Re: [PATCH] scsi: cxlflash: Select SCSI_SCAN_ASYNC
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2018-02-20 08:56:39
Also in:
linux-scsi, lkml
Vaibhav Jain [off-list ref] writes:
The cxlflash driver uses "Asynchronous SCSI scanning" enabled by CONFIG_SCSI_SCAN_ASYNC. Without this enabled the modprobe of cxlflash module gets hung with following backtrace: Call Trace: __switch_to+0x2cc/0x470 __schedule+0x288/0xab0 schedule+0x40/0xc0 schedule_timeout+0x254/0x4f0 wait_for_common+0xdc/0x260 flush_work+0x140/0x2a0 work_on_cpu+0x88/0xb0 pci_device_probe+0x1d0/0x220 driver_probe_device+0x408/0x5b0 __driver_attach+0x16c/0x1a0 bus_for_each_dev+0xb8/0x110 driver_attach+0x3c/0x60 bus_add_driver+0x1d8/0x370 driver_register+0x9c/0x180 __pci_register_driver+0x74/0xa0 init_cxlflash+0x158/0x1cc do_one_initcall+0x68/0x1e0 do_init_module+0x90/0x254 load_module+0x2f8c/0x3720 SyS_finit_module+0xcc/0x140 system_call+0x58/0x6c
Why does it "hang"? That's kind of bizarre, I would expect either a build or runtime failure if a feature the driver requires is missing.
quoted hunk ↗ jump to hunk
diff --git a/drivers/scsi/cxlflash/Kconfig b/drivers/scsi/cxlflash/Kconfig index a011c5dbf214..f054c1b0fff3 100644 --- a/drivers/scsi/cxlflash/Kconfig +++ b/drivers/scsi/cxlflash/Kconfig@@ -6,6 +6,7 @@ config CXLFLASH tristate "Support for IBM CAPI Flash" depends on PCI && SCSI && CXL && EEH select IRQ_POLL + select SCSI_SCAN_ASYNC
It's user configurable, so it's rude to select it. It can also be disabled on the kernel command line, so this seems like a fragile solution. cheers