raid5-cache: new helper: r5_reserve_log_entry
Factor out code to reserve log space.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 8875828..ea20d74 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -271,6 +271,23 @@
return bio;
}
+static void r5_reserve_log_entry(struct r5l_log *log, struct r5l_io_unit *io)
+{
+ log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS);
+
+ /*
+ * If we filled up the log device start from the beginning again,
+ * which will require a new bio.
+ *
+ * Note: for this to work properly the log size needs to me a multiple
+ * of BLOCK_SECTORS.
+ */
+ if (log->log_start == 0)
+ io->current_bio = NULL;
+
+ io->log_end = log->log_start;
+}
+
static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log)
{
struct r5l_io_unit *io;
@@ -299,11 +316,7 @@
bio_add_page(io->current_bio, io->meta_page, PAGE_SIZE, 0);
log->seq++;
- log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS);
- io->log_end = log->log_start;
- /* current bio hit disk end */
- if (log->log_start == 0)
- io->current_bio = NULL;
+ r5_reserve_log_entry(log, io);
spin_lock_irq(&log->io_list_lock);
list_add_tail(&io->log_sibling, &log->running_ios);
@@ -357,13 +370,8 @@
io->current_bio = NULL;
goto alloc_bio;
}
- log->log_start = r5l_ring_add(log, log->log_start,
- BLOCK_SECTORS);
- /* current bio hit disk end */
- if (log->log_start == 0)
- io->current_bio = NULL;
- io->log_end = log->log_start;
+ r5_reserve_log_entry(log, io);
}
static void r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh,