iov_iter: Separate type from direction and use accessor functions

In the iov_iter struct, separate the iterator type from the iterator
direction and use accessor functions to access them in most places.

Convert a bunch of places to use switch-statements to access them rather
then chains of bitwise-AND statements.  This makes it easier to add further
iterator types.  Also, this can be more efficient as to implement a switch
of small contiguous integers, the compiler can use ~50% fewer compare
instructions than it has to use bitwise-and instructions.

Further, cease passing the iterator type into the iterator setup function.
The iterator function can set that itself.  Only the direction is required.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells
2018-10-20 00:57:56 +01:00
parent 00e2370744
commit aa563d7bca
40 changed files with 96 additions and 105 deletions

View File

@ -286,7 +286,7 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
*/
krflags = MSG_PEEK | MSG_WAITALL;
smc->clcsock->sk->sk_rcvtimeo = CLC_WAIT_TIME;
iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &vec, 1,
iov_iter_kvec(&msg.msg_iter, READ, &vec, 1,
sizeof(struct smc_clc_msg_hdr));
len = sock_recvmsg(smc->clcsock, &msg, krflags);
if (signal_pending(current)) {
@ -325,7 +325,7 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
/* receive the complete CLC message */
memset(&msg, 0, sizeof(struct msghdr));
iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &vec, 1, datlen);
iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, datlen);
krflags = MSG_WAITALL;
len = sock_recvmsg(smc->clcsock, &msg, krflags);
if (len < datlen || !smc_clc_msg_hdr_valid(clcm)) {