[1/3] fs: super: remove obsolete usage of unnamed_dev_start

Commit Message

Heiner Kallweit July 26, 2016, 5 a.m. UTC

Commit c63e09ecccb5 "Make allocation of anon devices cheaper" made
a performance-driven change in 2009.

With commit 2c57a0e233d7 "lib: find_*_bit reimplementation" the
performance of the related functionality was much improved in 2015,
so I think we can remove this older extension.
However I didn't do any benchmarking.

As a result of this change we use the idr functionality the same way
as other parts of the kernel.

Signed-off-by: Heiner Kallweit <[e-mail]>
---
 fs/super.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

Patch

diff --git a/fs/super.c b/fs/super.c
index c2ff475..362e765 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -881,10 +881,6 @@  void emergency_remount(void)
 
 static DEFINE_IDA(unnamed_dev_ida);
 static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
-/* Many userspace utilities consider an FSID of 0 invalid.
- * Always return at least 1 from get_anon_bdev.
- */
-static int unnamed_dev_start = 1;
 
 int get_anon_bdev(dev_t *p)
 {
@@ -895,9 +891,10 @@  int get_anon_bdev(dev_t *p)
 	if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0)
 		return -ENOMEM;
 	spin_lock(&unnamed_dev_lock);
-	error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev);
-	if (!error)
-		unnamed_dev_start = dev + 1;
+	/* Many userspace utilities consider an FSID of 0 invalid.
+	 * Always return at least 1 from get_anon_bdev.
+	 */
+	error = ida_get_new_above(&unnamed_dev_ida, 1, &dev);
 	spin_unlock(&unnamed_dev_lock);
 	if (error == -EAGAIN)
 		/* We raced and lost with another CPU. */
@@ -908,8 +905,6 @@  int get_anon_bdev(dev_t *p)
 	if (dev >= (1 << MINORBITS)) {
 		spin_lock(&unnamed_dev_lock);
 		ida_remove(&unnamed_dev_ida, dev);
-		if (unnamed_dev_start > dev)
-			unnamed_dev_start = dev;
 		spin_unlock(&unnamed_dev_lock);
 		return -EMFILE;
 	}
@@ -923,8 +918,6 @@  void free_anon_bdev(dev_t dev)
 	int slot = MINOR(dev);
 	spin_lock(&unnamed_dev_lock);
 	ida_remove(&unnamed_dev_ida, slot);
-	if (slot < unnamed_dev_start)
-		unnamed_dev_start = slot;
 	spin_unlock(&unnamed_dev_lock);
 }
 EXPORT_SYMBOL(free_anon_bdev);