* [PATCH] xen/grant-table: remove unnecessary BUG_ON on gnttab_interface
@ 2019-12-15 20:13 ` Aditya Pakki
0 siblings, 0 replies; 4+ messages in thread
From: Aditya Pakki @ 2019-12-15 20:13 UTC (permalink / raw)
To: pakki001
Cc: kjlu, Boris Ostrovsky, Juergen Gross, Stefano Stabellini,
xen-devel, linux-kernel
grow_gnttab_list() checks for NULL on gnttab_interface immediately
after gnttab_expand() check. The patch removes the redundant assertion
and replaces the BUG_ON call with recovery code.
Signed-off-by: Aditya Pakki <pakki001@umn.edu>
---
drivers/xen/grant-table.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 49b381e104ef..f59694c352be 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -664,7 +664,6 @@ static int grow_gnttab_list(unsigned int more_frames)
unsigned int nr_glist_frames, new_nr_glist_frames;
unsigned int grefs_per_frame;
- BUG_ON(gnttab_interface == NULL);
grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
new_nr_grant_frames = nr_grant_frames + more_frames;
@@ -1388,7 +1387,9 @@ static int gnttab_expand(unsigned int req_entries)
int rc;
unsigned int cur, extra;
- BUG_ON(gnttab_interface == NULL);
+ if (!gnttab_interface)
+ return -EINVAL;
+
cur = nr_grant_frames;
extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
gnttab_interface->grefs_per_grant_frame);
@@ -1423,7 +1424,9 @@ int gnttab_init(void)
/* Determine the maximum number of frames required for the
* grant reference free list on the current hypervisor.
*/
- BUG_ON(gnttab_interface == NULL);
+ if (!gnttab_interface)
+ return -EINVAL;
+
max_nr_glist_frames = (max_nr_grant_frames *
gnttab_interface->grefs_per_grant_frame / RPP);
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [Xen-devel] [PATCH] xen/grant-table: remove unnecessary BUG_ON on gnttab_interface
@ 2019-12-15 20:13 ` Aditya Pakki
0 siblings, 0 replies; 4+ messages in thread
From: Aditya Pakki @ 2019-12-15 20:13 UTC (permalink / raw)
To: pakki001
Cc: Juergen Gross, Stefano Stabellini, kjlu, linux-kernel, xen-devel,
Boris Ostrovsky
grow_gnttab_list() checks for NULL on gnttab_interface immediately
after gnttab_expand() check. The patch removes the redundant assertion
and replaces the BUG_ON call with recovery code.
Signed-off-by: Aditya Pakki <pakki001@umn.edu>
---
drivers/xen/grant-table.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 49b381e104ef..f59694c352be 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -664,7 +664,6 @@ static int grow_gnttab_list(unsigned int more_frames)
unsigned int nr_glist_frames, new_nr_glist_frames;
unsigned int grefs_per_frame;
- BUG_ON(gnttab_interface == NULL);
grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
new_nr_grant_frames = nr_grant_frames + more_frames;
@@ -1388,7 +1387,9 @@ static int gnttab_expand(unsigned int req_entries)
int rc;
unsigned int cur, extra;
- BUG_ON(gnttab_interface == NULL);
+ if (!gnttab_interface)
+ return -EINVAL;
+
cur = nr_grant_frames;
extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
gnttab_interface->grefs_per_grant_frame);
@@ -1423,7 +1424,9 @@ int gnttab_init(void)
/* Determine the maximum number of frames required for the
* grant reference free list on the current hypervisor.
*/
- BUG_ON(gnttab_interface == NULL);
+ if (!gnttab_interface)
+ return -EINVAL;
+
max_nr_glist_frames = (max_nr_grant_frames *
gnttab_interface->grefs_per_grant_frame / RPP);
--
2.20.1
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] xen/grant-table: remove unnecessary BUG_ON on gnttab_interface
2019-12-15 20:13 ` [Xen-devel] " Aditya Pakki
@ 2019-12-16 7:38 ` Jürgen Groß
-1 siblings, 0 replies; 4+ messages in thread
From: Jürgen Groß @ 2019-12-16 7:38 UTC (permalink / raw)
To: Aditya Pakki
Cc: kjlu, Boris Ostrovsky, Stefano Stabellini, xen-devel, linux-kernel
On 15.12.19 21:13, Aditya Pakki wrote:
> grow_gnttab_list() checks for NULL on gnttab_interface immediately
> after gnttab_expand() check. The patch removes the redundant assertion
> and replaces the BUG_ON call with recovery code.
