From mboxrd@z Thu Jan 1 00:00:00 1970 From: keith.busch@intel.com (Keith Busch) Date: Thu, 31 Dec 2015 09:41:52 -0700 Subject: [PATCHv2 1/5] NVMe: Fix admin queue ring wrap In-Reply-To: <1451580116-12252-1-git-send-email-keith.busch@intel.com> References: <1451580116-12252-1-git-send-email-keith.busch@intel.com> Message-ID: <1451580116-12252-2-git-send-email-keith.busch@intel.com> The tag set queue depth needs to be one less than the h/w queue depth so we don't wrap the circular buffer. This conforms to the specification defined "Full Queue" condition. Signed-off-by: Keith Busch --- drivers/nvme/host/pci.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index b82bbea..67cb406 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -1271,7 +1271,12 @@ static int nvme_alloc_admin_tags(struct nvme_dev *dev) if (!dev->ctrl.admin_q) { dev->admin_tagset.ops = &nvme_mq_admin_ops; dev->admin_tagset.nr_hw_queues = 1; - dev->admin_tagset.queue_depth = NVME_AQ_BLKMQ_DEPTH; + + /* + * Subtract one to leave an empty queue entry for 'Full Queue' + * condition. See NVM-Express 1.2 specification, section 4.1.2. + */ + dev->admin_tagset.queue_depth = NVME_AQ_BLKMQ_DEPTH - 1; dev->admin_tagset.timeout = ADMIN_TIMEOUT; dev->admin_tagset.numa_node = dev_to_node(dev->dev); dev->admin_tagset.cmd_size = nvme_cmd_size(dev); -- 2.6.2.307.g37023ba