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From:   Dominique Martinet <asmadeus@codewreck.org>
To:     v9fs-developer@lists.sourceforge.net
Cc:     Christian Schoenebeck <linux_oss@crudebyte.com>,
        linux-kernel@vger.kernel.org, Hangyu Hua <hbh25y@gmail.com>,
        Dominique Martinet <asmadeus@codewreck.org>
Subject: [PATCH] 9p: roll p9_tag_remove into p9_req_put
Date:   Tue, 12 Jul 2022 15:08:01 +0900
Message-Id: <20220712060801.2487140-1-asmadeus@codewreck.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

mempool prep commit removed the awkward kref usage which didn't
allow passing client pointer easily with the ref, so we no longer
need a separate function to remove the tag from idr.

This has the side benefit that it should be more robust in detecting
leaks: umount will now properly catch unfreed requests as they still
will be in the idr until the last ref is dropped

Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
---
Discussion with Hangyu Hua made me notice we don't warn on all leaks on
umount, we can make this more coherent.
The patche requires Kent's first two cosmetic patches to apply, please use
my 9p-next branch for testing:
https://github.com/martinetd/linux/commits/9p-next


 net/9p/client.c   | 122 +++++++++++++++++++++-------------------------
 net/9p/trans_fd.c |   2 +
 2 files changed, 58 insertions(+), 66 deletions(-)

diff --git a/net/9p/client.c b/net/9p/client.c
index 0be19ab1f693..9aaef9c90666 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -298,7 +298,7 @@ p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
 	/* Init ref to two because in the general case there is one ref
 	 * that is put asynchronously by a writer thread, one ref
 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
-	 * in the recv thread, and one ref put by p9_tag_remove in the
+	 * in the recv thread, and one ref put by p9_req_put in the
 	 * main thread. The only exception is virtio that does not use
 	 * p9_tag_lookup but does not have a writer thread either
 	 * (the write happens synchronously in the request/zc_request
@@ -351,28 +351,18 @@ struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
 }
 EXPORT_SYMBOL(p9_tag_lookup);
 
-/**
- * p9_tag_remove - Remove a tag.
- * @c: Client session.
- * @r: Request of reference.
- *
- * Context: Any context.
- */
-static int p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
-{
-	unsigned long flags;
-	u16 tag = r->tc.tag;
-
-	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
-	spin_lock_irqsave(&c->lock, flags);
-	idr_remove(&c->reqs, tag);
-	spin_unlock_irqrestore(&c->lock, flags);
-	return p9_req_put(c, r);
-}
-
 int p9_req_put(struct p9_client *c, struct p9_req_t *r)
 {
 	if (refcount_dec_and_test(&r->refcount)) {
+		unsigned long flags;
+		u16 tag = r->tc.tag;
+
+		p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
+
+		spin_lock_irqsave(&c->lock, flags);
+		idr_remove(&c->reqs, tag);
+		spin_unlock_irqrestore(&c->lock, flags);
+
 		p9_fcall_fini(&r->tc);
 		p9_fcall_fini(&r->rc);
 		kmem_cache_free(p9_req_cache, r);
@@ -397,7 +387,7 @@ static void p9_tag_cleanup(struct p9_client *c)
 	rcu_read_lock();
 	idr_for_each_entry(&c->reqs, req, id) {
 		pr_info("Tag %d still in use\n", id);
-		if (p9_tag_remove(c, req) == 0)
+		if (p9_req_put(c, req) == 0)
 			pr_warn("Packet with tag %d has still references",
 				req->tc.tag);
 	}
@@ -670,7 +660,7 @@ static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
 			c->trans_mod->cancelled(c, oldreq);
 	}
 
-	p9_tag_remove(c, req);
+	p9_req_put(c, req);
 	return 0;
 }
 
@@ -704,7 +694,7 @@ static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
 	trace_9p_client_req(c, type, req->tc.tag);
 	return req;
 reterr:
-	p9_tag_remove(c, req);
+	p9_req_put(c, req);
 	/* We have to put also the 2nd reference as it won't be used */
 	p9_req_put(c, req);
 	return ERR_PTR(err);
@@ -716,7 +706,7 @@ static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
  * @type: type of request
  * @fmt: protocol format string (see protocol.c)
  *
- * Returns request structure (which client must free using p9_tag_remove)
+ * Returns request structure (which client must free using p9_req_put)
  */
 
 static struct p9_req_t *
@@ -794,7 +784,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 	if (!err)
 		return req;
 reterr:
-	p9_tag_remove(c, req);
+	p9_req_put(c, req);
 	return ERR_PTR(safe_errno(err));
 }
 
@@ -809,7 +799,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
  * @in_hdrlen: reader header size, This is the size of response protocol data
  * @fmt: protocol format string (see protocol.c)
  *
- * Returns request structure (which client must free using p9_tag_remove)
+ * Returns request structure (which client must free using p9_req_put)
  */
 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
 					 struct iov_iter *uidata,
@@ -876,7 +866,7 @@ 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);
+	p9_req_put(c, req);
 	return ERR_PTR(safe_errno(err));
 }
 
@@ -1005,7 +995,7 @@ static int p9_client_version(struct p9_client *c)
 
 error:
 	kfree(version);
-	p9_tag_remove(c, req);
+	p9_req_put(c, req);
 
 	return err;
 }
@@ -1159,7 +1149,7 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
 	if (err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto error;
 	}
 
