[PATCH 03/13] ksocknal_lib_send_kiov(): sendmsg doesn't bugger iovec...

Oleg Drokin
2016-08-20T21:35:04Z

From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
---
.../lustre/lnet/klnds/socklnd/socklnd_lib.c | 29 ++++------------------
1 file changed, 5 insertions(+), 24 deletions(-)

diff --git a/drivers/staging/lustre/lnet/klnds/socklnd/socklnd_lib.c b/drivers/staging/lustre/lnet/klnds/socklnd/socklnd_lib.c
index 8eb4a68..6c95e98 100644
--- a/drivers/staging/lustre/lnet/klnds/socklnd/socklnd_lib.c
+++ b/drivers/staging/lustre/lnet/klnds/socklnd/socklnd_lib.c
@@ -106,10 +106,6 @@ ksocknal_lib_send_kiov(struct ksock_conn *conn, struct ksock_tx *tx)
/* Not NOOP message */
LASSERT(tx->tx_lnetmsg);

- /*
- * NB we can't trust socket ops to either consume our iovs
- * or leave them alone.
- */
if (tx->tx_msg.ksm_zc_cookies[0]) {
/* Zero copy is enabled */
struct sock *sk = sock->sk;
@@ -132,34 +128,19 @@ ksocknal_lib_send_kiov(struct ksock_conn *conn, struct ksock_tx *tx)
rc = tcp_sendpage(sk, page, offset, fragsize, msgflg);
}
} else {
-#if SOCKNAL_SINGLE_FRAG_TX || !SOCKNAL_RISK_KMAP_DEADLOCK
- struct kvec scratch;
- struct kvec *scratchiov = &scratch;
- unsigned int niov = 1;
-#else
-#ifdef CONFIG_HIGHMEM
-#warning "XXX risk of kmap deadlock on multiple frags..."
-#endif
- struct kvec *scratchiov = conn->ksnc_scheduler->kss_scratch_iov;
- unsigned int niov = tx->tx_nkiov;
-#endif
struct msghdr msg = {.msg_flags = MSG_DONTWAIT};
int i;

- for (nob = i = 0; i < niov; i++) {
- scratchiov[i].iov_base = kmap(kiov[i].bv_page) +
- kiov[i].bv_offset;
- nob += scratchiov[i].iov_len = kiov[i].bv_len;
- }
+ for (nob = i = 0; i < tx->tx_nkiov; i++)
+ nob += kiov[i].bv_len;

if (!list_empty(&conn->ksnc_tx_queue) ||
nob < tx->tx_resid)
msg.msg_flags |= MSG_MORE;

- rc = kernel_sendmsg(sock, &msg, (struct kvec *)scratchiov, niov, nob);
-
- for (i = 0; i < niov; i++)
- kunmap(kiov[i].bv_page);
+ iov_iter_bvec(&msg.msg_iter, WRITE | ITER_BVEC,
+ kiov, tx->tx_nkiov, nob);
+ rc = sock_sendmsg(sock, &msg);
}
return rc;
}
--
2.7.4