ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/libev/ev_epoll.c
(Generate patch)

Comparing libev/ev_epoll.c (file contents):
Revision 1.34 by root, Fri May 23 16:37:38 2008 UTC vs.
Revision 1.35 by root, Thu Oct 23 04:56:49 2008 UTC

… …
55 * epoll_ctl syscalls for common usage patterns. 55 * epoll_ctl syscalls for common usage patterns.
56 */ 56 */
57 57
58#include <sys/epoll.h> 58#include <sys/epoll.h>
59 59
60void inline_size
61unsigned_char_init (unsigned char *base, int count)
62{
63 /* memset might be overkill */
64 while (count--)
65 *base++ = 0;
66}
67
60static void 68static void
61epoll_modify (EV_P_ int fd, int oev, int nev) 69epoll_modify (EV_P_ int fd, int oev, int nev)
62{ 70{
63 struct epoll_event ev; 71 struct epoll_event ev;
72 unsigned char oldmask;
64 73
65 /* 74 /*
66 * we handle EPOLL_CTL_DEL by ignoring it here 75 * we handle EPOLL_CTL_DEL by ignoring it here
67 * on the assumption that the fd is gone anyways 76 * on the assumption that the fd is gone anyways
68 * if that is wrong, we have to handle the spurious 77 * if that is wrong, we have to handle the spurious
69 * event in epoll_poll. 78 * event in epoll_poll.
79 * the fd is later added, we try to ADD it, and, if that
80 * fails, we assume it still has the same eventmask.
70 */ 81 */
71 if (!nev) 82 if (!nev)
72 return; 83 return;
73 84
85 oldmask = anfds [fd].emask;
86 anfds [fd].emask = nev;
87
74 ev.data.u64 = fd; /* use u64 to fully initialise the struct, for nicer strace etc. */ 88 ev.data.u64 = fd; /* use u64 to fully initialise the struct, for nicer strace etc. */
75 ev.events = (nev & EV_READ ? EPOLLIN : 0) 89 ev.events = (nev & EV_READ ? EPOLLIN : 0)
76 | (nev & EV_WRITE ? EPOLLOUT : 0); 90 | (nev & EV_WRITE ? EPOLLOUT : 0);
77 91
78 if (expect_true (!epoll_ctl (backend_fd, oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev))) 92 if (expect_true (!epoll_ctl (backend_fd, oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev)))
79 return; 93 return;
80 94
81 if (expect_true (errno == ENOENT)) 95 if (expect_true (errno == ENOENT))
82 { 96 {
83 /* on ENOENT the fd went away, so try to do the right thing */ 97 /* if ENOENT then the fd went away, so try to do the right thing */
84 if (!nev) 98 if (!nev)
85 return; 99 return;
86 100
87 if (!epoll_ctl (backend_fd, EPOLL_CTL_ADD, fd, &ev)) 101 if (!epoll_ctl (backend_fd, EPOLL_CTL_ADD, fd, &ev))
88 return; 102 return;
89 } 103 }
90 else if (expect_true (errno == EEXIST)) 104 else if (expect_true (errno == EEXIST))
91 { 105 {
92 /* on EEXIST we ignored a previous DEL */ 106 /* EEXIST means we ignored a previous DEL, but the fd is still active */
107 /* if the kernel mask is the same as the new mask, we assume it hasn't changed */
93 if (!epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev)) 108 if (oldmask == nev || !epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev))
94 return; 109 return;
95 } 110 }
96 111
97 fd_kill (EV_A_ fd); 112 fd_kill (EV_A_ fd);
98} 113}
… …
120 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0); 135 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0);
121 int want = anfds [fd].events; 136 int want = anfds [fd].events;
122 137
123 if (expect_false (got & ~want)) 138 if (expect_false (got & ~want))
124 { 139 {
140 anfds [fd].emask = want;
141
125 /* we received an event but are not interested in it, try mod or del */ 142 /* we received an event but are not interested in it, try mod or del */
143 /* I don't think we ever need MOD, but let's handle it anyways */
126 ev->events = (want & EV_READ ? EPOLLIN : 0) 144 ev->events = (want & EV_READ ? EPOLLIN : 0)
127 | (want & EV_WRITE ? EPOLLOUT : 0); 145 | (want & EV_WRITE ? EPOLLOUT : 0);
128 146
129 epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev); 147 epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev);
130 } 148 }

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines