lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

net/9p: handle correctly interrupted 9P requests

Browse Source 
Currently the 9p code crashes when a operation is interrupted, i.e. for
example when the user presses ^C while reading from a file.

This patch fixes the code that is responsible for interruption and flushing
of 9P operations.

Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
This commit is contained in:
Latchesar Ionkov
2009-04-05 16:28:59 -05:00
committed by Eric Van Hensbergen
parent 742b11a7ec
commit 1bab88b231
5 changed files with 30 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
net/9p/client.c
View File

@@ -203,7 +203,6 @@ static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
p9pdu_reset(req->tc);
p9pdu_reset(req->rc);
req->flush_tag = 0;
req->tc->tag = tag-1;
req->status = REQ_STATUS_ALLOC;
@@ -324,35 +323,9 @@ static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
*/
void p9_client_cb(struct p9_client *c, struct p9_req_t *req)
{
struct p9_req_t *other_req;
unsigned long flags;
P9_DPRINTK(P9_DEBUG_MUX, " tag %d\n", req->tc->tag);
if (req->status == REQ_STATUS_ERROR)
wake_up(req->wq);
if (req->flush_tag) { /* flush receive path */
P9_DPRINTK(P9_DEBUG_9P, "<<< RFLUSH %d\n", req->tc->tag);
spin_lock_irqsave(&c->lock, flags);
other_req = p9_tag_lookup(c, req->flush_tag);
if (other_req->status != REQ_STATUS_FLSH) /* stale flush */
spin_unlock_irqrestore(&c->lock, flags);
else {
other_req->status = REQ_STATUS_FLSHD;
spin_unlock_irqrestore(&c->lock, flags);
wake_up(other_req->wq);
}
p9_free_req(c, req);
} else { /* normal receive path */
P9_DPRINTK(P9_DEBUG_MUX, "normal: tag %d\n", req->tc->tag);
spin_lock_irqsave(&c->lock, flags);
if (req->status != REQ_STATUS_FLSHD)
req->status = REQ_STATUS_RCVD;
spin_unlock_irqrestore(&c->lock, flags);
wake_up(req->wq);
P9_DPRINTK(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
}
wake_up(req->wq);
P9_DPRINTK(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
}
EXPORT_SYMBOL(p9_client_cb);
@@ -486,9 +459,15 @@ static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
if (IS_ERR(req))
return PTR_ERR(req);
req->flush_tag = oldtag;
/* we don't free anything here because RPC isn't complete */
/* if we haven't received a response for oldreq,
remove it from the list. */
spin_lock(&c->lock);
if (oldreq->status == REQ_STATUS_FLSH)
list_del(&oldreq->req_list);
spin_unlock(&c->lock);
p9_free_req(c, req);
return 0;
}
@@ -509,7 +488,6 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
struct p9_req_t *req;
unsigned long flags;
int sigpending;
int flushed = 0;
P9_DPRINTK(P9_DEBUG_MUX, "client %p op %d\n", c, type);
@@ -546,42 +524,28 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
goto reterr;
}
/* if it was a flush we just transmitted, return our tag */
if (type == P9_TFLUSH)
return req;
again:
P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d\n", req->wq, tag);
err = wait_event_interruptible(*req->wq,
req->status >= REQ_STATUS_RCVD);
P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d (flushed=%d)\n",
req->wq, tag, err, flushed);
P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d\n",
req->wq, tag, err);
if (req->status == REQ_STATUS_ERROR) {
P9_DPRINTK(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
err = req->t_err;
} else if (err == -ERESTARTSYS && flushed) {
P9_DPRINTK(P9_DEBUG_MUX, "flushed - going again\n");
goto again;
} else if (req->status == REQ_STATUS_FLSHD) {
P9_DPRINTK(P9_DEBUG_MUX, "flushed - erestartsys\n");
err = -ERESTARTSYS;
}
if ((err == -ERESTARTSYS) && (c->status == Connected) && (!flushed)) {
if ((err == -ERESTARTSYS) && (c->status == Connected)) {
P9_DPRINTK(P9_DEBUG_MUX, "flushing\n");
spin_lock_irqsave(&c->lock, flags);
if (req->status == REQ_STATUS_SENT)
req->status = REQ_STATUS_FLSH;
spin_unlock_irqrestore(&c->lock, flags);
sigpending = 1;
flushed = 1;
clear_thread_flag(TIF_SIGPENDING);
if (c->trans_mod->cancel(c, req)) {
err = p9_client_flush(c, req);
if (err == 0)
goto again;
}
if (c->trans_mod->cancel(c, req))
p9_client_flush(c, req);
/* if we received the response anyway, don't signal error */
if (req->status == REQ_STATUS_RCVD)
err = 0;
}
if (sigpending) {