7ea7e98fd8
The existing implementation of pci_block_user_cfg_access() was recently criticised for providing out of date information and for returning errors on write, which applications won't be expecting. This reimplementation uses a global wait queue and a bit per device. I've open-coded prepare_to_wait() / finish_wait() as I could optimise it significantly by knowing that the pci_lock protected us at all points. It looked a bit funny to be doing a spin_unlock_irqsave(); schedule(), so I used spin_lock_irq() for the _user versions of pci_read_config and pci_write_config. Not carrying a flags pointer around made the code much less nasty. Attempts to block an already blocked device hit a BUG() and attempts to unblock an already unblocked device hit a WARN(). If we need to block access to a device from userspace, it's because it's unsafe for even another bit of the kernel to access the device. An attempt to block a device for a second time means we're about to access the device to perform some other operation, which could provoke undefined behaviour from the device. Signed-off-by: Matthew Wilcox <matthew@wil.cx> Acked-by: Adam Belay <abelay@novell.com> Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
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| .. | ||
| hotplug | ||
| pcie | ||
| .gitignore | ||
| access.c | ||
| bus.c | ||
| hotplug.c | ||
| htirq.c | ||
| Kconfig | ||
| Makefile | ||
| msi.c | ||
| msi.h | ||
| pci-acpi.c | ||
| pci-driver.c | ||
| pci-sysfs.c | ||
| pci.c | ||
| pci.h | ||
| probe.c | ||
| proc.c | ||
| quirks.c | ||
| remove.c | ||
| rom.c | ||
| search.c | ||
| setup-bus.c | ||
| setup-irq.c | ||
| setup-res.c | ||
| syscall.c | ||