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PCI: Export pci_intx_unmanaged() and pcim_intx()

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pci_intx() is a hybrid function which sometimes performs devres operations,
depending on whether pcim_enable_device() has been used to enable the
pci_dev. This sometimes-managed nature of the function is problematic.
Notably, it causes the function to allocate under some circumstances which
makes it unusable from interrupt context.

Export pcim_intx() (which is always managed) and rename __pcim_intx()
(which is never managed) to pci_intx_unmanaged() and export it as well.

Then all callers of pci_intx() can be ported to the version they need,
depending whether they use pci_enable_device() or pcim_enable_device().

Link: https://lore.kernel.org/r/20241209130632.132074-3-pstanner@redhat.com
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
This commit is contained in:
Philipp Stanner 2024-12-09 14:06:23 +01:00 committed by Bjorn Helgaas
parent 40384c840e
commit d3b337c5d7
3 changed files with 34 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
drivers/pci/devres.c
View File

@ -411,31 +411,12 @@ static inline bool mask_contains_bar(int mask, int bar)
return mask & BIT(bar);
}
/*
* This is a copy of pci_intx() used to bypass the problem of recursive
* function calls due to the hybrid nature of pci_intx().
*/
static void __pcim_intx(struct pci_dev *pdev, int enable)
{
u16 pci_command, new;
pci_read_config_word(pdev, PCI_COMMAND, &pci_command);
if (enable)
new = pci_command & ~PCI_COMMAND_INTX_DISABLE;
else
new = pci_command | PCI_COMMAND_INTX_DISABLE;
if (new != pci_command)
pci_write_config_word(pdev, PCI_COMMAND, new);
}
static void pcim_intx_restore(struct device *dev, void *data)
{
struct pci_dev *pdev = to_pci_dev(dev);
struct pcim_intx_devres *res = data;
__pcim_intx(pdev, res->orig_intx);
pci_intx_unmanaged(pdev, res->orig_intx);
}
static struct pcim_intx_devres *get_or_create_intx_devres(struct device *dev)
@ -472,10 +453,11 @@ int pcim_intx(struct pci_dev *pdev, int enable)
return -ENOMEM;
res->orig_intx = !enable;
__pcim_intx(pdev, enable);
pci_intx_unmanaged(pdev, enable);
return 0;
}
EXPORT_SYMBOL_GPL(pcim_intx);
static void pcim_disable_device(void *pdev_raw)
{

29
drivers/pci/pci.c
View File

@ -4482,6 +4482,35 @@ void pci_disable_parity(struct pci_dev *dev)
}
}
/**
* pci_intx_unmanaged - enables/disables PCI INTx for device dev,
* unmanaged version
* @pdev: the PCI device to operate on
* @enable: boolean: whether to enable or disable PCI INTx
*
* Enables/disables PCI INTx for device @pdev
*
* This function behavios identically to pci_intx(), but is never managed with
* devres.
*/
void pci_intx_unmanaged(struct pci_dev *pdev, int enable)
{
u16 pci_command, new;
pci_read_config_word(pdev, PCI_COMMAND, &pci_command);
if (enable)
new = pci_command & ~PCI_COMMAND_INTX_DISABLE;
else
new = pci_command | PCI_COMMAND_INTX_DISABLE;
if (new == pci_command)
return;
pci_write_config_word(pdev, PCI_COMMAND, new);
}
EXPORT_SYMBOL_GPL(pci_intx_unmanaged);
/**
* pci_intx - enables/disables PCI INTx for device dev
* @pdev: the PCI device to operate on

2
include/linux/pci.h
View File

@ -1350,6 +1350,7 @@ int __must_check pcim_set_mwi(struct pci_dev *dev);
int pci_try_set_mwi(struct pci_dev *dev);
void pci_clear_mwi(struct pci_dev *dev);
void pci_disable_parity(struct pci_dev *dev);
void pci_intx_unmanaged(struct pci_dev *pdev, int enable);
void pci_intx(struct pci_dev *dev, int enable);
bool pci_check_and_mask_intx(struct pci_dev *dev);
bool pci_check_and_unmask_intx(struct pci_dev *dev);
@ -2297,6 +2298,7 @@ static inline void pci_fixup_device(enum pci_fixup_pass pass,
struct pci_dev *dev) { }
#endif
int pcim_intx(struct pci_dev *pdev, int enabled);
int pcim_request_all_regions(struct pci_dev *pdev, const char *name);
void __iomem *pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen);
void __iomem *pcim_iomap_region(struct pci_dev *pdev, int bar,