@@ -1168,7 +1158,7 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 
 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return fid;
 
 error:
@@ -1215,10 +1205,10 @@ struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
 	if (err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto clunk_fid;
 	}
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 
 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
 
@@ -1294,7 +1284,7 @@ int p9_client_open(struct p9_fid *fid, int mode)
 	fid->iounit = iounit;
 
 free_and_error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1338,7 +1328,7 @@ int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
 	ofid->iounit = iounit;
 
 free_and_error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1382,7 +1372,7 @@ int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
 	fid->iounit = iounit;
 
 free_and_error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1416,7 +1406,7 @@ int p9_client_symlink(struct p9_fid *dfid, const char *name,
 		 qid->type, qid->path, qid->version);
 
 free_and_error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1436,7 +1426,7 @@ int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newna
 		return PTR_ERR(req);
 
 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return 0;
 }
 EXPORT_SYMBOL(p9_client_link);
@@ -1460,7 +1450,7 @@ int p9_client_fsync(struct p9_fid *fid, int datasync)
 
 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 
 error:
 	return err;
@@ -1488,7 +1478,7 @@ int p9_client_clunk(struct p9_fid *fid)
 
 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	/* Fid is not valid even after a failed clunk
 	 * If interrupted, retry once then give up and
@@ -1522,7 +1512,7 @@ int p9_client_remove(struct p9_fid *fid)
 
 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	if (err == -ERESTARTSYS)
 		p9_fid_put(fid);
@@ -1549,7 +1539,7 @@ int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
 	}
 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1617,7 +1607,7 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
 			   "D", &count, &dataptr);
 	if (*err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		return 0;
 	}
 	if (rsize < count) {
@@ -1632,13 +1622,13 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
 
 		if (n != count) {
 			*err = -EFAULT;
-			p9_tag_remove(clnt, req);
+			p9_req_put(clnt, req);
 			return n;
 		}
 	} else {
 		iov_iter_advance(to, count);
 	}
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return count;
 }
 EXPORT_SYMBOL(p9_client_read_once);
@@ -1681,7 +1671,7 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
 		if (*err) {
 			trace_9p_protocol_dump(clnt, &req->rc);
-			p9_tag_remove(clnt, req);
+			p9_req_put(clnt, req);
 			break;
 		}
 		if (rsize < count) {
@@ -1691,7 +1681,7 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
 
 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
 
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		iov_iter_advance(from, count);
 		total += count;
 		offset += count;
@@ -1726,7 +1716,7 @@ struct p9_wstat *p9_client_stat(struct p9_fid *fid)
 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
 	if (err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto error;
 	}
 
@@ -1743,7 +1733,7 @@ struct p9_wstat *p9_client_stat(struct p9_fid *fid)
 		 from_kgid(&init_user_ns, ret->n_gid),
 		 from_kuid(&init_user_ns, ret->n_muid));
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return ret;
 
 error:
@@ -1779,7 +1769,7 @@ struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
 	if (err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto error;
 	}
 
@@ -1805,7 +1795,7 @@ struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
 		 ret->st_btime_sec, ret->st_btime_nsec,
 		 ret->st_gen, ret->st_data_version);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return ret;
 
 error:
@@ -1877,7 +1867,7 @@ int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
 
 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1909,7 +1899,7 @@ int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
 		goto error;
 	}
 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1937,7 +1927,7 @@ int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
 	if (err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto error;
 	}
 
@@ -1946,7 +1936,7 @@ int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1974,7 +1964,7 @@ int p9_client_rename(struct p9_fid *fid,
 
 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -2004,7 +1994,7 @@ int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
 		 newdirfid->fid, new_name);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -2040,10 +2030,10 @@ struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
 	if (err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto clunk_fid;
 	}
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
 		 attr_fid->fid, *attr_size);
 	return attr_fid;
@@ -2077,7 +2067,7 @@ int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
 		goto error;
 	}
 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -2139,11 +2129,11 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
 	if (non_zc)
 		memmove(data, dataptr, count);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return count;
 
 free_and_error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -2175,7 +2165,7 @@ int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
 		 qid->type, qid->path, qid->version);
 
 error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return err;
 }
 EXPORT_SYMBOL(p9_client_mknod_dotl);
@@ -2205,7 +2195,7 @@ int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
 		 qid->path, qid->version);
 
 error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return err;
 }
 EXPORT_SYMBOL(p9_client_mkdir_dotl);
@@ -2237,7 +2227,7 @@ int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
 	}
 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
 error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return err;
 }
 EXPORT_SYMBOL(p9_client_lock_dotl);
@@ -2274,7 +2264,7 @@ int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
 		 glock->type, glock->start, glock->length,
 		 glock->proc_id, glock->client_id);
 error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return err;
 }
 EXPORT_SYMBOL(p9_client_getlock_dotl);
@@ -2300,7 +2290,7 @@ int p9_client_readlink(struct p9_fid *fid, char **target)
 	}
 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
 error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return err;
 }
 EXPORT_SYMBOL(p9_client_readlink);
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 007c3f45fe05..507974ce880c 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -272,6 +272,8 @@ static int p9_fd_read(struct p9_client *client, void *v, int len)
  *
  */
 
+static int failme;
+
 static void p9_read_work(struct work_struct *work)
 {
 	__poll_t n;
-- 
2.35.1