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

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Message-Id: <20220702015610.2849494-3-baolu.lu@linux.intel.com>
Date:   Sat,  2 Jul 2022 09:56:06 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>, Steve Wahl <steve.wahl@....com>,
        Kevin Tian <kevin.tian@...el.com>
Cc:     David Woodhouse <dwmw2@...radead.org>,
        Jerry Snitselaar <jsnitsel@...hat.com>,
        Mike Travis <mike.travis@....com>,
        Dimitri Sivanich <sivanich@....com>,
        Russ Anderson <russ.anderson@....com>, iommu@...ts.linux.dev,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH v2 2/6] iommu/vt-d: Use IDA interface to manage iommu sequence id

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

Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 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