[PATCH v7 15/21] iov_iter: introduce iov_iter_get_pages_[alloc_]flags()

Logan Gunthorpe
2022-06-15T16:14:09Z

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>
---
include/linux/uio.h | 6 ++++++
lib/iov_iter.c | 25 +++++++++++++++++++------
2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 739285fe5a2f..ddf9e4cf4a59 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -232,8 +232,14 @@ 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_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(struct iov_iter *i, struct page **pages,
size_t maxsize, unsigned maxpages, size_t *start);
+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);
ssize_t iov_iter_get_pages_alloc(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 6dd5330f7a99..9bf6e3af5120 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1515,9 +1515,9 @@ 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;
@@ -1528,7 +1528,6 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
return 0;

if (likely(iter_is_iovec(i))) {
- unsigned int gup_flags = 0;
unsigned long addr;

if (iov_iter_rw(i) != WRITE)
@@ -1558,6 +1557,13 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
return iter_xarray_get_pages(i, pages, maxsize, maxpages, start);
return -EFAULT;
}
+EXPORT_SYMBOL_GPL(iov_iter_get_pages_flags);
+
+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);
+}
EXPORT_SYMBOL(iov_iter_get_pages);

static struct page **get_pages_array(size_t n)
@@ -1640,9 +1646,9 @@ 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;
@@ -1654,7 +1660,6 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
return 0;

if (likely(iter_is_iovec(i))) {
- unsigned int gup_flags = 0;
unsigned long addr;

if (iov_iter_rw(i) != WRITE)
@@ -1667,6 +1672,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
p = get_pages_array(n);
if (!p)
return -ENOMEM;
+
res = get_user_pages_fast(addr, n, gup_flags, p);
if (unlikely(res <= 0)) {
kvfree(p);
@@ -1694,6 +1700,13 @@ 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_GPL(iov_iter_get_pages_alloc_flags);
+
+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);
+}
EXPORT_SYMBOL(iov_iter_get_pages_alloc);

size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
--
2.30.2