From: Christoph Hellwig <hch@lst.de>
To: Robin Murphy <robin.murphy@arm.com>
Cc: saravanak@google.com, konrad.wilk@oracle.com, marcorr@google.com,
gregkh@linuxfoundation.org, linux-nvme@lists.infradead.org,
kbusch@kernel.org, iommu@lists.linux-foundation.org,
erdemaktas@google.com, m.szyprowski@samsung.com,
Christoph Hellwig <hch@lst.de>,
jxgao@google.com
Subject: Re: [PATCH 3/8] swiotlb: factor out a nr_slots helper
Date: Fri, 5 Feb 2021 10:45:11 +0100 [thread overview]
Message-ID: <20210205094511.GA2801@lst.de> (raw)
In-Reply-To: <ae995e9d-4476-cea2-a4d7-9e9cbab5aafd@arm.com>
On Thu, Feb 04, 2021 at 10:09:02PM +0000, Robin Murphy wrote:
>> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
>> index 838dbad10ab916..0c0b81799edbdb 100644
>> --- a/kernel/dma/swiotlb.c
>> +++ b/kernel/dma/swiotlb.c
>> @@ -194,6 +194,11 @@ static inline unsigned long io_tlb_offset(unsigned long val)
>> return val & (IO_TLB_SEGSIZE - 1);
>> }
>> +static unsigned long nr_slots(u64 val)
>> +{
>> + return ALIGN(val, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
>
> Would DIV_ROUND_UP(val, 1 << IOTLB_SHIFT) be even clearer?
Not sure it is all that much cleaner, but it does fit a common pattern,
so I'll switch to that.
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next prev parent reply other threads:[~2021-02-05 9:45 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-04 19:30 preserve DMA offsets when using swiotlb Christoph Hellwig
2021-02-04 19:30 ` [PATCH 1/8] driver core: add a min_align_mask field to struct device_dma_parameters Christoph Hellwig
2021-02-04 19:44 ` Greg KH
2021-02-04 19:30 ` [PATCH 2/8] swiotlb: add a io_tlb_offset helper Christoph Hellwig
2021-02-04 19:30 ` [PATCH 3/8] swiotlb: factor out a nr_slots helper Christoph Hellwig
2021-02-04 22:09 ` Robin Murphy
2021-02-05 9:45 ` Christoph Hellwig [this message]
2021-02-04 19:30 ` [PATCH 4/8] swiotlb: clean up swiotlb_tbl_unmap_single Christoph Hellwig
2021-02-04 19:30 ` [PATCH 5/8] swiotlb: refactor swiotlb_tbl_map_single Christoph Hellwig
2021-02-04 22:12 ` Robin Murphy
2021-02-05 9:45 ` Christoph Hellwig
2021-02-04 19:30 ` [PATCH 6/8] swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single Christoph Hellwig
2021-02-04 19:30 ` [PATCH 7/8] swiotlb: respect min_align_mask Christoph Hellwig
2021-02-04 23:13 ` Robin Murphy
2021-02-05 10:34 ` Christoph Hellwig
2021-02-04 19:30 ` [PATCH 8/8] nvme-pci: set min_align_mask Christoph Hellwig
2021-02-04 19:32 ` Christoph Hellwig
2021-02-05 11:50 ` preserve DMA offsets when using swiotlb Christoph Hellwig
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