Do not block the submitting thread when handling a SYNCHRONIZE CACHE command,
but implement it asynchronously by sending the FLUSH command ourself and
calling transport_complete_sync_cache from the completion handler.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: lio-core/drivers/target/target_core_iblock.c
===================================================================
--- lio-core.orig/drivers/target/target_core_iblock.c 2011-10-13 12:16:31.756397481 +0200
+++ lio-core/drivers/target/target_core_iblock.c 2011-10-13 12:19:49.127894821 +0200
@@ -313,37 +313,42 @@ static unsigned long long iblock_emulate
return blocks_long;
}
+static void iblock_end_io_flush(struct bio *bio, int err)
+{
+ struct se_cmd *cmd = bio->bi_private;
+
+ if (err)
+ pr_err("IBLOCK: cache flush failed: %d\n", err);
+
+ if (cmd)
+ transport_complete_sync_cache(cmd, err == 0);
+ bio_put(bio);
+}
+
/*
- * Emulate SYCHRONIZE_CACHE_*
+ * Implement SYCHRONIZE CACHE. Note that we can handle lba ranges and must
+ * always flush the whole cache.
*/
static void iblock_emulate_sync_cache(struct se_task *task)
{
struct se_cmd *cmd = task->task_se_cmd;
struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
int immed = (cmd->t_task_cdb[1] & 0x2);
- sector_t error_sector;
- int ret;
+ struct bio *bio;
/*
* If the Immediate bit is set, queue up the GOOD response
- * for this SYNCHRONIZE_CACHE op
+ * for this SYNCHRONIZE_CACHE op.
*/
if (immed)
transport_complete_sync_cache(cmd, 1);
- /*
- * blkdev_issue_flush() does not support a specifying a range, so
- * we have to flush the entire cache.
- */
- ret = blkdev_issue_flush(ib_dev->ibd_bd, GFP_KERNEL, &error_sector);
- if (ret != 0) {
- pr_err("IBLOCK: block_issue_flush() failed: %d "
- " error_sector: %llu\n", ret,
- (unsigned long long)error_sector);
- }
-
+ bio = bio_alloc(GFP_KERNEL, 0);
+ bio->bi_end_io = iblock_end_io_flush;
+ bio->bi_bdev = ib_dev->ibd_bd;
if (!immed)
- transport_complete_sync_cache(cmd, ret == 0);
+ bio->bi_private = cmd;
+ submit_bio(WRITE_FLUSH, bio);
}
/*
--
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