* [PATCH v2] block: drop dead assignments in loop_init()
@ 2020-12-11 18:46 Lukas Bulwahn
2020-12-11 19:29 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Lukas Bulwahn @ 2020-12-11 18:46 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
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 | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index d2ce1ddc192d..10c7c154c114 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 +2340,7 @@ static int __init loop_init(void)
* /dev/loop-control interface, or be instantiated by accessing
* a 'dead' device node.
*/
- if (max_loop) {
- nr = max_loop;
- range = max_loop << part_shift;
- } else {
- nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT;
- range = 1UL << MINORBITS;
- }
+ nr = max_loop ? max_loop : CONFIG_BLK_DEV_LOOP_MIN_COUNT;
err = misc_register(&loop_misc);
if (err < 0)
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] block: drop dead assignments in loop_init()
2020-12-11 18:46 [PATCH v2] block: drop dead assignments in loop_init() Lukas Bulwahn
@ 2020-12-11 19:29 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2020-12-11 19:29 UTC (permalink / raw)
To: Lukas Bulwahn, Christoph Hellwig, linux-block
Cc: Hannes Reinecke, linux-kernel, clang-built-linux, kernel-janitors
On 12/11/20 11:46 AM, 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.
>
> Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
> ---
> v1 -> v2:
> - replaced if block with ternary operator after Julia's style comment
>
> 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 | 9 +--------
> 1 file changed, 1 insertion(+), 8 deletions(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index d2ce1ddc192d..10c7c154c114 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 +2340,7 @@ static int __init loop_init(void)
> * /dev/loop-control interface, or be instantiated by accessing
> * a 'dead' device node.
> */
> - if (max_loop) {
> - nr = max_loop;
> - range = max_loop << part_shift;
> - } else {
> - nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT;
> - range = 1UL << MINORBITS;
> - }
> + nr = max_loop ? max_loop : CONFIG_BLK_DEV_LOOP_MIN_COUNT;
I greatly prefer an if/else to ternary, it's a lot easier to read imho.
--
Jens Axboe
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