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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-ppp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Guillaume Nault Subject: [PATCH net-next 1/3] ppp: convert rlock to rwlock to improve RX concurrency Date: Wed, 25 Jun 2025 11:40:18 +0800 Message-ID: <20250625034021.3650359-2-dqfext@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250625034021.3650359-1-dqfext@gmail.com> References: <20250625034021.3650359-1-dqfext@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The rlock spinlock in struct ppp protects the receive path, but it is frequently used in a read-mostly manner. Converting it to rwlock_t allows multiple CPUs to concurrently enter the receive path (e.g., ppp_do_recv()), improving RX performance. Write locking is preserved for code paths that mutate state. Signed-off-by: Qingfang Deng --- drivers/net/ppp/ppp_generic.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index 4cf9d1822a83..f0f8a75e3aef 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -118,7 +118,7 @@ struct ppp { struct file *owner; /* file that owns this unit 48 */ struct list_head channels; /* list of attached channels 4c */ int n_channels; /* how many channels are attached 54 */ - spinlock_t rlock; /* lock for receive side 58 */ + rwlock_t rlock; /* lock for receive side 58 */ spinlock_t wlock; /* lock for transmit side 5c */ int __percpu *xmit_recursion; /* xmit recursion detect */ int mru; /* max receive unit 60 */ @@ -371,12 +371,14 @@ static const int npindex_to_ethertype[NUM_NP] =3D { */ #define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock) #define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock) -#define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock) -#define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock) +#define ppp_recv_lock(ppp) write_lock_bh(&(ppp)->rlock) +#define ppp_recv_unlock(ppp) write_unlock_bh(&(ppp)->rlock) #define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \ ppp_recv_lock(ppp); } while (0) #define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \ ppp_xmit_unlock(ppp); } while (0) +#define ppp_recv_read_lock(ppp) read_lock_bh(&(ppp)->rlock) +#define ppp_recv_read_unlock(ppp) read_unlock_bh(&(ppp)->rlock) =20 /* * /dev/ppp device routines. @@ -1246,7 +1248,7 @@ static int ppp_dev_configure(struct net *src_net, str= uct net_device *dev, for (indx =3D 0; indx < NUM_NP; ++indx) ppp->npmode[indx] =3D NPMODE_PASS; INIT_LIST_HEAD(&ppp->channels); - spin_lock_init(&ppp->rlock); + rwlock_init(&ppp->rlock); spin_lock_init(&ppp->wlock); =20 ppp->xmit_recursion =3D alloc_percpu(int); @@ -2193,12 +2195,12 @@ struct ppp_mp_skb_parm { static inline void ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) { - ppp_recv_lock(ppp); + ppp_recv_read_lock(ppp); if (!ppp->closing) ppp_receive_frame(ppp, skb, pch); else kfree_skb(skb); - ppp_recv_unlock(ppp); + ppp_recv_read_unlock(ppp); } =20 /** --=20 2.43.0