[PATCH 3/5] mm: gup: use get_user_pages_unlocked within get_user_pages_fast

[Andrea Arcangeli]

This allows the get_user_pages_fast slow path to release the mmap_sem
before blocking.

Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
---
 arch/mips/mm/gup.c  |  8 +++-----
 arch/s390/mm/gup.c  |  6 ++----
 arch/sh/mm/gup.c    |  6 ++----
 arch/sparc/mm/gup.c |  6 ++----
 arch/x86/mm/gup.c   |  7 +++----
 mm/gup.c            |  6 ++----
 mm/util.c           | 10 ++--------
 7 files changed, 16 insertions(+), 33 deletions(-)

diff --git a/arch/mips/mm/gup.c b/arch/mips/mm/gup.c
index 70795a6..349995d 100644
--- a/arch/mips/mm/gup.c
+++ b/arch/mips/mm/gup.c
@@ -301,11 +301,9 @@ slow_irqon:
 	start += nr << PAGE_SHIFT;
 	pages += nr;
 
-	down_read(&mm->mmap_sem);
-	ret = get_user_pages(current, mm, start,
-				(end - start) >> PAGE_SHIFT,
-				write, 0, pages, NULL);
-	up_read(&mm->mmap_sem);
+	ret = get_user_pages_unlocked(current, mm, start,
+				      (end - start) >> PAGE_SHIFT,
+				      write, 0, pages);
 
 	/* Have to be a bit careful with return values */
 	if (nr > 0) {
diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index 639fce46..5c586c7 100644
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -235,10 +235,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 	/* Try to get the remaining pages with get_user_pages */
 	start += nr << PAGE_SHIFT;
 	pages += nr;
-	down_read(&mm->mmap_sem);
-	ret = get_user_pages(current, mm, start,
-			     nr_pages - nr, write, 0, pages, NULL);
-	up_read(&mm->mmap_sem);
+	ret = get_user_pages_unlocked(current, mm, start,
+			     nr_pages - nr, write, 0, pages);
 	/* Have to be a bit careful with return values */
 	if (nr > 0)
 		ret = (ret < 0) ? nr : ret + nr;
diff --git a/arch/sh/mm/gup.c b/arch/sh/mm/gup.c
index 37458f3..e15f52a 100644
--- a/arch/sh/mm/gup.c
+++ b/arch/sh/mm/gup.c
@@ -257,10 +257,8 @@ slow_irqon:
 		start += nr << PAGE_SHIFT;
 		pages += nr;
 
-		down_read(&mm->mmap_sem);
-		ret = get_user_pages(current, mm, start,
-			(end - start) >> PAGE_SHIFT, write, 0, pages, NULL);
-		up_read(&mm->mmap_sem);
+		ret = get_user_pages_unlocked(current, mm, start,
+			(end - start) >> PAGE_SHIFT, write, 0, pages);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {
diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index ae6ce38..2e5c4fc 100644
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -249,10 +249,8 @@ slow:
 		start += nr << PAGE_SHIFT;
 		pages += nr;
 
-		down_read(&mm->mmap_sem);
-		ret = get_user_pages(current, mm, start,
-			(end - start) >> PAGE_SHIFT, write, 0, pages, NULL);
-		up_read(&mm->mmap_sem);
+		ret = get_user_pages_unlocked(current, mm, start,
+			(end - start) >> PAGE_SHIFT, write, 0, pages);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {
diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index d754782..4548dd8 100644
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -388,10 +388,9 @@ slow_irqon:
 		start += nr << PAGE_SHIFT;
 		pages += nr;
 
-		down_read(&mm->mmap_sem);
-		ret = get_user_pages(current, mm, start,
-			(end - start) >> PAGE_SHIFT, write, 0, pages, NULL);
-		up_read(&mm->mmap_sem);
+		ret = get_user_pages_unlocked(current, mm, start,
+					      (end - start) >> PAGE_SHIFT,
+					      write, 0, pages);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {
diff --git a/mm/gup.c b/mm/gup.c
index d616811..da200a1 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1252,10 +1252,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 		start += nr << PAGE_SHIFT;
 		pages += nr;
 
-		down_read(&mm->mmap_sem);
-		ret = get_user_pages(current, mm, start,
-				     nr_pages - nr, write, 0, pages, NULL);
-		up_read(&mm->mmap_sem);
+		ret = get_user_pages_unlocked(current, mm, start,
+					      nr_pages - nr, write, 0, pages);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {
diff --git a/mm/util.c b/mm/util.c
index fec39d4..f3ef639 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -240,14 +240,8 @@ int __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;
+	return get_user_pages_unlocked(current, mm, start, nr_pages,
+				       write, 0, pages);
 }
 EXPORT_SYMBOL_GPL(get_user_pages_fast);
 
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