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* [PATCH v3] block: drop dead assignments in loop_init()
@ 2020-12-12  5:13 Lukas Bulwahn
  2020-12-12 18:19 ` Jens Axboe
  0 siblings, 1 reply; 2+ messages in thread
From: Lukas Bulwahn @ 2020-12-12  5:13 UTC (permalink / raw)
  To: Christoph Hellwig, Jens Axboe, linux-block
  Cc: Hannes Reinecke, linux-kernel, clang-built-linux,
	kernel-janitors, Lukas Bulwahn

Commit 8410d38c2552 ("loop: use __register_blkdev to allocate devices on
demand") simplified loop_init(); so computing the range of the block region
is not required anymore and can be dropped.

Drop dead assignments in loop_init().

As compilers will detect these unneeded assignments and optimize this,
the resulting object code is identical before and after this change.

No functional change. No change in object code.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
---
v1 -> v2:
  - replaced if block with ternary operator after Julia's style comment

v2 -> v3:
  - use if instead of ternary following Jens' preference

Christoph, please ack.

Jens, please pick this minor non-urgent clean-up patch on your
block -next tree on top of Christoph's commit above.


 drivers/block/loop.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index d2ce1ddc192d..e5ff328f0917 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2304,7 +2304,6 @@ MODULE_ALIAS("devname:loop-control");
 static int __init loop_init(void)
 {
 	int i, nr;
-	unsigned long range;
 	struct loop_device *lo;
 	int err;
 
@@ -2341,13 +2340,10 @@ static int __init loop_init(void)
 	 * /dev/loop-control interface, or be instantiated by accessing
 	 * a 'dead' device node.
 	 */
-	if (max_loop) {
+	if (max_loop)
 		nr = max_loop;
-		range = max_loop << part_shift;
-	} else {
+	else
 		nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT;
-		range = 1UL << MINORBITS;
-	}
 
 	err = misc_register(&loop_misc);
 	if (err < 0)
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH v3] block: drop dead assignments in loop_init()
  2020-12-12  5:13 [PATCH v3] block: drop dead assignments in loop_init() Lukas Bulwahn
@ 2020-12-12 18:19 ` Jens Axboe
  0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2020-12-12 18:19 UTC (permalink / raw)
  To: Lukas Bulwahn, Christoph Hellwig, linux-block
  Cc: Hannes Reinecke, linux-kernel, clang-built-linux, kernel-janitors

On 12/11/20 10:13 PM, Lukas Bulwahn wrote:
> Commit 8410d38c2552 ("loop: use __register_blkdev to allocate devices on
> demand") simplified loop_init(); so computing the range of the block region
> is not required anymore and can be dropped.
> 
> Drop dead assignments in loop_init().
> 
> As compilers will detect these unneeded assignments and optimize this,
> the resulting object code is identical before and after this change.
> 
> No functional change. No change in object code.

Applied, thanks.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 2+ messages in thread

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