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Subject[PATCH] timerfd: show procfs fdinfo helper, and now accepts write()
Date
| pos:	0
| flags: 02004002
| clockid: 0
| ticks: 6

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Shawn Landden <shawn@churchofgit.com>
---
fs/timerfd.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)

diff --git a/fs/timerfd.c b/fs/timerfd.c
index 9293121..2e81bdb 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -25,6 +25,7 @@
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <linux/rcupdate.h>
+#include <linux/seq_file.h>

struct timerfd_ctx {
union {
@@ -284,10 +285,73 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
return res;
}

+#ifdef CONFIG_PROC_FS
+static int timerfd_show_fdinfo(struct seq_file *m, struct file *f)
+{
+ struct timerfd_ctx *ctx = f->private_data;
+
+ seq_printf(m, "clockid:\t%d\n"
+ "ticks:\t%llu\n", ctx->clockid, ctx->ticks);
+
+ return 0;
+}
+#endif
+
+static ssize_t timerfd_write(struct file *file, const char __user *buf, size_t count,
+ loff_t *ppos)
+{
+ struct timerfd_ctx *ctx = file->private_data;
+ ssize_t res;
+ __u64 ucnt;
+ DECLARE_WAITQUEUE(wait, current);
+
+ if (count < sizeof(ucnt))
+ return -EINVAL;
+ if (copy_from_user(&ucnt, buf, sizeof(ucnt)))
+ return -EFAULT;
+ if (ucnt == ULLONG_MAX)
+ return -EINVAL;
+ spin_lock_irq(&ctx->wqh.lock);
+ res = -EAGAIN;
+ if (ULLONG_MAX - ctx->ticks > ucnt)
+ res = sizeof(ucnt);
+ else if (!(file->f_flags & O_NONBLOCK)) {
+ __add_wait_queue(&ctx->wqh, &wait);
+ for (res = 0;;) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (ULLONG_MAX - ctx->ticks > ucnt) {
+ res = sizeof(ucnt);
+ break;
+ }
+ if (signal_pending(current)) {
+ res = -ERESTARTSYS;
+ break;
+ }
+ spin_unlock_irq(&ctx->wqh.lock);
+ schedule();
+ spin_lock_irq(&ctx->wqh.lock);
+ }
+ __remove_wait_queue(&ctx->wqh, &wait);
+ __set_current_state(TASK_RUNNING);
+ }
+ if (likely(res > 0)) {
+ ctx->ticks += ucnt;
+ if (waitqueue_active(&ctx->wqh))
+ wake_up_locked_poll(&ctx->wqh, POLLIN);
+ }
+ spin_unlock_irq(&ctx->wqh.lock);
+
+ return res;
+}
+
static const struct file_operations timerfd_fops = {
+#ifdef CONFIG_PROC_FS
+ .show_fdinfo = timerfd_show_fdinfo,
+#endif
.release = timerfd_release,
.poll = timerfd_poll,
.read = timerfd_read,
+ .write = timerfd_write,
.llseek = noop_llseek,
};

--
1.8.5.2.297.g3e57c29


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