path: root/fs/eventfd.c
diff options
authorCyrill Gorcunov <gorcunov@openvz.org>2012-12-17 16:04:57 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-17 17:15:27 -0800
commitcbac5542d48127b546a23d816380a7926eee1c25 (patch)
tree08ae343d94b427ed971bffc507edaaade053c294 /fs/eventfd.c
parent55985dd72ab27b47530dcc8bdddd28b69f4abe8b (diff)
fs, eventfd: add procfs fdinfo helper
This allows us to print out raw counter value. The /proc/pid/fdinfo/fd output is | pos: 0 | flags: 04002 | eventfd-count: 5a Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrey Vagin <avagin@openvz.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: James Bottomley <jbottomley@parallels.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Matthew Helsley <matt.helsley@gmail.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@onelan.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/eventfd.c')
1 files changed, 20 insertions, 0 deletions
diff --git a/fs/eventfd.c b/fs/eventfd.c
index d81b9f65408..35470d9b96e 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -19,6 +19,8 @@
#include <linux/export.h>
#include <linux/kref.h>
#include <linux/eventfd.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
struct eventfd_ctx {
struct kref kref;
@@ -284,7 +286,25 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c
return res;
+static int eventfd_show_fdinfo(struct seq_file *m, struct file *f)
+ struct eventfd_ctx *ctx = f->private_data;
+ int ret;
+ spin_lock_irq(&ctx->wqh.lock);
+ ret = seq_printf(m, "eventfd-count: %16llx\n",
+ (unsigned long long)ctx->count);
+ spin_unlock_irq(&ctx->wqh.lock);
+ return ret;
static const struct file_operations eventfd_fops = {
+ .show_fdinfo = eventfd_show_fdinfo,
.release = eventfd_release,
.poll = eventfd_poll,
.read = eventfd_read,