From: Michael Ellerman <mpe@ellerman.id.au>
To: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>,
"Manoj N . Kumar" <manoj@linux.vnet.ibm.com>
Cc: linux-scsi@vger.kernel.org,
"Matthew R . Ochs" <mrochs@linux.vnet.ibm.com>,
Vaibhav Jain <vaibhav@linux.vnet.ibm.com>,
Frederic Barrat <fbarrat@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org,
Uma Krishnan <ukrishn@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] scsi: cxlflash: Select SCSI_SCAN_ASYNC
Date: Tue, 20 Feb 2018 19:56:35 +1100 [thread overview]
Message-ID: <87sh9wrqd8.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <20180219071037.27938-1-vaibhav@linux.vnet.ibm.com>
Vaibhav Jain <vaibhav@linux.vnet.ibm.com> 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.
> 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
next prev parent reply other threads:[~2018-02-20 8:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-19 7:10 Vaibhav Jain
2018-02-20 8:56 ` Michael Ellerman [this message]
2018-02-21 3:23 ` Matthew R. Ochs
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