linux-kernel - [PATCH 03/18] ioasid: Convert ioasid

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Date:   Mon,  8 Apr 2019 16:59:18 -0700
From:   Jacob Pan <jacob.jun.pan@...ux.intel.com>
To:     iommu@...ts.linux-foundation.org,
        LKML <linux-kernel@...r.kernel.org>,
        Joerg Roedel <joro@...tes.org>,
        David Woodhouse <dwmw2@...radead.org>,
        Alex Williamson <alex.williamson@...hat.com>,
        Jean-Philippe Brucker <jean-philippe.brucker@....com>
Cc:     "Yi Liu" <yi.l.liu@...el.com>,
        "Tian, Kevin" <kevin.tian@...el.com>,
        Raj Ashok <ashok.raj@...el.com>,
        "Christoph Hellwig" <hch@...radead.org>,
        "Lu Baolu" <baolu.lu@...ux.intel.com>,
        Andriy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>
Subject: [PATCH 03/18] ioasid: Convert ioasid_idr to XArray

IDR is to be replaced by XArray, keep up with the changes.
XArray has internal locking for normal APIs used here, also removed
radix tree related preload.

Suggested-by: Ira Weiny <ira.weiny@...el.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
---
 drivers/base/ioasid.c | 35 ++++++++++++++++-------------------
 1 file changed, 16 insertions(+), 19 deletions(-)

diff --git a/drivers/base/ioasid.c b/drivers/base/ioasid.c
index 294e856..35bdc680 100644
--- a/drivers/base/ioasid.c
+++ b/drivers/base/ioasid.c
@@ -4,7 +4,7 @@
  * subsets. Users create a subset with DECLARE_IOASID_SET, then allocate and
  * free IOASIDs with ioasid_alloc and ioasid_free.
  */
-#include <linux/idr.h>
+#include <linux/xarray.h>
 #include <linux/ioasid.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -16,7 +16,7 @@ struct ioasid_data {
 	struct rcu_head rcu;
 };
 
-static DEFINE_IDR(ioasid_idr);
+static DEFINE_XARRAY_ALLOC(ioasid_xa);
 static DEFINE_MUTEX(ioasid_allocator_lock);
 static const struct ioasid_allocator *ioasid_allocator;
 
@@ -24,9 +24,9 @@ static const struct ioasid_allocator *ioasid_allocator;
 /**
  * ioasid_set_allocator - register a custom allocator
  *
- * Custom allocator take precedence over the default IDR based allocator.
+ * Custom allocator take precedence over the default xarray based allocator.
  * Private data associated with the ASID are managed by ASID common code
- * similar to IDR data.
+ * similar to data stored in xa.
  */
 int ioasid_set_allocator(struct ioasid_allocator *allocator)
 {
@@ -72,13 +72,12 @@ int ioasid_set_data(ioasid_t ioasid, void *data)
 	struct ioasid_data *ioasid_data;
 	int ret = 0;
 
-	idr_lock(&ioasid_idr);
-	ioasid_data = idr_find(&ioasid_idr, ioasid);
+	ioasid_data = xa_load(&ioasid_xa, ioasid);
 	if (ioasid_data)
 		ioasid_data->private = data;
 	else
 		ret = -ENOENT;
-	idr_unlock(&ioasid_idr);
+
 	/* getter may use the private data */
 	synchronize_rcu();
 
@@ -110,7 +109,7 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
 	data->set = set;
 	data->private = private;
 
-	/* Use custom allocator if available, otherwise default to IDR */
+	/* Use custom allocator if available, otherwise default to xarray */
 	if (ioasid_allocator) {
 		mutex_lock(&ioasid_allocator_lock);
 		id = ioasid_allocator->alloc(min, max, ioasid_allocator->pdata);
@@ -120,17 +119,18 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
 			goto exit_free;
 		}
 		/*
-		 * Use IDR to manage private data also sanitiy check custom
+		 * Use XA to manage private data also sanitiy check custom
 		 * allocator for duplicates.
 		 */
 		min = id;
 		max = id + 1;
 	}
-	idr_preload(GFP_KERNEL);
-	idr_lock(&ioasid_idr);
-	data->id = id = idr_alloc(&ioasid_idr, data, min, max, GFP_ATOMIC);
-	idr_unlock(&ioasid_idr);
-	idr_preload_end();
+
+	if (xa_alloc(&ioasid_xa, &id, data, XA_LIMIT(min, max), GFP_KERNEL)) {
+		pr_err("Failed to alloc ioasid from %d to %d\n", min, max);
+		goto exit_free;
+	}
+	data->id = id;
 
 exit_free:
 	if (id < 0 || id == INVALID_IOASID) {
@@ -160,10 +160,7 @@ int ioasid_free(ioasid_t ioasid)
 		return ret;
 	}
 
-	idr_lock(&ioasid_idr);
-	ioasid_data = idr_remove(&ioasid_idr, ioasid);
-	idr_unlock(&ioasid_idr);
-
+	ioasid_data = xa_erase(&ioasid_xa, ioasid);
 	if (ioasid_data)
 		kfree_rcu(ioasid_data, rcu);
 
@@ -192,7 +189,7 @@ void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
 	struct ioasid_data *ioasid_data;
 
 	rcu_read_lock();
-	ioasid_data = idr_find(&ioasid_idr, ioasid);
+	ioasid_data = xa_load(&ioasid_xa, ioasid);
 	if (!ioasid_data) {
 		priv = ERR_PTR(-ENOENT);
 		goto unlock;
-- 
2.7.4