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From:   Dominique Martinet <asmadeus@codewreck.org>
To:     Christian Schoenebeck <linux_oss@crudebyte.com>
Cc:     v9fs-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org,
        Dominique Martinet <asmadeus@codewreck.org>
Subject: [PATCH v2] 9p: roll p9_tag_remove into p9_req_put
Date:   Fri, 15 Jul 2022 20:27:04 +0900
Message-Id: <20220715112704.2556071-1-asmadeus@codewreck.org>
In-Reply-To: <20220712060801.2487140-1-asmadeus@codewreck.org>
References: <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

Link: https://lkml.kernel.org/r/20220712060801.2487140-1-asmadeus@codewreck.org
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
---
v1->v2: restored p9_tag_remove for the idr_remove() call with lock
as per Christian's suggestion. Thanks!

And yes, sorry about that 'failme'...

 net/9p/client.c | 101 ++++++++++++++++++++++++------------------------
 1 file changed, 51 insertions(+), 50 deletions(-)

diff --git a/net/9p/client.c b/net/9p/client.c
index 0be19ab1f693..89c5aeb00076 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
@@ -358,21 +358,22 @@ EXPORT_SYMBOL(p9_tag_lookup);
  *
  * Context: Any context.
  */
-static int p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
+static void 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);
+	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);
-	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)) {
+		p9_tag_remove(c, r);
+
 		p9_fcall_fini(&r->tc);
 		p9_fcall_fini(&r->rc);
 		kmem_cache_free(p9_req_cache, r);
@@ -397,7 +398,7 @@ 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 +671,7 @@ 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 +705,7 @@ 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 +717,7 @@ 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 +795,7 @@ 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 +810,7 @@ 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 +877,7 @@ 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 +1006,7 @@ 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 +1160,7 @@ 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 +1169,7 @@ 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 +1216,10 @@ 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 +1295,7 @@ 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 +1339,7 @@ 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 +1383,7 @@ 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 +1417,7 @@ 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 +1437,7 @@ 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 +1461,7 @@ 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 +1489,7 @@ 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 +1523,7 @@ 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 +1550,7 @@ 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 +1618,7 @@ 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 +1633,13 @@ 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 +1682,7 @@ 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 +1692,7 @@ 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 +1727,7 @@ 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 +1744,7 @@ 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 +1780,7 @@ 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 +1806,7 @@ 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 +1878,7 @@ 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 +1910,7 @@ 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 +1938,7 @@ 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 +1947,7 @@ 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 +1975,7 @@ 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 +2005,7 @@ 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 +2041,10 @@ 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 +2078,7 @@ 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 +2140,11 @@ 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 +2176,7 @@ 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 +2206,7 @@ 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 +2238,7 @@ 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 +2275,7 @@ 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 +2301,7 @@ 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);
-- 
2.35.1