On Thu, 18 Nov 2021, Matthew Wilcox wrote: > On Wed, Nov 17, 2021 at 03:39:30PM +1100, NeilBrown wrote: > > +++ b/drivers/iommu/tegra-smmu.c > > @@ -676,12 +676,12 @@ static struct page *as_get_pde_page(struct tegra_smmu_as *as, > > * allocate page in a sleeping context if GFP flags permit. Hence > > * spinlock needs to be unlocked and re-locked after allocation. > > */ > > - if (!(gfp & __GFP_ATOMIC)) > > + if (gfp & __GFP_DIRECT_RECLAIM) > > spin_unlock_irqrestore(&as->lock, *flags); > > > > page = alloc_page(gfp | __GFP_DMA | __GFP_ZERO); > > > > - if (!(gfp & __GFP_ATOMIC)) > > + if (gfp & __GFP_DIRECT_RECLAIM) > > spin_lock_irqsave(&as->lock, *flags); > > > > /* > > Surely this should be gfpflags_allow_blocking() instead of poking about > in the innards of gfp flags? Possibly. Didn't know about gfpflags_allow_blocking(). From a quick grep in the kernel, a whole lot of other people don't know about it either, though clearly some do. Maybe we should reaname "__GFP_DIRECT_RECLAIM" to "__GFP_ALLOW_BLOCKING", because that is what most users seems to care about. If not, then we probably want a gfpflags_without_block() function that removes that flag, as lots of code wants to do that - and using the flag for one, and an inline for the other is not consistent. My leaning would be to __GFP_ALLOW_BLOCKING NeilBrown > > This patch seems like a good simplification to me. > > Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Thanks, NeilBrown
