Revision 44bda4b7d26e9fffed6d7152d98a2e9edaeb2a76 authored by Hari Vyas on 03 July 2018, 09:05:41 UTC, committed by Bjorn Helgaas on 31 July 2018, 16:27:54 UTC
When a PCI device is detected, pdev->is_added is set to 1 and proc and sysfs entries are created. When the device is removed, pdev->is_added is checked for one and then device is detached with clearing of proc and sys entries and at end, pdev->is_added is set to 0. is_added and is_busmaster are bit fields in pci_dev structure sharing same memory location. A strange issue was observed with multiple removal and rescan of a PCIe NVMe device using sysfs commands where is_added flag was observed as zero instead of one while removing device and proc,sys entries are not cleared. This causes issue in later device addition with warning message "proc_dir_entry" already registered. Debugging revealed a race condition between the PCI core setting the is_added bit in pci_bus_add_device() and the NVMe driver reset work-queue setting the is_busmaster bit in pci_set_master(). As these fields are not handled atomically, that clears the is_added bit. Move the is_added bit to a separate private flag variable and use atomic functions to set and retrieve the device addition state. This avoids the race because is_added no longer shares a memory location with is_busmaster. Link: https://bugzilla.kernel.org/show_bug.cgi?id=200283 Signed-off-by: Hari Vyas <hari.vyas@broadcom.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de> Acked-by: Michael Ellerman <mpe@ellerman.id.au>
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File | Mode | Size |
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accessibility | ||
acpi | ||
amba | ||
android | ||
ata | ||
atm | ||
auxdisplay | ||
base | ||
bcma | ||
block | ||
bluetooth | ||
bus | ||
cdrom | ||
char | ||
clk | ||
clocksource | ||
connector | ||
cpufreq | ||
cpuidle | ||
crypto | ||
dax | ||
dca | ||
devfreq | ||
dio | ||
dma | ||
dma-buf | ||
edac | ||
eisa | ||
extcon | ||
firewire | ||
firmware | ||
fmc | ||
fpga | ||
fsi | ||
gpio | ||
gpu | ||
hid | ||
hsi | ||
hv | ||
hwmon | ||
hwspinlock | ||
hwtracing | ||
i2c | ||
ide | ||
idle | ||
iio | ||
infiniband | ||
input | ||
iommu | ||
ipack | ||
irqchip | ||
isdn | ||
leds | ||
lightnvm | ||
macintosh | ||
mailbox | ||
mcb | ||
md | ||
media | ||
memory | ||
memstick | ||
message | ||
mfd | ||
misc | ||
mmc | ||
mtd | ||
mux | ||
net | ||
nfc | ||
ntb | ||
nubus | ||
nvdimm | ||
nvme | ||
nvmem | ||
of | ||
opp | ||
oprofile | ||
parisc | ||
parport | ||
pci | ||
pcmcia | ||
perf | ||
phy | ||
pinctrl | ||
platform | ||
pnp | ||
power | ||
powercap | ||
pps | ||
ps3 | ||
ptp | ||
pwm | ||
rapidio | ||
ras | ||
regulator | ||
remoteproc | ||
reset | ||
rpmsg | ||
rtc | ||
s390 | ||
sbus | ||
scsi | ||
sfi | ||
sh | ||
siox | ||
slimbus | ||
sn | ||
soc | ||
soundwire | ||
spi | ||
spmi | ||
ssb | ||
staging | ||
target | ||
tc | ||
tee | ||
thermal | ||
thunderbolt | ||
tty | ||
uio | ||
usb | ||
uwb | ||
vfio | ||
vhost | ||
video | ||
virt | ||
virtio | ||
visorbus | ||
vlynq | ||
vme | ||
w1 | ||
watchdog | ||
xen | ||
zorro | ||
Kconfig | -rw-r--r-- | 3.5 KB |
Makefile | -rw-r--r-- | 5.2 KB |
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