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| author | Jan Kiszka <jan.kiszka@siemens.com> | 2011-11-04 12:45:59 +0400 |
|---|---|---|
| committer | Jesse Barnes <jbarnes@virtuousgeek.org> | 2012-01-07 00:10:33 +0400 |
| commit | fb51ccbf217c1c994607b6519c7d85250928553d (patch) | |
| tree | d08ba9a0278da0e75b6c6714e9453e46068e27b4 /include/linux/pci.h | |
| parent | ae5cd86455381282ece162966183d3f208c6fad7 (diff) | |
| download | linux-fb51ccbf217c1c994607b6519c7d85250928553d.tar.xz | |
PCI: Rework config space blocking services
pci_block_user_cfg_access was designed for the use case that a single
context, the IPR driver, temporarily delays user space accesses to the
config space via sysfs. This assumption became invalid by the time
pci_dev_reset was added as locking instance. Today, if you run two loops
in parallel that reset the same device via sysfs, you end up with a
kernel BUG as pci_block_user_cfg_access detect the broken assumption.
This reworks the pci_block_user_cfg_access to a sleeping service
pci_cfg_access_lock and an atomic-compatible variant called
pci_cfg_access_trylock. The former not only blocks user space access as
before but also waits if access was already locked. The latter service
just returns false in this case, allowing the caller to resolve the
conflict instead of raising a BUG.
Adaptions of the ipr driver were originally written by Brian King.
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'include/linux/pci.h')
| -rw-r--r-- | include/linux/pci.h | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/include/linux/pci.h b/include/linux/pci.h index 84225c756bd1..72401596b2a8 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -308,7 +308,7 @@ struct pci_dev { unsigned int is_added:1; unsigned int is_busmaster:1; /* device is busmaster */ unsigned int no_msi:1; /* device may not use msi */ - unsigned int block_ucfg_access:1; /* userspace config space access is blocked */ + unsigned int block_cfg_access:1; /* config space access is blocked */ unsigned int broken_parity_status:1; /* Device generates false positive parity */ unsigned int irq_reroute_variant:2; /* device needs IRQ rerouting variant */ unsigned int msi_enabled:1; @@ -1085,8 +1085,9 @@ int ht_create_irq(struct pci_dev *dev, int idx); void ht_destroy_irq(unsigned int irq); #endif /* CONFIG_HT_IRQ */ -extern void pci_block_user_cfg_access(struct pci_dev *dev); -extern void pci_unblock_user_cfg_access(struct pci_dev *dev); +extern void pci_cfg_access_lock(struct pci_dev *dev); +extern bool pci_cfg_access_trylock(struct pci_dev *dev); +extern void pci_cfg_access_unlock(struct pci_dev *dev); /* * PCI domain support. Sometimes called PCI segment (eg by ACPI), @@ -1283,10 +1284,13 @@ static inline void pci_release_regions(struct pci_dev *dev) #define pci_dma_burst_advice(pdev, strat, strategy_parameter) do { } while (0) -static inline void pci_block_user_cfg_access(struct pci_dev *dev) +static inline void pci_block_cfg_access(struct pci_dev *dev) { } -static inline void pci_unblock_user_cfg_access(struct pci_dev *dev) +static inline int pci_block_cfg_access_in_atomic(struct pci_dev *dev) +{ return 0; } + +static inline void pci_unblock_cfg_access(struct pci_dev *dev) { } static inline struct pci_bus *pci_find_next_bus(const struct pci_bus *from) |