fuse: rework fuse_perform_write()
The patch allocates as many page pointers in fuse_req as needed to cover
interval [pos .. pos+len-1]. Inline helper fuse_wr_pages() is introduced
to hide this cumbersome arithmetic.
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 5fd06ba..b997250 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -881,11 +881,19 @@
if (!fc->big_writes)
break;
} while (iov_iter_count(ii) && count < fc->max_write &&
- req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0);
+ req->num_pages < req->max_pages && offset == 0);
return count > 0 ? count : err;
}
+static inline unsigned fuse_wr_pages(loff_t pos, size_t len)
+{
+ return min_t(unsigned,
+ ((pos + len - 1) >> PAGE_CACHE_SHIFT) -
+ (pos >> PAGE_CACHE_SHIFT) + 1,
+ FUSE_MAX_PAGES_PER_REQ);
+}
+
static ssize_t fuse_perform_write(struct file *file,
struct address_space *mapping,
struct iov_iter *ii, loff_t pos)
@@ -901,8 +909,9 @@
do {
struct fuse_req *req;
ssize_t count;
+ unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
- req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ);
+ req = fuse_get_req(fc, nr_pages);
if (IS_ERR(req)) {
err = PTR_ERR(req);
break;