| Message ID | 20220308194704.14061-8-fnu.vikram@xilinx.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dynamic node programming using overlay dtbo | expand |
> On 8 Mar 2022, at 19:46, Vikram Garhwal <fnu.vikram@xilinx.com> wrote: > > Rename iommu_dt_device_is_assigned() to iommu_dt_device_is_assigned_lock(). > > Moving spin_lock to caller was done to prevent the concurrent access to > iommu_dt_device_is_assigned while doing add/remove/assign/deassign. > > Signed-off-by: Vikram Garhwal <fnu.vikram@xilinx.com> > --- > xen/drivers/passthrough/device_tree.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c > index 98f2aa0dad..b3b04f8e03 100644 > --- a/xen/drivers/passthrough/device_tree.c > +++ b/xen/drivers/passthrough/device_tree.c > @@ -83,16 +83,14 @@ fail: > return rc; > } > > -static bool_t iommu_dt_device_is_assigned(const struct dt_device_node *dev) > +static bool_t iommu_dt_device_is_assigned_lock(const struct dt_device_node *dev) > { > bool_t assigned = 0; > You can add an ASSERT(spin_is_locked(&dtdevs_lock)); to be sure, however the name is pretty clear, so for me with or without it: Reviewed-by: Luca Fancellu <luca.fancellu@arm.com> > if ( !dt_device_is_protected(dev) ) > return 0; > > - spin_lock(&dtdevs_lock); > assigned = !list_empty(&dev->domain_list); > - spin_unlock(&dtdevs_lock); > > return assigned; > } > @@ -225,12 +223,17 @@ int iommu_do_dt_domctl(struct xen_domctl *domctl, struct domain *d, > > if ( domctl->cmd == XEN_DOMCTL_test_assign_device ) > { > - if ( iommu_dt_device_is_assigned(dev) ) > + spin_lock(&dtdevs_lock); > + > + if ( iommu_dt_device_is_assigned_lock(dev) ) > { > printk(XENLOG_G_ERR "%s already assigned.\n", > dt_node_full_name(dev)); > ret = -EINVAL; > } > + > + spin_unlock(&dtdevs_lock); > + > break; > } > >
Hi, On 08/03/2022 19:46, Vikram Garhwal wrote: > Rename iommu_dt_device_is_assigned() to iommu_dt_device_is_assigned_lock(). > > Moving spin_lock to caller was done to prevent the concurrent access to > iommu_dt_device_is_assigned while doing add/remove/assign/deassign. > > Signed-off-by: Vikram Garhwal <fnu.vikram@xilinx.com> > --- > xen/drivers/passthrough/device_tree.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c > index 98f2aa0dad..b3b04f8e03 100644 > --- a/xen/drivers/passthrough/device_tree.c > +++ b/xen/drivers/passthrough/device_tree.c > @@ -83,16 +83,14 @@ fail: > return rc; > } > > -static bool_t iommu_dt_device_is_assigned(const struct dt_device_node *dev) > +static bool_t iommu_dt_device_is_assigned_lock(const struct dt_device_node *dev) NIT: We tend to use "_locked" when a function should be called with the lock taken. > { > bool_t assigned = 0; > > if ( !dt_device_is_protected(dev) ) > return 0; > > - spin_lock(&dtdevs_lock); > assigned = !list_empty(&dev->domain_list); > - spin_unlock(&dtdevs_lock); > > return assigned; > } > @@ -225,12 +223,17 @@ int iommu_do_dt_domctl(struct xen_domctl *domctl, struct domain *d, > > if ( domctl->cmd == XEN_DOMCTL_test_assign_device ) > { > - if ( iommu_dt_device_is_assigned(dev) ) > + spin_lock(&dtdevs_lock); Is this actually sufficient? IOW what will ensure that the "dev" doesn't disappear between the time we look it up (see dt_find_node_by_gpath()) and we check the assignment? Cheers,
diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c index 98f2aa0dad..b3b04f8e03 100644 --- a/xen/drivers/passthrough/device_tree.c +++ b/xen/drivers/passthrough/device_tree.c @@ -83,16 +83,14 @@ fail: return rc; } -static bool_t iommu_dt_device_is_assigned(const struct dt_device_node *dev) +static bool_t iommu_dt_device_is_assigned_lock(const struct dt_device_node *dev) { bool_t assigned = 0; if ( !dt_device_is_protected(dev) ) return 0; - spin_lock(&dtdevs_lock); assigned = !list_empty(&dev->domain_list); - spin_unlock(&dtdevs_lock); return assigned; } @@ -225,12 +223,17 @@ int iommu_do_dt_domctl(struct xen_domctl *domctl, struct domain *d, if ( domctl->cmd == XEN_DOMCTL_test_assign_device ) { - if ( iommu_dt_device_is_assigned(dev) ) + spin_lock(&dtdevs_lock); + + if ( iommu_dt_device_is_assigned_lock(dev) ) { printk(XENLOG_G_ERR "%s already assigned.\n", dt_node_full_name(dev)); ret = -EINVAL; } + + spin_unlock(&dtdevs_lock); + break; }
Rename iommu_dt_device_is_assigned() to iommu_dt_device_is_assigned_lock(). Moving spin_lock to caller was done to prevent the concurrent access to iommu_dt_device_is_assigned while doing add/remove/assign/deassign. Signed-off-by: Vikram Garhwal <fnu.vikram@xilinx.com> --- xen/drivers/passthrough/device_tree.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)