kvm tools, qcow: Move L2 cache to 'struct qcow_l1_table'

In preparation for refcount block cache, move L2 cache data structures to
'struct qcow_l1_table'.

Cc: Prasad Joshi <prasadjoshi124@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --git a/tools/kvm/disk/qcow.c b/tools/kvm/disk/qcow.c
index ff2892a22fb92b00d01ddafab1d5c5419b63c066..fee2136246c899e7ada8dd390d06e18f73455953 100644 (file)
--- a/tools/kvm/disk/qcow.c
+++ b/tools/kvm/disk/qcow.c
@@ -71,13 +71,13 @@ out:
        return NULL;
 }
 
-static void free_cache(struct qcow *q)
+static void free_cache(struct qcow_l1_table *l1t)
 {
+       struct rb_root *r = &l1t->root;
        struct list_head *pos, *n;
        struct qcow_l2_table *t;
-       struct rb_root *r = &q->root;
 
-       list_for_each_safe(pos, n, &q->lru_list) {
+       list_for_each_safe(pos, n, &l1t->lru_list) {
                /* Remove cache table from the list and RB tree */
                list_del(pos);
                t = list_entry(pos, struct qcow_l2_table, list);
@@ -108,15 +108,16 @@ static int qcow_l2_cache_write(struct qcow *q, struct qcow_l2_table *c)
 
 static int cache_table(struct qcow *q, struct qcow_l2_table *c)
 {
-       struct rb_root *r = &q->root;
+       struct qcow_l1_table *l1t = &q->table;
+       struct rb_root *r = &l1t->root;
        struct qcow_l2_table *lru;
 
-       if (q->nr_cached == MAX_CACHE_NODES) {
+       if (l1t->nr_cached == MAX_CACHE_NODES) {
                /*
                 * The node at the head of the list is least recently used
                 * node. Remove it from the list and replaced with a new node.
                 */
-               lru = list_first_entry(&q->lru_list, struct qcow_l2_table, list);
+               lru = list_first_entry(&l1t->lru_list, struct qcow_l2_table, list);
 
                if (qcow_l2_cache_write(q, lru) < 0)
                        goto error;
@@ -124,7 +125,7 @@ static int cache_table(struct qcow *q, struct qcow_l2_table *c)
                /* Remove the node from the cache */
                rb_erase(&lru->node, r);
                list_del_init(&lru->list);
-               q->nr_cached--;
+               l1t->nr_cached--;
 
                /* Free the LRUed node */
                free(lru);
@@ -135,8 +136,8 @@ static int cache_table(struct qcow *q, struct qcow_l2_table *c)
                goto error;
 
        /* Add in LRU replacement list */
-       list_add_tail(&c->list, &q->lru_list);
-       q->nr_cached++;
+       list_add_tail(&c->list, &l1t->lru_list);
+       l1t->nr_cached++;
 
        return 0;
 error:
@@ -145,14 +146,15 @@ error:
 
 static struct qcow_l2_table *search_table(struct qcow *q, u64 offset)
 {
+       struct qcow_l1_table *l1t = &q->table;
        struct qcow_l2_table *l2t;
 
-       l2t = search(&q->root, offset);
+       l2t = search(&l1t->root, offset);
        if (!l2t)
                return NULL;
 
        /* Update the LRU state, by moving the searched node to list tail */
-       list_move_tail(&l2t->list, &q->lru_list);
+       list_move_tail(&l2t->list, &l1t->lru_list);
 
        return l2t;
 }
@@ -547,14 +549,14 @@ static int qcow_disk_flush(struct disk_image *disk)
        struct qcow *q = disk->priv;
        struct qcow_header *header;
        struct list_head *pos, *n;
-       struct qcow_l1_table *table;
+       struct qcow_l1_table *l1t;
 
-       header  = q->header;
-       table   = &q->table;
+       header = q->header;
+       l1t = &q->table;
 
        mutex_lock(&q->mutex);
 
-       list_for_each_safe(pos, n, &q->lru_list) {
+       list_for_each_safe(pos, n, &l1t->lru_list) {
                struct qcow_l2_table *c = list_entry(pos, struct qcow_l2_table, list);
 
                if (qcow_l2_cache_write(q, c) < 0)
@@ -564,7 +566,7 @@ static int qcow_disk_flush(struct disk_image *disk)
        if (fdatasync(disk->fd) < 0)
                goto error_unlock;
 
-       if (pwrite_in_full(disk->fd, table->l1_table, table->table_size * sizeof(u64), header->l1_table_offset) < 0)
+       if (pwrite_in_full(disk->fd, l1t->l1_table, l1t->table_size * sizeof(u64), header->l1_table_offset) < 0)
                goto error_unlock;
 
        mutex_unlock(&q->mutex);
@@ -585,7 +587,7 @@ static int qcow_disk_close(struct disk_image *disk)
 
        q = disk->priv;
 
-       free_cache(q);
+       free_cache(&q->table);
        free(q->table.l1_table);
        free(q->header);
        free(q);
@@ -661,9 +663,10 @@ static void *qcow2_read_header(int fd)
 
 static struct disk_image *qcow2_probe(int fd, bool readonly)
 {
-       struct qcow *q;
-       struct qcow_header *h;
        struct disk_image *disk_image;
+       struct qcow_l1_table *l1t;
+       struct qcow_header *h;
+       struct qcow *q;
 
        q = calloc(1, sizeof(struct qcow));
        if (!q)
@@ -671,8 +674,11 @@ static struct disk_image *qcow2_probe(int fd, bool readonly)
 
        mutex_init(&q->mutex);
        q->fd = fd;
-       q->root = RB_ROOT;
-       INIT_LIST_HEAD(&q->lru_list);
+
+       l1t = &q->table;
+
+       l1t->root = RB_ROOT;
+       INIT_LIST_HEAD(&l1t->lru_list);
 
        h = q->header = qcow2_read_header(fd);
        if (!h)
@@ -760,9 +766,10 @@ static void *qcow1_read_header(int fd)
 
 static struct disk_image *qcow1_probe(int fd, bool readonly)
 {
-       struct qcow *q;
-       struct qcow_header *h;
        struct disk_image *disk_image;
+       struct qcow_l1_table *l1t;
+       struct qcow_header *h;
+       struct qcow *q;
 
        q = calloc(1, sizeof(struct qcow));
        if (!q)
@@ -770,8 +777,11 @@ static struct disk_image *qcow1_probe(int fd, bool readonly)
 
        mutex_init(&q->mutex);
        q->fd = fd;
-       q->root = RB_ROOT;
-       INIT_LIST_HEAD(&q->lru_list);
+
+       l1t = &q->table;
+
+       l1t->root = RB_ROOT;
+       INIT_LIST_HEAD(&l1t->lru_list);
 
        h = q->header = qcow1_read_header(fd);
        if (!h)

diff --git a/tools/kvm/include/kvm/qcow.h b/tools/kvm/include/kvm/qcow.h
index 64629439981fb5de7b69f56bc9f61aabf0cc1e9f..4ddc2b2cba22f119ffc89d654bbf96a9f76290e3 100644 (file)
--- a/tools/kvm/include/kvm/qcow.h
+++ b/tools/kvm/include/kvm/qcow.h
@@ -33,6 +33,11 @@ struct qcow_l2_table {
 struct qcow_l1_table {
        u32                             table_size;
        u64                             *l1_table;
+
+       /* Level2 caching data structures */
+       struct rb_root                  root;
+       struct list_head                lru_list;
+       int                             nr_cached;
 };
 
 struct qcow {
@@ -40,11 +45,6 @@ struct qcow {
        void                            *header;
        struct qcow_l1_table            table;
        int                             fd;
-
-       /* Level2 caching data structures */
-       struct rb_root                  root;
-       struct list_head                lru_list;
-       int                             nr_cached;
 };
 
 struct qcow_header {