iov_iter: introduce iov_iter_get_pages_[alloc_]flags()

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 <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221021174116.7200-4-logang@deltatee.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 2e3134b..9ede533 100644 (file)
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -247,8 +247,14 @@ 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,
+               unsigned gup_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 gup_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);

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index c3ca28c..53efad0 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1430,7 +1430,8 @@ 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 maxpages, size_t *start,
+                  unsigned int gup_flags)
 {
        unsigned int n;
 
@@ -1442,7 +1443,6 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
                maxsize = MAX_RW_COUNT;
 
        if (likely(user_backed_iter(i))) {
-               unsigned int gup_flags = 0;
                unsigned long addr;
                int res;
 
@@ -1492,33 +1492,49 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
        return -EFAULT;
 }
 
-ssize_t iov_iter_get_pages2(struct iov_iter *i,
+ssize_t iov_iter_get_pages(struct iov_iter *i,
                   struct page **pages, size_t maxsize, unsigned maxpages,
-                  size_t *start)
+                  size_t *start, unsigned gup_flags)
 {
        if (!maxpages)
                return 0;
        BUG_ON(!pages);
 
-       return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start);
+       return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages,
+                                         start, gup_flags);
+}
+EXPORT_SYMBOL_GPL(iov_iter_get_pages);
+
+ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
+               size_t maxsize, unsigned maxpages, size_t *start)
+{
+       return iov_iter_get_pages(i, pages, maxsize, maxpages, start, 0);
 }
 EXPORT_SYMBOL(iov_iter_get_pages2);
 
-ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
+ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
                   struct page ***pages, size_t maxsize,
-                  size_t *start)
+                  size_t *start, unsigned gup_flags)
 {
        ssize_t len;
 
        *pages = NULL;
 
-       len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start);
+       len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start,
+                                        gup_flags);
        if (len <= 0) {
                kvfree(*pages);
                *pages = NULL;
        }
        return len;
 }
+EXPORT_SYMBOL_GPL(iov_iter_get_pages_alloc);
+
+ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
+               struct page ***pages, size_t maxsize, size_t *start)
+{
+       return iov_iter_get_pages_alloc(i, pages, maxsize, start, 0);
+}
 EXPORT_SYMBOL(iov_iter_get_pages_alloc2);
 
 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,