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Read lock rather than write lock TCP inpcbs in monitoring sysctls. In

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some cases, add explicit inpcb locking rather than relying on the global
lock, as we dereference inp_socket, but also allowing us to drop the
global lock more quickly.

MFC after:	1 week
This commit is contained in:
Robert Watson 2008-05-29 14:28:26 +00:00
parent 06d425f92e
commit c28cb4d82f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=179414
1 changed files with 31 additions and 35 deletions
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66
sys/netinet/tcp_subr.c
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@ -946,7 +946,7 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
INP_INFO_RLOCK(&tcbinfo);
for (inp = LIST_FIRST(tcbinfo.ipi_listhead), i = 0; inp != NULL && i
< n; inp = LIST_NEXT(inp, inp_list)) {
INP_WLOCK(inp);
INP_RLOCK(inp);
if (inp->inp_gencnt <= gencnt) {
/*
* XXX: This use of cr_cansee(), introduced with
@ -965,7 +965,7 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
if (error == 0)
inp_list[i++] = inp;
}
INP_WUNLOCK(inp);
INP_RUNLOCK(inp);
}
INP_INFO_RUNLOCK(&tcbinfo);
n = i;
@ -973,7 +973,7 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
error = 0;
for (i = 0; i < n; i++) {
inp = inp_list[i];
INP_WLOCK(inp);
INP_RLOCK(inp);
if (inp->inp_gencnt <= gencnt) {
struct xtcpcb xt;
void *inp_ppcb;
@ -997,10 +997,10 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
xt.xt_socket.xso_protocol = IPPROTO_TCP;
}
xt.xt_inp.inp_gencnt = inp->inp_gencnt;
INP_WUNLOCK(inp);
INP_RUNLOCK(inp);
error = SYSCTL_OUT(req, &xt, sizeof xt);
} else
INP_WUNLOCK(inp);
INP_RUNLOCK(inp);
}
if (!error) {
@ -1042,23 +1042,21 @@ tcp_getcred(SYSCTL_HANDLER_ARGS)
INP_INFO_RLOCK(&tcbinfo);
inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
if (inp == NULL) {
if (inp != NULL) {
INP_RLOCK(inp);
INP_INFO_RUNLOCK(&tcbinfo);
if (inp->inp_socket == NULL)
error = ENOENT;
if (error == 0)
error = cr_canseesocket(req->td->td_ucred,
inp->inp_socket);
if (error == 0)
cru2x(inp->inp_socket->so_cred, &xuc);
INP_RUNLOCK(inp);
} else {
INP_INFO_RUNLOCK(&tcbinfo);
error = ENOENT;
goto outunlocked;
}
INP_WLOCK(inp);
if (inp->inp_socket == NULL) {
error = ENOENT;
goto out;
}
error = cr_canseesocket(req->td->td_ucred, inp->inp_socket);
if (error)
goto out;
cru2x(inp->inp_socket->so_cred, &xuc);
out:
INP_WUNLOCK(inp);
outunlocked:
INP_INFO_RUNLOCK(&tcbinfo);
if (error == 0)
error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
return (error);
@ -1106,23 +1104,21 @@ tcp6_getcred(SYSCTL_HANDLER_ARGS)
inp = in6_pcblookup_hash(&tcbinfo,
&addrs[1].sin6_addr, addrs[1].sin6_port,
&addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL);
if (inp == NULL) {
if (inp != NULL) {
INP_RLOCK(inp);
INP_INFO_RUNLOCK(&tcbinfo);
if (inp->inp_socket == NULL)
error = ENOENT;
if (error == 0)
error = cr_canseesocket(req->td->td_ucred,
inp->inp_socket);
if (error == 0)
cru2x(inp->inp_socket->so_cred, &xuc);
INP_RUNLOCK(inp);
} else {
INP_INFO_RUNLOCK(&tcbinfo);
error = ENOENT;
goto outunlocked;
}
INP_WLOCK(inp);
if (inp->inp_socket == NULL) {
error = ENOENT;
goto out;
}
error = cr_canseesocket(req->td->td_ucred, inp->inp_socket);
if (error)
goto out;
cru2x(inp->inp_socket->so_cred, &xuc);
out:
INP_WUNLOCK(inp);
outunlocked:
INP_INFO_RUNLOCK(&tcbinfo);
if (error == 0)
error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
return (error);