Re: [Xen-devel] [PATCH v3 2/3] xen/pciback: avoid multiple entries in slot list
On 23/09/16 12:15, David Vrabel wrote: > On 22/09/16 22:02, Boris Ostrovsky wrote: >> On 09/22/2016 04:45 AM, Juergen Gross wrote: >>> The Xen pciback driver has a list of all pci devices it is ready to >>> seize. There is no check whether a to be added entry already exists. >>> While this might be no problem in the common case it might confuse >>> those which consume the list via sysfs. >>> >>> Modify the handling of this list by not adding an entry which already >>> exists. As this will be needed later split out the list handling into >>> a separate function. >>> >>> Signed-off-by: Juergen Gross >>> --- >>> drivers/xen/xen-pciback/pci_stub.c | 39 >>> ++ >>> 1 file changed, 31 insertions(+), 8 deletions(-) >>> >>> diff --git a/drivers/xen/xen-pciback/pci_stub.c >>> b/drivers/xen/xen-pciback/pci_stub.c >>> index 79a9e4d..0179333 100644 >>> --- a/drivers/xen/xen-pciback/pci_stub.c >>> +++ b/drivers/xen/xen-pciback/pci_stub.c >>> @@ -478,6 +478,36 @@ static int __init pcistub_init_devices_late(void) >>> return 0; >>> } >>> >>> +static void pcistub_device_id_add_list(struct pcistub_device_id *new, >>> + int domain, int bus, unsigned int devfn) > > I think this should allocate the new pcistub_device_id if needed. You > can pass in GFP flags if needed. > > Then it can return the newly allocated one, or the existing one. > > static struct pcistub_device_id *pcistub_device_id_add_list( > int domain, int bus, unsigned int devfn) Patch 3 will be very nasty then: in case of an allocation failure all of the actions done in pcistub_seize() will have to be undone again. I'd really like to avoid that. Juergen ___ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH v3 2/3] xen/pciback: avoid multiple entries in slot list
On 22/09/16 22:02, Boris Ostrovsky wrote: > On 09/22/2016 04:45 AM, Juergen Gross wrote: >> The Xen pciback driver has a list of all pci devices it is ready to >> seize. There is no check whether a to be added entry already exists. >> While this might be no problem in the common case it might confuse >> those which consume the list via sysfs. >> >> Modify the handling of this list by not adding an entry which already >> exists. As this will be needed later split out the list handling into >> a separate function. >> >> Signed-off-by: Juergen Gross >> --- >> drivers/xen/xen-pciback/pci_stub.c | 39 >> ++ >> 1 file changed, 31 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/xen/xen-pciback/pci_stub.c >> b/drivers/xen/xen-pciback/pci_stub.c >> index 79a9e4d..0179333 100644 >> --- a/drivers/xen/xen-pciback/pci_stub.c >> +++ b/drivers/xen/xen-pciback/pci_stub.c >> @@ -478,6 +478,36 @@ static int __init pcistub_init_devices_late(void) >> return 0; >> } >> >> +static void pcistub_device_id_add_list(struct pcistub_device_id *new, >> + int domain, int bus, unsigned int devfn) I think this should allocate the new pcistub_device_id if needed. You can pass in GFP flags if needed. Then it can return the newly allocated one, or the existing one. static struct pcistub_device_id *pcistub_device_id_add_list( int domain, int bus, unsigned int devfn) David ___ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH v3 2/3] xen/pciback: avoid multiple entries in slot list
