Re: [PATCH v6 18/42] powerpc/powernv: Allocate PE# in deasending order
From: Alexey Kardashevskiy <hidden>
Date: 2015-08-10 14:39:02
Also in:
linux-devicetree, linux-pci
On 08/06/2015 02:11 PM, Gavin Shan wrote:
The available PE#, represented by a bitmap in the PHB, is allocated in ascending order.
Available PE# is available exactly because it is not allocated ;)
It conflicts with the fact that M64 segments are assigned in same order. In order to avoid the conflict, the patch allocates PE# in descending order.
What kind of conflict?
quoted hunk ↗ jump to hunk
Signed-off-by: Gavin Shan <redacted> --- arch/powerpc/platforms/powernv/pci-ioda.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index 56b058c..1c950e8 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c@@ -161,13 +161,18 @@ static struct pnv_ioda_pe *pnv_ioda_reserve_pe(struct pnv_phb *phb, int pe_no) static struct pnv_ioda_pe *pnv_ioda_alloc_pe(struct pnv_phb *phb) { unsigned long pe; + unsigned long limit = phb->ioda.total_pe_num - 1; do { pe = find_next_zero_bit(phb->ioda.pe_alloc, - phb->ioda.total_pe_num, 0); - if (pe >= phb->ioda.total_pe_num) + phb->ioda.total_pe_num, limit); + if (pe < phb->ioda.total_pe_num && + !test_and_set_bit(pe, phb->ioda.pe_alloc)) + break; + + if (--limit >= phb->ioda.total_pe_num) return NULL; - } while(test_and_set_bit(pe, phb->ioda.pe_alloc)); + } while (1);
Usually, if it is "while(1)", then it is "while(1){}" rather than
"do{}while(1)" :)
return pnv_ioda_init_pe(phb, pe); }
-- Alexey