Re: [PATCH v4 2/2] dma: replace zone_dma_bits by zone_dma_limit
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2024-08-01 10:09:11
Also in:
linux-iommu, linux-s390, linuxppc-dev, lkml
On Thu, Aug 01, 2024 at 11:25:07AM +0300, Baruch Siach wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 9b5ab6818f7f..c45e2152ca9e 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c@@ -115,35 +115,35 @@ static void __init arch_reserve_crashkernel(void) } /* - * Return the maximum physical address for a zone accessible by the given bits - * limit. If DRAM starts above 32-bit, expand the zone to the maximum + * Return the maximum physical address for a zone given its limit. + * If DRAM starts above 32-bit, expand the zone to the maximum * available memory, otherwise cap it at 32-bit. */ -static phys_addr_t __init max_zone_phys(unsigned int zone_bits) +static phys_addr_t __init max_zone_phys(phys_addr_t zone_limit) { - phys_addr_t zone_mask = DMA_BIT_MASK(zone_bits); phys_addr_t phys_start = memblock_start_of_DRAM(); if (phys_start > U32_MAX) - zone_mask = PHYS_ADDR_MAX; - else if (phys_start > zone_mask) - zone_mask = U32_MAX; + zone_limit = PHYS_ADDR_MAX; + else if (phys_start > zone_limit) + zone_limit = U32_MAX; - return min(zone_mask, memblock_end_of_DRAM() - 1) + 1; + return min(zone_limit, memblock_end_of_DRAM() - 1) + 1; }
OK, so no functional change here which is good. But isn't this series missing some additional patches to limit ZONE_DMA? For you platform, the above function expands ZONE_DMA to the whole RAM which IIUC it's not what you want eventually. -- Catalin