Patch "null_blk: don't cap max_hw_sectors to BLK_DEF_MAX_SECTORS" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    null_blk: don't cap max_hw_sectors to BLK_DEF_MAX_SECTORS

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     null_blk-don-t-cap-max_hw_sectors-to-blk_def_max_sec.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3a6f64d3ca41ae8a0e5e17446c76cd6e4a730ab6
Author: Christoph Hellwig <hch@xxxxxx>
Date:   Wed Dec 27 09:23:02 2023 +0000

    null_blk: don't cap max_hw_sectors to BLK_DEF_MAX_SECTORS
    
    [ Upstream commit 9a9525de865410047fa962867b4fcd33943b206f ]
    
    null_blk has some rather odd capping of the max_hw_sectors value to
    BLK_DEF_MAX_SECTORS, which doesn't make sense - max_hw_sector is the
    hardware limit, and BLK_DEF_MAX_SECTORS despite the confusing name is the
    default cap for the max_sectors field used for normal file system I/O.
    
    Remove all the capping, and simply leave it to the block layer or
    user to take up or not all of that for file system I/O.
    
    Fixes: ea17fd354ca8 ("null_blk: Allow controlling max_hw_sectors limit")
    Signed-off-by: Christoph Hellwig <hch@xxxxxx>
    Link: https://lore.kernel.org/r/20231227092305.279567-2-hch@xxxxxx
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 968090935eb2..9544746de168 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -2165,10 +2165,8 @@ static int null_add_dev(struct nullb_device *dev)
 
 	blk_queue_logical_block_size(nullb->q, dev->blocksize);
 	blk_queue_physical_block_size(nullb->q, dev->blocksize);
-	if (!dev->max_sectors)
-		dev->max_sectors = queue_max_hw_sectors(nullb->q);
-	dev->max_sectors = min(dev->max_sectors, BLK_DEF_MAX_SECTORS);
-	blk_queue_max_hw_sectors(nullb->q, dev->max_sectors);
+	if (dev->max_sectors)
+		blk_queue_max_hw_sectors(nullb->q, dev->max_sectors);
 
 	if (dev->virt_boundary)
 		blk_queue_virt_boundary(nullb->q, PAGE_SIZE - 1);
@@ -2268,12 +2266,6 @@ static int __init null_init(void)
 		g_bs = PAGE_SIZE;
 	}
 
-	if (g_max_sectors > BLK_DEF_MAX_SECTORS) {
-		pr_warn("invalid max sectors\n");
-		pr_warn("defaults max sectors to %u\n", BLK_DEF_MAX_SECTORS);
-		g_max_sectors = BLK_DEF_MAX_SECTORS;
-	}
-
 	if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) {
 		pr_err("invalid home_node value\n");
 		g_home_node = NUMA_NO_NODE;