Re: [PATCH 01/16] x86/PCI: Replace spin_is_locked() with lockdep
On Wed, Oct 03, 2018 at 11:00:51AM -0500, Bjorn Helgaas wrote: > On Tue, Oct 02, 2018 at 10:38:47PM -0700, Lance Roy wrote: > > lockdep_assert_held() is better suited to checking locking requirements, > > since it won't get confused when someone else holds the lock. This is > > also a step towards possibly removing spin_is_locked(). > > > > Signed-off-by: Lance Roy > > Cc: Bjorn Helgaas > > Cc: Thomas Gleixner > > Cc: Ingo Molnar > > Cc: Borislav Petkov > > Cc: "H. Peter Anvin" > > Cc: > > Cc: > > I assume you plan to merge the whole series together. I don't object > to that, but I don't know enough to be able to formally ack this. > > It would be useful to include a tiny bit more detail in the changelog. > The spin_is_locked() documentation doesn't mention anything about > differences with respect to the lock being held by self vs by someone > else, so I can't tell where the confusion arises. The difference is that spin_is_locked() will return true when someone else holds the lock, while lockdep_assert_held() asserts that the current thread holds the lock. How about the following for an new changelog? lockdep_assert_held() is better suited to checking locking requirements, since it only checks if the current thread holds the lock regardless of whether someone else does. This is also a step towards possibly removing spin_is_locked(). Thanks, Lance > Bjorn > > > --- > > arch/x86/pci/i386.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c > > index ed4ac215305d..24bb58a007de 100644 > > --- a/arch/x86/pci/i386.c > > +++ b/arch/x86/pci/i386.c > > @@ -59,7 +59,7 @@ static struct pcibios_fwaddrmap > > *pcibios_fwaddrmap_lookup(struct pci_dev *dev) > > { > > struct pcibios_fwaddrmap *map; > > > > - WARN_ON_SMP(!spin_is_locked(&pcibios_fwaddrmap_lock)); > > + lockdep_assert_held(&pcibios_fwaddrmap_lock); > > > > list_for_each_entry(map, &pcibios_fwaddrmappings, list) > > if (map->dev == dev) > > -- > > 2.19.0 > >
Re: [PATCH 01/16] x86/PCI: Replace spin_is_locked() with lockdep
On Tue, Oct 02, 2018 at 10:38:47PM -0700, Lance Roy wrote: > lockdep_assert_held() is better suited to checking locking requirements, > since it won't get confused when someone else holds the lock. This is > also a step towards possibly removing spin_is_locked(). > > Signed-off-by: Lance Roy > Cc: Bjorn Helgaas > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: Borislav Petkov > Cc: "H. Peter Anvin" > Cc: > Cc: I assume you plan to merge the whole series together. I don't object to that, but I don't know enough to be able to formally ack this. It would be useful to include a tiny bit more detail in the changelog. The spin_is_locked() documentation doesn't mention anything about differences with respect to the lock being held by self vs by someone else, so I can't tell where the confusion arises. Bjorn > --- > arch/x86/pci/i386.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c > index ed4ac215305d..24bb58a007de 100644 > --- a/arch/x86/pci/i386.c > +++ b/arch/x86/pci/i386.c > @@ -59,7 +59,7 @@ static struct pcibios_fwaddrmap > *pcibios_fwaddrmap_lookup(struct pci_dev *dev) > { > struct pcibios_fwaddrmap *map; > > - WARN_ON_SMP(!spin_is_locked(&pcibios_fwaddrmap_lock)); > + lockdep_assert_held(&pcibios_fwaddrmap_lock); > > list_for_each_entry(map, &pcibios_fwaddrmappings, list) > if (map->dev == dev) > -- > 2.19.0 >
[PATCH 01/16] x86/PCI: Replace spin_is_locked() with lockdep
lockdep_assert_held() is better suited to checking locking requirements, since it won't get confused when someone else holds the lock. This is also a step towards possibly removing spin_is_locked(). Signed-off-by: Lance Roy Cc: Bjorn Helgaas Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Cc: --- arch/x86/pci/i386.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c index ed4ac215305d..24bb58a007de 100644 --- a/arch/x86/pci/i386.c +++ b/arch/x86/pci/i386.c @@ -59,7 +59,7 @@ static struct pcibios_fwaddrmap *pcibios_fwaddrmap_lookup(struct pci_dev *dev) { struct pcibios_fwaddrmap *map; - WARN_ON_SMP(!spin_is_locked(&pcibios_fwaddrmap_lock)); + lockdep_assert_held(&pcibios_fwaddrmap_lock); list_for_each_entry(map, &pcibios_fwaddrmappings, list) if (map->dev == dev) -- 2.19.0