linux-kernel - [PATCH 08/26] sd: Convert to new IDA interface

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Date:   Thu, 21 Jun 2018 14:28:17 -0700
From:   Matthew Wilcox <willy@...radead.org>
To:     linux-kernel@...r.kernel.org
Cc:     Matthew Wilcox <willy@...radead.org>,
        "James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        linux-scsi@...r.kernel.org
Subject: [PATCH 08/26] sd: Convert to new IDA interface

Allows us to remove an explicit spinlock.

Signed-off-by: Matthew Wilcox <willy@...radead.org>
---
 drivers/scsi/sd.c | 21 ++++-----------------
 1 file changed, 4 insertions(+), 17 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 9421d9877730..8a493e64856c 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -123,7 +123,6 @@ static void scsi_disk_release(struct device *cdev);
 static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);
 static void sd_print_result(const struct scsi_disk *, const char *, int);
 
-static DEFINE_SPINLOCK(sd_index_lock);
 static DEFINE_IDA(sd_index_ida);
 
 /* This semaphore is used to mediate the 0->1 reference get in the
@@ -3339,16 +3338,8 @@ static int sd_probe(struct device *dev)
 	if (!gd)
 		goto out_free;
 
-	do {
-		if (!ida_pre_get(&sd_index_ida, GFP_KERNEL))
-			goto out_put;
-
-		spin_lock(&sd_index_lock);
-		error = ida_get_new(&sd_index_ida, &index);
-		spin_unlock(&sd_index_lock);
-	} while (error == -EAGAIN);
-
-	if (error) {
+	index = ida_alloc(&sd_index_ida, GFP_KERNEL);
+	if (index < 0) {
 		sdev_printk(KERN_WARNING, sdp, "sd_probe: memory exhausted.\n");
 		goto out_put;
 	}
@@ -3392,9 +3383,7 @@ static int sd_probe(struct device *dev)
 	return 0;
 
  out_free_index:
-	spin_lock(&sd_index_lock);
-	ida_remove(&sd_index_ida, index);
-	spin_unlock(&sd_index_lock);
+	ida_free(&sd_index_ida, index);
  out_put:
 	put_disk(gd);
  out_free:
@@ -3459,9 +3448,7 @@ static void scsi_disk_release(struct device *dev)
 	struct scsi_disk *sdkp = to_scsi_disk(dev);
 	struct gendisk *disk = sdkp->disk;
 	
-	spin_lock(&sd_index_lock);
-	ida_remove(&sd_index_ida, sdkp->index);
-	spin_unlock(&sd_index_lock);
+	ida_free(&sd_index_ida, sdkp->index);
 
 	disk->private_data = NULL;
 	put_disk(disk);
-- 
2.17.1