[PATCH v3 02/13] fuse: add support in virtio for requests using folios

[Joanne Koong <joannelkoong@gmail.com>]

Until all requests have been converted to use folios instead of pages,
virtio will need to support both types. Once all requests have been
converted, then virtio will support just folios.

No functional changes.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/fuse/virtio_fs.c | 87 +++++++++++++++++++++++++++++----------------
 1 file changed, 56 insertions(+), 31 deletions(-)

diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index f68527891929..9f0d98cc20d3 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -766,6 +766,7 @@ static void virtio_fs_request_complete(struct fuse_req *req,
 	struct fuse_args_pages *ap;
 	unsigned int len, i, thislen;
 	struct page *page;
+	struct folio *folio;
 
 	/*
 	 * TODO verify that server properly follows FUSE protocol
@@ -777,15 +778,29 @@ static void virtio_fs_request_complete(struct fuse_req *req,
 	if (args->out_pages && args->page_zeroing) {
 		len = args->out_args[args->out_numargs - 1].size;
 		ap = container_of(args, typeof(*ap), args);
-		for (i = 0; i < ap->num_pages; i++) {
-			thislen = ap->descs[i].length;
-			if (len < thislen) {
-				WARN_ON(ap->descs[i].offset);
-				page = ap->pages[i];
-				zero_user_segment(page, len, thislen);
-				len = 0;
-			} else {
-				len -= thislen;
+		if (ap->uses_folios) {
+			for (i = 0; i < ap->num_folios; i++) {
+				thislen = ap->folio_descs[i].length;
+				if (len < thislen) {
+					WARN_ON(ap->folio_descs[i].offset);
+					folio = ap->folios[i];
+					folio_zero_segment(folio, len, thislen);
+					len = 0;
+				} else {
+					len -= thislen;
+				}
+			}
+		} else {
+			for (i = 0; i < ap->num_pages; i++) {
+				thislen = ap->descs[i].length;
+				if (len < thislen) {
+					WARN_ON(ap->descs[i].offset);
+					page = ap->pages[i];
+					zero_user_segment(page, len, thislen);
+					len = 0;
+				} else {
+					len -= thislen;
+				}
 			}
 		}
 	}
@@ -1272,16 +1287,22 @@ static void virtio_fs_send_interrupt(struct fuse_iqueue *fiq, struct fuse_req *r
 }
 
 /* Count number of scatter-gather elements required */
-static unsigned int sg_count_fuse_pages(struct fuse_page_desc *page_descs,
-				       unsigned int num_pages,
-				       unsigned int total_len)
+static unsigned int sg_count_fuse_pages(struct fuse_args_pages *ap,
+					unsigned int total_len)
 {
 	unsigned int i;
 	unsigned int this_len;
 
-	for (i = 0; i < num_pages && total_len; i++) {
-		this_len =  min(page_descs[i].length, total_len);
-		total_len -= this_len;
+	if (ap->uses_folios) {
+		for (i = 0; i < ap->num_folios && total_len; i++) {
+			this_len =  min(ap->folio_descs[i].length, total_len);
+			total_len -= this_len;
+		}
+	} else {
+		for (i = 0; i < ap->num_pages && total_len; i++) {
+			this_len =  min(ap->descs[i].length, total_len);
+			total_len -= this_len;
+		}
 	}
 
 	return i;
@@ -1299,8 +1320,7 @@ static unsigned int sg_count_fuse_req(struct fuse_req *req)
 
 	if (args->in_pages) {
 		size = args->in_args[args->in_numargs - 1].size;
-		total_sgs += sg_count_fuse_pages(ap->descs, ap->num_pages,
-						 size);
+		total_sgs += sg_count_fuse_pages(ap, size);
 	}
 
 	if (!test_bit(FR_ISREPLY, &req->flags))
@@ -1313,28 +1333,35 @@ static unsigned int sg_count_fuse_req(struct fuse_req *req)
 
 	if (args->out_pages) {
 		size = args->out_args[args->out_numargs - 1].size;
-		total_sgs += sg_count_fuse_pages(ap->descs, ap->num_pages,
-						 size);
+		total_sgs += sg_count_fuse_pages(ap, size);
 	}
 
 	return total_sgs;
 }
 
-/* Add pages to scatter-gather list and return number of elements used */
+/* Add pages/folios to scatter-gather list and return number of elements used */
 static unsigned int sg_init_fuse_pages(struct scatterlist *sg,
-				       struct page **pages,
-				       struct fuse_page_desc *page_descs,
-				       unsigned int num_pages,
+				       struct fuse_args_pages *ap,
 				       unsigned int total_len)
 {
 	unsigned int i;
 	unsigned int this_len;
 
-	for (i = 0; i < num_pages && total_len; i++) {
-		sg_init_table(&sg[i], 1);
-		this_len =  min(page_descs[i].length, total_len);
-		sg_set_page(&sg[i], pages[i], this_len, page_descs[i].offset);
-		total_len -= this_len;
+	if (ap->uses_folios) {
+		for (i = 0; i < ap->num_folios && total_len; i++) {
+			sg_init_table(&sg[i], 1);
+			this_len =  min(ap->folio_descs[i].length, total_len);
+			sg_set_folio(&sg[i], ap->folios[i], this_len,
+				     ap->folio_descs[i].offset);
+			total_len -= this_len;
+		}
+	} else {
+		for (i = 0; i < ap->num_pages && total_len; i++) {
+			sg_init_table(&sg[i], 1);
+			this_len =  min(ap->descs[i].length, total_len);
+			sg_set_page(&sg[i], ap->pages[i], this_len, ap->descs[i].offset);
+			total_len -= this_len;
+		}
 	}
 
 	return i;
@@ -1358,9 +1385,7 @@ static unsigned int sg_init_fuse_args(struct scatterlist *sg,
 		sg_init_one(&sg[total_sgs++], argbuf, len);
 
 	if (argpages)
-		total_sgs += sg_init_fuse_pages(&sg[total_sgs],
-						ap->pages, ap->descs,
-						ap->num_pages,
+		total_sgs += sg_init_fuse_pages(&sg[total_sgs], ap,
 						args[numargs - 1].size);
 
 	if (len_used)
-- 
2.43.5