2022-11-29 23:48:05

by Chaitanya Kulkarni

Subject: [PATCH V4 7/8] null_blk: add param to set max write-zeroes sects

Instead of hardcoding value for the maximum write-zeroes sector to
UINT_MAX >> 9, allow user to set the value with newly added module
parameter max_write_zeroes_sectors.

Signed-off-by: Chaitanya Kulkarni <[email protected]>
---
drivers/block/null_blk/main.c | 10 +++++++++-
drivers/block/null_blk/null_blk.h | 1 +
2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 2f787807cf63..8b7f42024f14 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -224,6 +224,10 @@ static bool g_write_zeroes;
module_param_named(write_zeroes, g_write_zeroes, bool, 0444);
MODULE_PARM_DESC(write_zeroes, "Support write-zeores operations. Default: false");

+static unsigned int g_max_write_zeroes_sectors = UINT_MAX >> 9;
+module_param_named(max_write_zeroes_sectors, g_max_write_zeroes_sectors, uint, 0444);
+MODULE_PARM_DESC(max_write_zeroes_sectors, "Maximum size of a REQ_OP_WRITE_ZEROES command (in 512B sectors).");
+
static unsigned long g_cache_size;
module_param_named(cache_size, g_cache_size, ulong, 0444);
MODULE_PARM_DESC(mbps, "Cache size in MiB for memory-backed device. Default: 0 (none)");
@@ -425,6 +429,7 @@ NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
NULLB_DEVICE_ATTR(blocksize, uint, NULL);
NULLB_DEVICE_ATTR(max_sectors, uint, NULL);
NULLB_DEVICE_ATTR(max_discard_sectors, uint, NULL);
+NULLB_DEVICE_ATTR(max_write_zeroes_sectors, uint, NULL);
NULLB_DEVICE_ATTR(irqmode, uint, NULL);
NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL);
NULLB_DEVICE_ATTR(index, uint, NULL);
@@ -550,6 +555,7 @@ static struct configfs_attribute *nullb_device_attrs[] = {
&nullb_device_attr_blocksize,
&nullb_device_attr_max_sectors,
&nullb_device_attr_max_discard_sectors,
+ &nullb_device_attr_max_write_zeroes_sectors,
&nullb_device_attr_irqmode,
&nullb_device_attr_hw_queue_depth,
&nullb_device_attr_index,
@@ -693,6 +699,7 @@ static struct nullb_device *null_alloc_dev(void)
dev->blocksize = g_bs;
dev->max_sectors = g_max_sectors;
dev->max_discard_sectors = g_max_discard_sectors;
+ dev->max_write_zeroes_sectors = g_max_write_zeroes_sectors;
dev->irqmode = g_irqmode;
dev->hw_queue_depth = g_hw_queue_depth;
dev->blocking = g_blocking;
@@ -1865,7 +1872,8 @@ static void null_config_write_zeroes(struct nullb *nullb)
{
if (!nullb->dev->write_zeroes)
return;
- blk_queue_max_write_zeroes_sectors(nullb->q, UINT_MAX >> 9);
+ blk_queue_max_write_zeroes_sectors(nullb->q,
+ nullb->dev->max_write_zeroes_sectors);
}

static const struct block_device_operations null_bio_ops = {
diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/null_blk.h
index 09940211326d..e692c2a7369e 100644
--- a/drivers/block/null_blk/null_blk.h
+++ b/drivers/block/null_blk/null_blk.h
@@ -103,6 +103,7 @@ struct nullb_device {
unsigned int blocksize; /* block size */
unsigned int max_sectors; /* Max sectors per command */
unsigned int max_discard_sectors; /* Max discard sectors per command */
+ unsigned int max_write_zeroes_sectors; /* Max write-zeroes sectors per command */
unsigned int irqmode; /* IRQ completion handler */
unsigned int hw_queue_depth; /* queue depth */
unsigned int index; /* index of the disk, only valid with a disk */
--
2.29.0

2022-11-30 08:16:29

by Shinichiro Kawasaki

Subject: Re: [PATCH V4 7/8] null_blk: add param to set max write-zeroes sects

On Nov 29, 2022 / 15:28, Chaitanya Kulkarni wrote:
> Instead of hardcoding value for the maximum write-zeroes sector to
> UINT_MAX >> 9, allow user to set the value with newly added module
> parameter max_write_zeroes_sectors.
>
> Signed-off-by: Chaitanya Kulkarni <[email protected]>

Nit: it would be the better to note in the commit message why the default value
is UINT_MAX >> 9. Other than that, looks good.

Reviewed-by: Shin'ichiro Kawasaki <[email protected]>

--
Shin'ichiro Kawasaki