Commit 94568f64 authored by Artur Paszkiewicz's avatar Artur Paszkiewicz Committed by Shaohua Li
Browse files

raid5-ppl: move no_mem_stripes to struct ppl_conf 



Use a single no_mem_stripes list instead of per member device lists for
handling stripes that need retrying in case of failed io_unit
allocation. Because io_units are allocated from a memory pool shared
between all member disks, the no_mem_stripes list should be checked when
an io_unit for any member is freed. This fixes a deadlock that could
happen if there are stripes in more than one no_mem_stripes list.

Signed-off-by: default avatarArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 0c9d5b12

drivers/md/raid5-ppl.c

+23 −13
Original line number Diff line number Diff line
@@ -107,6 +107,10 @@ struct ppl_conf { 
	/* used only for recovery */

	int recovered_entries;

	int mismatch_count;



	/* stripes to retry if failed to allocate io_unit */

	struct list_head no_mem_stripes;

	spinlock_t no_mem_stripes_lock;

};



struct ppl_log {
@@ -119,8 +123,6 @@ struct ppl_log { 
					 * always at the end of io_list */

	spinlock_t io_list_lock;

	struct list_head io_list;	/* all io_units of this log */

	struct list_head no_mem_stripes;/* stripes to retry if failed to

					 * allocate io_unit */

};



#define PPL_IO_INLINE_BVECS 32
@@ -347,9 +349,9 @@ int ppl_write_stripe(struct r5conf *conf, struct stripe_head *sh) 
	atomic_inc(&sh->count);



	if (ppl_log_stripe(log, sh)) {

		spin_lock_irq(&log->io_list_lock);

		list_add_tail(&sh->log_list, &log->no_mem_stripes);

		spin_unlock_irq(&log->io_list_lock);

		spin_lock_irq(&ppl_conf->no_mem_stripes_lock);

		list_add_tail(&sh->log_list, &ppl_conf->no_mem_stripes);

		spin_unlock_irq(&ppl_conf->no_mem_stripes_lock);

	}



	mutex_unlock(&log->io_mutex);
@@ -492,25 +494,32 @@ void ppl_write_stripe_run(struct r5conf *conf) 
static void ppl_io_unit_finished(struct ppl_io_unit *io)

{

	struct ppl_log *log = io->log;

	struct ppl_conf *ppl_conf = log->ppl_conf;

	unsigned long flags;



	pr_debug("%s: seq: %llu\n", __func__, io->seq);



	spin_lock_irqsave(&log->io_list_lock, flags);

	local_irq_save(flags);



	spin_lock(&log->io_list_lock);

	list_del(&io->log_sibling);

	mempool_free(io, log->ppl_conf->io_pool);

	spin_unlock(&log->io_list_lock);



	mempool_free(io, ppl_conf->io_pool);



	spin_lock(&ppl_conf->no_mem_stripes_lock);

	if (!list_empty(&ppl_conf->no_mem_stripes)) {

		struct stripe_head *sh;



	if (!list_empty(&log->no_mem_stripes)) {

		struct stripe_head *sh = list_first_entry(&log->no_mem_stripes,

							  struct stripe_head,

							  log_list);

		sh = list_first_entry(&ppl_conf->no_mem_stripes,

				      struct stripe_head, log_list);

		list_del_init(&sh->log_list);

		set_bit(STRIPE_HANDLE, &sh->state);

		raid5_release_stripe(sh);

	}

	spin_unlock(&ppl_conf->no_mem_stripes_lock);



	spin_unlock_irqrestore(&log->io_list_lock, flags);

	local_irq_restore(flags);

}



void ppl_stripe_write_finished(struct stripe_head *sh)
@@ -1135,6 +1144,8 @@ int ppl_init_log(struct r5conf *conf) 
	}



	atomic64_set(&ppl_conf->seq, 0);

	INIT_LIST_HEAD(&ppl_conf->no_mem_stripes);

	spin_lock_init(&ppl_conf->no_mem_stripes_lock);



	if (!mddev->external) {

		ppl_conf->signature = ~crc32c_le(~0, mddev->uuid, sizeof(mddev->uuid));
@@ -1150,7 +1161,6 @@ int ppl_init_log(struct r5conf *conf) 
		mutex_init(&log->io_mutex);

		spin_lock_init(&log->io_list_lock);

		INIT_LIST_HEAD(&log->io_list);

		INIT_LIST_HEAD(&log->no_mem_stripes);



		log->ppl_conf = ppl_conf;

		log->rdev = rdev;

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