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swiotlb: consolidate rounding up default_nslabs

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default_nslabs are rounded up in two cases with exactly same comments.
Add a simple wrapper to reduce duplicate code/comments. It is preparatory
to adding more logics into the round-up.

No functional change intended.

Signed-off-by: Chao Gao <chao.gao@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Chao Gao 2022-07-15 18:45:34 +08:00 committed by Christoph Hellwig
parent 91561d4ecb
commit 44335487ba
1 changed files with 16 additions and 17 deletions
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33
kernel/dma/swiotlb.c
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@ -88,6 +88,20 @@ struct io_tlb_area {
spinlock_t lock;
};
/*
* Round up number of slabs to the next power of 2. The last area is going
* be smaller than the rest if default_nslabs is not power of two.
*
* Return true if default_nslabs is rounded up.
*/
static bool round_up_default_nslabs(void)
{
if (!default_nareas || is_power_of_2(default_nslabs))
return false;
default_nslabs = roundup_pow_of_two(default_nslabs);
return true;
}
static void swiotlb_adjust_nareas(unsigned int nareas)
{
if (!is_power_of_2(nareas))
@ -96,16 +110,9 @@ static void swiotlb_adjust_nareas(unsigned int nareas)
default_nareas = nareas;
pr_info("area num %d.\n", nareas);
/*
* Round up number of slabs to the next power of 2.
* The last area is going be smaller than the rest if
* default_nslabs is not power of two.
*/
if (nareas && !is_power_of_2(default_nslabs)) {
default_nslabs = roundup_pow_of_two(default_nslabs);
if (round_up_default_nslabs())
pr_info("SWIOTLB bounce buffer size roundup to %luMB",
(default_nslabs << IO_TLB_SHIFT) >> 20);
}
}
static int __init
@ -154,18 +161,10 @@ void __init swiotlb_adjust_size(unsigned long size)
if (default_nslabs != IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT)
return;
/*
* Round up number of slabs to the next power of 2.
* The last area is going be smaller than the rest if
* default_nslabs is not power of two.
*/
size = ALIGN(size, IO_TLB_SIZE);
default_nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
if (default_nareas) {
default_nslabs = roundup_pow_of_two(default_nslabs);
if (round_up_default_nslabs())
size = default_nslabs << IO_TLB_SHIFT;
}
pr_info("SWIOTLB bounce buffer size adjusted to %luMB", size >> 20);
}