lightnvm: Inherit mdts from the parent nvme device

Current lightnvm and pblk implementation does not care about NVMe max
data transfer size, which can be smaller than 64*K=256K. There are
existing NVMe controllers which NVMe max data transfer size is lower
that 256K (for example 128K, which happens for existing NVMe
controllers which are NVMe spec compliant). Such a controllers are not
able to handle command which contains 64 PPAs, since the the size of
DMAed buffer will be above the capabilities of such a controller.

Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
Reviewed-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Reviewed-by: Javier González <javier@javigon.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 5f82036..c01f83b 100644 (file)
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -325,6 +325,7 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct nvm_ioctl_create *create)
        struct nvm_target *t;
        struct nvm_tgt_dev *tgt_dev;
        void *targetdata;
+       unsigned int mdts;
        int ret;
 
        switch (create->conf.type) {
@@ -412,8 +413,12 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct nvm_ioctl_create *create)
        tdisk->private_data = targetdata;
        tqueue->queuedata = targetdata;
 
-       blk_queue_max_hw_sectors(tqueue,
-                       (dev->geo.csecs >> 9) * NVM_MAX_VLBA);
+       mdts = (dev->geo.csecs >> 9) * NVM_MAX_VLBA;
+       if (dev->geo.mdts) {
+               mdts = min_t(u32, dev->geo.mdts,
+                               (dev->geo.csecs >> 9) * NVM_MAX_VLBA);
+       }
+       blk_queue_max_hw_sectors(tqueue, mdts);
 
        set_capacity(tdisk, tt->capacity(targetdata));
        add_disk(tdisk);

diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
index 949e29e..4f20a10 100644 (file)
--- a/drivers/nvme/host/lightnvm.c
+++ b/drivers/nvme/host/lightnvm.c
@@ -977,6 +977,7 @@ int nvme_nvm_register(struct nvme_ns *ns, char *disk_name, int node)
        geo->csecs = 1 << ns->lba_shift;
        geo->sos = ns->ms;
        geo->ext = ns->ext;
+       geo->mdts = ns->ctrl->max_hw_sectors;
 
        dev->q = q;
        memcpy(dev->name, disk_name, DISK_NAME_LEN);

diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
index 5d865a5..d3b0270 100644 (file)
--- a/include/linux/lightnvm.h
+++ b/include/linux/lightnvm.h
@@ -358,6 +358,7 @@ struct nvm_geo {
        u16     csecs;          /* sector size */
        u16     sos;            /* out-of-band area size */
        bool    ext;            /* metadata in extended data buffer */
+       u32     mdts;           /* Max data transfer size*/
 
        /* device write constrains */
        u32     ws_min;         /* minimum write size */