nvme-pci: implement the HMB entry number and size limitations
Adds support for the new Host Memory Buffer Minimum Descriptor Entry Size
and Host Memory Maximum Descriptors Entries field that were added in
TP 4002 HMB Enhancements. These allow the controller to advertise
limits for the usual number of segments in the host memory buffer, as
well as a minimum usable per-segment size.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 5ed12fb..4a21213 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1625,6 +1625,10 @@ static int __nvme_alloc_host_mem(struct nvme_dev *dev, u64 preferred,
tmp = (preferred + chunk_size - 1);
do_div(tmp, chunk_size);
max_entries = tmp;
+
+ if (dev->ctrl.hmmaxd && dev->ctrl.hmmaxd < max_entries)
+ max_entries = dev->ctrl.hmmaxd;
+
descs = dma_zalloc_coherent(dev->dev, max_entries * sizeof(*descs),
&descs_dma, GFP_KERNEL);
if (!descs)
@@ -1681,7 +1685,7 @@ static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred)
/* start big and work our way down */
for (chunk_size = min_t(u64, preferred, PAGE_SIZE * MAX_ORDER_NR_PAGES);
- chunk_size >= PAGE_SIZE * 2;
+ chunk_size >= max_t(u32, dev->ctrl.hmminds * 4096, PAGE_SIZE * 2);
chunk_size /= 2) {
if (!__nvme_alloc_host_mem(dev, preferred, chunk_size)) {
if (!min || dev->host_mem_size >= min)