
+ int ret;
+
+ down_read(&mm->mmap_sem);
+ ret = get_user_pages(current, mm, start, nr_pages,
+ write, 0, pages, NULL);
+ up_read(&mm->mmap_sem);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(get_user_pages_fast);
+
pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
spinlock_t **ptl)
{
Index: linux-2.6/arch/x86/Kconfig
===================================================================
--- linux-2.6.orig/arch/x86/Kconfig 2008-07-31 18:45:20.000000000 +1000
+++ linux-2.6/arch/x86/Kconfig 2008-07-31 18:53:43.000000000 +1000
@@ -22,7 +22,6 @@ config X86
select HAVE_IDE
select HAVE_OPROFILE
select HAVE_IOREMAP_PROT
- select HAVE_GET_USER_PAGES_FAST
select HAVE_KPROBES
select ARCH_WANT_OPTIONAL_GPIOLIB
select HAVE_KRETPROBES
Index: linux-2.6/arch/x86/mm/Makefile
===================================================================
--- linux-2.6.orig/arch/x86/mm/Makefile 2008-07-31 18:45:20.000000000 +1000
+++ linux-2.6/arch/x86/mm/Makefile 2008-07-31 18:53:43.000000000 +1000
@@ -1,7 +1,6 @@
obj-y := init_$(BITS).o fault.o ioremap.o extable.o pageattr.o mmap.o \
- pat.o pgtable.o
+ pat.o pgtable.o gup.o
-obj-$(CONFIG_HAVE_GET_USER_PAGES_FAST) += gup.o
obj-$(CONFIG_X86_32) += pgtable_32.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
Index: linux-2.6/arch/powerpc/Kconfig
===================================================================
--- linux-2.6.orig/arch/powerpc/Kconfig 2008-07-31 18:53:45.000000000 +1000
+++ linux-2.6/arch/powerpc/Kconfig 2008-07-31 18:53:51.000000000 +1000
@@ -42,9 +42,6 @@ config GENERIC_HARDIRQS
bool
default y
-config HAVE_GET_USER_PAGES_FAST
- def_bool PPC64
-
config HAVE_SETUP_PER_CPU_AREA
def_bool PPC64
Index: linux-2.6/mm/Kconfig
===================================================================
--- linux-2.6.orig/mm/Kconfig 2008-07-31 18:55:16.000000000 +1000
+++ linux-2.6/mm/Kconfig 2008-07-31 18:55:20.000000000 +1000
@@ -77,9 +77,6 @@ config FLAT_NODE_MEM_MAP
def_bool y
depends on !SPARSEMEM
-config HAVE_GET_USER_PAGES_FAST
- bool
-
#
# Both the NUMA code and DISCONTIGMEM use arrays of pg_data_t's
# to represent different areas of memory. This variable allows
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