On 02/25/13 10:49, Jun'ichi Nomura wrote:
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 314a0e2..51fefb5 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1973,15 +1973,27 @@ static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
{
struct dm_md_mempools *p = dm_table_get_md_mempools(t);
- if (md->io_pool && (md->tio_pool || dm_table_get_type(t) == DM_TYPE_BIO_BASED) && md->bs) {
- /*
- * The md already has necessary mempools. Reload just the
- * bioset because front_pad may have changed because
- * a different table was loaded.
- */
- bioset_free(md->bs);
- md->bs = p->bs;
- p->bs = NULL;
+ if (md->io_pool && md->bs) {
+ /* The md already has necessary mempools. */
+ if (dm_table_get_type(t) == DM_TYPE_BIO_BASED) {
+ /*
+ * Reload bioset because front_pad may have changed
+ * because a different table was loaded.
+ */
+ bioset_free(md->bs);
+ md->bs = p->bs;
+ p->bs = NULL;
+ } else if (dm_table_get_type(t) == DM_TYPE_REQUEST_BASED) {
+ BUG_ON(!md->tio_pool);
+ /*
+ * No need to reload in case of request-based dm
+ * because of fixed size front_pad.
+ * Note for future: if you are to reload bioset,
+ * prep-ed requests in queue may have reference
+ * to bio from the old bioset.
+ * So you must walk through the queue to unprep.
+ */
+ }
goto out;
}
Without your patch my test failed after two or three iterations. With
your patch my test is still running after 53 iterations. So if you want
you can add Tested-by: Bart Van Assche <bvanassche@xxxxxxx>.
Your e-mail and the above patch are also interesting because these
explain why reverting to the v3.7 of drivers/md made my test succeed.
Note: even if this patch gets accepted I think it's still useful to
modify blk_run_queue() such that it converts recursion into iteration.
Bart.
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