| Message ID | 20231202012556.2012281-2-volodymyr_babchuk@epam.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | PCI devices passthrough on Arm, part 3 | expand |
On Sat, 2 Dec 2023, Volodymyr Babchuk wrote: > Previously pci_enable_msi() function obtained pdev pointer by itself, > but taking into account upcoming changes to PCI locking, it is better > when caller passes already acquired pdev pointer to the function, > because caller knows better how to obtain the pointer and which locks > are needed to be used. Also, in most cases caller already has pointer > to pdev, so we can avoid an extra list walk. > > Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com> > > --- > In v11: > - Made pdev parameter very first in pci_enable_msi() and friends. > - Extended the commit message > - Added check for pdev into ns16550 driver > - Replaced hard tabs with spaces > > Changes in v10: > > - New in v10. This is the result of discussion in "vpci: add initial > support for virtual PCI bus topology" > --- > xen/arch/x86/include/asm/msi.h | 5 +++-- > xen/arch/x86/irq.c | 2 +- > xen/arch/x86/msi.c | 19 ++++++++++--------- > xen/drivers/char/ns16550.c | 28 ++++++++++++++++++---------- > 4 files changed, 32 insertions(+), 22 deletions(-) > > diff --git a/xen/arch/x86/include/asm/msi.h b/xen/arch/x86/include/asm/msi.h > index c1ece2786e..07b3ee55e9 100644 > --- a/xen/arch/x86/include/asm/msi.h > +++ b/xen/arch/x86/include/asm/msi.h > @@ -81,8 +81,9 @@ struct irq_desc; > struct hw_interrupt_type; > struct msi_desc; > /* Helper functions */ > -extern int pci_enable_msi(struct msi_info *msi, struct msi_desc **desc); > -extern void pci_disable_msi(struct msi_desc *msi_desc); > +extern int pci_enable_msi(struct pci_dev *pdev, struct msi_info *msi, > + struct msi_desc **desc); > +extern void pci_disable_msi(struct msi_desc *desc); As the parameters name should match between declaration and definition, you should also rename msi_desc to desc in the implementation of pci_disable_msi. Or keep the parameter called "msi_desc" for pci_disable_msi here. That change could be done on commit and everything else looks OK: Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > extern int pci_prepare_msix(u16 seg, u8 bus, u8 devfn, bool off); > extern void pci_cleanup_msi(struct pci_dev *pdev); > extern int setup_msi_irq(struct irq_desc *desc, struct msi_desc *msidesc); > diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c > index 6e668b1b4f..50e49e1a4b 100644 > --- a/xen/arch/x86/irq.c > +++ b/xen/arch/x86/irq.c > @@ -2176,7 +2176,7 @@ int map_domain_pirq( > if ( !pdev ) > goto done; > > - ret = pci_enable_msi(msi, &msi_desc); > + ret = pci_enable_msi(pdev, msi, &msi_desc); > if ( ret ) > { > if ( ret > 0 ) > diff --git a/xen/arch/x86/msi.c b/xen/arch/x86/msi.c > index 7f8e794254..335c0868a2 100644 > --- a/xen/arch/x86/msi.c > +++ b/xen/arch/x86/msi.c > @@ -983,13 +983,13 @@ static int msix_capability_init(struct pci_dev *dev, > * irq or non-zero for otherwise. > **/ > > -static int __pci_enable_msi(struct msi_info *msi, struct msi_desc **desc) > +static int __pci_enable_msi(struct pci_dev *pdev, struct msi_info *msi, > + struct msi_desc **desc) > { > - struct pci_dev *pdev; > struct