[PATCH v2 04/10] IOMMU: iommu_unique_seq_id()

[Yinghai Lu]

So for hot-remove/hot-add will reuse seq_id.

Signed-off-by: Yinghai Lu <ying...@kernel.org>
Cc: Joerg Roedel <j...@8bytes.org>
Cc: Donald Dutile <ddut...@redhat.com>
---
 drivers/iommu/dmar.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index a14867c..f5e0718 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -785,11 +785,22 @@ out:
        return err;
 }
 
+static DECLARE_BITMAP(iommu_allocated, 1024);
+
+static int iommu_unique_seq_id(void)
+{
+       int id;
+
+       id = find_first_zero_bit(iommu_allocated, 1024);
+       __set_bit(id, iommu_allocated);
+
+       return id;
+}
+
 int alloc_iommu(struct dmar_drhd_unit *drhd)
 {
        struct intel_iommu *iommu;
        u32 ver, sts;
-       static int iommu_allocated = 0;
        int agaw = 0;
        int msagaw = 0;
        int err;
@@ -803,7 +814,7 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
        if (!iommu)
                return -ENOMEM;
 
-       iommu->seq_id = iommu_allocated++;
+       iommu->seq_id = iommu_unique_seq_id();
        sprintf (iommu->name, "dmar%d", iommu->seq_id);
 
        err = map_iommu(iommu, drhd->reg_base_addr);
@@ -855,6 +866,7 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
  err_unmap:
        unmap_iommu(iommu);
  error:
+       __clear_bit(iommu->seq_id, iommu_allocated);
        kfree(iommu);
        return err;
 }
@@ -869,6 +881,8 @@ void free_iommu(struct intel_iommu *iommu)
        if (iommu->reg)
                unmap_iommu(iommu);
 
+       __clear_bit(iommu->seq_id, iommu_allocated);
+
        kfree(iommu);
 }
 
-- 
1.8.4

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