| Message ID | 20250313130321.695027112@linutronix.de (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | genirq/msi: Spring cleaning | expand |
On Thu, 13 Mar 2025 14:03:44 +0100 (CET) Thomas Gleixner <tglx@linutronix.de> wrote: > Convert the code to use the new guard(msi_descs_lock). > > No functional change intended. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: linux-pci@vger.kernel.org > --- > V2: Remove the gotos - Jonathan Hi Thomas, There is a bit of the original code that is carried forwards here that superficially seemed overly complex. However as far as I can tell this is functionally the same as you intended. So with that in mind if my question isn't complete garbage, maybe a readability issue for another day. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > --- a/drivers/pci/msi/msi.c > +++ b/drivers/pci/msi/msi.c > +static int msix_setup_interrupts(struct pci_dev *dev, struct msix_entry *entries, > + int nvec, struct irq_affinity *affd) > +{ > + struct irq_affinity_desc *masks __free(kfree) = > + affd ? irq_create_affinity_masks(nvec, affd) : NULL; > + > + guard(msi_descs_lock)(&dev->dev); > + int ret = __msix_setup_interrupts(dev, entries, nvec, masks); > + if (ret) > + pci_free_msi_irqs(dev); It's not immediately obvious what this is undoing (i.e. where the alloc is). I think it is at least mostly the pci_msi_setup_msi_irqs in __msix_setup_interrupts Why not handle the error in __msix_setup_interrupts and make that function side effect free. Does require gotos but in a function that isn't doing any cleanup magic so should be fine. Mind you I'm not following the logic in msix_setup_interrupts() before this series either. i.e. why doesn't msix_setup_msi_descs() clean up after itself on failure (i.e. undo loop iterations that weren't failures) as that at least superficially looks like it would give more readable code. So this is the same as current and as such the patch is fine I think. > return ret; > } >
On Thu, Mar 13 2025 at 15:50, Jonathan Cameron wrote: >> + guard(msi_descs_lock)(&dev->dev); >> + int ret = __msix_setup_interrupts(dev, entries, nvec, masks); >> + if (ret) >> + pci_free_msi_irqs(dev); > > It's not immediately obvious what this is undoing (i.e. where the alloc > is). I think it is at least mostly the pci_msi_setup_msi_irqs in > __msix_setup_interrupts It's a universal cleanup for all possible error cases. > Why not handle the error in __msix_setup_interrupts and make that function > side effect free. Does require gotos but in a function that isn't > doing any cleanup magic so should be fine. I had the gotos first and then hated them. But you are right, it's better to have them than having the magic clean up at the call site. I'll fold the delta patch below. Thanks, tglx --- --- a/drivers/pci/msi/msi.c +++ b/drivers/pci/msi/msi.c @@ -671,19 +671,23 @@ static int __msix_setup_interrupts(struc int ret = msix_setup_msi_descs(dev, entries, nvec, masks); if (ret) - return ret; + goto fail; ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); if (ret) - return ret; + goto fail; /* Check if all MSI entries honor device restrictions */ ret = msi_verify_entries(dev); if (ret) - return ret; + goto fail; msix_update_entries(dev, entries); return 0; + +fail: + pci_free_msi_irqs(dev); + return ret; } static int msix_setup_interrupts(struct pci_dev *dev, struct msix_entry *entries, @@ -693,10 +697,7 @@ static int msix_setup_interrupts(struct affd ? irq_create_affinity_masks(nvec, affd) : NULL; guard(msi_descs_lock)(&dev->dev); - int ret = __msix_setup_interrupts(dev, entries, nvec, masks); - if (ret) - pci_free_msi_irqs(dev); - return ret; + return __msix_setup_interrupts(dev, entries, nvec, masks); } /**
