fs, epoll: add procfs fdinfo helper
This allows us to print out eventpoll target file descriptor, events and
data, the /proc/pid/fdinfo/fd consists of
| pos: 0
| flags: 02
| tfd: 5 events: 1d data: ffffffffffffffff enabled: 1
[avagin@: fix for unitialized ret variable]
Signed-off-by: Cyrill Gorcunov <[email protected]>
Acked-by: Pavel Emelyanov <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Andrey Vagin <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: "Aneesh Kumar K.V" <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Matthew Helsley <[email protected]>
Cc: "J. Bruce Fields" <[email protected]>
Cc: "Aneesh Kumar K.V" <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index cd96649..be56b21 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -38,6 +38,8 @@
#include <asm/io.h>
#include <asm/mman.h>
#include <linux/atomic.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
/*
* LOCKING:
@@ -783,8 +785,34 @@
return pollflags != -1 ? pollflags : 0;
}
+#ifdef CONFIG_PROC_FS
+static int ep_show_fdinfo(struct seq_file *m, struct file *f)
+{
+ struct eventpoll *ep = f->private_data;
+ struct rb_node *rbp;
+ int ret = 0;
+
+ mutex_lock(&ep->mtx);
+ for (rbp = rb_first(&ep->rbr); rbp; rbp = rb_next(rbp)) {
+ struct epitem *epi = rb_entry(rbp, struct epitem, rbn);
+
+ ret = seq_printf(m, "tfd: %8d events: %8x data: %16llx\n",
+ epi->ffd.fd, epi->event.events,
+ (long long)epi->event.data);
+ if (ret)
+ break;
+ }
+ mutex_unlock(&ep->mtx);
+
+ return ret;
+}
+#endif
+
/* File callbacks that implement the eventpoll file behaviour */
static const struct file_operations eventpoll_fops = {
+#ifdef CONFIG_PROC_FS
+ .show_fdinfo = ep_show_fdinfo,
+#endif
.release = ep_eventpoll_release,
.poll = ep_eventpoll_poll,
.llseek = noop_llseek,
