Re: [PATCH v2 2/3] scsi: ufs: Modulize ufs-bsg

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 12/15/19 8:36 PM, cang@xxxxxxxxxxxxxx wrote:
On 2019-12-16 05:49, Bart Van Assche wrote:
On 2019-12-11 22:37, Bjorn Andersson wrote:
It's the asymmetry that I don't like.

Perhaps if you instead make ufshcd platform_device_register_data() the
bsg device you would solve the probe ordering, the remove will be
symmetric and module autoloading will work as well (although then you
need a MODULE_ALIAS of platform:device-name).

Hi Bjorn,

From Documentation/driver-api/driver-model/platform.rst:
"Platform devices are devices that typically appear as autonomous
entities in the system. This includes legacy port-based devices and
host bridges to peripheral buses, and most controllers integrated
into system-on-chip platforms.  What they usually have in common
is direct addressing from a CPU bus.  Rarely, a platform_device will
be connected through a segment of some other kind of bus; but its
registers will still be directly addressable."

Do you agree that the above description is not a good match for the
ufs-bsg kernel module?

I missed this one.
How about making it a plain device and add it from ufs driver?

Hi Can,

Since the ufs_bsg kernel module already creates one device node under /dev/bsg for each UFS host I don't think that we need to create any additional device nodes for ufs-bsg devices. My proposal is to modify the original patch 2/3 from this series as follows:
* Use module_init() instead of late_initcall_sync().
* Remove the ufshcd_get_hba_list_lock() and
  ufshcd_put_hba_list_unlock() functions.
* Implement a notification mechanism in the UFS core that invokes a
  callback function after an UFS host has been created and also after an
  UFS host has been removed.
* Register for these notifications from inside the ufs-bsg driver.
* During registration for notifications, invoke the UFS host creation
  callback function for all known UFS hosts.
* If the UFS core is unloaded, invoke the UFS host removal callback
  function for all known UFS hosts.

I think there are several examples of similar notification mechanisms in the Linux kernel, e.g. the probe and remove callback functions in struct pci_driver.

Bart.



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Linux IIO]     [Samba]     [Device Mapper]

  Powered by Linux