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Subject: [PATCH 4/7] cifs: Add a function to read into an iter from a socket
From:   David Howells <dhowells@redhat.com>
To:     Steve French <smfrench@gmail.com>
Cc:     Steve French <sfrench@samba.org>,
        Shyam Prasad N <nspmangalore@gmail.com>,
        Rohith Surabattula <rohiths.msft@gmail.com>,
        linux-cifs@vger.kernel.org, dhowells@redhat.com,
        Shyam Prasad N <nspmangalore@gmail.com>,
        Rohith Surabattula <rohiths.msft@gmail.com>,
        Jeff Layton <jlayton@kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>, linux-cifs@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Wed, 25 May 2022 15:26:36 +0100
Message-ID: <165348879662.2106726.16881134187242702351.stgit@warthog.procyon.org.uk>
In-Reply-To: <165348876794.2106726.9240233279581920208.stgit@warthog.procyon.org.uk>
References: <165348876794.2106726.9240233279581920208.stgit@warthog.procyon.org.uk>
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Add a helper function to read data from a socket into the given iterator.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: linux-cifs@vger.kernel.org
---

 fs/cifs/cifsproto.h |    3 +++
 fs/cifs/connect.c   |   16 ++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 0df3b24a0bf4..dd4931308ea6 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -245,6 +245,9 @@ extern int cifs_read_page_from_socket(struct TCP_Server_Info *server,
 					unsigned int page_offset,
 					unsigned int to_read);
 extern int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb);
+extern int cifs_read_iter_from_socket(struct TCP_Server_Info *server,
+				      struct iov_iter *iter,
+				      unsigned int to_read);
 extern int cifs_match_super(struct super_block *, void *);
 extern int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx);
 extern void cifs_umount(struct cifs_sb_info *);
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 42e14f408856..0d532d559f70 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -764,6 +764,22 @@ cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
 	return cifs_readv_from_socket(server, &smb_msg);
 }
 
+int
+cifs_read_iter_from_socket(struct TCP_Server_Info *server, struct iov_iter *iter,
+			   unsigned int to_read)
+{
+	struct msghdr smb_msg;
+	int ret;
+
+	smb_msg.msg_iter = *iter;
+	if (smb_msg.msg_iter.count > to_read)
+		smb_msg.msg_iter.count = to_read;
+	ret = cifs_readv_from_socket(server, &smb_msg);
+	if (ret > 0)
+		iov_iter_advance(iter, ret);
+	return ret;
+}
+
 static bool
 is_smb_response(struct TCP_Server_Info *server, unsigned char type)
 {