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authorKeith Busch <keith.busch@intel.com>2016-01-04 09:10:55 -0700
committerJens Axboe <axboe@fb.com>2016-01-12 13:33:33 -0700
commite3e9d50cd6ed392bb716e35c134d1e82707c51b4 (patch)
treef661137d04089a35834a17034d2aebab8fef8196 /drivers/nvme/host/pci.c
parentnvme: make SG_IO support optional (diff)
downloadlinux-dev-e3e9d50cd6ed392bb716e35c134d1e82707c51b4.tar.xz
linux-dev-e3e9d50cd6ed392bb716e35c134d1e82707c51b4.zip
NVMe: Fix admin queue ring wrap
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 <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/nvme/host/pci.c')
-rw-r--r--drivers/nvme/host/pci.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index a7e549969462..30ed2ab2cadb 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);