>
> Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> ---
> drivers/xen/grant-table.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> index 49b381e104ef..f59694c352be 100644
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -664,7 +664,6 @@ static int grow_gnttab_list(unsigned int more_frames)
> unsigned int nr_glist_frames, new_nr_glist_frames;
> unsigned int grefs_per_frame;
>
> - BUG_ON(gnttab_interface == NULL);
> grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
>
> new_nr_grant_frames = nr_grant_frames + more_frames;
> @@ -1388,7 +1387,9 @@ static int gnttab_expand(unsigned int req_entries)
> int rc;
> unsigned int cur, extra;
>
> - BUG_ON(gnttab_interface == NULL);
> + if (!gnttab_interface)
> + return -EINVAL;
> +
> cur = nr_grant_frames;
> extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
> gnttab_interface->grefs_per_grant_frame);
> @@ -1423,7 +1424,9 @@ int gnttab_init(void)
> /* Determine the maximum number of frames required for the
> * grant reference free list on the current hypervisor.
> */
> - BUG_ON(gnttab_interface == NULL);
> + if (!gnttab_interface)
> + return -EINVAL;
> +
I'd just remove the BUG_ON().
gnttab_request_version() called some lines up always sets
gnttab_interface.
The BUG_ON() in nr_status_frames() can be removed, too. It is either
called by v2 specific functions (for those to be reached
gnttab_interface must be set) or by gnttab_init() (reasoning see
above).
Juergen
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Xen-devel] [PATCH] xen/grant-table: remove unnecessary BUG_ON on gnttab_interface
@ 2019-12-16 7:38 ` Jürgen Groß
0 siblings, 0 replies; 4+ messages in thread
From: Jürgen Groß @ 2019-12-16 7:38 UTC (permalink / raw)
To: Aditya Pakki
Cc: xen-devel, Boris Ostrovsky, Stefano Stabellini, kjlu, linux-kernel
On 15.12.19 21:13, Aditya Pakki wrote:
> grow_gnttab_list() checks for NULL on gnttab_interface immediately
> after gnttab_expand() check. The patch removes the redundant assertion
> and replaces the BUG_ON call with recovery code.
>
> Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> ---
> drivers/xen/grant-table.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> index 49b381e104ef..f59694c352be 100644
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -664,7 +664,6 @@ static int grow_gnttab_list(unsigned int more_frames)
> unsigned int nr_glist_frames, new_nr_glist_frames;
> unsigned int grefs_per_frame;
>
> - BUG_ON(gnttab_interface == NULL);
> grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
>
> new_nr_grant_frames = nr_grant_frames + more_frames;
> @@ -1388,7 +1387,9 @@ static int gnttab_expand(unsigned int req_entries)
> int rc;
> unsigned int cur, extra;
>
> - BUG_ON(gnttab_interface == NULL);
> + if (!gnttab_interface)
> + return -EINVAL;
> +
> cur = nr_grant_frames;
> extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
> gnttab_interface->grefs_per_grant_frame);
> @@ -1423,7 +1424,9 @@ int gnttab_init(void)
> /* Determine the maximum number of frames required for the
> * grant reference free list on the current hypervisor.
> */
> - BUG_ON(gnttab_interface == NULL);
> + if (!gnttab_interface)
> + return -EINVAL;
> +
I'd just remove the BUG_ON().
gnttab_request_version() called some lines up always sets
gnttab_interface.
The BUG_ON() in nr_status_frames() can be removed, too. It is either
called by v2 specific functions (for those to be reached
gnttab_interface must be set) or by gnttab_init() (reasoning see
above).
Juergen
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-12-16 7:38 UTC | newest]
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2019-12-15 20:13 [PATCH] xen/grant-table: remove unnecessary BUG_ON on gnttab_interface Aditya Pakki
2019-12-15 20:13 ` [Xen-devel] " Aditya Pakki
2019-12-16 7:38 ` Jürgen Groß
2019-12-16 7:38 ` [Xen-devel] " Jürgen Groß
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