Commit cf0604a6 authored by David Howells's avatar David Howells Committed by Steve French
Browse files

cifs: use discard iterator to discard unneeded network data more efficiently 



The iterator, ITER_DISCARD, that can only be used in READ mode and
just discards any data copied to it, was added to allow a network
filesystem to discard any unwanted data sent by a server.
Convert cifs_discard_from_socket() to use this.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 5ff2836e

fs/cifs/cifsproto.h

+2 −0
Original line number Diff line number Diff line
@@ -232,6 +232,8 @@ extern unsigned int setup_special_user_owner_ACE(struct cifs_ace *pace); 
extern void dequeue_mid(struct mid_q_entry *mid, bool malformed);

extern int cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,

			         unsigned int to_read);

extern ssize_t cifs_discard_from_socket(struct TCP_Server_Info *server,

					size_t to_read);

extern int cifs_read_page_from_socket(struct TCP_Server_Info *server,

					struct page *page,

					unsigned int page_offset,

fs/cifs/cifssmb.c

+3 −3
Original line number Diff line number Diff line
@@ -1451,8 +1451,8 @@ cifs_discard_remaining_data(struct TCP_Server_Info *server) 
	while (remaining > 0) {

		int length;



		length = cifs_read_from_socket(server, server->bigbuf,

				min_t(unsigned int, remaining,

		length = cifs_discard_from_socket(server,

				min_t(size_t, remaining,

				      CIFSMaxBufSize + MAX_HEADER_SIZE(server)));

		if (length < 0)

			return length;

fs/cifs/connect.c

+17 −0
Original line number Diff line number Diff line
@@ -564,6 +564,23 @@ cifs_read_from_socket(struct TCP_Server_Info *server, char *buf, 
	return cifs_readv_from_socket(server, &smb_msg);

}



ssize_t

cifs_discard_from_socket(struct TCP_Server_Info *server, size_t to_read)

{

	struct msghdr smb_msg;



	/*

	 *  iov_iter_discard already sets smb_msg.type and count and iov_offset

	 *  and cifs_readv_from_socket sets msg_control and msg_controllen

	 *  so little to initialize in struct msghdr

	 */

	smb_msg.msg_name = NULL;

	smb_msg.msg_namelen = 0;

	iov_iter_discard(&smb_msg.msg_iter, READ, to_read);



	return cifs_readv_from_socket(server, &smb_msg);

}



int

cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,

	unsigned int page_offset, unsigned int to_read)