linux-kernel - [PATCH v2 4/5] xen/blkback: move persistent grants flags to bool

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Date:   Wed,  8 Aug 2018 16:25:27 +0200
From:   Juergen Gross <jgross@...e.com>
To:     linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org,
        linux-block@...r.kernel.org
Cc:     konrad.wilk@...cle.com, roger.pau@...rix.com, axboe@...nel.dk,
        boris.ostrovsky@...cle.com, Juergen Gross <jgross@...e.com>
Subject: [PATCH v2 4/5] xen/blkback: move persistent grants flags to bool

The struct persistent_gnt flags member is meant to be a bitfield of
different flags. There is only PERSISTENT_GNT_ACTIVE flag left, so
convert it to a bool named "active".

Signed-off-by: Juergen Gross <jgross@...e.com>
---
 drivers/block/xen-blkback/blkback.c | 13 ++++++-------
 drivers/block/xen-blkback/common.h  |  7 +------
 2 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index f341ac84b853..2483931a3e01 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -255,8 +255,7 @@ static int add_persistent_gnt(struct xen_blkif_ring *ring,
 		}
 	}
 
-	bitmap_zero(persistent_gnt->flags, PERSISTENT_GNT_FLAGS_SIZE);
-	set_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags);
+	persistent_gnt->active = true;
 	/* Add new node and rebalance tree. */
 	rb_link_node(&(persistent_gnt->node), parent, new);
 	rb_insert_color(&(persistent_gnt->node), &ring->persistent_gnts);
@@ -280,11 +279,11 @@ static struct persistent_gnt *get_persistent_gnt(struct xen_blkif_ring *ring,
 		else if (gref > data->gnt)
 			node = node->rb_right;
 		else {
-			if(test_bit(PERSISTENT_GNT_ACTIVE, data->flags)) {
+			if (data->active) {
 				pr_alert_ratelimited("requesting a grant already in use\n");
 				return NULL;
 			}
-			set_bit(PERSISTENT_GNT_ACTIVE, data->flags);
+			data->active = true;
 			atomic_inc(&ring->persistent_gnt_in_use);
 			return data;
 		}
@@ -295,10 +294,10 @@ static struct persistent_gnt *get_persistent_gnt(struct xen_blkif_ring *ring,
 static void put_persistent_gnt(struct xen_blkif_ring *ring,
                                struct persistent_gnt *persistent_gnt)
 {
-	if(!test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags))
+	if (!persistent_gnt->active)
 		pr_alert_ratelimited("freeing a grant already unused\n");
 	persistent_gnt->last_used = jiffies;
-	clear_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags);
+	persistent_gnt->active = false;
 	atomic_dec(&ring->persistent_gnt_in_use);
 }
 
@@ -429,7 +428,7 @@ static void purge_persistent_gnt(struct xen_blkif_ring *ring)
 		BUG_ON(persistent_gnt->handle ==
 			BLKBACK_INVALID_HANDLE);
 
-		if (test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags))
+		if (persistent_gnt->active)
 			continue;
 		if (!scan_used && !persistent_gnt_timeout(persistent_gnt))
 			continue;
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 7bff72db3b7e..2339b8d39c5e 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -233,11 +233,6 @@ struct xen_vbd {
 
 struct backend_info;
 
-/* Number of available flags */
-#define PERSISTENT_GNT_FLAGS_SIZE	1
-/* This persistent grant is currently in use */
-#define PERSISTENT_GNT_ACTIVE		0
-
 /* Number of requests that we can fit in a ring */
 #define XEN_BLKIF_REQS_PER_PAGE		32
 
@@ -246,7 +241,7 @@ struct persistent_gnt {
 	grant_ref_t gnt;
 	grant_handle_t handle;
 	unsigned long last_used;
-	DECLARE_BITMAP(flags, PERSISTENT_GNT_FLAGS_SIZE);
+	bool active;
 	struct rb_node node;
 	struct list_head remove_node;
 };
-- 
2.13.7