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Date: Tue, 11 Dec 2018 13:41:48 +0100
From: Dominique Martinet <asmadeus@...ewreck.org>
To: v9fs-developer@...ts.sourceforge.net
Cc: Dominique Martinet <dominique.martinet@....fr>,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
Eric Van Hensbergen <ericvh@...il.com>,
Latchesar Ionkov <lucho@...kov.net>,
Tomas Bortoli <tomasbortoli@...il.com>,
Dmitry Vyukov <dvyukov@...gle.com>
Subject: [PATCH 3/3] 9p/net: make flush asynchronous
From: Dominique Martinet <dominique.martinet@....fr>
Make the client flush asynchronous so we don't need to ignore signals in
rpc functions:
- on signal, send a flush request as we previously did but use the new
asynchronous helper and return immediately
- when the reply has been received or connection is destroyed, free
both tags in the handler
Signed-off-by: Dominique Martinet <dominique.martinet@....fr>
Cc: Eric Van Hensbergen <ericvh@...il.com>
Cc: Latchesar Ionkov <lucho@...kov.net>
Cc: Tomas Bortoli <tomasbortoli@...il.com>
Cc: Dmitry Vyukov <dvyukov@...gle.com>
---
include/net/9p/client.h | 2 +
net/9p/client.c | 172 ++++++++++++++++++----------------------
2 files changed, 78 insertions(+), 96 deletions(-)
diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index 75d7f83e5b94..dcd40e7ef202 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -91,6 +91,7 @@ enum p9_req_status_t {
* @aux: transport specific data (provided for trans_fd migration)
* @req_list: link used by trans_fd
* @async_list: link used to check on async requests
+ * @flushed_req: for flush, points to matching flushed req
* @clunked_fid: for clunk, points to fid
*/
struct p9_req_t {
@@ -104,6 +105,7 @@ struct p9_req_t {
struct list_head req_list;
struct list_head async_list;
union {
+ struct p9_req_t *flushed_req;
struct p9_fid *clunked_fid;
};
};
diff --git a/net/9p/client.c b/net/9p/client.c
index a47b5a54573d..666a722088e9 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -694,50 +694,6 @@ static void p9_fid_destroy(struct p9_fid *fid)
kfree(fid);
}
-static struct p9_req_t *
-p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
-
-/**
- * p9_client_flush - flush (cancel) a request
- * @c: client state
- * @oldreq: request to cancel
- *
- * This sents a flush for a particular request and links
- * the flush request to the original request. The current
- * code only supports a single flush request although the protocol
- * allows for multiple flush requests to be sent for a single request.
- *
- */
-
-static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
-{
- struct p9_req_t *req;
- int16_t oldtag;
- int err;
-
- err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
- if (err)
- return err;
-
- p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
-
- req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
- if (IS_ERR(req))
- return PTR_ERR(req);
-
- /*
- * if we haven't received a response for oldreq,
- * remove it from the list
- */
- if (oldreq->status == REQ_STATUS_SENT) {
- if (c->trans_mod->cancelled)
- c->trans_mod->cancelled(c, oldreq);
- }
-
- p9_tag_remove(c, req);
- return 0;
-}
-
static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
int8_t type, int req_size,
const char *fmt, va_list ap)
@@ -800,6 +756,39 @@ p9_client_async_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
return req;
}
+/**
+ * p9_client_flush - flush (cancel) a request
+ * @c: client state
+ * @oldreq: request to cancel
+ *
+ * This sents a flush for a particular request and links
+ * the flush request to the original request. The current
+ * code only supports a single flush request although the protocol
+ * allows for multiple flush requests to be sent for a single request.
