From: Matthew Wilcox <willy@infradead.org>
Date: Tue, 12 Feb 2019 13:47:51 +0000 (-0500)
Subject: tpm: Convert dev_nums to XArray
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7afd80bf8f63e705b57a242867e377be51e1ad27;p=users%2Fwilly%2Fxarray.git

tpm: Convert dev_nums to XArray

Also fix a couple of memory leaks on allocation failure.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
---

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 4838c6a9f0f2..8d25c932c2ae 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -25,8 +25,7 @@
 #include <linux/hw_random.h>
 #include "tpm.h"
 
-DEFINE_IDR(dev_nums_idr);
-static DEFINE_MUTEX(idr_lock);
+static DEFINE_XARRAY_ALLOC(dev_nums);
 
 struct class *tpm_class;
 struct class *tpmrm_class;
@@ -195,25 +194,16 @@ EXPORT_SYMBOL_GPL(tpm_put_ops);
  */
 struct tpm_chip *tpm_default_chip(void)
 {
-	struct tpm_chip *chip, *res = NULL;
-	int chip_num = 0;
-	int chip_prev;
-
-	mutex_lock(&idr_lock);
-
-	do {
-		chip_prev = chip_num;
-		chip = idr_get_next(&dev_nums_idr, &chip_num);
-		if (chip) {
-			get_device(&chip->dev);
-			res = chip;
-			break;
-		}
-	} while (chip_prev != chip_num);
+	struct tpm_chip *chip;
+	unsigned long chip_num = 0;
 
-	mutex_unlock(&idr_lock);
+	xa_lock(&dev_nums);
+	chip = xa_find(&dev_nums, &chip_num, ULONG_MAX, XA_PRESENT);
+	if (chip)
+		get_device(&chip->dev);
+	xa_unlock(&dev_nums);
 
-	return res;
+	return chip;
 }
 EXPORT_SYMBOL_GPL(tpm_default_chip);
 
@@ -263,9 +253,7 @@ static void tpm_dev_release(struct device *dev)
 {
 	struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
 
-	mutex_lock(&idr_lock);
-	idr_remove(&dev_nums_idr, chip->dev_num);
-	mutex_unlock(&idr_lock);
+	xa_erase(&dev_nums, chip->dev_num);
 
 	kfree(chip->log.bios_event_log);
 	kfree(chip->work_space.context_buf);
@@ -336,15 +324,13 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 
 	chip->ops = ops;
 
-	mutex_lock(&idr_lock);
-	rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
-	mutex_unlock(&idr_lock);
+	rc = xa_alloc(&dev_nums, &chip->dev_num, NULL,
+			XA_LIMIT(0, TPM_NUM_DEVICES - 1), GFP_KERNEL);
 	if (rc < 0) {
 		dev_err(pdev, "No available tpm device numbers\n");
 		kfree(chip);
 		return ERR_PTR(rc);
 	}
-	chip->dev_num = rc;
 
 	device_initialize(&chip->dev);
 	device_initialize(&chip->devs);
@@ -404,8 +390,11 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 	return chip;
 
 out:
+	kfree(chip->work_space.context_buf);
 	put_device(&chip->devs);
 	put_device(&chip->dev);
+	xa_erase(&dev_nums, chip->dev_num);
+	kfree(chip);
 	return ERR_PTR(rc);
 }
 EXPORT_SYMBOL_GPL(tpm_chip_alloc);
@@ -464,9 +453,7 @@ static int tpm_add_char_device(struct tpm_chip *chip)
 	}
 
 	/* Make the chip available. */
-	mutex_lock(&idr_lock);
-	idr_replace(&dev_nums_idr, chip, chip->dev_num);
-	mutex_unlock(&idr_lock);
+	xa_store(&dev_nums, chip->dev_num, chip, GFP_KERNEL);
 
 	return rc;
 }
@@ -476,9 +463,7 @@ static void tpm_del_char_device(struct tpm_chip *chip)
 	cdev_device_del(&chip->cdev, &chip->dev);
 
 	/* Make the chip unavailable. */
-	mutex_lock(&idr_lock);
-	idr_replace(&dev_nums_idr, NULL, chip->dev_num);
-	mutex_unlock(&idr_lock);
+	xa_store(&dev_nums, chip->dev_num, NULL, GFP_KERNEL);
 
 	/* Make the driver uncallable. */
 	down_write(&chip->ops_sem);
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 1b4f95c13e00..4eb672d2d33d 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -553,7 +553,6 @@ out_destroy_tpm_class:
 
 static void __exit tpm_exit(void)
 {
-	idr_destroy(&dev_nums_idr);
 	class_destroy(tpm_class);
 	class_destroy(tpmrm_class);
 	unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index a7fea3e0ca86..9e66be9ff1b5 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -375,7 +375,6 @@ extern struct class *tpmrm_class;
 extern dev_t tpm_devt;
 extern const struct file_operations tpm_fops;
 extern const struct file_operations tpmrm_fops;
-extern struct idr dev_nums_idr;
 
 ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz);
 ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,