From: John Garry <john.g.garry@oracle.com> mainline inclusion from mainline-v6.17-rc7 commit ac30cd304347f2daeece6998bb5f0ae2db64e397 category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/8862 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- As described at [0], much of the atomic write parts of the specification are lacking. For now, there is nothing which we can do in software about the lack of a dedicated NVMe write atomic command. As for reading the atomic write limits, it is felt that the per-namespace values are mostly properly specified and it is assumed that they are properly implemented. The specification of NAWUPF is quite clear. However the specification of NABSPF is less clear. The lack of clarity in NABSPF comes from deciding whether NABSPF applies when NSABP is 0 - it is assumed that NSABPF does not apply when NSABP is 0. As for the per-controller AWUPF, how this value applies to shared namespaces is missing in the specification. Furthermore, the value is in terms of logical blocks, which is an NS entity. Since AWUPF is so poorly defined, stop using it already together. Hopefully this will force vendors to implement NAWUPF support always. Note that AWUPF not only effects atomic write support, but also the physical block size reported for the device. To help users know this restriction, log an info message per NS. [0] https://lore.kernel.org/linux-nvme/20250707141834.GA30198@lst.de/ Tested-by: Nilay Shroff <nilay@linux.ibm.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: John Garry <john.g.garry@oracle.com> Signed-off-by: Keith Busch <kbusch@kernel.org> Conflicts: drivers/nvme/host/core.c [Context conflicts] Signed-off-by: Long Li <leo.lilong@huawei.com> --- drivers/nvme/host/core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index c1c6ffa32b17..b66250bffbac 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -1946,10 +1946,14 @@ static void nvme_update_disk_info(struct gendisk *disk, * and whether it should be used instead of AWUPF. If NAWUPF == * 0 then AWUPF must be used instead. */ - if (id->nsfeat & NVME_NS_FEAT_ATOMICS && id->nawupf) + if (id->nsfeat & NVME_NS_FEAT_ATOMICS && id->nawupf) { atomic_bs = (1 + le16_to_cpu(id->nawupf)) * bs; - else - atomic_bs = (1 + ns->ctrl->subsys->awupf) * bs; + } else { + if (ns->ctrl->subsys->awupf) + dev_info_once(ns->ctrl->device, + "AWUPF ignored, only NAWUPF accepted\n"); + atomic_bs = bs; + } nvme_update_atomic_write_disk_info(ns, id, &disk->queue->limits, bs, atomic_bs); -- 2.52.0