[PATCH v5 3/9] export __get_user_pages_fast() function

From: Xiao Guangrong
Date: Tue Jul 06 2010 - 06:50:55 EST


This function is used by KVM to pin process's page in the atomic context.

Define the 'weak' function to avoid other architecture not support it

Acked-by: Nick Piggin <npiggin@xxxxxxx>
Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
---
mm/util.c | 13 +++++++++++++
1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/mm/util.c b/mm/util.c
index f5712e8..4f0d32b 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -250,6 +250,19 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
}
#endif

+/*
+ * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
+ * back to the regular GUP.
+ * If the architecture not support this fucntion, simply return with no
+ * page pinned
+ */
+int __attribute__((weak)) __get_user_pages_fast(unsigned long start,
+ int nr_pages, int write, struct page **pages)
+{
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__get_user_pages_fast);
+
/**
* get_user_pages_fast() - pin user pages in memory
* @start: starting user address
--
1.6.1.2


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