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Message-ID: Mail-Followup-To: jdmason@kudzu.us, dave.jiang@intel.com, allenbh@gmail.com, ntb@lists.linux.dev, linux-kernel@vger.kernel.org Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Since the CPU selected by schedule_work is uncertain, multiple link_event callbacks may be executed at same time. For example, after peer's link is up, it is down quickly before local link_work completed. If link_cleanup is added to the workqueue of another CPU, then link_work and link_cleanup may be executed at the same time. So add a mutex to prevent them from being executed concurrently. Signed-off-by: fuyuanli --- drivers/ntb/ntb_transport.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c index 4f775c3e218f..902968e24c7a 100644 --- a/drivers/ntb/ntb_transport.c +++ b/drivers/ntb/ntb_transport.c @@ -59,6 +59,7 @@ #include #include #include +#include #include "linux/ntb.h" #include "linux/ntb_transport.h" =20 @@ -241,6 +242,9 @@ struct ntb_transport_ctx { struct work_struct link_cleanup; =20 struct dentry *debugfs_node_dir; + + /* Make sure workq of link event be executed serially */ + struct mutex link_event_lock; }; =20 enum { @@ -1024,7 +1028,9 @@ static void ntb_transport_link_cleanup_work(struct wo= rk_struct *work) struct ntb_transport_ctx *nt =3D container_of(work, struct ntb_transport_ctx, link_cleanup); =20 + mutex_lock(&nt->link_event_lock); ntb_transport_link_cleanup(nt); + mutex_unlock(&nt->link_event_lock); } =20 static void ntb_transport_event_callback(void *data) @@ -1047,6 +1053,8 @@ static void ntb_transport_link_work(struct work_struc= t *work) u32 val; int rc =3D 0, i, spad; =20 + mutex_lock(&nt->link_event_lock); + /* send the local info, in the opposite order of the way we read it */ =20 if (nt->use_msi) { @@ -1125,6 +1133,7 @@ static void ntb_transport_link_work(struct work_struc= t *work) schedule_delayed_work(&qp->link_work, 0); } =20 + mutex_unlock(&nt->link_event_lock); return; =20 out1: @@ -1132,10 +1141,13 @@ static void ntb_transport_link_work(struct work_str= uct *work) ntb_free_mw(nt, i); =20 /* if there's an actual failure, we should just bail */ - if (rc < 0) + if (rc < 0) { + mutex_unlock(&nt->link_event_lock); return; + } =20 out: + mutex_unlock(&nt->link_event_lock); if (ntb_link_is_up(ndev, NULL, NULL) =3D=3D 1) schedule_delayed_work(&nt->link_work, msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT)); --=20 2.34.1