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From: Aditya Pakki <pakki001@umn.edu>
To: pakki001@umn.edu
Cc: kjlu@umn.edu, Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Subject: [PATCH] xen/grant-table: remove unnecessary BUG_ON on gnttab_interface
Date: Sun, 15 Dec 2019 14:13:21 -0600	[thread overview]
Message-ID: <20191215201321.7439-1-pakki001@umn.edu> (raw)

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


WARNING: multiple messages have this Message-ID (diff)
From: Aditya Pakki <pakki001@umn.edu>
To: pakki001@umn.edu
Cc: Juergen Gross <jgross@suse.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	kjlu@umn.edu, linux-kernel@vger.kernel.org,
	xen-devel@lists.xenproject.org,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: [Xen-devel] [PATCH] xen/grant-table: remove unnecessary BUG_ON on gnttab_interface
Date: Sun, 15 Dec 2019 14:13:21 -0600	[thread overview]
Message-ID: <20191215201321.7439-1-pakki001@umn.edu> (raw)

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


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             reply	other threads:[~2019-12-15 20:13 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-15 20:13 Aditya Pakki [this message]
2019-12-15 20:13 ` [Xen-devel] [PATCH] xen/grant-table: remove unnecessary BUG_ON on gnttab_interface Aditya Pakki
2019-12-16  7:38 ` Jürgen Groß
2019-12-16  7:38   ` [Xen-devel] " Jürgen Groß

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