splice: implement default splice_read method
If f_op->splice_read() is not implemented, fall back to a plain read.
Use vfs_readv() to read into previously allocated pages.
This will allow splice and functions using splice, such as the loop
device, to work on all filesystems. This includes "direct_io" files
in fuse which bypass the page cache.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fs/coda/file.c b/fs/coda/file.c
index 6a347fb..ffd4281 100644
--- a/fs/coda/file.c
+++ b/fs/coda/file.c
@@ -47,6 +47,8 @@
struct pipe_inode_info *pipe, size_t count,
unsigned int flags)
{
+ ssize_t (*splice_read)(struct file *, loff_t *,
+ struct pipe_inode_info *, size_t, unsigned int);
struct coda_file_info *cfi;
struct file *host_file;
@@ -54,10 +56,11 @@
BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
host_file = cfi->cfi_container;
- if (!host_file->f_op || !host_file->f_op->splice_read)
- return -EINVAL;
+ splice_read = host_file->f_op->splice_read;
+ if (!splice_read)
+ splice_read = default_file_splice_read;
- return host_file->f_op->splice_read(host_file, ppos, pipe, count,flags);
+ return splice_read(host_file, ppos, pipe, count, flags);
}
static ssize_t