From: Will Deacon <will@kernel.org>
To: Petr Tesarik <petrtesarik@huaweicloud.com>
Cc: Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>,
Petr Tesarik <petr.tesarik1@huawei-partners.com>,
Michael Kelley <mhklinux@outlook.com>,
open list <linux-kernel@vger.kernel.org>,
"open list:DMA MAPPING HELPERS" <iommu@lists.linux.dev>,
Roberto Sassu <roberto.sassu@huaweicloud.com>,
Petr Tesarik <petr@tesarici.cz>
Subject: Re: [PATCH v3 0/2] swiotlb: allocate padding slots if necessary
Date: Fri, 22 Mar 2024 15:09:41 +0000 [thread overview]
Message-ID: <20240322150941.GA5634@willie-the-truck> (raw)
In-Reply-To: <20240321171902.85-1-petrtesarik@huaweicloud.com>
Hi Petr,
On Thu, Mar 21, 2024 at 06:19:00PM +0100, Petr Tesarik wrote:
> From: Petr Tesarik <petr.tesarik1@huawei-partners.com>
>
> If the allocation alignment is bigger than IO_TLB_SIZE and min_align_mask
> covers some bits in the original address between IO_TLB_SIZE and
> alloc_align_mask, preserve these bits by allocating additional padding
> slots before the actual swiotlb buffer.
Thanks for fixing this! I was out at a conference last week, so I didn't
get very far with it myself, but I ended up in a pickle trying to avoid
extending 'struct io_tlb_slot'. Your solution is much better than the
crazy avenue I started going down...
With your changes, can we now simplify swiotlb_align_offset() to ignore
dma_get_min_align_mask() altogether and just:
return addr & (IO_TLB_SIZE - 1);
?
Will
next prev parent reply other threads:[~2024-03-22 15:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-21 17:19 [PATCH v3 0/2] swiotlb: allocate padding slots if necessary Petr Tesarik
2024-03-21 17:19 ` [PATCH v3 1/2] swiotlb: extend buffer pre-padding to alloc_align_mask " Petr Tesarik
2024-03-22 4:29 ` Michael Kelley
2024-03-22 10:29 ` Petr Tesarik
2024-03-21 17:19 ` [PATCH v3 2/2] bug: introduce ASSERT_VAR_CAN_HOLD() Petr Tesarik
2024-03-22 4:33 ` Michael Kelley
2024-03-22 15:37 ` Will Deacon
2024-03-22 17:33 ` Petr Tesařík
2024-03-22 15:09 ` Will Deacon [this message]
2024-03-22 17:51 ` [PATCH v3 0/2] swiotlb: allocate padding slots if necessary Petr Tesařík
2024-03-27 19:42 ` Will Deacon
2024-03-22 18:11 ` Michael Kelley
2024-03-22 19:31 ` Petr Tesařík
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