+ *
+ */
+
+static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
+{
+ struct p9_req_t *req;
+ int16_t oldtag = oldreq->tc.tag;
+
+ p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
+ req = p9_client_async_rpc(c, P9_TFLUSH, "w", oldtag);
+ if (IS_ERR(req)) {
+ return PTR_ERR(req);
+ }
+
+ p9_debug(P9_DEBUG_MUX, "sent flush for oldreq %d type %d with flush tag %d\n",
+ oldtag, oldreq->tc.id, req->tc.tag);
+ req->flushed_req = oldreq;
+ spin_lock_irq(&c->lock);
+ list_add(&req->async_list, &c->async_req_list);
+ spin_unlock_irq(&c->lock);
+
+ return 0;
+}
+
static void p9_client_handle_async(struct p9_client *c, bool free_all)
{
struct p9_req_t *req, *nreq;
@@ -823,6 +812,24 @@ static void p9_client_handle_async(struct p9_client *c, bool free_all)
}
if (free_all || req->status >= REQ_STATUS_RCVD) {
/* Put old refs whatever reqs actually returned */
+ if (req->tc.id == P9_TFLUSH) {
+ p9_debug(P9_DEBUG_MUX,
+ "flushing oldreq tag %d status %d, flush_req tag %d\n",
+ req->flushed_req->tc.tag,
+ req->flushed_req->status,
+ req->tc.tag);
+ if (req->flushed_req->status < REQ_STATUS_RCVD) {
+ /* won't receive reply now */
+ if (c->trans_mod->cancelled)
+ c->trans_mod->cancelled(c, req);
+ p9_req_put(req->flushed_req);
+ }
+ if (!p9_tag_remove(c, req->flushed_req))
+ p9_debug(P9_DEBUG_ERROR,
+ "oldreq tag %d status %d still has ref\n",
+ req->flushed_req->tc.tag,
+ req->flushed_req->status);
+ }
if (req->tc.id == P9_TCLUNK) {
p9_fid_destroy(req->clunked_fid);
}
@@ -846,8 +853,8 @@ static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
{
va_list ap;
- int sigpending, err;
- unsigned long flags;
+ int err;
+ int flushing = 0;
struct p9_req_t *req;
p9_client_handle_async(c, 0);
@@ -859,10 +866,11 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
return req;
if (signal_pending(current)) {
- sigpending = 1;
- clear_thread_flag(TIF_SIGPENDING);
- } else
- sigpending = 0;
+ err = -ERESTARTSYS;
+ /* write won't happen */
+ p9_req_put(req);
+ goto reterr;
+ }
err = c->trans_mod->request(c, req);
if (err < 0) {
@@ -870,9 +878,9 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
p9_req_put(req);
if (err != -ERESTARTSYS && err != -EFAULT)
c->status = Disconnected;
- goto recalc_sigpending;
+ goto reterr;
}
-again:
+
/* Wait for the response */
err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
@@ -882,34 +890,15 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
*/
smp_rmb();
- if ((err == -ERESTARTSYS) && (c->status == Connected)
- && (type == P9_TFLUSH)) {
- sigpending = 1;
- clear_thread_flag(TIF_SIGPENDING);
- goto again;
- }
-
if (req->status == REQ_STATUS_ERROR) {
p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
err = req->t_err;
}
if ((err == -ERESTARTSYS) && (c->status == Connected)) {
p9_debug(P9_DEBUG_MUX, "flushing\n");
- sigpending = 1;
- clear_thread_flag(TIF_SIGPENDING);
-
- 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;
- }
-recalc_sigpending:
- if (sigpending) {
- spin_lock_irqsave(¤t->sighand->siglock, flags);
- recalc_sigpending();
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);
+ if (c->trans_mod->cancel(c, req) && !p9_client_flush(c, req))
+ flushing = 1;
}
if (err < 0)
goto reterr;
@@ -919,7 +908,8 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
if (!err)
return req;
reterr:
- p9_tag_remove(c, req);
+ if (!flushing)
+ p9_tag_remove(c, req);
return ERR_PTR(safe_errno(err));
}
@@ -943,8 +933,8 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
const char *fmt, ...)
{
va_list ap;
- int sigpending, err;
- unsigned long flags;
+ int err;
+ int flushing = 0;
struct p9_req_t *req;
p9_client_handle_async(c, 0);
@@ -960,10 +950,11 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
return req;
if (signal_pending(current)) {
- sigpending = 1;
- clear_thread_flag(TIF_SIGPENDING);
- } else
- sigpending = 0;
+ err = -ERESTARTSYS;
+ /* write won't happen */
+ p9_req_put(req);
+ goto reterr;
+ }
err = c->trans_mod->zc_request(c, req, uidata, uodata,
inlen, olen, in_hdrlen);
@@ -971,7 +962,7 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
if (err == -EIO)
c->status = Disconnected;
if (err != -ERESTARTSYS)
- goto recalc_sigpending;
+ goto reterr;
}
if (req->status == REQ_STATUS_ERROR) {
p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
@@ -979,21 +970,9 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
}
if ((err == -ERESTARTSYS) && (c->status == Connected)) {
p9_debug(P9_DEBUG_MUX, "flushing\n");
- sigpending = 1;
- clear_thread_flag(TIF_SIGPENDING);
-
- 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;
- }
-recalc_sigpending:
- if (sigpending) {
- spin_lock_irqsave(¤t->sighand->siglock, flags);
- recalc_sigpending();
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);
+ if (c->trans_mod->cancel(c, req) && !p9_client_flush(c, req))
+ flushing = 1;
}
if (err < 0)
goto reterr;
@@ -1003,7 +982,8 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
if (!err)
return req;
reterr:
- p9_tag_remove(c, req);
+ if (!flushing)
+ p9_tag_remove(c, req);
return ERR_PTR(safe_errno(err));
}
--
2.19.2
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