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/core.c b/drivers/nvme/host/core.c
index 8040fc1..acc816b 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1897,6 +1897,8 @@ int nvme_init_identify(struct nvme_ctrl *ctrl)
                ctrl->cntlid = le16_to_cpu(id->cntlid);
                ctrl->hmpre = le32_to_cpu(id->hmpre);
                ctrl->hmmin = le32_to_cpu(id->hmmin);
+               ctrl->hmminds = le32_to_cpu(id->hmminds);
+               ctrl->hmmaxd = le16_to_cpu(id->hmmaxd);
        }
 
        kfree(id);

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index b8ba7c8..d3f3c44 100644 (file)
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -181,8 +181,11 @@ struct nvme_ctrl {
        u64 ps_max_latency_us;
        bool apst_enabled;
 
+       /* PCIe only: */
        u32 hmpre;
        u32 hmmin;
+       u32 hmminds;
+       u16 hmmaxd;
 
        /* Fabrics only */
        u16 sqsize;

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 5ed12fb..4a21213 100644 (file)
--- 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)

diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 5144f91..87723c8 100644 (file)
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -226,7 +226,9 @@ struct nvme_id_ctrl {
        __le16                  mntmt;
        __le16                  mxtmt;
        __le32                  sanicap;
-       __u8                    rsvd332[180];
+       __le32                  hmminds;
+       __le16                  hmmaxd;
+       __u8                    rsvd338[174];
        __u8                    sqes;
        __u8                    cqes;
        __le16                  maxcmd;