[PATCH] gnttab: remove pointless NULL check

[PATCH] gnttab: remove pointless NULL check

[Jan Beulich]

[-- Attachment #1: Type: text/plain, Size: 938 bytes --]

Domains in the domain hash (and hence locatable via the usual lookup
functions) can't have a NULL grant table pointer; no other function
performs such a check, so remove it from gnttab_prepare_for_transfer()
for consistency.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -1390,17 +1390,11 @@ static int 
 gnttab_prepare_for_transfer(
     struct domain *rd, struct domain *ld, grant_ref_t ref)
 {
-    struct grant_table *rgt;
+    struct grant_table *rgt = rd->grant_table;
     grant_entry_header_t *sha;
     union grant_combo   scombo, prev_scombo, new_scombo;
     int                 retries = 0;
 
-    if ( unlikely((rgt = rd->grant_table) == NULL) )
-    {
-        gdprintk(XENLOG_INFO, "Dom %d has no grant table.\n", rd->domain_id);
-        return 0;
-    }
-
     spin_lock(&rgt->lock);
 
     if ( rgt->gt_version == 0 )




[-- Attachment #2: gnttab-pointless-check.patch --]
[-- Type: text/plain, Size: 971 bytes --]

gnttab: remove pointless NULL check

Domains in the domain hash (and hence locatable via the usual lookup
functions) can't have a NULL grant table pointer; no other function
performs such a check, so remove it from gnttab_prepare_for_transfer()
for consistency.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -1390,17 +1390,11 @@ static int 
 gnttab_prepare_for_transfer(
     struct domain *rd, struct domain *ld, grant_ref_t ref)
 {
-    struct grant_table *rgt;
+    struct grant_table *rgt = rd->grant_table;
     grant_entry_header_t *sha;
     union grant_combo   scombo, prev_scombo, new_scombo;
     int                 retries = 0;
 
-    if ( unlikely((rgt = rd->grant_table) == NULL) )
-    {
-        gdprintk(XENLOG_INFO, "Dom %d has no grant table.\n", rd->domain_id);
-        return 0;
-    }
-
     spin_lock(&rgt->lock);
 
     if ( rgt->gt_version == 0 )

[-- Attachment #3: Type: text/plain, Size: 126 bytes --]

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Re: [PATCH] gnttab: remove pointless NULL check

[Keir Fraser]

On 17/04/2012 13:34, "Jan Beulich" <JBeulich@suse.com> wrote:

> Domains in the domain hash (and hence locatable via the usual lookup
> functions) can't have a NULL grant table pointer; no other function
> performs such a check, so remove it from gnttab_prepare_for_transfer()
> for consistency.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Acked-by: Keir Fraser <keir@xen.org>

> --- a/xen/common/grant_table.c
> +++ b/xen/common/grant_table.c
> @@ -1390,17 +1390,11 @@ static int
>  gnttab_prepare_for_transfer(
>      struct domain *rd, struct domain *ld, grant_ref_t ref)
>  {
> -    struct grant_table *rgt;
> +    struct grant_table *rgt = rd->grant_table;
>      grant_entry_header_t *sha;
>      union grant_combo   scombo, prev_scombo, new_scombo;
>      int                 retries = 0;
>  
> -    if ( unlikely((rgt = rd->grant_table) == NULL) )
> -    {
> -        gdprintk(XENLOG_INFO, "Dom %d has no grant table.\n", rd->domain_id);
> -        return 0;
> -    }
> -
>      spin_lock(&rgt->lock);
>  
>      if ( rgt->gt_version == 0 )
> 
> 
> 
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