From: Steffen Maier <maier@linux.ibm.com>
To: asutoshd@codeaurora.org, linux-scsi@vger.kernel.org
Subject: Re: Query: SCSI Device node creation when UFS is loaded as a module
Date: Thu, 24 Oct 2019 11:50:26 +0200 [thread overview]
Message-ID: <d2804026-7908-4601-3216-e60d51131984@linux.ibm.com> (raw)
In-Reply-To: <468eb805fa69da76c88a0a37aa209c7f@codeaurora.org>
On 10/24/19 1:51 AM, asutoshd@codeaurora.org wrote:
> Hi
> I'm loading the ufs-qcom driver as a module but am not seeing the /dev/sda*
> device nodes.
> Looks like it's not being created.
>
> I find the sda nodes in other paths being enumerated though:
>
> / # find /sys -name sda
> /sys/kernel/debug/block/sda
> /sys/class/block/sda
> /sys/devices/platform/<...>/<xxx>.ufshc/host0/target0:0:0/0:0:0:0/block/sda
> /sys/block/sda
>
> All Luns are detected and I see sda is detected and prints for all the Luns as
> below -:
> sd 0:0:0:0: [sda] .... ....-byte logical blocks:
>
> ... so on ...
>
> But if I link it statically instead of a module, it works fine. All device
> nodes are created.
>
> I'm trying to figure out where/how in SCSI does it create these device nodes -
> /dev/sd<a/b/c/d> ?
That's from (systemd-)udevd user space based on uevents from the kernel.
> I've looked into sd.c but I couldn't figure out the exact place yet.
Yeah, based on the SCSI device probe and add lun, the high level driver sd
would emit udev events for block devices.
--
Mit freundlichen Gruessen / Kind regards
Steffen Maier
Linux on IBM Z Development
https://www.ibm.com/privacy/us/en/
IBM Deutschland Research & Development GmbH
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next prev parent reply other threads:[~2019-10-24 9:50 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-23 23:51 Query: SCSI Device node creation when UFS is loaded as a module asutoshd
2019-10-24 6:14 ` Avri Altman
2019-10-24 9:50 ` Steffen Maier [this message]
2019-10-24 17:05 ` asutoshd
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