| Message ID | KL1P15301MB0006E2FA71F87B312D9DECA4BFD00@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
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 <decui@microsoft.com> > Reviewed-by: Michael Kelley <mikelley@microsoft.com> > Acked-by: Haiyang Zhang <haiyangz@microsoft.com> > Cc: Vitaly Kuznetsov <vkuznets@redhat.com> > Cc: Jack Morgenstein <jackm@mellanox.com> > Cc: Stephen Hemminger <sthemmin@microsoft.com> > Cc: K. Y. Srinivasan <kys@microsoft.com> > --- > 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 <lorenzo.pieralisi@arm.com> > 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 <lorenzo.pieralisi@arm.com> > > 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 <lorenzo.pieralisi@arm.com> > 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
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);