1d541ddd74
Instead of doing a memset then initialization of the fields of the scm structure, just initialize all the members explicitly. Prevent reloading of current on x86 and x86-64 by storing the value in a local variable for subsequent dereferences. This is worth a ~7KB/s increase in af_unix bandwidth. Note that we avoid the issues surrounding potentially uninitialized members of the ucred structure by constructing a struct ucred instead of assigning the members individually, which forces the compiler to zero any padding. [ I modified the patch not to use the aggregate assignment since gcc-3.4.x and earlier cannot optimize that properly at all even though gcc-4.0.x and later can -DaveM ] Signed-off-by: Benjamin LaHaise <benjamin.c.lahaise@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
73 lines
1.7 KiB
C
73 lines
1.7 KiB
C
#ifndef __LINUX_NET_SCM_H
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#define __LINUX_NET_SCM_H
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#include <linux/limits.h>
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#include <linux/net.h>
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/* Well, we should have at least one descriptor open
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* to accept passed FDs 8)
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*/
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#define SCM_MAX_FD (OPEN_MAX-1)
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struct scm_fp_list
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{
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int count;
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struct file *fp[SCM_MAX_FD];
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};
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struct scm_cookie
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{
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struct ucred creds; /* Skb credentials */
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struct scm_fp_list *fp; /* Passed files */
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unsigned long seq; /* Connection seqno */
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};
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extern void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
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extern void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
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extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
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extern void __scm_destroy(struct scm_cookie *scm);
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extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl);
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static __inline__ void scm_destroy(struct scm_cookie *scm)
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{
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if (scm && scm->fp)
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__scm_destroy(scm);
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}
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static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
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struct scm_cookie *scm)
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{
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struct task_struct *p = current;
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scm->creds.uid = p->uid;
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scm->creds.gid = p->gid;
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scm->creds.pid = p->tgid;
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scm->fp = NULL;
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scm->seq = 0;
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if (msg->msg_controllen <= 0)
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return 0;
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return __scm_send(sock, msg, scm);
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}
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static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
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struct scm_cookie *scm, int flags)
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{
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if (!msg->msg_control)
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{
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if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
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msg->msg_flags |= MSG_CTRUNC;
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scm_destroy(scm);
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return;
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}
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if (test_bit(SOCK_PASSCRED, &sock->flags))
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put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
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if (!scm->fp)
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return;
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scm_detach_fds(msg, scm);
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}
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#endif /* __LINUX_NET_SCM_H */
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