[PATCH v21 14/30] 9p: Add splice_read stub

David Howells
2023-05-20T00:01:46Z

Add a splice_read stub for 9p. We should use copy_splice_read() if
9PL_DIRECT is set and filemap_splice_read() otherwise. Note that this
doesn't seem to be particularly related to O_DIRECT.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: v9fs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-mm@kvack.org
---
fs/9p/vfs_file.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 6c31b8c8112d..2996fb00387f 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -374,6 +374,28 @@ v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
return ret;
}

+/*
+ * v9fs_file_splice_read - splice-read from a file
+ * @in: The 9p file to read from
+ * @ppos: Where to find/update the file position
+ * @pipe: The pipe to splice into
+ * @len: The maximum amount of data to splice
+ * @flags: SPLICE_F_* flags
+ */
+static ssize_t v9fs_file_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe,
+ size_t len, unsigned int flags)
+{
+ struct p9_fid *fid = in->private_data;
+
+ p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",
+ fid->fid, len, *ppos);
+
+ if (fid->mode & P9L_DIRECT)
+ return copy_splice_read(in, ppos, pipe, len, flags);
+ return filemap_splice_read(in, ppos, pipe, len, flags);
+}
+
/**
* v9fs_file_write_iter - write to a file
* @iocb: The operation parameters
@@ -569,7 +591,7 @@ const struct file_operations v9fs_file_operations = {
.release = v9fs_dir_release,
.lock = v9fs_file_lock,
.mmap = generic_file_readonly_mmap,
- .splice_read = generic_file_splice_read,
+ .splice_read = v9fs_file_splice_read,
.splice_write = iter_file_splice_write,
.fsync = v9fs_file_fsync,
};
@@ -583,7 +605,7 @@ const struct file_operations v9fs_file_operations_dotl = {
.lock = v9fs_file_lock_dotl,
.flock = v9fs_file_flock_dotl,
.mmap = v9fs_file_mmap,
- .splice_read = generic_file_splice_read,
+ .splice_read = v9fs_file_splice_read,
.splice_write = iter_file_splice_write,
.fsync = v9fs_file_fsync_dotl,
};