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 <chunguang.xu@shopee.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Keith Busch <kbusch@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Portia Stephens <portia.stephens@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
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Stefan Bader
parent
ff667f4698
commit
9da5b5e58e
@@ -180,7 +180,7 @@ int nvmf_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val)
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cmd.prop_get.offset = cpu_to_le32(off);
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ret = __nvme_submit_sync_cmd(ctrl->fabrics_q, &cmd, &res, NULL, 0,
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NVME_QID_ANY, 0);
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NVME_QID_ANY, NVME_SUBMIT_RESERVED);
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if (ret >= 0)
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*val = le64_to_cpu(res.u64);
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@@ -226,7 +226,7 @@ int nvmf_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val)
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cmd.prop_get.offset = cpu_to_le32(off);
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ret = __nvme_submit_sync_cmd(ctrl->fabrics_q, &cmd, &res, NULL, 0,
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NVME_QID_ANY, 0);
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NVME_QID_ANY, NVME_SUBMIT_RESERVED);
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if (ret >= 0)
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*val = le64_to_cpu(res.u64);
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@@ -271,7 +271,7 @@ int nvmf_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val)
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cmd.prop_set.value = cpu_to_le64(val);
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ret = __nvme_submit_sync_cmd(ctrl->fabrics_q, &cmd, NULL, NULL, 0,
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NVME_QID_ANY, 0);
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NVME_QID_ANY, NVME_SUBMIT_RESERVED);
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if (unlikely(ret))
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dev_err(ctrl->device,
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"Property Set error: %d, offset %#x\n",
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