[PATCH v2 2/6] iommu/vt-d: Use IDA interface to manage iommu sequence id

From: Lu Baolu
Date: Fri Jul 01 2022 - 22:00:47 EST


Switch dmar unit sequence id allocation and release from bitmap to IDA
interface.

Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
drivers/iommu/intel/dmar.c | 35 ++++++++---------------------------
1 file changed, 8 insertions(+), 27 deletions(-)

diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 2a5e0f91e647..6327b34f5aa7 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -60,7 +60,7 @@ LIST_HEAD(dmar_drhd_units);

struct acpi_table_header * __initdata dmar_tbl;
static int dmar_dev_scope_status = 1;
-static unsigned long dmar_seq_ids[BITS_TO_LONGS(DMAR_UNITS_SUPPORTED)];
+static DEFINE_IDA(dmar_seq_ids);

static int alloc_iommu(struct dmar_drhd_unit *drhd);
static void free_iommu(struct intel_iommu *iommu);
@@ -1023,28 +1023,6 @@ static int map_iommu(struct intel_iommu *iommu, u64 phys_addr)
return err;
}

-static int dmar_alloc_seq_id(struct intel_iommu *iommu)
-{
- iommu->seq_id = find_first_zero_bit(dmar_seq_ids,
- DMAR_UNITS_SUPPORTED);
- if (iommu->seq_id >= DMAR_UNITS_SUPPORTED) {
- iommu->seq_id = -1;
- } else {
- set_bit(iommu->seq_id, dmar_seq_ids);
- sprintf(iommu->name, "dmar%d", iommu->seq_id);
- }
-
- return iommu->seq_id;
-}
-
-static void dmar_free_seq_id(struct intel_iommu *iommu)
-{
- if (iommu->seq_id >= 0) {
- clear_bit(iommu->seq_id, dmar_seq_ids);
- iommu->seq_id = -1;
- }
-}
-
static int alloc_iommu(struct dmar_drhd_unit *drhd)
{
struct intel_iommu *iommu;
@@ -1062,11 +1040,14 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
if (!iommu)
return -ENOMEM;

- if (dmar_alloc_seq_id(iommu) < 0) {
+ iommu->seq_id = ida_alloc_range(&dmar_seq_ids, 0,
+ DMAR_UNITS_SUPPORTED - 1, GFP_KERNEL);
+ if (iommu->seq_id < 0) {
pr_err("Failed to allocate seq_id\n");
- err = -ENOSPC;
+ err = iommu->seq_id;
goto error;
}
+ sprintf(iommu->name, "dmar%d", iommu->seq_id);

err = map_iommu(iommu, drhd->reg_base_addr);
if (err) {
@@ -1150,7 +1131,7 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
err_unmap:
unmap_iommu(iommu);
error_free_seq_id:
- dmar_free_seq_id(iommu);
+ ida_free(&dmar_seq_ids, iommu->seq_id);
error:
kfree(iommu);
return err;
@@ -1183,7 +1164,7 @@ static void free_iommu(struct intel_iommu *iommu)
if (iommu->reg)
unmap_iommu(iommu);

- dmar_free_seq_id(iommu);
+ ida_free(&dmar_seq_ids, iommu->seq_id);
kfree(iommu);
}

--
2.25.1