From: Petr Tesarik <ptesarik@suse•com>
To: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel•org>
Cc: iommu@lists•linux.dev, linux-arm-kernel@lists•infradead.org,
linux-kernel@vger•kernel.org, linux-coco@lists•linux.dev,
Robin Murphy <robin.murphy@arm•com>,
Marek Szyprowski <m.szyprowski@samsung•com>,
Will Deacon <will@kernel•org>, Marc Zyngier <maz@kernel•org>,
Steven Price <steven.price@arm•com>,
Suzuki K Poulose <Suzuki.Poulose@arm•com>,
Catalin Marinas <catalin.marinas@arm•com>,
Jiri Pirko <jiri@resnulli•us>, Jason Gunthorpe <jgg@ziepe•ca>,
Mostafa Saleh <smostafa@google•com>,
Alexey Kardashevskiy <aik@amd•com>,
Dan Williams <dan.j.williams@intel•com>,
Xu Yilun <yilun.xu@linux•intel.com>,
linuxppc-dev@lists•ozlabs.org, linux-s390@vger•kernel.org,
Madhavan Srinivasan <maddy@linux•ibm.com>,
Michael Ellerman <mpe@ellerman•id.au>,
Nicholas Piggin <npiggin@gmail•com>,
"Christophe Leroy (CS GROUP)" <chleroy@kernel•org>,
Alexander Gordeev <agordeev@linux•ibm.com>,
Gerald Schaefer <gerald.schaefer@linux•ibm.com>,
Heiko Carstens <hca@linux•ibm.com>,
Vasily Gorbik <gor@linux•ibm.com>,
Christian Borntraeger <borntraeger@linux•ibm.com>,
Sven Schnelle <svens@linux•ibm.com>,
x86@kernel•org
Subject: Re: [PATCH v6 20/20] swiotlb: remove unused SWIOTLB_FORCE flag
Date: Tue, 9 Jun 2026 15:44:34 +0200 [thread overview]
Message-ID: <20260609154434.13dba7b9@mordecai> (raw)
In-Reply-To: <20260604083959.1265923-21-aneesh.kumar@kernel.org>
On Thu, 4 Jun 2026 14:09:59 +0530
"Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel•org> wrote:
> SWIOTLB_FORCE has no remaining in-tree users. Forced bouncing is now
> controlled through the swiotlb=force command line option via
> swiotlb_force_bounce.
>
> Remove the unused flag and simplify the force_bounce initialization.
>
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel•org>
> ---
> include/linux/swiotlb.h | 1 -
> kernel/dma/swiotlb.c | 3 +--
> 2 files changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index 526f82e9da45..af88ca7182f4 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -15,7 +15,6 @@ struct page;
> struct scatterlist;
>
> #define SWIOTLB_VERBOSE (1 << 0) /* verbose initialization */
> -#define SWIOTLB_FORCE (1 << 1) /* force bounce buffering */
> #define SWIOTLB_ANY (1 << 2) /* allow any memory for the buffer */
These constants are kernel-internal, so let's not leave a hole in the
bitmask... I mean, what about changing SWIOTLB_ANY to (1 << 1) after
you remove SWIOTLB_FORCE?
Other than that, LGTM.
I consider this whole series a big step towards saner handling of
encrypted/decrypted memory for DMA buffers. Thank you for your effort!
