[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v2] xen/pvcalls: don't call bind_evtchn_to_irqhandler() under lock
On Mon, 3 Apr 2023, Juergen Gross wrote: > bind_evtchn_to_irqhandler() shouldn't be called under spinlock, as it > can sleep. > > This requires to move the calls of create_active() out of the locked > regions. This is no problem, as the worst which could happen would be > a spurious call of the interrupt handler, causing a spurious wake_up(). > > Reported-by: Dan Carpenter <error27@xxxxxxxxx> > Link: https://lore.kernel.org/lkml/Y+JUIl64UDmdkboh@kadam/ > Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx> > --- > V2: > - remove stale spin_unlock() (Oleksandr Tyshchenko) > --- > drivers/xen/pvcalls-front.c | 46 +++++++++++++++++++++---------------- > 1 file changed, 26 insertions(+), 20 deletions(-) > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > index d5d589bda243..b72ee9379d77 100644 > --- a/drivers/xen/pvcalls-front.c > +++ b/drivers/xen/pvcalls-front.c > @@ -227,22 +227,30 @@ static irqreturn_t pvcalls_front_event_handler(int irq, > void *dev_id) > > static void free_active_ring(struct sock_mapping *map); > > -static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, > - struct sock_mapping *map) > +static void pvcalls_front_destroy_active(struct pvcalls_bedata *bedata, > + struct sock_mapping *map) > { > int i; > > unbind_from_irqhandler(map->active.irq, map); > > - spin_lock(&bedata->socket_lock); > - if (!list_empty(&map->list)) > - list_del_init(&map->list); > - spin_unlock(&bedata->socket_lock); > + if (bedata) { > + spin_lock(&bedata->socket_lock); > + if (!list_empty(&map->list)) > + list_del_init(&map->list); > + spin_unlock(&bedata->socket_lock); > + } > > for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++) > gnttab_end_foreign_access(map->active.ring->ref[i], NULL); > gnttab_end_foreign_access(map->active.ref, NULL); > free_active_ring(map); > +} > + > +static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, > + struct sock_mapping *map) > +{ > + pvcalls_front_destroy_active(bedata, map); > > kfree(map); > } > @@ -433,19 +441,18 @@ int pvcalls_front_connect(struct socket *sock, struct > sockaddr *addr, > pvcalls_exit_sock(sock); > return ret; > } > - > - spin_lock(&bedata->socket_lock); > - ret = get_request(bedata, &req_id); > + ret = create_active(map, &evtchn); > if (ret < 0) { > - spin_unlock(&bedata->socket_lock); > free_active_ring(map); > pvcalls_exit_sock(sock); > return ret; > } > - ret = create_active(map, &evtchn); > + > + spin_lock(&bedata->socket_lock); > + ret = get_request(bedata, &req_id); > if (ret < 0) { > spin_unlock(&bedata->socket_lock); > - free_active_ring(map); > + pvcalls_front_destroy_active(NULL, map); > pvcalls_exit_sock(sock); > return ret; > } > @@ -821,28 +828,27 @@ int pvcalls_front_accept(struct socket *sock, struct > socket *newsock, int flags) > pvcalls_exit_sock(sock); > return ret; > } > - spin_lock(&bedata->socket_lock); > - ret = get_request(bedata, &req_id); > + ret = create_active(map2, &evtchn); > if (ret < 0) { > - clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, > - (void *)&map->passive.flags); > - spin_unlock(&bedata->socket_lock); > free_active_ring(map2); > kfree(map2); > + clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, > + (void *)&map->passive.flags); > pvcalls_exit_sock(sock); > return ret; > } > > - ret = create_active(map2, &evtchn); > + spin_lock(&bedata->socket_lock); > + ret = get_request(bedata, &req_id); > if (ret < 0) { > - free_active_ring(map2); > - kfree(map2); > clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, > (void *)&map->passive.flags); > spin_unlock(&bedata->socket_lock); > + pvcalls_front_free_map(bedata, map2); > pvcalls_exit_sock(sock); > return ret; > } > + > list_add_tail(&map2->list, &bedata->socket_mappings); > > req = RING_GET_REQUEST(&bedata->ring, req_id); > -- > 2.35.3 >
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