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authorAl Viro <viro@zeniv.linux.org.uk>2005-11-07 17:15:49 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-07 18:18:10 -0800
commit5addc5dd8836aa061f6efc4a0d9ba6323726297a (patch)
treea5ce3703bbb421c93482b6043ebd57137276808f /fs/proc
parent1abe77b0fc4b485927f1f798ae81a752677e1d05 (diff)
[PATCH] make /proc/mounts pollable
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/base.c62
1 files changed, 47 insertions, 15 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a170450aadb..634355e1698 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -70,6 +70,7 @@
#include <linux/seccomp.h>
#include <linux/cpuset.h>
#include <linux/audit.h>
+#include <linux/poll.h>
#include "internal.h"
/*
@@ -660,26 +661,38 @@ static struct file_operations proc_smaps_operations = {
#endif
extern struct seq_operations mounts_op;
+struct proc_mounts {
+ struct seq_file m;
+ int event;
+};
+
static int mounts_open(struct inode *inode, struct file *file)
{
struct task_struct *task = proc_task(inode);
- int ret = seq_open(file, &mounts_op);
+ struct namespace *namespace;
+ struct proc_mounts *p;
+ int ret = -EINVAL;
- if (!ret) {
- struct seq_file *m = file->private_data;
- struct namespace *namespace;
- task_lock(task);
- namespace = task->namespace;
- if (namespace)
- get_namespace(namespace);
- task_unlock(task);
-
- if (namespace)
- m->private = namespace;
- else {
- seq_release(inode, file);
- ret = -EINVAL;
+ task_lock(task);
+ namespace = task->namespace;
+ if (namespace)
+ get_namespace(namespace);
+ task_unlock(task);
+
+ if (namespace) {
+ ret = -ENOMEM;
+ p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
+ if (p) {
+ file->private_data = &p->m;
+ ret = seq_open(file, &mounts_op);
+ if (!ret) {
+ p->m.private = namespace;
+ p->event = namespace->event;
+ return 0;
+ }
+ kfree(p);
}
+ put_namespace(namespace);
}
return ret;
}
@@ -692,11 +705,30 @@ static int mounts_release(struct inode *inode, struct file *file)
return seq_release(inode, file);
}
+static unsigned mounts_poll(struct file *file, poll_table *wait)
+{
+ struct proc_mounts *p = file->private_data;
+ struct namespace *ns = p->m.private;
+ unsigned res = 0;
+
+ poll_wait(file, &ns->poll, wait);
+
+ spin_lock(&vfsmount_lock);
+ if (p->event != ns->event) {
+ p->event = ns->event;
+ res = POLLERR;
+ }
+ spin_unlock(&vfsmount_lock);
+
+ return res;
+}
+
static struct file_operations proc_mounts_operations = {
.open = mounts_open,
.read = seq_read,
.llseek = seq_lseek,
.release = mounts_release,
+ .poll = mounts_poll,
};
#define PROC_BLOCK_SIZE (3*1024) /* 4K page size but our output routines use some slack for overruns */