Petr T
>
> /*
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index e4bd8c9eaeda..81cc4928e949 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -400,8 +400,7 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
> if (swiotlb_force_disable)
> return;
>
> - io_tlb_default_mem.force_bounce =
> - swiotlb_force_bounce || (flags & SWIOTLB_FORCE);
> + io_tlb_default_mem.force_bounce = swiotlb_force_bounce;
>
> #ifdef CONFIG_SWIOTLB_DYNAMIC
> if (!remap)
next prev parent reply other threads:[~2026-06-09 13:44 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-04 8:39 [PATCH v6 00/20] dma-mapping: Use DMA_ATTR_CC_SHARED through direct, pool and swiotlb paths Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 01/20] s390: Expose protected virtualization through cc_platform_has() Aneesh Kumar K.V (Arm)
2026-06-06 0:34 ` JAEHOON KIM
2026-06-09 13:44 ` Catalin Marinas
2026-06-04 8:39 ` [PATCH v6 02/20] dma-direct: swiotlb: handle swiotlb alloc/free outside __dma_direct_alloc_pages Aneesh Kumar K.V (Arm)
2026-06-09 12:15 ` Petr Tesarik
2026-06-04 8:39 ` [PATCH v6 03/20] dma-direct: use DMA_ATTR_CC_SHARED in alloc/free paths Aneesh Kumar K.V (Arm)
2026-06-09 12:18 ` Petr Tesarik
2026-06-04 8:39 ` [PATCH v6 04/20] dma-pool: track decrypted atomic pools and select them via attrs Aneesh Kumar K.V (Arm)
2026-06-09 12:23 ` Petr Tesarik
2026-06-09 14:32 ` Jason Gunthorpe
2026-06-04 8:39 ` [PATCH v6 05/20] dma: swiotlb: pass mapping attributes by reference Aneesh Kumar K.V (Arm)
2026-06-09 12:21 ` Petr Tesarik
2026-06-04 8:39 ` [PATCH v6 06/20] dma: swiotlb: track pool encryption state and honor DMA_ATTR_CC_SHARED Aneesh Kumar K.V (Arm)
2026-06-09 12:48 ` Petr Tesarik
2026-06-04 8:39 ` [PATCH v6 07/20] dma-mapping: make dma_pgprot() " Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 08/20] dma-direct: pass attrs to dma_capable() for DMA_ATTR_CC_SHARED checks Aneesh Kumar K.V (Arm)
2026-06-09 12:50 ` Petr Tesarik
2026-06-04 8:39 ` [PATCH v6 09/20] dma-direct: make dma_direct_map_phys() honor DMA_ATTR_CC_SHARED Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 10/20] dma-direct: set decrypted flag for remapped DMA allocations Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 11/20] dma-direct: select DMA address encoding from DMA_ATTR_CC_SHARED Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 12/20] dma-pool: fix page leak in atomic_pool_expand() cleanup Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 13/20] dma-direct: rename ret to cpu_addr in alloc helpers Aneesh Kumar K.V (Arm)
2026-06-09 12:54 ` Petr Tesarik
2026-06-04 8:39 ` [PATCH v6 14/20] dma-direct: return struct page from dma_direct_alloc_from_pool() Aneesh Kumar K.V (Arm)
2026-06-09 13:12 ` Petr Tesarik
2026-06-09 13:45 ` Catalin Marinas
2026-06-09 14:15 ` Jason Gunthorpe
2026-06-04 8:39 ` [PATCH v6 15/20] iommu/dma: Check atomic pool allocation result directly Aneesh Kumar K.V (Arm)
2026-06-09 13:13 ` Petr Tesarik
2026-06-04 8:39 ` [PATCH v6 16/20] dma: swiotlb: free dynamic pools from process context Aneesh Kumar K.V (Arm)
2026-06-09 13:23 ` Petr Tesarik
2026-06-04 8:39 ` [PATCH v6 17/20] dma: swiotlb: handle set_memory_decrypted() failures Aneesh Kumar K.V (Arm)
2026-06-09 13:32 ` Petr Tesarik
2026-06-04 8:39 ` [PATCH v6 18/20] dma: free atomic pool pages by physical address Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 19/20] swiotlb: Preserve allocation virtual address for dynamic pools Aneesh Kumar K.V (Arm)
2026-06-09 13:40 ` Petr Tesarik
2026-06-04 8:39 ` [PATCH v6 20/20] swiotlb: remove unused SWIOTLB_FORCE flag Aneesh Kumar K.V (Arm)
2026-06-09 13:44 ` Petr Tesarik [this message]
2026-06-09 13:43 ` [PATCH v6 00/20] dma-mapping: Use DMA_ATTR_CC_SHARED through direct, pool and swiotlb paths Catalin Marinas
2026-06-09 14:47 ` Jason Gunthorpe
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