[PATCH] procfs: fix numbering in /proc/locks

From: Jerome Marchand
Date: Mon Sep 27 2010 - 11:13:49 EST



The lock number in /proc/locks (first field) is implemented by a counter
(private field of struct seq_file) which is incremented at each call of
locks_show(). Currently it is reset each time locks_start() is called,
that is each time we call the read() syscall on /proc/locks. Because of
that, the numbering erratically restarts at 1 several times when reading
a long /proc/locks file.
We want the counter to be initialized at opening time and then never
reset until we close the file. Fortunately, seq_open() memzeros the
seq_file structure, so we can just drop the reset in locks_start() and
move the increment the counter before actually printing the line so the
numbering still starts at 1.

Signed-off-by: Jerome Marchand <jmarchan@xxxxxxxxxx>
---
diff --git a/fs/locks.c b/fs/locks.c
index ab24d49..a5eab5e 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2161,19 +2161,18 @@ static int locks_show(struct seq_file *f, void *v)

fl = list_entry(v, struct file_lock, fl_link);

+ f->private++;
lock_get_status(f, fl, (long)f->private, "");

list_for_each_entry(bfl, &fl->fl_block, fl_block)
lock_get_status(f, bfl, (long)f->private, " ->");

- f->private++;
return 0;
}

static void *locks_start(struct seq_file *f, loff_t *pos)
{
lock_kernel();
- f->private = (void *)1;
return seq_list_start(&file_lock_list, *pos);
}

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