On Thu, Mar 13, 2025 at 06:55:12PM +0100, Thomas Gleixner wrote: > On Thu, Mar 13 2025 at 15:50, Jonathan Cameron wrote: > >> + guard(msi_descs_lock)(&dev->dev); > >> + int ret = __msix_setup_interrupts(dev, entries, nvec, masks); > >> + if (ret) > >> + pci_free_msi_irqs(dev); > > > > It's not immediately obvious what this is undoing (i.e. where the alloc > > is). I think it is at least mostly the pci_msi_setup_msi_irqs in > > __msix_setup_interrupts > > It's a universal cleanup for all possible error cases. > > > Why not handle the error in __msix_setup_interrupts and make that function > > side effect free. Does require gotos but in a function that isn't > > doing any cleanup magic so should be fine. > > I had the gotos first and then hated them. But you are right, it's better > to have them than having the magic clean up at the call site. > > I'll fold the delta patch below. > > Thanks, > > tglx > --- > --- a/drivers/pci/msi/msi.c > +++ b/drivers/pci/msi/msi.c > @@ -671,19 +671,23 @@ static int __msix_setup_interrupts(struc > int ret = msix_setup_msi_descs(dev, entries, nvec, masks); > > if (ret) > - return ret; > + goto fail; > > ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); > if (ret) > - return ret; > + goto fail; > > /* Check if all MSI entries honor device restrictions */ > ret = msi_verify_entries(dev); > if (ret) > - return ret; > + goto fail; > > msix_update_entries(dev, entries); > return 0; > + > +fail: > + pci_free_msi_irqs(dev); > + return ret; > } How about something like: int __msix_setup_interrupts(struct device *_dev,... ) { struct device *dev __free(msi_irqs) = _dev; int ret = msix_setup_msi_descs(dev, entries, nvec, masks); if (ret) return ret; ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); if (ret) return ret; /* Check if all MSI entries honor device restrictions */ ret = msi_verify_entries(dev); if (ret) return ret; retain_ptr(dev); msix_update_entries(dev, entries); return 0; } ?
--- a/drivers/pci/msi/api.c +++ b/drivers/pci/msi/api.c @@ -53,10 +53,9 @@ void pci_disable_msi(struct pci_dev *dev if (!pci_msi_enabled() || !dev || !dev->msi_enabled) return; - msi_lock_descs(&dev->dev); + guard(msi_descs_lock)(&dev->dev); pci_msi_shutdown(dev); pci_free_msi_irqs(dev); - msi_unlock_descs(&dev->dev); } EXPORT_SYMBOL(pci_disable_msi); @@ -196,10 +195,9 @@ void pci_disable_msix(struct pci_dev *de if (!pci_msi_enabled() || !dev || !dev->msix_enabled) return; - msi_lock_descs(&dev->dev); + guard(msi_descs_lock)(&dev->dev); pci_msix_shutdown(dev); pci_free_msi_irqs(dev); - msi_unlock_descs(&dev->dev); } EXPORT_SYMBOL(pci_disable_msix); --- a/drivers/pci/msi/msi.c +++ b/drivers/pci/msi/msi.c @@ -336,41 +336,11 @@ static int msi_verify_entries(struct pci return !entry ? 0 : -EIO; } -/** - * msi_capability_init - configure device's MSI capability structure - * @dev: pointer to the pci_dev data structure of MSI device function - * @nvec: number of interrupts to allocate - * @affd: description of automatic IRQ affinity assignments (may be %NULL) - * - * Setup the MSI capability structure of the device with the requested - * number of interrupts. A return value of zero indicates the successful - * setup of an entry with the new MSI IRQ. A negative return value indicates - * an error, and a positive return value indicates the number of interrupts - * which could have been allocated. - */ -static int msi_capability_init(struct pci_dev *dev, int nvec, - struct irq_affinity *affd) +static int __msi_capability_init(struct pci_dev *dev, int nvec, struct irq_affinity_desc *masks) { - struct irq_affinity_desc *masks = NULL; + int ret = msi_setup_msi_desc(dev, nvec, masks); struct msi_desc *entry, desc; - int ret; - - /* Reject multi-MSI early on irq domain enabled architectures */ - if (nvec > 1 && !pci_msi_domain_supports(dev, MSI_FLAG_MULTI_PCI_MSI, ALLOW_LEGACY)) - return 1; - - /* - * Disable MSI during setup in the hardware, but mark it enabled - * so that setup code can evaluate it. - */ - pci_msi_set_enable(dev, 0); - dev->msi_enabled = 1; - - if (affd) - masks = irq_create_affinity_masks(nvec, affd); - msi_lock_descs(&dev->dev); - ret = msi_setup_msi_desc(dev, nvec, masks); if (ret) goto fail; @@ -399,19 +369,48 @@ static int msi_capability_init(struct pc