23 Mar
2021
23 Mar
'21
4:06 p.m.
On Tue, Mar 23, 2021 at 04:46:00PM +0100, Thomas Hellström (Intel) wrote:
+static inline bool is_cow_mapping(vm_flags_t flags) +{
- return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
+}
Most driver places are just banning VM_SHARED.
I see you copied this from remap_pfn_range(), but that logic is so special I'm not sure..
It's actually used all over the place. Both in drivers and also redefined with CONFIG_MEM_SOFT_DIRTY which makes me think Daniels idea of vma_is_cow_mapping() is better since it won't clash and cause compilation failures...
Well, lets update more mmap fops to use this new helper then? Searching for VM_SHARED gives a good list, there are several in drivers/infiniband
Jason