SUNRPC: rpc_timeout_upcall_queue should not sleep
The function rpc_timeout_upcall_queue runs from a workqueue, and hence
sleeping is not recommended. Convert the protection of the upcall queue
from being mutex-based to being spinlock-based.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 9764c80..7281746 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -38,44 +38,42 @@
#define RPC_UPCALL_TIMEOUT (30*HZ)
-static void
-__rpc_purge_list(struct rpc_inode *rpci, struct list_head *head, int err)
+static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
+ void (*destroy_msg)(struct rpc_pipe_msg *), int err)
{
struct rpc_pipe_msg *msg;
- void (*destroy_msg)(struct rpc_pipe_msg *);
- destroy_msg = rpci->ops->destroy_msg;
- while (!list_empty(head)) {
+ if (list_empty(head))
+ return;
+ do {
msg = list_entry(head->next, struct rpc_pipe_msg, list);
- list_del_init(&msg->list);
+ list_del(&msg->list);
msg->errno = err;
destroy_msg(msg);
- }
-}
-
-static void
-__rpc_purge_upcall(struct inode *inode, int err)
-{
- struct rpc_inode *rpci = RPC_I(inode);
-
- __rpc_purge_list(rpci, &rpci->pipe, err);
- rpci->pipelen = 0;
+ } while (!list_empty(head));
wake_up(&rpci->waitq);
}
static void
rpc_timeout_upcall_queue(void *data)
{
+ LIST_HEAD(free_list);
struct rpc_inode *rpci = (struct rpc_inode *)data;
struct inode *inode = &rpci->vfs_inode;
+ void (*destroy_msg)(struct rpc_pipe_msg *);
- mutex_lock(&inode->i_mutex);
- if (rpci->ops == NULL)
- goto out;
- if (rpci->nreaders == 0 && !list_empty(&rpci->pipe))
- __rpc_purge_upcall(inode, -ETIMEDOUT);
-out:
- mutex_unlock(&inode->i_mutex);
+ spin_lock(&inode->i_lock);
+ if (rpci->ops == NULL) {
+ spin_unlock(&inode->i_lock);
+ return;
+ }
+ destroy_msg = rpci->ops->destroy_msg;
+ if (rpci->nreaders == 0) {
+ list_splice_init(&rpci->pipe, &free_list);
+ rpci->pipelen = 0;
+ }
+ spin_unlock(&inode->i_lock);
+ rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
}
int
@@ -84,7 +82,7 @@
struct rpc_inode *rpci = RPC_I(inode);
int res = -EPIPE;
- mutex_lock(&inode->i_mutex);
+ spin_lock(&inode->i_lock);
if (rpci->ops == NULL)
goto out;
if (rpci->nreaders) {
@@ -100,7 +98,7 @@
res = 0;
}
out:
- mutex_unlock(&inode->i_mutex);
+ spin_unlock(&inode->i_lock);
wake_up(&rpci->waitq);
return res;
}
@@ -115,21 +113,29 @@
rpc_close_pipes(struct inode *inode)
{
struct rpc_inode *rpci = RPC_I(inode);
+ struct rpc_pipe_ops *ops;
mutex_lock(&inode->i_mutex);
- if (rpci->ops != NULL) {
+ ops = rpci->ops;
+ if (ops != NULL) {
+ LIST_HEAD(free_list);
+
+ spin_lock(&inode->i_lock);
rpci->nreaders = 0;
- __rpc_purge_list(rpci, &rpci->in_upcall, -EPIPE);
- __rpc_purge_upcall(inode, -EPIPE);
- rpci->nwriters = 0;
- if (rpci->ops->release_pipe)
- rpci->ops->release_pipe(inode);
+ list_splice_init(&rpci->in_upcall, &free_list);
+ list_splice_init(&rpci->pipe, &free_list);
+ rpci->pipelen = 0;
rpci->ops = NULL;
+ spin_unlock(&inode->i_lock);
+ rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
+ rpci->nwriters = 0;
+ if (ops->release_pipe)
+ ops->release_pipe(inode);
+ cancel_delayed_work(&rpci->queue_timeout);
+ flush_scheduled_work();
}
rpc_inode_setowner(inode, NULL);
mutex_unlock(&inode->i_mutex);
- cancel_delayed_work(&rpci->queue_timeout);
- flush_scheduled_work();
}
static struct inode *
@@ -177,16 +183,26 @@
goto out;
msg = (struct rpc_pipe_msg *)filp->private_data;
if (msg != NULL) {
+ spin_lock(&inode->i_lock);
msg->errno = -EAGAIN;
- list_del_init(&msg->list);
+ list_del(&msg->list);
+ spin_unlock(&inode->i_lock);
rpci->ops->destroy_msg(msg);
}
if (filp->f_mode & FMODE_WRITE)
rpci->nwriters --;
- if (filp->f_mode & FMODE_READ)
+ if (filp->f_mode & FMODE_READ) {
rpci->nreaders --;
- if (!rpci->nreaders)
- __rpc_purge_upcall(inode, -EAGAIN);
+ if (rpci->nreaders == 0) {
+ LIST_HEAD(free_list);
+ spin_lock(&inode->i_lock);
+ list_splice_init(&rpci->pipe, &free_list);
+ rpci->pipelen = 0;
+ spin_unlock(&inode->i_lock);
+ rpc_purge_list(rpci, &free_list,
+ rpci->ops->destroy_msg, -EAGAIN);
+ }
+ }
if (rpci->ops->release_pipe)
rpci->ops->release_pipe(inode);
out:
@@ -209,6 +225,7 @@
}
msg = filp->private_data;
if (msg == NULL) {
+ spin_lock(&inode->i_lock);
if (!list_empty(&rpci->pipe)) {
msg = list_entry(rpci->pipe.next,
struct rpc_pipe_msg,
@@ -218,6 +235,7 @@
filp->private_data = msg;
msg->copied = 0;
}
+ spin_unlock(&inode->i_lock);
if (msg == NULL)
goto out_unlock;
}
@@ -225,7 +243,9 @@
res = rpci->ops->upcall(filp, msg, buf, len);
if (res < 0 || msg->len == msg->copied) {
filp->private_data = NULL;
- list_del_init(&msg->list);
+ spin_lock(&inode->i_lock);
+ list_del(&msg->list);
+ spin_unlock(&inode->i_lock);
rpci->ops->destroy_msg(msg);
}
out_unlock: