[patch 4/5] dio: use get_user_pages_fast

[npiggin@xxxxxxx]

Use get_user_pages_fast in the common/generic block and fs direct IO paths.

Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Cc: shaggy@xxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: apw@xxxxxxxxxxxx

---
 fs/bio.c       |    8 ++------
 fs/direct-io.c |   10 ++--------
 2 files changed, 4 insertions(+), 14 deletions(-)

Index: linux-2.6/fs/bio.c
===================================================================
--- linux-2.6.orig/fs/bio.c
+++ linux-2.6/fs/bio.c
@@ -713,12 +713,8 @@ static struct bio *__bio_map_user_iov(st
 		const int local_nr_pages = end - start;
 		const int page_limit = cur_page + local_nr_pages;
 		
-		down_read(&current->mm->mmap_sem);
-		ret = get_user_pages(current, current->mm, uaddr,
-				     local_nr_pages,
-				     write_to_vm, 0, &pages[cur_page], NULL);
-		up_read(&current->mm->mmap_sem);
-
+		ret = get_user_pages_fast(uaddr, local_nr_pages,
+				write_to_vm, &pages[cur_page]);
 		if (ret < local_nr_pages) {
 			ret = -EFAULT;
 			goto out_unmap;
Index: linux-2.6/fs/direct-io.c
===================================================================
--- linux-2.6.orig/fs/direct-io.c
+++ linux-2.6/fs/direct-io.c
@@ -150,17 +150,11 @@ static int dio_refill_pages(struct dio *
 	int nr_pages;
 
 	nr_pages = min(dio->total_pages - dio->curr_page, DIO_PAGES);
-	down_read(&current->mm->mmap_sem);
-	ret = get_user_pages(
-		current,			/* Task for fault acounting */
-		current->mm,			/* whose pages? */
+	ret = get_user_pages_fast(
 		dio->curr_user_address,		/* Where from? */
 		nr_pages,			/* How many pages? */
 		dio->rw == READ,		/* Write to memory? */
-		0,				/* force (?) */
-		&dio->pages[0],
-		NULL);				/* vmas */
-	up_read(&current->mm->mmap_sem);
+		&dio->pages[0]);		/* Put results here */
 
 	if (ret < 0 && dio->blocks_available && (dio->rw & WRITE)) {
 		struct page *page = ZERO_PAGE(0);

-- 

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