Re: [PATCH 2/2] xen/scsiback: avoid warnings when adding multiple LUNs to a domain

From: Boris Ostrovsky
Date: Fri Feb 05 2016 - 12:24:52 EST




On 02/05/2016 11:59 AM, Juergen Gross wrote:
On 05/02/16 16:50, Boris Ostrovsky wrote:

On 02/05/2016 08:21 AM, Juergen Gross wrote:
When adding more than one LUN to a frontend a warning for a failed
assignment is issued in dom0 for each already existing LUN. Avoid this
warning.
Aren't you just factoring out the check? The warning is still printed
for each scsiback_add_translation_entry() invocation, no?
I don't call scsiback_add_translation_entry() in the critical case.

Which is scsiback_do_add_lun()? If yes then perhaps you could mention it in the commit message since there are few changes that this patch provides and it's not clear which is the one that prevents the warning.


@@ -962,33 +973,31 @@ static int scsiback_del_translation_entry(struct
vscsibk_info *info,
struct ids_tuple *v)
{
struct v2p_entry *entry;
- struct list_head *head = &(info->v2p_entry_lists);
unsigned long flags;
spin_lock_irqsave(&info->v2p_lock, flags);
/* Find out the translation entry specified */
- list_for_each_entry(entry, head, l) {
- if ((entry->v.chn == v->chn) &&
- (entry->v.tgt == v->tgt) &&
- (entry->v.lun == v->lun)) {
- goto found;
- }
- }
-
- spin_unlock_irqrestore(&info->v2p_lock, flags);
- return 1;
-
-found:
- /* Delete the translation entry specfied */
- __scsiback_del_translation_entry(entry);
+ entry = scsiback_chk_translation_entry(info, v);
+ if (entry)
+ __scsiback_del_translation_entry(entry);
spin_unlock_irqrestore(&info->v2p_lock, flags);
- return 0;
+ return entry == NULL;
Might be better to return -ENOENT instead of 1 above and -EEXISTS if
entry!=NULL, given that this returns an int.
I just didn't want to change more than necessary. In case it is
okay to do some cleanup as well I'd rather change the return type
to "bool".

I don't think using error code will require changing anything except the last line above (which is already a change anyway)

But using a bool is OK too.

-boris