Since we serialize the present/eject work items now, we don't need the
semaphore any more.
Signed-off-by: Dexuan Cui <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Acked-by: Haiyang Zhang <[email protected]>
Cc: Vitaly Kuznetsov <[email protected]>
Cc: Jack Morgenstein <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: K. Y. Srinivasan <[email protected]>
---
drivers/pci/host/pci-hyperv.c | 17 ++---------------
1 file changed, 2 insertions(+), 15 deletions(-)
diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index 1d2e1cb617f4..0dc2ecdbbe45 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -447,7 +447,6 @@ struct hv_pcibus_device {
spinlock_t device_list_lock; /* Protect lists below */
void __iomem *cfg_addr;
- struct semaphore enum_sem;
struct list_head resources_for_children;
struct list_head children;
@@ -1648,12 +1647,8 @@ static struct hv_pci_dev *get_pcichild_wslot(struct hv_pcibus_device *hbus,
* It must also treat the omission of a previously observed device as
* notification that the device no longer exists.
*
- * Note that this function is a work item, and it may not be
- * invoked in the order that it was queued. Back to back
- * updates of the list of present devices may involve queuing
- * multiple work items, and this one may run before ones that
- * were sent later. As such, this function only does something
- * if is the last one in the queue.
+ * Note that this function is serialized with hv_eject_device_work(),
+ * because both are pushed to the ordered workqueue hbus->wq.
*/
static void pci_devices_present_work(struct work_struct *work)
{
@@ -1674,11 +1669,6 @@ static void pci_devices_present_work(struct work_struct *work)
INIT_LIST_HEAD(&removed);
- if (down_interruptible(&hbus->enum_sem)) {
- put_hvpcibus(hbus);
- return;
- }
-
/* Pull this off the queue and process it if it was the last one. */
spin_lock_irqsave(&hbus->device_list_lock, flags);
while (!list_empty(&hbus->dr_list)) {
@@ -1695,7 +1685,6 @@ static void pci_devices_present_work(struct work_struct *work)
spin_unlock_irqrestore(&hbus->device_list_lock, flags);
if (!dr) {
- up(&hbus->enum_sem);
put_hvpcibus(hbus);
return;
}
@@ -1782,7 +1771,6 @@ static void pci_devices_present_work(struct work_struct *work)
break;
}
- up(&hbus->enum_sem);
put_hvpcibus(hbus);
kfree(dr);
}
@@ -2516,7 +2504,6 @@ static int hv_pci_probe(struct hv_device *hdev,
spin_lock_init(&hbus->config_lock);
spin_lock_init(&hbus->device_list_lock);
spin_lock_init(&hbus->retarget_msi_interrupt_lock);
- sema_init(&hbus->enum_sem, 1);
init_completion(&hbus->remove_event);
hbus->wq = alloc_ordered_workqueue("hv_pci_%x", 0,
hbus->sysdata.domain);
--
2.7.4
On Thu, Mar 15, 2018 at 02:21:51PM +0000, Dexuan Cui wrote:
> Since we serialize the present/eject work items now, we don't need the
> semaphore any more.
>
> Signed-off-by: Dexuan Cui <[email protected]>
> Reviewed-by: Michael Kelley <[email protected]>
> Acked-by: Haiyang Zhang <[email protected]>
> Cc: Vitaly Kuznetsov <[email protected]>
> Cc: Jack Morgenstein <[email protected]>
> Cc: Stephen Hemminger <[email protected]>
> Cc: K. Y. Srinivasan <[email protected]>
> ---
> drivers/pci/host/pci-hyperv.c | 17 ++---------------
> 1 file changed, 2 insertions(+), 15 deletions(-)
Dexuan,
while applying/updating these patches I notice this one may be squashed
into:
https://patchwork.ozlabs.org/patch/886266/
since they logically belong in the same patch. Are you OK with me doing
that ? Is my reading correct ?
Thanks,
Lorenzo
> diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
> index 1d2e1cb617f4..0dc2ecdbbe45 100644
> --- a/drivers/pci/host/pci-hyperv.c
> +++ b/drivers/pci/host/pci-hyperv.c
> @@ -447,7 +447,6 @@ struct hv_pcibus_device {
> spinlock_t device_list_lock; /* Protect lists below */
> void __iomem *cfg_addr;
>
> - struct semaphore enum_sem;
> struct list_head resources_for_children;
>
> struct list_head children;
> @@ -1648,12 +1647,8 @@ static struct hv_pci_dev *get_pcichild_wslot(struct hv_pcibus_device *hbus,
> * It must also treat the omission of a previously observed device as
> * notification that the device no longer exists.
