NVMe: Wait for device to acknowledge shutdown

A recent update to the specification makes it clear that the host
is expected to wait for the device to acknowledge the Enable bit
transitioning to 0 as well as waiting for the device to acknowledge a
transition to 1.

Reported-by: Khosrow Panah <Khosrow.Panah@idt.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>

1 files changed, 46 insertions, 19 deletions

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index a232dfc1cd4a..2b1b5a74dc72 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1108,15 +1108,57 @@ static struct nvme_queue *nvme_create_queue(struct nvme_dev *dev, int qid,
         return ERR_PTR(result);
 }
 
+static int nvme_wait_ready(struct nvme_dev *dev, u64 cap, bool enabled)
+{
+        unsigned long timeout;
+        u32 bit = enabled ? NVME_CSTS_RDY : 0;
+
+        timeout = ((NVME_CAP_TIMEOUT(cap) + 1) * HZ / 2) + jiffies;
+
+        while ((readl(&dev->bar->csts) & NVME_CSTS_RDY) != bit) {
+                msleep(100);
+                if (fatal_signal_pending(current))
+                        return -EINTR;
+                if (time_after(jiffies, timeout)) {
+                        dev_err(&dev->pci_dev->dev,
+                                "Device not ready; aborting initialisation\n");
+                        return -ENODEV;
+                }
+        }
+
+        return 0;
+}
+
+/*
+ * If the device has been passed off to us in an enabled state, just clear
+ * the enabled bit.  The spec says we should set the 'shutdown notification
+ * bits', but doing so may cause the device to complete commands to the
+ * admin queue ... and we don't know what memory that might be pointing at!
+ */
+static int nvme_disable_ctrl(struct nvme_dev *dev, u64 cap)
+{
+        writel(0, &dev->bar->cc);
+        return nvme_wait_ready(dev, cap, false);
+}
+
+static int nvme_enable_ctrl(struct nvme_dev *dev, u64 cap)
+{
+        return nvme_wait_ready(dev, cap, true);
+}
+
 static int nvme_configure_admin_queue(struct nvme_dev *dev)
 {
-        int result = 0;
+        int result;
         u32 aqa;
-        u64 cap;
-        unsigned long timeout;
+        u64 cap = readq(&dev->bar->cap);
         struct nvme_queue *nvmeq;
 
         dev->dbs = ((void __iomem *)dev->bar) + 4096;
+        dev->db_stride = NVME_CAP_STRIDE(cap);
+
+        result = nvme_disable_ctrl(dev, cap);
+        if (result < 0)
+                return result;
 
         nvmeq = nvme_alloc_queue(dev, 0, 64, 0);
         if (!nvmeq)
@@ -1130,27 +1172,12 @@ static int nvme_configure_admin_queue(struct nvme_dev *dev)
         dev->ctrl_config |= NVME_CC_ARB_RR | NVME_CC_SHN_NONE;
         dev->ctrl_config |= NVME_CC_IOSQES | NVME_CC_IOCQES;
 
-        writel(0, &dev->bar->cc);
         writel(aqa, &dev->bar->aqa);
         writeq(nvmeq->sq_dma_addr, &dev->bar->asq);
         writeq(nvmeq->cq_dma_addr, &dev->bar->acq);
         writel(dev->ctrl_config, &dev->bar->cc);
 
-        cap = readq(&dev->bar->cap);
-        timeout = ((NVME_CAP_TIMEOUT(cap) + 1) * HZ / 2) + jiffies;
-        dev->db_stride = NVME_CAP_STRIDE(cap);
-
-        while (!result && !(readl(&dev->bar->csts) & NVME_CSTS_RDY)) {
-                msleep(100);
-                if (fatal_signal_pending(current))
-                        result = -EINTR;
-                if (time_after(jiffies, timeout)) {
-                        dev_err(&dev->pci_dev->dev,
-                                "Device not ready; aborting initialisation\n");
-                        result = -ENODEV;
-                }
-        }
-
+        result = nvme_enable_ctrl(dev, cap);
         if (result)
                 goto free_q;