Add iov_iter_get_pages_flags() and iov_iter_get_pages_alloc_flags()
which take a flags argument that is passed to get_user_pages_fast().

This is so that FOLL_PCI_P2PDMA can be passed when appropriate.

Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
---
 include/linux/uio.h | 21 +++++++++++++++++----
 lib/iov_iter.c      | 28 ++++++++++++++++------------
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 5265024e8b90..d4ce252db728 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -228,10 +228,23 @@ void iov_iter_pipe(struct iov_iter *i, unsigned int 
direction, struct pipe_inode
 void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t 
count);
 void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray 
*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);
-ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
-                       size_t maxsize, size_t *start);
+ssize_t iov_iter_get_pages_flags(struct iov_iter *i, struct page **pages,
+               size_t maxsize, unsigned maxpages, size_t *start,
+               unsigned int gup_flags);
+ssize_t iov_iter_get_pages_alloc_flags(struct iov_iter *i,
+               struct page ***pages, size_t maxsize, size_t *start,
+               unsigned int gup_flags);
+static inline ssize_t iov_iter_get_pages(struct iov_iter *i,
+               struct page **pages, size_t maxsize, unsigned maxpages,
+               size_t *start)
+{
+       return iov_iter_get_pages_flags(i, pages, maxsize, maxpages, start, 0);
+}
+static inline ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
+               struct page ***pages, size_t maxsize, size_t *start)
+{
+       return iov_iter_get_pages_alloc_flags(i, pages, maxsize, start, 0);
+}
 int iov_iter_npages(const struct iov_iter *i, int maxpages);
 
 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index f2d50d69a6c3..bbf0fb6736a9 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1468,9 +1468,9 @@ static struct page *first_bvec_segment(const struct 
iov_iter *i,
        return page;
 }
 
-ssize_t iov_iter_get_pages(struct iov_iter *i,
+ssize_t iov_iter_get_pages_flags(struct iov_iter *i,
                   struct page **pages, size_t maxsize, unsigned maxpages,
-                  size_t *start)
+                  size_t *start, unsigned int gup_flags)
 {
        size_t len;
        int n, res;
@@ -1485,9 +1485,11 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
 
                addr = first_iovec_segment(i, &len, start, maxsize, maxpages);
                n = DIV_ROUND_UP(len, PAGE_SIZE);
-               res = get_user_pages_fast(addr, n,
-                               iov_iter_rw(i) != WRITE ?  FOLL_WRITE : 0,
-                               pages);
+
+               if (iov_iter_rw(i) != WRITE)
+                       gup_flags |= FOLL_WRITE;
+
+               res = get_user_pages_fast(addr, n, gup_flags, pages);
                if (unlikely(res < 0))
                        return res;
                return (res == n ? len : res * PAGE_SIZE) - *start;
@@ -1507,7 +1509,7 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
                return iter_xarray_get_pages(i, pages, maxsize, maxpages, 
start);
        return -EFAULT;
 }
-EXPORT_SYMBOL(iov_iter_get_pages);
+EXPORT_SYMBOL(iov_iter_get_pages_flags);
 
 static struct page **get_pages_array(size_t n)
 {
@@ -1589,9 +1591,9 @@ static ssize_t iter_xarray_get_pages_alloc(struct 
iov_iter *i,
        return actual;
 }
 
-ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
+ssize_t iov_iter_get_pages_alloc_flags(struct iov_iter *i,
                   struct page ***pages, size_t maxsize,
-                  size_t *start)
+                  size_t *start, unsigned int gup_flags)
 {
        struct page **p;
        size_t len;
@@ -1604,14 +1606,16 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 
        if (likely(iter_is_iovec(i))) {
                unsigned long addr;
-
                addr = first_iovec_segment(i, &len, start, maxsize, ~0U);
                n = DIV_ROUND_UP(len, PAGE_SIZE);
                p = get_pages_array(n);
                if (!p)
                        return -ENOMEM;
-               res = get_user_pages_fast(addr, n,
-                               iov_iter_rw(i) != WRITE ?  FOLL_WRITE : 0, p);
+
+               if (iov_iter_rw(i) != WRITE)
+                       gup_flags |= FOLL_WRITE;
+
+               res = get_user_pages_fast(addr, n, gup_flags, p);
                if (unlikely(res < 0)) {
                        kvfree(p);
                        return res;
@@ -1637,7 +1641,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
                return iter_xarray_get_pages_alloc(i, pages, maxsize, start);
        return -EFAULT;
 }
-EXPORT_SYMBOL(iov_iter_get_pages_alloc);
+EXPORT_SYMBOL(iov_iter_get_pages_alloc_flags);
 
 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
                               struct iov_iter *i)
-- 
2.30.2

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