ocfs2: cluster: use an on-stack bio for the heartbeat write

The disk heartbeat write always covers this node's own single slot, i.e. 
one heartbeat block that lives within a single page.  It is submitted by
o2hb_issue_node_write() and waited on by the caller before the ctxt goes
out of scope, so its lifetime is well bounded.

Turn it into an on-stack bio embedded in struct o2hb_bio_wait_ctxt rather
than allocating one from the mempool.  This removes any allocation from
the fence-critical write path entirely: a delayed or blocked heartbeat
write is what leads to the local node being fenced, so it should not
depend on the state of a shared bio pool.

Because the bio is embedded rather than allocated, add a dedicated
o2hb_write_bio_end_io() that does not call bio_put(), and tear the bio
down with bio_uninit() once the caller has waited on the I/O.

The read path still allocates via o2hb_setup_one_bio() with GFP_NOFS,
since it issues a variable number of bios in a loop.

Link: https://lore.kernel.org/20260710071756.3586797-2-joseph.qi@linux.alibaba.com
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions