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[73.241.150.58]) by smtp.gmail.com with ESMTPSA id 207sm102999pfw.190.2020.06.05.09.43.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 05 Jun 2020 09:43:28 -0700 (PDT) Subject: Re: [PATCH] qrtr: Convert qrtr_ports from IDR to XArray To: Matthew Wilcox , Bjorn Andersson , Manivannan Sadhasivam , Jakub Kicinski , "David S. Miller" , netdev@vger.kernel.org, Eric Biggers References: <20200605120037.17427-1-willy@infradead.org> From: Eric Dumazet Message-ID: <9aa67df2-a539-29eb-c9e9-4dddcb73ec19@gmail.com> Date: Fri, 5 Jun 2020 09:43:25 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200605120037.17427-1-willy@infradead.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 6/5/20 5:00 AM, Matthew Wilcox wrote: > From: "Matthew Wilcox (Oracle)" > > The XArray interface is easier for this driver to use. Also fixes a > bug reported by the improper use of GFP_ATOMIC. > This does not look stable candidate. If you try to add a Fixes: tag, you might discover that this bug is old, and I do not believe XArray has been backported to stable branches ? Please submit a fix suitable for old kernels (as old as v4.7) Then when net-next is open in ~2 weeks, the Xarray stuff can be proposed. Thanks. > Signed-off-by: Matthew Wilcox (Oracle) > --- > net/qrtr/qrtr.c | 39 +++++++++++++-------------------------- > 1 file changed, 13 insertions(+), 26 deletions(-) > > diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c > index 2d8d6131bc5f..488f8f326ee5 100644 > --- a/net/qrtr/qrtr.c > +++ b/net/qrtr/qrtr.c > @@ -20,6 +20,7 @@ > /* auto-bind range */ > #define QRTR_MIN_EPH_SOCKET 0x4000 > #define QRTR_MAX_EPH_SOCKET 0x7fff > +#define QRTR_PORT_RANGE XA_LIMIT(QRTR_MIN_EPH_SOCKET, QRTR_MAX_EPH_SOCKET) > > /** > * struct qrtr_hdr_v1 - (I|R)PCrouter packet header version 1 > @@ -106,8 +107,7 @@ static LIST_HEAD(qrtr_all_nodes); > static DEFINE_MUTEX(qrtr_node_lock); > > /* local port allocation management */ > -static DEFINE_IDR(qrtr_ports); > -static DEFINE_MUTEX(qrtr_port_lock); > +static DEFINE_XARRAY_ALLOC(qrtr_ports); > > /** > * struct qrtr_node - endpoint node > @@ -623,7 +623,7 @@ static struct qrtr_sock *qrtr_port_lookup(int port) > port = 0; > > rcu_read_lock(); > - ipc = idr_find(&qrtr_ports, port); > + ipc = xa_load(&qrtr_ports, port); > if (ipc) > sock_hold(&ipc->sk); > rcu_read_unlock(); > @@ -665,9 +665,7 @@ static void qrtr_port_remove(struct qrtr_sock *ipc) > > __sock_put(&ipc->sk); > > - mutex_lock(&qrtr_port_lock); > - idr_remove(&qrtr_ports, port); > - mutex_unlock(&qrtr_port_lock); > + xa_erase(&qrtr_ports, port); > > /* Ensure that if qrtr_port_lookup() did enter the RCU read section we > * wait for it to up increment the refcount */ > @@ -688,25 +686,18 @@ static int qrtr_port_assign(struct qrtr_sock *ipc, int *port) > { > int rc; > > - mutex_lock(&qrtr_port_lock); > if (!*port) { > - rc = idr_alloc(&qrtr_ports, ipc, > - QRTR_MIN_EPH_SOCKET, QRTR_MAX_EPH_SOCKET + 1, > - GFP_ATOMIC); > - if (rc >= 0) > - *port = rc; > + rc = xa_alloc(&qrtr_ports, port, ipc, QRTR_PORT_RANGE, > + GFP_KERNEL); > } else if (*port < QRTR_MIN_EPH_SOCKET && !capable(CAP_NET_ADMIN)) { > rc = -EACCES; > } else if (*port == QRTR_PORT_CTRL) { > - rc = idr_alloc(&qrtr_ports, ipc, 0, 1, GFP_ATOMIC); > + rc = xa_insert(&qrtr_ports, 0, ipc, GFP_KERNEL); > } else { > - rc = idr_alloc(&qrtr_ports, ipc, *port, *port + 1, GFP_ATOMIC); > - if (rc >= 0) > - *port = rc; > + rc = xa_insert(&qrtr_ports, *port, ipc, GFP_KERNEL); > } > - mutex_unlock(&qrtr_port_lock); > > - if (rc == -ENOSPC) > + if (rc == -EBUSY) > return -EADDRINUSE; > else if (rc < 0) > return rc; > @@ -720,20 +711,16 @@ static int qrtr_port_assign(struct qrtr_sock *ipc, int *port) > static void qrtr_reset_ports(void) > { > struct qrtr_sock *ipc; > - int id; > - > - mutex_lock(&qrtr_port_lock); > - idr_for_each_entry(&qrtr_ports, ipc, id) { > - /* Don't reset control port */ > - if (id == 0) > - continue; > + unsigned long index; > > + rcu_read_lock(); > + xa_for_each_start(&qrtr_ports, index, ipc, 1) { > sock_hold(&ipc->sk); > ipc->sk.sk_err = ENETRESET; > ipc->sk.sk_error_report(&ipc->sk); > sock_put(&ipc->sk); > } > - mutex_unlock(&qrtr_port_lock); > + rcu_read_unlock(); > } > > /* Bind socket to address. >