From 053c095a82cf773075e83d7233b5cc19a1f73ece Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 16 Jan 2015 22:09:00 +0100 Subject: netlink: make nlmsg_end() and genlmsg_end() void Contrary to common expectations for an "int" return, these functions return only a positive value -- if used correctly they cannot even return 0 because the message header will necessarily be in the skb. This makes the very common pattern of if (genlmsg_end(...) < 0) { ... } be a whole bunch of dead code. Many places also simply do return nlmsg_end(...); and the caller is expected to deal with it. This also commonly (at least for me) causes errors, because it is very common to write if (my_function(...)) /* error condition */ and if my_function() does "return nlmsg_end()" this is of course wrong. Additionally, there's not a single place in the kernel that actually needs the message length returned, and if anyone needs it later then it'll be very easy to just use skb->len there. Remove this, and make the functions void. This removes a bunch of dead code as described above. The patch adds lines because I did - return nlmsg_end(...); + nlmsg_end(...); + return 0; I could have preserved all the function's return values by returning skb->len, but instead I've audited all the places calling the affected functions and found that none cared. A few places actually compared the return value with <= 0 in dump functionality, but that could just be changed to < 0 with no change in behaviour, so I opted for the more efficient version. One instance of the error I've made numerous times now is also present in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't check for <0 or <=0 and thus broke out of the loop every single time. I've preserved this since it will (I think) have caused the messages to userspace to be formatted differently with just a single message for every SKB returned to userspace. It's possible that this isn't needed for the tools that actually use this, but I don't even know what they are so couldn't test that changing this behaviour would be acceptable. Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- fs/dlm/netlink.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'fs') diff --git a/fs/dlm/netlink.c b/fs/dlm/netlink.c index e7cfbaf8d0e2..1e6e227134d7 100644 --- a/fs/dlm/netlink.c +++ b/fs/dlm/netlink.c @@ -56,13 +56,8 @@ static int send_data(struct sk_buff *skb) { struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data); void *data = genlmsg_data(genlhdr); - int rv; - rv = genlmsg_end(skb, data); - if (rv < 0) { - nlmsg_free(skb); - return rv; - } + genlmsg_end(skb, data); return genlmsg_unicast(&init_net, skb, listener_nlportid); } -- cgit v1.2.3 From 2e90b1c45e34240eeeacab0b37d5f8f739462bdc Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 27 Nov 2014 21:50:31 -0500 Subject: rxrpc: make the users of rxrpc_kernel_send_data() set kvec-backed msg_iter properly Use iov_iter_kvec() there, get rid of set_fs() games - now that rxrpc_send_data() uses iov_iter primitives, it'll handle ITER_KVEC just fine. Signed-off-by: Al Viro --- fs/afs/rxrpc.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'fs') diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c index 06e14bfb3496..dbc732e9a5c0 100644 --- a/fs/afs/rxrpc.c +++ b/fs/afs/rxrpc.c @@ -306,8 +306,8 @@ static int afs_send_pages(struct afs_call *call, struct msghdr *msg, _debug("- range %u-%u%s", offset, to, msg->msg_flags ? " [more]" : ""); - iov_iter_init(&msg->msg_iter, WRITE, - (struct iovec *) iov, 1, to - offset); + iov_iter_kvec(&msg->msg_iter, WRITE | ITER_KVEC, + iov, 1, to - offset); /* have to change the state *before* sending the last * packet as RxRPC might give us the reply before it @@ -384,7 +384,7 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp, msg.msg_name = NULL; msg.msg_namelen = 0; - iov_iter_init(&msg.msg_iter, WRITE, (struct iovec *)iov, 1, + iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, call->request_size); msg.msg_control = NULL; msg.msg_controllen = 0; @@ -770,7 +770,7 @@ static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb, void afs_send_empty_reply(struct afs_call *call) { struct msghdr msg; - struct iovec iov[1]; + struct kvec iov[1]; _enter(""); @@ -778,7 +778,7 @@ void afs_send_empty_reply(struct afs_call *call) iov[0].iov_len = 0; msg.msg_name = NULL; msg.msg_namelen = 0; - iov_iter_init(&msg.msg_iter, WRITE, iov, 0, 0); /* WTF? */ + iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 0, 0); /* WTF? */ msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = 0; @@ -805,7 +805,7 @@ void afs_send_empty_reply(struct afs_call *call) void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len) { struct msghdr msg; - struct iovec iov[1]; + struct kvec iov[1]; int n; _enter(""); @@ -814,7 +814,7 @@ void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len) iov[0].iov_len = len; msg.msg_name = NULL; msg.msg_namelen = 0; - iov_iter_init(&msg.msg_iter, WRITE, iov, 1, len); + iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, len); msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = 0; -- cgit v1.2.3