9p: switch p9_client_read() to passing struct iov_iter *

... and make it loop

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 16 insertions, 32 deletions

diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
index d4cab07f668d..0cf44b6cccd6 100644
--- a/fs/9p/xattr.c
+++ b/fs/9p/xattr.c
@@ -26,50 +26,34 @@ ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
 			   void *buffer, size_t buffer_size)
 {
 	ssize_t retval;
-	int msize, read_count;
-	u64 offset = 0, attr_size;
+	u64 attr_size;
 	struct p9_fid *attr_fid;
+	struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size};
+	struct iov_iter to;
+	int err;
+
+	iov_iter_kvec(&to, READ | ITER_KVEC, &kvec, 1, buffer_size);
 
 	attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
 	if (IS_ERR(attr_fid)) {
 		retval = PTR_ERR(attr_fid);
 		p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n",
 			 retval);
-		attr_fid = NULL;
-		goto error;
-	}
-	if (!buffer_size) {
-		/* request to get the attr_size */
-		retval = attr_size;
-		goto error;
+		return retval;
 	}
 	if (attr_size > buffer_size) {
-		retval = -ERANGE;
-		goto error;
-	}
-	msize = attr_fid->clnt->msize;
-	while (attr_size) {
-		if (attr_size > (msize - P9_IOHDRSZ))
-			read_count = msize - P9_IOHDRSZ;
+		if (!buffer_size) /* request to get the attr_size */
+			retval = attr_size;
 		else
-			read_count = attr_size;
-		read_count = p9_client_read(attr_fid, ((char *)buffer)+offset,
-					NULL, offset, read_count);
-		if (read_count < 0) {
-			/* error in xattr read */
-			retval = read_count;
-			goto error;
-		}
-		offset += read_count;
-		attr_size -= read_count;
+			retval = -ERANGE;
+	} else {
+		iov_iter_truncate(&to, attr_size);
+		retval = p9_client_read(attr_fid, 0, &to, &err);
+		if (err)
+			retval = err;
 	}
-	/* Total read xattr bytes */
-	retval = offset;
-error:
-	if (attr_fid)
-		p9_client_clunk(attr_fid);
+	p9_client_clunk(attr_fid);
 	return retval;
-
 }