Avoid hitting the host-wide free_list lock unless we need to put a command back onto the freelist. Signed-off-by: Christoph Hellwig Acked-by: Hannes Reinecke --- drivers/scsi/scsi.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index d8afec8..fb86479 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -320,13 +320,14 @@ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd, { unsigned long flags; - /* changing locks here, don't need to restore the irq state */ - spin_lock_irqsave(&shost->free_list_lock, flags); if (unlikely(list_empty(&shost->free_list))) { - list_add(&cmd->list, &shost->free_list); - cmd = NULL; + spin_lock_irqsave(&shost->free_list_lock, flags); + if (list_empty(&shost->free_list)) { + list_add(&cmd->list, &shost->free_list); + cmd = NULL; + } + spin_unlock_irqrestore(&shost->free_list_lock, flags); } - spin_unlock_irqrestore(&shost->free_list_lock, flags); if (likely(cmd != NULL)) scsi_pool_free_command(shost->cmd_pool, cmd); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/