[PATCH] iov_iter: Use __bitwise with the extraction_flags

[David Howells <dhowells@redhat.com>]

X-Mailer: MH-E 8.6+git; nmh 1.7.1; GNU Emacs 28.2
--------
David Hildenbrand <david@redhat.com> wrote:

> >> Just a note that the usage of new __bitwise types instead of "unsigned" is
> >> encouraged for flags.

Something like the attached?

> $ git grep "typedef int" | grep __bitwise | wc -l
> 27
> $ git grep "typedef unsigned" | grep __bitwise | wc -l
> 23

git grep __bitwise | grep typedef | grep __u | wc -l
62

*shrug*

Interestingly, things like __be32 are __bitwise.  I wonder if that actually
makes sense or if it was just convenient so stop people doing arithmetic on
them.  I guess doing AND/OR/XOR on them isn't a problem provided both
arguments are appropriately byte-swapped.

David
---
 block/bio.c         |    2 +-
 block/blk-map.c     |    2 +-
 include/linux/uio.h |   13 ++++++++-----
 lib/iov_iter.c      |   14 +++++++-------
 4 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index 466956779d2c..fc57f0aa098e 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1244,11 +1244,11 @@ static int bio_iov_add_zone_append_page(struct bio *bio, struct page *page,
  */
 static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 {
+	iov_iter_extraction_t extraction_flags = 0;
 	unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
 	unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
 	struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
 	struct page **pages = (struct page **)bv;
-	unsigned int extraction_flags = 0;
 	ssize_t size, left;
 	unsigned len, i = 0;
 	size_t offset, trim;
diff --git a/block/blk-map.c b/block/blk-map.c
index 9c7ccea3f334..0f1593e144da 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -265,9 +265,9 @@ static struct bio *blk_rq_map_bio_alloc(struct request *rq,
 static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
 		gfp_t gfp_mask)
 {
+	iov_iter_extraction_t extraction_flags = 0;
 	unsigned int max_sectors = queue_max_hw_sectors(rq->q);
 	unsigned int nr_vecs = iov_iter_npages(iter, BIO_MAX_VECS);
-	unsigned int extraction_flags = 0;
 	struct bio *bio;
 	int ret;
 	int j;
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 47ebb59a0202..b1be128bb2fa 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -13,6 +13,8 @@
 struct page;
 struct pipe_inode_info;
 
+typedef unsigned int iov_iter_extraction_t;
+
 struct kvec {
 	void *iov_base; /* and that should *never* hold a userland pointer */
 	size_t iov_len;
@@ -252,12 +254,12 @@ void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *
 		     loff_t start, size_t count);
 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
 		size_t maxsize, unsigned maxpages, size_t *start,
-		unsigned extraction_flags);
+		iov_iter_extraction_t extraction_flags);
 ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
 			size_t maxsize, unsigned maxpages, size_t *start);
 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 		struct page ***pages, size_t maxsize, size_t *start,
-		unsigned extraction_flags);
+		iov_iter_extraction_t extraction_flags);
 ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages,
 			size_t maxsize, size_t *start);
 int iov_iter_npages(const struct iov_iter *i, int maxpages);
@@ -359,13 +361,14 @@ static inline void iov_iter_ubuf(struct iov_iter *i, unsigned int direction,
 		.count = count
 	};
 }
-
 /* Flags for iov_iter_get/extract_pages*() */
-#define ITER_ALLOW_P2PDMA	0x01	/* Allow P2PDMA on the extracted pages */
+/* Allow P2PDMA on the extracted pages */
+#define ITER_ALLOW_P2PDMA	((__force iov_iter_extraction_t)0x01)
 
 ssize_t iov_iter_extract_pages(struct iov_iter *i, struct page ***pages,
 			       size_t maxsize, unsigned int maxpages,
-			       unsigned int extraction_flags, size_t *offset0);
+			       iov_iter_extraction_t extraction_flags,
+			       size_t *offset0);
 
 /**
  * iov_iter_extract_will_pin - Indicate how pages from the iterator will be retained
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index cea503b2ec30..d70496019b1d 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1432,7 +1432,7 @@ static struct page *first_bvec_segment(const struct iov_iter *i,
 static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
 		   struct page ***pages, size_t maxsize,
 		   unsigned int maxpages, size_t *start,
-		   unsigned int extraction_flags)
+		   iov_iter_extraction_t extraction_flags)
 {
 	unsigned int n, gup_flags = 0;
 
@@ -1929,7 +1929,7 @@ void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state)
 static ssize_t iov_iter_extract_pipe_pages(struct iov_iter *i,
 					   struct page ***pages, size_t maxsize,
 					   unsigned int maxpages,
-					   unsigned int extraction_flags,
+					   iov_iter_extraction_t extraction_flags,
 					   size_t *offset0)
 {
 	unsigned int nr, offset, chunk, j;
@@ -1971,7 +1971,7 @@ static ssize_t iov_iter_extract_pipe_pages(struct iov_iter *i,
 static ssize_t iov_iter_extract_xarray_pages(struct iov_iter *i,
 					     struct page ***pages, size_t maxsize,
 					     unsigned int maxpages,
-					     unsigned int extraction_flags,
+					     iov_iter_extraction_t extraction_flags,
 					     size_t *offset0)
 {
 	struct page *page, **p;
@@ -2017,7 +2017,7 @@ static ssize_t iov_iter_extract_xarray_pages(struct iov_iter *i,
 static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i,
 					   struct page ***pages, size_t maxsize,
 					   unsigned int maxpages,
-					   unsigned int extraction_flags,
+					   iov_iter_extraction_t extraction_flags,
 					   size_t *offset0)
 {
 	struct page **p, *page;
@@ -2060,7 +2060,7 @@ static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i,
 static ssize_t iov_iter_extract_kvec_pages(struct iov_iter *i,
 					   struct page ***pages, size_t maxsize,
 					   unsigned int maxpages,
-					   unsigned int extraction_flags,
+					   iov_iter_extraction_t extraction_flags,
 					   size_t *offset0)
 {
 	struct page **p, *page;
@@ -2125,7 +2125,7 @@ static ssize_t iov_iter_extract_user_pages(struct iov_iter *i,
 					   struct page ***pages,
 					   size_t maxsize,
 					   unsigned int maxpages,
-					   unsigned int extraction_flags,
+					   iov_iter_extraction_t extraction_flags,
 					   size_t *offset0)
 {
 	unsigned long addr;
@@ -2207,7 +2207,7 @@ ssize_t iov_iter_extract_pages(struct iov_iter *i,
 			       struct page ***pages,
 			       size_t maxsize,
 			       unsigned int maxpages,
-			       unsigned int extraction_flags,
+			       iov_iter_extraction_t extraction_flags,
 			       size_t *offset0)
 {
 	maxsize = min_t(size_t, min_t(size_t, maxsize, i->count), MAX_RW_COUNT);