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-rw-r--r--fs/fuse/virtio_fs.c32
1 files changed, 27 insertions, 5 deletions
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index 5200ad50ed10..f9c1aa1d289c 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -1018,18 +1018,37 @@ __releases(fiq->lock)
spin_unlock(&fiq->lock);
}
+/* 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)
+{
+ 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;
+ }
+
+ return i;
+}
+
/* Return the number of scatter-gather list elements required */
static unsigned int sg_count_fuse_req(struct fuse_req *req)
{
struct fuse_args *args = req->args;
struct fuse_args_pages *ap = container_of(args, typeof(*ap), args);
- unsigned int total_sgs = 1 /* fuse_in_header */;
+ unsigned int size, total_sgs = 1 /* fuse_in_header */;
if (args->in_numargs - args->in_pages)
total_sgs += 1;
- if (args->in_pages)
- total_sgs += ap->num_pages;
+ 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);
+ }
if (!test_bit(FR_ISREPLY, &req->flags))
return total_sgs;
@@ -1039,8 +1058,11 @@ static unsigned int sg_count_fuse_req(struct fuse_req *req)
if (args->out_numargs - args->out_pages)
total_sgs += 1;
- if (args->out_pages)
- total_sgs += ap->num_pages;
+ 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);
+ }
return total_sgs;
}