[PATCH v2 6/7] NFS: direct-io: convert to FOLL_PIN pages

John Hubbard
2022-08-31T04:20:21Z

Convert the NFS Direct IO layer to use pin_user_pages_fast() and
unpin_user_page(), instead of get_user_pages_fast() and put_page().

The user of pin_user_pages_fast() depends upon:

1) CONFIG_BLK_USE_PIN_USER_PAGES_FOR_DIO, and

2) User-space-backed pages: user_backed_iter(i) == true

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
fs/nfs/direct.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 1707f46b1335..71b794f39ee2 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -142,11 +142,13 @@ int nfs_swap_rw(struct kiocb *iocb, struct iov_iter *iter)
return 0;
}

-static void nfs_direct_release_pages(struct page **pages, unsigned int npages)
+static void nfs_direct_release_pages(struct iov_iter *iter, struct page **pages,
+ unsigned int npages)
{
- unsigned int i;
- for (i = 0; i < npages; i++)
- put_page(pages[i]);
+ if (user_backed_iter(iter) || iov_iter_is_bvec(iter))
+ dio_w_unpin_user_pages(pages, npages);
+ else
+ release_pages(pages, npages);
}

void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo,
@@ -332,11 +334,11 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
size_t pgbase;
unsigned npages, i;

- result = iov_iter_get_pages_alloc2(iter, &pagevec,
+ result = dio_w_iov_iter_pin_pages_alloc(iter, &pagevec,
rsize, &pgbase);
if (result < 0)
break;
-
+
bytes = result;
npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE;
for (i = 0; i < npages; i++) {
@@ -362,7 +364,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
pos += req_len;
dreq->bytes_left -= req_len;
}
- nfs_direct_release_pages(pagevec, npages);
+ nfs_direct_release_pages(iter, pagevec, npages);
kvfree(pagevec);
if (result < 0)
break;
@@ -791,8 +793,8 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
size_t pgbase;
unsigned npages, i;

- result = iov_iter_get_pages_alloc2(iter, &pagevec,
- wsize, &pgbase);
+ result = dio_w_iov_iter_pin_pages_alloc(iter, &pagevec,
+ wsize, &pgbase);
if (result < 0)
break;

@@ -829,7 +831,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
pos += req_len;
dreq->bytes_left -= req_len;
}
- nfs_direct_release_pages(pagevec, npages);
+ nfs_direct_release_pages(iter, pagevec, npages);
kvfree(pagevec);
if (result < 0)
break;
--
2.37.2