msi_desc *old_desc; > > ASSERT(pcidevs_locked()); > - pdev = pci_get_pdev(NULL, msi->sbdf); > + > if ( !pdev ) > return -ENODEV; > > @@ -1038,13 +1038,13 @@ static void __pci_disable_msi(struct msi_desc *entry) > * of irqs available. Driver should use the returned value to re-send > * its request. > **/ > -static int __pci_enable_msix(struct msi_info *msi, struct msi_desc **desc) > +static int __pci_enable_msix(struct pci_dev *pdev, struct msi_info *msi, > + struct msi_desc **desc) > { > - struct pci_dev *pdev; > struct msi_desc *old_desc; > > ASSERT(pcidevs_locked()); > - pdev = pci_get_pdev(NULL, msi->sbdf); > + > if ( !pdev || !pdev->msix ) > return -ENODEV; > > @@ -1151,15 +1151,16 @@ int pci_prepare_msix(u16 seg, u8 bus, u8 devfn, bool off) > * Notice: only construct the msi_desc > * no change to irq_desc here, and the interrupt is masked > */ > -int pci_enable_msi(struct msi_info *msi, struct msi_desc **desc) > +int pci_enable_msi(struct pci_dev *pdev, struct msi_info *msi, > + struct msi_desc **desc) > { > ASSERT(pcidevs_locked()); > > if ( !use_msi ) > return -EPERM; > > - return msi->table_base ? __pci_enable_msix(msi, desc) : > - __pci_enable_msi(msi, desc); > + return msi->table_base ? __pci_enable_msix(pdev, msi, desc) : > + __pci_enable_msi(pdev, msi, desc); > } > > /* > diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c > index ddf2a48be6..cfe9ff8d2a 100644 > --- a/xen/drivers/char/ns16550.c > +++ b/xen/drivers/char/ns16550.c > @@ -452,21 +452,29 @@ static void __init cf_check ns16550_init_postirq(struct serial_port *port) > if ( rc > 0 ) > { > struct msi_desc *msi_desc = NULL; > + struct pci_dev *pdev; > > pcidevs_lock(); > > - rc = pci_enable_msi(&msi, &msi_desc); > - if ( !rc ) > + pdev = pci_get_pdev(NULL, msi.sbdf); > + if ( pdev ) > { > - struct irq_desc *desc = irq_to_desc(msi.irq); > - unsigned long flags; > - > - spin_lock_irqsave(&desc->lock, flags); > - rc = setup_msi_irq(desc, msi_desc); > - spin_unlock_irqrestore(&desc->lock, flags); > - if ( rc ) > - pci_disable_msi(msi_desc); > + rc = pci_enable_msi(pdev, &msi, &msi_desc); > + > + if ( !rc ) > + { > + struct irq_desc *desc = irq_to_desc(msi.irq); > + unsigned long flags; > + > + spin_lock_irqsave(&desc->lock, flags); > + rc = setup_msi_irq(desc, msi_desc); > + spin_unlock_irqrestore(&desc->lock, flags); > + if ( rc ) > + pci_disable_msi(msi_desc); > + } > } > + else > + rc = -ENODEV; > > pcidevs_unlock(); > > -- > 2.42.0 >
On 20.12.2023 03:10, Stefano Stabellini wrote: > On Sat, 2 Dec 2023, Volodymyr Babchuk wrote: >> --- a/xen/arch/x86/include/asm/msi.h >> +++ b/xen/arch/x86/include/asm/msi.h >> @@ -81,8 +81,9 @@ struct irq_desc; >> struct hw_interrupt_type; >> struct msi_desc; >> /* Helper functions */ >> -extern int pci_enable_msi(struct msi_info *msi, struct msi_desc **desc); >> -extern void pci_disable_msi(struct msi_desc *msi_desc); >> +extern int pci_enable_msi(struct pci_dev *pdev, struct msi_info *msi, >> + struct msi_desc **desc); >> +extern void pci_disable_msi(struct msi_desc *desc); > > As the parameters name should match between declaration and definition, > you should also rename msi_desc to desc in the implementation of > pci_disable_msi. Or keep the parameter called "msi_desc" for > pci_disable_msi here. It's not clear at all why pci_disable_msi() is touched here; the description says nothing in this regard. > That change could be done on commit and everything > else looks OK: > > Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
