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author | Alberto Garcia <berto@igalia.com> | 2015-05-11 15:54:54 +0300 |
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committer | Kevin Wolf <kwolf@redhat.com> | 2015-05-22 17:08:01 +0200 |
commit | baf07d60f5c5d5d0f0c9e844cde75691f1ceb3d1 (patch) | |
tree | 795df88d7f949ffd0ccc8f93463383d3a3e6cf6f /block/qcow2-cache.c | |
parent | 72e80b89015bab196f0f0e83b12b0eee75fa0574 (diff) | |
download | qemu-baf07d60f5c5d5d0f0c9e844cde75691f1ceb3d1.zip qemu-baf07d60f5c5d5d0f0c9e844cde75691f1ceb3d1.tar.gz qemu-baf07d60f5c5d5d0f0c9e844cde75691f1ceb3d1.tar.bz2 |
qcow2: simplify qcow2_cache_put() and qcow2_cache_entry_mark_dirty()
Since all tables are now stored together, it is possible to obtain
the position of a particular table directly from its address, so the
operation becomes O(1).
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/qcow2-cache.c')
-rw-r--r-- | block/qcow2-cache.c | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c index f0dfb69..6e78c8f 100644 --- a/block/qcow2-cache.c +++ b/block/qcow2-cache.c @@ -49,6 +49,16 @@ static inline void *qcow2_cache_get_table_addr(BlockDriverState *bs, return (uint8_t *) c->table_array + (size_t) table * s->cluster_size; } +static inline int qcow2_cache_get_table_idx(BlockDriverState *bs, + Qcow2Cache *c, void *table) +{ + BDRVQcowState *s = bs->opaque; + ptrdiff_t table_offset = (uint8_t *) table - (uint8_t *) c->table_array; + int idx = table_offset / s->cluster_size; + assert(idx >= 0 && idx < c->size && table_offset % s->cluster_size == 0); + return idx; +} + Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables) { BDRVQcowState *s = bs->opaque; @@ -337,16 +347,12 @@ int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table) { - int i; + int i = qcow2_cache_get_table_idx(bs, c, *table); - for (i = 0; i < c->size; i++) { - if (qcow2_cache_get_table_addr(bs, c, i) == *table) { - goto found; - } + if (c->entries[i].offset == 0) { + return -ENOENT; } - return -ENOENT; -found: c->entries[i].ref--; *table = NULL; @@ -357,15 +363,7 @@ found: void qcow2_cache_entry_mark_dirty(BlockDriverState *bs, Qcow2Cache *c, void *table) { - int i; - - for (i = 0; i < c->size; i++) { - if (qcow2_cache_get_table_addr(bs, c, i) == table) { - goto found; - } - } - abort(); - -found: + int i = qcow2_cache_get_table_idx(bs, c, table); + assert(c->entries[i].offset != 0); c->entries[i].dirty = true; } |