fuse: skip blocking on allocations of synchronous requests

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@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index f563e78..c59c097 100644 (file)
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -504,7 +504,6 @@ static int cuse_channel_open(struct inode *inode, struct file *file)
        cc->fc.release = cuse_fc_release;
 
        cc->fc.connected = 1;
-       cc->fc.blocked = 0;
        cc->fc.initialized = 1;
        rc = cuse_send_init(cc);
        if (rc) {

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 39c2fe3..d692b85 100644 (file)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -130,21 +130,30 @@ static void fuse_req_init_context(struct fuse_req *req)
        req->in.h.pid = current->pid;
 }
 
+static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
+{
+       return !fc->initialized || (for_background && fc->blocked);
+}
+
 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
                                       bool for_background)
 {
        struct fuse_req *req;
-       sigset_t oldset;
-       int intr;
        int err;
-
        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 (fuse_block_alloc(fc, for_background)) {
+               sigset_t oldset;
+               int intr;
+
+               block_sigs(&oldset);
+               intr = wait_event_interruptible(fc->blocked_waitq,
+                               !fuse_block_alloc(fc, for_background));
+               restore_sigs(&oldset);
+               err = -EINTR;
+               if (intr)
+                       goto out;
+       }
 
        err = -ENOTCONN;
        if (!fc->connected)
@@ -239,7 +248,7 @@ struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
        struct fuse_req *req;
 
        atomic_inc(&fc->num_waiting);
-       wait_event(fc->blocked_waitq, !fc->blocked);
+       wait_event(fc->blocked_waitq, fc->initialized);
        req = fuse_request_alloc(0);
        if (!req)
                req = get_reserved_req(fc, file);
@@ -2106,6 +2115,7 @@ int fuse_dev_release(struct inode *inode, struct file *file)
                spin_lock(&fc->lock);
                fc->connected = 0;
                fc->blocked = 0;
+               fc->initialized = 1;
                end_queued_requests(fc);
                end_polls(fc);
                wake_up_all(&fc->blocked_waitq);

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 4958f80..17ec1f7 100644 (file)
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -583,7 +583,7 @@ void fuse_conn_init(struct fuse_conn *fc)
        fc->khctr = 0;
        fc->polled_files = RB_ROOT;
        fc->reqctr = 0;
-       fc->blocked = 1;
+       fc->blocked = 0;
        fc->initialized = 0;
        fc->attr_version = 1;
        get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
@@ -883,7 +883,6 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
                fc->max_write = max_t(unsigned, 4096, fc->max_write);
                fc->conn_init = 1;
        }
-       fc->blocked = 0;
        fc->initialized = 1;
        wake_up_all(&fc->blocked_waitq);
 }