On 02.12.2023 02:27, Volodymyr Babchuk wrote: > --- a/xen/drivers/char/ns16550.c > +++ b/xen/drivers/char/ns16550.c > @@ -452,21 +452,29 @@ static void __init cf_check ns16550_init_postirq(struct serial_port *port) > if ( rc > 0 ) > { > struct msi_desc *msi_desc = NULL; > + struct pci_dev *pdev; > > pcidevs_lock(); > > - rc = pci_enable_msi(&msi, &msi_desc); > - if ( !rc ) > + pdev = pci_get_pdev(NULL, msi.sbdf); > + if ( pdev ) > { > - struct irq_desc *desc = irq_to_desc(msi.irq); > - unsigned long flags; > - > - spin_lock_irqsave(&desc->lock, flags); > - rc = setup_msi_irq(desc, msi_desc); > - spin_unlock_irqrestore(&desc->lock, flags); > - if ( rc ) > - pci_disable_msi(msi_desc); > + rc = pci_enable_msi(pdev, &msi, &msi_desc); > + > + if ( !rc ) > + { > + struct irq_desc *desc = irq_to_desc(msi.irq); > + unsigned long flags; > + > + spin_lock_irqsave(&desc->lock, flags); > + rc = setup_msi_irq(desc, msi_desc); > + spin_unlock_irqrestore(&desc->lock, flags); > + if ( rc ) > + pci_disable_msi(msi_desc); > + } > } > + else > + rc = -ENODEV; > > pcidevs_unlock(); When mere re-indenting is needed, and even more so when indentation gets this deep, I think it is necessary to consider alternatives: With pdev = pci_get_pdev(NULL, msi.sbdf); rc = pdev ? pci_enable_msi(pdev, &msi, &msi_desc) : -ENODEV; I think all of the other code churn could be avoided. Jan
diff --git a/xen/arch/x86/include/asm/msi.h b/xen/arch/x86/include/asm/msi.h index c1ece2786e..07b3ee55e9 100644 --- a/xen/arch/x86/include/asm/msi.h +++ b/xen/arch/x86/include/asm/msi.h @@ -81,8 +81,9 @@ struct irq_desc; struct hw_interrupt_type; struct msi_desc; /* Helper functions */ -extern int pci_enable_msi(struct msi_info *msi, struct msi_desc **desc); -extern void pci_disable_msi(struct msi_desc *msi_desc); +extern int pci_enable_msi(struct pci_dev *pdev, struct msi_info *msi, + struct msi_desc **desc); +extern void pci_disable_msi(struct msi_desc *desc); extern int pci_prepare_msix(u16 seg, u8 bus, u8 devfn, bool off); extern void pci_cleanup_msi(struct pci_dev *pdev); extern int setup_msi_irq(struct irq_desc *desc, struct msi_desc *msidesc); diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c index 6e668b1b4f..50e49e1a4b 100644 --- a/xen/arch/x86/irq.c +++ b/xen/arch/x86/irq.c @@ -2176,7 +2176,7 @@ int map_domain_pirq( if ( !pdev ) goto done; - ret = pci_enable_msi(msi, &msi_desc); + ret = pci_enable_msi(pdev, msi, &msi_desc); if ( ret ) { if ( ret > 0 ) diff --git a/xen/arch/x86/msi.c b/xen/arch/x86/msi.c index 7f8e794254..335c0868a2 100644 --- a/xen/arch/x86/msi.c +++ b/xen/arch/x86/msi.c @@ -983,13 +983,13 @@ static int msix_capability_init(struct pci_dev *dev, * irq or non-zero for otherwise. **/ -static int __pci_enable_msi(struct msi_info *msi, struct msi_desc **desc) +static int __pci_enable_msi(struct pci_dev *pdev, struct msi_info *msi, + struct msi_desc **desc) { - struct pci_dev *pdev; struct msi_desc *old_desc; ASSERT(pcidevs_locked()); - pdev = pci_get_pdev(NULL, msi->sbdf); + if ( !pdev ) return -ENODEV; @@ -1038,13 +1038,13 @@ static void __pci_disable_msi(struct msi_desc *entry) * of irqs available. Driver should use the returned value to re-send * its request. **/ -static int __pci_enable_msix(struct msi_info *msi, struct msi_desc **desc) +static int __pci_enable_msix(struct pci_dev *pdev, struct msi_info *msi, + struct msi_desc **desc) { - struct pci_dev *pdev; struct msi_desc *old_desc; ASSERT(pcidevs_locked()); - pdev = pci_get_pdev(NULL, msi->sbdf); + if ( !pdev || !pdev->msix ) return -ENODEV; @@ -1151,15 +1151,16 @@ int pci_prepare_msix(u16 seg, u8 bus, u8 devfn, bool off) * Notice: only construct the msi_desc * no change to irq_desc here, and the interrupt is masked */ -int pci_enable_msi(struct msi_info *msi, struct msi_desc **desc) +int pci_enable_msi(struct pci_dev *pdev, struct msi_info *msi, + struct msi_desc **desc) { ASSERT(pcidevs_locked()); if ( !use_msi ) return -EPERM; - return msi->table_base ? __pci_enable_msix(msi, desc) : - __pci_enable_msi(msi, desc); + return msi->table_base ? __pci_enable_msix(pdev, msi, desc) : + __pci_enable_msi(pdev, msi, desc); } /* diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c index ddf2a48be6..cfe9ff8d2a 100644 --- a/xen/drivers/char/ns16550.c +++ b/xen/drivers/char/ns16550.c @@ -452,21 +452,29 @@ static void __init cf_check ns16550_init_postirq(struct serial_port *port) if ( rc > 0 ) { struct msi_desc *msi_desc = NULL; + struct pci_dev *pdev; pcidevs_lock(); - rc = pci_enable_msi(&msi, &msi_desc); - if ( !rc ) + pdev = pci_get_pdev(NULL, msi.sbdf); + if ( pdev ) { - struct irq_desc *desc = irq_to_desc(msi.irq); - unsigned long flags; - - spin_lock_irqsave(&desc->lock, flags); - rc = setup_msi_irq(desc, msi_desc); - spin_unlock_irqrestore(&desc->lock, flags); - if ( rc ) - pci_disable_msi(msi_desc); + rc = pci_enable_msi(pdev, &msi, &msi_desc); + + if ( !rc ) + { + struct irq_desc *desc = irq_to_desc(msi.irq); + unsigned long flags; + + spin_lock_irqsave(&desc->lock, flags); + rc = setup_msi_irq(desc, msi_desc); + spin_unlock_irqrestore(&desc->lock, flags); + if ( rc ) + pci_disable_msi(msi_desc); + } } + else + rc = -ENODEV; pcidevs_unlock();
Previously pci_enable_msi() function obtained pdev pointer by itself, but taking into account upcoming changes to PCI locking, it is better when caller passes already acquired pdev pointer to the function, because caller knows better how to obtain the pointer and which locks are needed to be used. Also, in most cases caller already has pointer to pdev, so we can avoid an extra list walk. Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com> --- In v11: - Made pdev parameter very first in pci_enable_msi() and friends. - Extended the commit message - Added check for pdev into ns16550 driver - Replaced hard tabs with spaces Changes in v10: - New in v10. This is the result of discussion in "vpci: add initial support for virtual PCI bus topology" --- xen/arch/x86/include/asm/msi.h | 5 +++-- xen/arch/x86/irq.c | 2 +- xen/arch/x86/msi.c | 19 ++++++++++--------- xen/drivers/char/ns16550.c | 28 ++++++++++++++++++---------- 4 files changed, 32 insertions(+), 22 deletions(-)