> *
> - * Note that this function is a work item, and it may not be
> - * invoked in the order that it was queued. Back to back
> - * updates of the list of present devices may involve queuing
> - * multiple work items, and this one may run before ones that
> - * were sent later. As such, this function only does something
> - * if is the last one in the queue.
> + * Note that this function is serialized with hv_eject_device_work(),
> + * because both are pushed to the ordered workqueue hbus->wq.
> */
> static void pci_devices_present_work(struct work_struct *work)
> {
> @@ -1674,11 +1669,6 @@ static void pci_devices_present_work(struct work_struct *work)
>
> INIT_LIST_HEAD(&removed);
>
> - if (down_interruptible(&hbus->enum_sem)) {
> - put_hvpcibus(hbus);
> - return;
> - }
> -
> /* Pull this off the queue and process it if it was the last one. */
> spin_lock_irqsave(&hbus->device_list_lock, flags);
> while (!list_empty(&hbus->dr_list)) {
> @@ -1695,7 +1685,6 @@ static void pci_devices_present_work(struct work_struct *work)
> spin_unlock_irqrestore(&hbus->device_list_lock, flags);
>
> if (!dr) {
> - up(&hbus->enum_sem);
> put_hvpcibus(hbus);
> return;
> }
> @@ -1782,7 +1771,6 @@ static void pci_devices_present_work(struct work_struct *work)
> break;
> }
>
> - up(&hbus->enum_sem);
> put_hvpcibus(hbus);
> kfree(dr);
> }
> @@ -2516,7 +2504,6 @@ static int hv_pci_probe(struct hv_device *hdev,
> spin_lock_init(&hbus->config_lock);
> spin_lock_init(&hbus->device_list_lock);
> spin_lock_init(&hbus->retarget_msi_interrupt_lock);
> - sema_init(&hbus->enum_sem, 1);
> init_completion(&hbus->remove_event);
> hbus->wq = alloc_ordered_workqueue("hv_pci_%x", 0,
> hbus->sysdata.domain);
> --
> 2.7.4
>
> From: Lorenzo Pieralisi <[email protected]>
> Sent: Friday, March 16, 2018 03:54
> ...
> Dexuan,
> while applying/updating these patches I notice this one may be squashed
> into: https://patchwork.ozlabs.org/patch/886266/
>
> since they logically belong in the same patch. Are you OK with me doing
> that ? Is my reading correct ?
> Lorenzo
I'm OK.
I used two patches
[PATCH v4 1/2] PCI: hv: Serialize the present and eject work items
[PATCH v4 3/4] PCI: hv: Remove hbus->enum_sem
only because the first fixed a real issue and hence IMO should go into
stable kernels, and the second is only a cleanup patch, which doesn't
need go into stable kernels.
Either way is ok to me.
Please feel free to do whatever you think is better. :-)
Thanks,
-- Dexuan
On Fri, Mar 16, 2018 at 05:41:27PM +0000, Dexuan Cui wrote:
> > From: Lorenzo Pieralisi <[email protected]>
> > Sent: Friday, March 16, 2018 03:54
> > ...
> > Dexuan,
> > while applying/updating these patches I notice this one may be squashed
> > into: https://patchwork.ozlabs.org/patch/886266/
> >
> > since they logically belong in the same patch. Are you OK with me doing
> > that ? Is my reading correct ?
> > Lorenzo
>
> I'm OK.
> I used two patches
> [PATCH v4 1/2] PCI: hv: Serialize the present and eject work items
> [PATCH v4 3/4] PCI: hv: Remove hbus->enum_sem
> only because the first fixed a real issue and hence IMO should go into
> stable kernels, and the second is only a cleanup patch, which doesn't
> need go into stable kernels.
>
> Either way is ok to me.
> Please feel free to do whatever you think is better. :-)
OK, patch series reworked and queued in my pci/hv branch please have
a look and let me know if that looks OK for you, I won't ask Bjorn
to move it into -next till you give me the go-ahead.
Thanks,
Lorenzo
> From: Lorenzo Pieralisi <[email protected]>
> Sent: Friday, March 16, 2018 11:32
> ...
>
> OK, patch series reworked and queued in my pci/hv branch please have
> a look and let me know if that looks OK for you, I won't ask Bjorn
> to move it into -next till you give me the go-ahead.
>
> Lorenzo
Yes, it looks good!
Thanks for updating the commit logs!
I'll try to follow the writing style in future. :-)
BTW, I hope these two still have the chance to go in v4.16:
PCI: hv: Fix 2 hang issues in hv_compose_msi_msg()
PCI: hv: Serialize the present and eject work items
Thanks,
-- Dexuan