1 files changed, 152 insertions, 0 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index 712d4f336adc..867031934f75 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -120,6 +120,154 @@ static int parse_opts(char *opts, struct p9_client *clnt)
         return ret;
 }
 
+/**
+ * p9_tag_alloc - lookup/allocate a request by tag
+ * @c: client session to lookup tag within
+ * @tag: numeric id for transaction
+ *
+ * this is a simple array lookup, but will grow the
+ * request_slots as necessary to accomodate transaction
+ * ids which did not previously have a slot.
+ *
+ * this code relies on the client spinlock to manage locks, its
+ * possible we should switch to something else, but I'd rather
+ * stick with something low-overhead for the common case.
+ *
+ */
+
+struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
+{
+        unsigned long flags;
+        int row, col;
+
+        /* This looks up the original request by tag so we know which
+         * buffer to read the data into */
+        tag++;
+
+        if (tag >= c->max_tag) {
+                spin_lock_irqsave(&c->lock, flags);
+                /* check again since original check was outside of lock */
+                while (tag >= c->max_tag) {
+                        row = (tag / P9_ROW_MAXTAG);
+                        c->reqs[row] = kcalloc(P9_ROW_MAXTAG,
+                                        sizeof(struct p9_req_t), GFP_ATOMIC);
+
+                        if (!c->reqs[row]) {
+                                printk(KERN_ERR "Couldn't grow tag array\n");
+                                BUG();
+                        }
+                        for (col = 0; col < P9_ROW_MAXTAG; col++) {
+                                c->reqs[row][col].status = REQ_STATUS_IDLE;
+                                c->reqs[row][col].flush_tag = P9_NOTAG;
+                                c->reqs[row][col].wq = kmalloc(
+                                        sizeof(wait_queue_head_t), GFP_ATOMIC);
+                                if (!c->reqs[row][col].wq) {
+                                        printk(KERN_ERR
+                                                "Couldn't grow tag array\n");
+                                        BUG();
+                                }
+                                init_waitqueue_head(c->reqs[row][col].wq);
+                        }
+                        c->max_tag += P9_ROW_MAXTAG;
+                }
+                spin_unlock_irqrestore(&c->lock, flags);
+        }
+        row = tag / P9_ROW_MAXTAG;
+        col = tag % P9_ROW_MAXTAG;
+
+        c->reqs[row][col].status = REQ_STATUS_ALLOC;
+        c->reqs[row][col].flush_tag = P9_NOTAG;
+
+        return &c->reqs[row][col];
+}
+EXPORT_SYMBOL(p9_tag_alloc);
+
+/**
+ * p9_tag_lookup - lookup a request by tag
+ * @c: client session to lookup tag within
+ * @tag: numeric id for transaction
+ *
+ */
+
+struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
+{
+        int row, col;
+
+        /* This looks up the original request by tag so we know which
+         * buffer to read the data into */
+        tag++;
+
+        BUG_ON(tag >= c->max_tag);
+
+        row = tag / P9_ROW_MAXTAG;
+        col = tag % P9_ROW_MAXTAG;
+
+        return &c->reqs[row][col];
+}
+EXPORT_SYMBOL(p9_tag_lookup);
+
+/**
+ * p9_tag_init - setup tags structure and contents
+ * @tags: tags structure from the client struct
+ *
+ * This initializes the tags structure for each client instance.
+ *
+ */
+
+static int p9_tag_init(struct p9_client *c)
+{
+        int err = 0;
+
+        c->tagpool = p9_idpool_create();
+        if (IS_ERR(c->tagpool)) {
+                err = PTR_ERR(c->tagpool);
+                c->tagpool = NULL;
+                goto error;
+        }
+
+        p9_idpool_get(c->tagpool); /* reserve tag 0 */
+
+        c->max_tag = 0;
+error:
+        return err;
+}
+
+/**
+ * p9_tag_cleanup - cleans up tags structure and reclaims resources
+ * @tags: tags structure from the client struct
+ *
+ * This frees resources associated with the tags structure
+ *
+ */
+static void p9_tag_cleanup(struct p9_client *c)
+{
+        int row, col;
+
+        /* check to insure all requests are idle */
+        for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
+                for (col = 0; col < P9_ROW_MAXTAG; col++) {
+                        if (c->reqs[row][col].status != REQ_STATUS_IDLE) {
+                                P9_DPRINTK(P9_DEBUG_MUX,
+                                  "Attempting to cleanup non-free tag %d,%d\n",
+                                  row, col);
+                                /* TODO: delay execution of cleanup */
+                                return;
+                        }
+                }
+        }
+
+        if (c->tagpool)
+                p9_idpool_destroy(c->tagpool);
+
+        /* free requests associated with tags */
+        for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
+                for (col = 0; col < P9_ROW_MAXTAG; col++)
+                        kfree(c->reqs[row][col].wq);
+                kfree(c->reqs[row]);
+        }
+        c->max_tag = 0;
+}
+
 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
 {
         int err;
@@ -209,6 +357,8 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
                 goto error;
         }
 
+        p9_tag_init(clnt);
+
         err = parse_opts(options, clnt);
         if (err < 0)
                 goto error;
@@ -285,6 +435,8 @@ void p9_client_destroy(struct p9_client *clnt)
         if (clnt->fidpool)
                 p9_idpool_destroy(clnt->fidpool);
 
+        p9_tag_cleanup(clnt);
+
         kfree(clnt);
 }
 EXPORT_SYMBOL(p9_client_destroy);