Messages in this thread | | | Date | Wed, 15 Jun 2022 14:44:54 +0100 | From | John Garry <> | Subject | Re: [PATCH RFC v2 02/18] scsi: core: Resurrect scsi_{get,free}_host_dev() |
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On 14/06/2022 20:33, Bart Van Assche wrote:
Hi Bart,
> On 6/9/22 03:29, John Garry wrote: >> +/** >> + * scsi_get_host_dev - Create a scsi_device that points to the host >> adapter itself > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > What does this mean? That part of the function description is not > clear to me. >
Agreed, this text is just as it was before (it was originally deleted) but I can fix it up to make sense.
>> + * @shost: Host that needs a scsi_device > ^^^^^^^^^^^^^ > This is not detailed enough. Consider changing "a scsi_device" into > "a scsi device for allocating reserved commands from". > >> + * >> + * Lock status: None assumed. >> + * >> + * Returns: The scsi_device or NULL >> + * >> + * Notes: >> + * Attach a single scsi_device to the Scsi_Host - this should >> + * be made to look like a "pseudo-device" that points to the >> + * HA itself. >> + * >> + * Note - this device is not accessible from any high-level >> + * drivers (including generics), which is probably not >> + * optimal. We can add hooks later to attach. > > The "which is probably not optimal. We can add hooks later to attach." > part probably should be moved to the patch description.
ok
> >> + */ >> +struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost) >> +{ >> + struct scsi_device *sdev = NULL; >> + struct scsi_target *starget; >> + >> + mutex_lock(&shost->scan_mutex); >> + if (!scsi_host_scan_allowed(shost)) >> + goto out; >> + starget = scsi_alloc_target(&shost->shost_gendev, 0, >> shost->this_id); > > ^^^^^^^^^^^^^^^^^^ > Is it guaranteed that this channel / id combination will not be used for > any other SCSI device?
Does it matter if the parent device is different?
> > What if shost->this_id == -1? > >> + if (!starget) >> + goto out; >> + >> + sdev = scsi_alloc_sdev(starget, 0, NULL); >> + if (sdev) >> + sdev->borken = 0; >> + else >> + scsi_target_reap(starget); >> + put_device(&starget->dev); >> + out: >> + mutex_unlock(&shost->scan_mutex); >> + return sdev; >> +} >> +EXPORT_SYMBOL(scsi_get_host_dev); > > Elsewhere in the SCSI core "get..dev" means increment the reference > count of > a SCSI device. Maybe scsi_alloc_host_dev() is a better name?
I think that the intention is to only use this once for a shost, i.e. get or allocate that scsi_device once and use it for the lifetime of the shost. But I can rename if you think it's better.
> >> +/* >> + * These two functions are used to allocate and free a pseudo device >> + * which will connect to the host adapter itself rather than any >> + * physical device. You must deallocate when you are done with the >> + * thing. This physical pseudo-device isn't real and won't be available >> + * from any high-level drivers. >> + */ > > Please keep function comments in .c files because that makes it more likely > that the comment and the implementation will remain in sync. >
fine, I can relocate this.
Thanks, John
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