pcibios_free_irq(dev); dev->irq = entry->irq; - goto unlock; - + return 0; err: pci_msi_unmask(&desc, msi_multi_mask(&desc)); pci_free_msi_irqs(dev); fail: dev->msi_enabled = 0; -unlock: - msi_unlock_descs(&dev->dev); - kfree(masks); return ret; } +/** + * msi_capability_init - configure device's MSI capability structure + * @dev: pointer to the pci_dev data structure of MSI device function + * @nvec: number of interrupts to allocate + * @affd: description of automatic IRQ affinity assignments (may be %NULL) + * + * Setup the MSI capability structure of the device with the requested + * number of interrupts. A return value of zero indicates the successful + * setup of an entry with the new MSI IRQ. A negative return value indicates + * an error, and a positive return value indicates the number of interrupts + * which could have been allocated. + */ +static int msi_capability_init(struct pci_dev *dev, int nvec, + struct irq_affinity *affd) +{ + /* Reject multi-MSI early on irq domain enabled architectures */ + if (nvec > 1 && !pci_msi_domain_supports(dev, MSI_FLAG_MULTI_PCI_MSI, ALLOW_LEGACY)) + return 1; + + /* + * Disable MSI during setup in the hardware, but mark it enabled + * so that setup code can evaluate it. + */ + pci_msi_set_enable(dev, 0); + dev->msi_enabled = 1; + + struct irq_affinity_desc *masks __free(kfree) = + affd ? irq_create_affinity_masks(nvec, affd) : NULL; + + guard(msi_descs_lock)(&dev->dev); + return __msi_capability_init(dev, nvec, masks); +} + int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec, struct irq_affinity *affd) { @@ -666,37 +665,37 @@ static void msix_mask_all(void __iomem * writel(ctrl, base + PCI_MSIX_ENTRY_VECTOR_CTRL); } -static int msix_setup_interrupts(struct pci_dev *dev, struct msix_entry *entries, - int nvec, struct irq_affinity *affd) +static int __msix_setup_interrupts(struct pci_dev *dev, struct msix_entry *entries, + int nvec, struct irq_affinity_desc *masks) { - struct irq_affinity_desc *masks = NULL; - int ret; + int ret = msix_setup_msi_descs(dev, entries, nvec, masks); - if (affd) - masks = irq_create_affinity_masks(nvec, affd); - - msi_lock_descs(&dev->dev); - ret = msix_setup_msi_descs(dev, entries, nvec, masks); if (ret) - goto out_free; + return ret; ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); if (ret) - goto out_free; + return ret; /* Check if all MSI entries honor device restrictions */ ret = msi_verify_entries(dev); if (ret) - goto out_free; + return ret; msix_update_entries(dev, entries); - goto out_unlock; + return 0; +} -out_free: - pci_free_msi_irqs(dev); -out_unlock: - msi_unlock_descs(&dev->dev); - kfree(masks); +static int msix_setup_interrupts(struct pci_dev *dev, struct msix_entry *entries, + int nvec, struct irq_affinity *affd) +{ + struct irq_affinity_desc *masks __free(kfree) = + affd ? irq_create_affinity_masks(nvec, affd) : NULL; + + guard(msi_descs_lock)(&dev->dev); + int ret = __msix_setup_interrupts(dev, entries, nvec, masks); + if (ret) + pci_free_msi_irqs(dev); return ret; } @@ -871,13 +870,13 @@ void __pci_restore_msix_state(struct pci write_msg = arch_restore_msi_irqs(dev); - msi_lock_descs(&dev->dev); - msi_for_each_desc(entry, &dev->dev, MSI_DESC_ALL) { - if (write_msg) - __pci_write_msi_msg(entry, &entry->msg); - pci_msix_write_vector_ctrl(entry, entry->pci.msix_ctrl); + scoped_guard (msi_descs_lock, &dev->dev) { + msi_for_each_desc(entry, &dev->dev, MSI_DESC_ALL) { + if (write_msg) + __pci_write_msi_msg(entry, &entry->msg); + pci_msix_write_vector_ctrl(entry, entry->pci.msix_ctrl); + } } - msi_unlock_descs(&dev->dev); pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0); }
Convert the code to use the new guard(msi_descs_lock). No functional change intended. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-pci@vger.kernel.org --- V2: Remove the gotos - Jonathan --- drivers/pci/msi/api.c | 6 -- drivers/pci/msi/msi.c | 121 ++++++++++++++++++++++++-------------------------- 2 files changed, 62 insertions(+), 65 deletions(-)