2023-05-30 15:50:24

by Daniel Gomez

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Subject: [PATCH] nvme: Increase block size variable size to 32-bit

Increase block size variable size to 32-bit unsigned to be able to
support block devices larger than 32k (starting from 64 KiB).

Physical and logical block size already support unsigned 32-bit.

Signed-off-by: Daniel Gomez <[email protected]>
---

While experimenting and doing code inspection for large block
devices, we found a limitation of a 32 KiB block size due to the bs
variable type. With that limitation and in combination with a large
block device, this results in a kernel BUG when the block layer
attempts to split a block size of 0 bytes.

Increasing the value to 32-bit unsigned, allows to support large block
devices starting from 64 KiB. In addition, this bs variable type
aligns with the queue_limits logical/physical_block_size types.


drivers/nvme/host/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 151b23400ada..b4bc48f2a011 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1835,7 +1835,7 @@ static void nvme_update_disk_info(struct gendisk *disk,
struct nvme_ns *ns, struct nvme_id_ns *id)
{
sector_t capacity = nvme_lba_to_sect(ns, le64_to_cpu(id->nsze));
- unsigned short bs = 1 << ns->lba_shift;
+ u32 bs = 1 << ns->lba_shift;
u32 atomic_bs, phys_bs, io_opt = 0;

/*
--
2.40.1


2023-05-30 16:27:47

by Luis Chamberlain

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Subject: Re: [PATCH] nvme: Increase block size variable size to 32-bit

On Tue, May 30, 2023 at 03:42:53PM +0000, Daniel Gomez wrote:
> Increase block size variable size to 32-bit unsigned to be able to
> support block devices larger than 32k (starting from 64 KiB).
>
> Physical and logical block size already support unsigned 32-bit.
>
> Signed-off-by: Daniel Gomez <[email protected]>

Reviewed-by: Luis Chamberlain <[email protected]>

Luis

2023-05-30 17:41:27

by Keith Busch

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Subject: Re: [PATCH] nvme: Increase block size variable size to 32-bit

On Tue, May 30, 2023 at 03:42:53PM +0000, Daniel Gomez wrote:
> Increase block size variable size to 32-bit unsigned to be able to
> support block devices larger than 32k (starting from 64 KiB).

Looks good,

Reviewed-by: Keith Busch <[email protected]>

2023-05-31 13:10:43

by Christoph Hellwig

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Subject: Re: [PATCH] nvme: Increase block size variable size to 32-bit

> + u32 bs = 1 << ns->lba_shift;

Make that 1 a 1U so that we're not going to run into sign extension
issues when using up all bits in the u32 :)

Otherwise looks good:

Reviewed-by: Christoph Hellwig <[email protected]>

2023-06-01 10:41:17

by David Laight

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Subject: RE: [PATCH] nvme: Increase block size variable size to 32-bit

From: Christoph Hellwig
> Sent: 31 May 2023 14:03
>
> > + u32 bs = 1 << ns->lba_shift;
>
> Make that 1 a 1U so that we're not going to run into sign extension
> issues when using up all bits in the u32 :)

Not 'sign extension' but obscure integer shift/conversion issues
that really only affect 1's compliment and sign-overpunch cpu.
I'm not even sure gcc/clang support any non 2's compliment systems.

> Otherwise looks good:

Probably improves the generated code as well.

David

-
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Registration No: 1397386 (Wales)


2023-06-01 17:52:47

by Keith Busch

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Subject: Re: [PATCH] nvme: Increase block size variable size to 32-bit

Thanks, applied to 6.5 with the '1U' suggestion folded in.