linux-kernel - [PATCH 3/4] fuse: skip blocking on allocations of synchronous requests

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Message-ID: <20130321140220.4051.16728.stgit@maximpc.sw.ru>
Date:	Thu, 21 Mar 2013 18:02:28 +0400
From:	"Maxim V. Patlasov" <MPatlasov@...allels.com>
To:	miklos@...redi.hu
Cc:	fuse-devel@...ts.sourceforge.net, xemul@...allels.com,
	linux-kernel@...r.kernel.org, devel@...nvz.org, dev@...allels.com
Subject: [PATCH 3/4] fuse: skip blocking on allocations of synchronous requests

Miklos wrote:

> A task may have at most one synchronous request allocated. So these
> requests need not be otherwise limited.

The patch re-works fuse_get_req() to follow this idea.

Signed-off-by: Maxim Patlasov <mpatlasov@...allels.com>
---
 fs/fuse/dev.c |   26 ++++++++++++++++++--------
 1 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 6137650..1f7ce89 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -137,17 +137,27 @@ struct fuse_req *fuse_get_req_internal(struct fuse_conn *fc, unsigned npages,
 				       bool for_background)
 {
 	struct fuse_req *req;
-	sigset_t oldset;
-	int intr;
 	int err;
+	int *flag_p = NULL;
 
 	atomic_inc(&fc->num_waiting);
-	block_sigs(&oldset);
-	intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
-	restore_sigs(&oldset);
-	err = -EINTR;
-	if (intr)
-		goto out;
+
+	if (for_background)
+		flag_p = &fc->blocked;
+	else if (fc->uninitialized)
+		flag_p = &fc->uninitialized;
+
+	if (flag_p) {
+		sigset_t oldset;
+		int intr;
+
+		block_sigs(&oldset);
+		intr = wait_event_interruptible(fc->blocked_waitq, !*flag_p);
+		restore_sigs(&oldset);
+		err = -EINTR;
+		if (intr)
+			goto out;
+	}
 
 	err = -ENOTCONN;
 	if (!fc->connected)

--
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