Re: [PATCH RFC PKS/PMEM 24/58] fs/freevxfs: Utilize new kmap_thread()
From: Ira Weiny <ira.weiny@intel.com>
Date: 2020-10-13 20:53:48
Also in:
amd-gfx, bpf, ceph-devel, dri-devel, intel-gfx, intel-wired-lan, io-uring, kexec, kvm, linux-bcache, linux-block, linux-btrfs, linux-cifs, linux-doc, linux-efi, linux-ext4, linux-f2fs-devel, linux-fsdevel, linux-kselftest, linux-mm, linux-mmc, linux-nfs, linux-rdma, linux-scsi, linux-um, lkml, netdev, nvdimm, target-devel, xen-devel
On Tue, Oct 13, 2020 at 12:25:44PM +0100, Christoph Hellwig wrote:
quoted
- kaddr = kmap(pp); + kaddr = kmap_thread(pp); memcpy(kaddr, vip->vii_immed.vi_immed + offset, PAGE_SIZE); - kunmap(pp); + kunmap_thread(pp);You only Cced me on this particular patch, which means I have absolutely no idea what kmap_thread and kunmap_thread actually do, and thus can't provide an informed review.
Sorry the list was so big I struggled with who to CC and on which patches.
That being said I think your life would be a lot easier if you add helpers for the above code sequence and its counterpart that copies to a potential hughmem page first, as that hides the implementation details from most users.
Matthew Wilcox and Al Viro have suggested similar ideas. https://lore.kernel.org/lkml/20201013205012.GI2046448@iweiny-DESK2.sc.intel.com/ (local) Ira