On 22/09/16 23:02, Boris Ostrovsky wrote: > On 09/22/2016 04:45 AM, Juergen Gross wrote: >> The Xen pciback driver has a list of all pci devices it is ready to >> seize. There is no check whether a to be added entry already exists. >> While this might be no problem in the common case it might confuse >> those which consume the list via sysfs. >> >> Modify the handling of this list by not adding an entry which already >> exists. As this will be needed later split out the list handling into >> a separate function. >> >> Signed-off-by: Juergen Gross >> --- >> drivers/xen/xen-pciback/pci_stub.c | 39 >> ++ >> 1 file changed, 31 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/xen/xen-pciback/pci_stub.c >> b/drivers/xen/xen-pciback/pci_stub.c >> index 79a9e4d..0179333 100644 >> --- a/drivers/xen/xen-pciback/pci_stub.c >> +++ b/drivers/xen/xen-pciback/pci_stub.c >> @@ -478,6 +478,36 @@ static int __init pcistub_init_devices_late(void) >> return 0; >> } >> >> +static void pcistub_device_id_add_list(struct pcistub_device_id *new, >> + int domain, int bus, unsigned int devfn) >> +{ >> +struct pcistub_device_id *pci_dev_id; >> +unsigned long flags; >> +int found = 0; >> + >> +spin_lock_irqsave(&device_ids_lock, flags); >> + >> +list_for_each_entry(pci_dev_id, &pcistub_device_ids, slot_list) { >> +if (pci_dev_id->domain == domain && pci_dev_id->bus == bus && >> +pci_dev_id->devfn == devfn) { >> +found = 1; >> +break; >> +} >> +} >> + >> +if (!found) { >> +new->domain = domain; >> +new->bus = bus; >> +new->devfn = devfn; >> +list_add_tail(&new->slot_list, &pcistub_device_ids); >> +} >> + >> +spin_unlock_irqrestore(&device_ids_lock, flags); >> + >> +if (found) >> +kfree(new); > > I'd rather free 'new' in the caller (who allocated it) and return > something like -EEXIST if device is already on the list. Hmm, I thought of this, but with two callers after the following patch having to deal with the situation I've chosen this way to do it. The code is smaller this way. Juergen ___ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH v3 2/3] xen/pciback: avoid multiple entries in slot list
On 09/22/2016 04:45 AM, Juergen Gross wrote: > The Xen pciback driver has a list of all pci devices it is ready to > seize. There is no check whether a to be added entry already exists. > While this might be no problem in the common case it might confuse > those which consume the list via sysfs. > > Modify the handling of this list by not adding an entry which already > exists. As this will be needed later split out the list handling into > a separate function. > > Signed-off-by: Juergen Gross > --- > drivers/xen/xen-pciback/pci_stub.c | 39 > ++ > 1 file changed, 31 insertions(+), 8 deletions(-) > > diff --git a/drivers/xen/xen-pciback/pci_stub.c > b/drivers/xen/xen-pciback/pci_stub.c > index 79a9e4d..0179333 100644 > --- a/drivers/xen/xen-pciback/pci_stub.c > +++ b/drivers/xen/xen-pciback/pci_stub.c > @@ -478,6 +478,36 @@ static int __init pcistub_init_devices_late(void) > return 0; > } > > +static void pcistub_device_id_add_list(struct pcistub_device_id *new, > +int domain, int bus, unsigned int devfn) > +{ > + struct pcistub_device_id *pci_dev_id; > + unsigned long flags; > + int found = 0; > + > + spin_lock_irqsave(&device_ids_lock, flags); > + > + list_for_each_entry(pci_dev_id, &pcistub_device_ids, slot_list) { > + if (pci_dev_id->domain == domain && pci_dev_id->bus == bus && > + pci_dev_id->devfn == devfn) { > + found = 1; > + break; > + } > + } > + > + if (!found) { > + new->domain = domain; > + new->bus = bus; > + new->devfn = devfn; > + list_add_tail(&new->slot_list, &pcistub_device_ids); > + } > + > + spin_unlock_irqrestore(&device_ids_lock, flags); > + > + if (found) > + kfree(new); I'd rather free 'new' in the caller (who allocated it) and return something like -EEXIST if device is already on the list. -boris > +} > + > static int pcistub_seize(struct pci_dev *dev) > { > struct pcistub_device *psdev; > @@ -1012,7 +1042,6 @@ static inline int str_to_quirk(const char *buf, int > *domain, int *bus, int > static int pcistub_device_id_add(int domain, int bus, int slot, int func) > { > struct pcistub_device_id *pci_dev_id; > - unsigned long flags; > int rc = 0, devfn = PCI_DEVFN(slot, func); > > if (slot < 0) { > @@ -1042,16 +1071,10 @@ static int pcistub_device_id_add(int domain, int bus, > int slot, int func) > if (!pci_dev_id) > return -ENOMEM; > > - pci_dev_id->domain = domain; > - pci_dev_id->bus = bus; > - pci_dev_id->devfn = devfn; > - > pr_debug("wants to seize %04x:%02x:%02x.%d\n", >domain, bus, slot, func); > > - spin_lock_irqsave(&device_ids_lock, flags); > - list_add_tail(&pci_dev_id->slot_list, &pcistub_device_ids); > - spin_unlock_irqrestore(&device_ids_lock, flags); > + pcistub_device_id_add_list(pci_dev_id, domain, bus, devfn); > > return 0; > } ___ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
[Xen-devel] [PATCH v3 2/3] xen/pciback: avoid multiple entries in slot list
The Xen pciback driver has a list of all pci devices it is ready to seize. There is no check whether a to be added entry already exists. While this might be no problem in the common case it might confuse those which consume the list via sysfs. Modify the handling of this list by not adding an entry which already exists. As this will be needed later split out the list handling into a separate function. Signed-off-by: Juergen Gross --- drivers/xen/xen-pciback/pci_stub.c | 39 ++ 1 file changed, 31 insertions(+), 8 deletions(-) diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c index 79a9e4d..0179333 100644 --- a/drivers/xen/xen-pciback/pci_stub.c +++ b/drivers/xen/xen-pciback/pci_stub.c @@ -478,6 +478,36 @@ static int __init pcistub_init_devices_late(void) return 0; } +static void pcistub_device_id_add_list(struct pcistub_device_id *new, + int domain, int bus, unsigned int devfn) +{ + struct pcistub_device_id *pci_dev_id; + unsigned long flags; + int found = 0; + + spin_lock_irqsave(&device_ids_lock, flags); + + list_for_each_entry(pci_dev_id, &pcistub_device_ids, slot_list) { + if (pci_dev_id->domain == domain && pci_dev_id->bus == bus && + pci_dev_id->devfn == devfn) { + found = 1; + break; + } + } + + if (!found) { + new->domain = domain; + new->bus = bus; + new->devfn = devfn; + list_add_tail(&new->slot_list, &pcistub_device_ids); + } + + spin_unlock_irqrestore(&device_ids_lock, flags); + + if (found) + kfree(new); +} + static int pcistub_seize(struct pci_dev *dev) { struct pcistub_device *psdev; @@ -1012,7 +1042,6 @@ static inline int str_to_quirk(const char *buf, int *domain, int *bus, int static int pcistub_device_id_add(int domain, int bus, int slot, int func) { struct pcistub_device_id *pci_dev_id; - unsigned long flags; int rc = 0, devfn = PCI_DEVFN(slot, func); if (slot < 0) { @@ -1042,16 +1071,10 @@ static int pcistub_device_id_add(int domain, int bus, int slot, int func) if (!pci_dev_id) return -ENOMEM; - pci_dev_id->domain = domain; - pci_dev_id->bus = bus; - pci_dev_id->devfn = devfn; - pr_debug("wants to seize %04x:%02x:%02x.%d\n", domain, bus, slot, func); - spin_lock_irqsave(&device_ids_lock, flags); - list_add_tail(&pci_dev_id->slot_list, &pcistub_device_ids); - spin_unlock_irqrestore(&device_ids_lock, flags); + pcistub_device_id_add_list(pci_dev_id, domain, bus, devfn); return 0; } -- 2.6.6 ___ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel