[patch 3/7] epoll: Use sequential fdinfo engine

From: Cyrill Gorcunov
Date: Wed Nov 06 2013 - 06:51:20 EST


Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Andrey Vagin <avagin@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: James Bottomley <jbottomley@xxxxxxxxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Matthew Helsley <matt.helsley@xxxxxxxxx>
Cc: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/eventpoll.c | 46 ++++++++++++++++++++++++++++++++++------------
1 file changed, 34 insertions(+), 12 deletions(-)

Index: linux-2.6.git/fs/eventpoll.c
===================================================================
--- linux-2.6.git.orig/fs/eventpoll.c
+++ linux-2.6.git/fs/eventpoll.c
@@ -833,32 +833,54 @@ static unsigned int ep_eventpoll_poll(st
}

#ifdef CONFIG_PROC_FS
-static int ep_show_fdinfo(struct seq_file *m, struct file *f)
+static void *seq_start(struct seq_file *m, loff_t *pos)
{
- struct eventpoll *ep = f->private_data;
+ struct eventpoll *ep = ((struct file *)m->private)->private_data;
struct rb_node *rbp;
- int ret = 0;
+ loff_t num = *pos;

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;
+ if (num-- == 0)
+ return rbp;
}
+ return NULL;
+}
+
+static void seq_stop(struct seq_file *m, void *v)
+{
+ struct eventpoll *ep = ((struct file *)m->private)->private_data;
mutex_unlock(&ep->mtx);
+}

- return ret;
+static void *seq_next(struct seq_file *m, void *p, loff_t *pos)
+{
+ ++*pos;
+ return (void *)rb_next(p);
}
+
+static int seq_show(struct seq_file *m, void *v)
+{
+ struct epitem *epi = rb_entry(v, struct epitem, rbn);
+
+ seq_printf(m, "tfd: %8d events: %8x data: %16llx\n",
+ epi->ffd.fd, epi->event.events,
+ (long long)epi->event.data);
+ return 0;
+}
+
+static struct seq_operations ep_fdinfo_op = {
+ .start = seq_start,
+ .next = seq_next,
+ .stop = seq_stop,
+ .show = seq_show,
+};
#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,
+ .fdinfo_op = &ep_fdinfo_op,
#endif
.release = ep_eventpoll_release,
.poll = ep_eventpoll_poll,

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