From 9da5b5e58e4055dd4c966cf010eb106767b13b38 Mon Sep 17 00:00:00 2001 From: Chunguang Xu Date: Fri, 31 May 2024 17:24:21 +0800 Subject: [PATCH] nvme-fabrics: use reserved tag for reg read/write command BugLink: https://bugs.launchpad.net/bugs/2078304 [ Upstream commit 7dc3bfcb4c9cc58970fff6aaa48172cb224d85aa ] In some scenarios, if too many commands are issued by nvme command in the same time by user tasks, this may exhaust all tags of admin_q. If a reset (nvme reset or IO timeout) occurs before these commands finish, reconnect routine may fail to update nvme regs due to insufficient tags, which will cause kernel hang forever. In order to workaround this issue, maybe we can let reg_read32()/reg_read64()/reg_write32() use reserved tags. This maybe safe for nvmf: 1. For the disable ctrl path, we will not issue connect command 2. For the enable ctrl / fw activate path, since connect and reg_xx() are called serially. So the reserved tags may still be enough while reg_xx() use reserved tags. Signed-off-by: Chunguang Xu Reviewed-by: Sagi Grimberg Reviewed-by: Chaitanya Kulkarni Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch Signed-off-by: Sasha Levin Signed-off-by: Portia Stephens Signed-off-by: Stefan Bader --- drivers/nvme/host/fabrics.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c index 495c171daead..a8be17081b2e 100644 --- a/drivers/nvme/host/fabrics.c +++ b/drivers/nvme/host/fabrics.c @@ -180,7 +180,7 @@ int nvmf_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val) cmd.prop_get.offset = cpu_to_le32(off); ret = __nvme_submit_sync_cmd(ctrl->fabrics_q, &cmd, &res, NULL, 0, - NVME_QID_ANY, 0); + NVME_QID_ANY, NVME_SUBMIT_RESERVED); if (ret >= 0) *val = le64_to_cpu(res.u64); @@ -226,7 +226,7 @@ int nvmf_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val) cmd.prop_get.offset = cpu_to_le32(off); ret = __nvme_submit_sync_cmd(ctrl->fabrics_q, &cmd, &res, NULL, 0, - NVME_QID_ANY, 0); + NVME_QID_ANY, NVME_SUBMIT_RESERVED); if (ret >= 0) *val = le64_to_cpu(res.u64); @@ -271,7 +271,7 @@ int nvmf_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val) cmd.prop_set.value = cpu_to_le64(val); ret = __nvme_submit_sync_cmd(ctrl->fabrics_q, &cmd, NULL, NULL, 0, - NVME_QID_ANY, 0); + NVME_QID_ANY, NVME_SUBMIT_RESERVED); if (unlikely(ret)) dev_err(ctrl->device, "Property Set error: %d, offset %#x\n",