devlink: report maximum number of snapshots with regions

Each region has an independently configurable number of maximum
snapshots. This information is not reported to userspace, making it not
very discoverable. Fix this by adding a new
DEVLINK_ATTR_REGION_MAX_SNAPSHOST attribute which is used to report this
maximum.

Ex:

  $devlink region
  pci/0000:af:00.0/nvm-flash: size 10485760 snapshot [] max 1
  pci/0000:af:00.0/device-caps: size 4096 snapshot [] max 10
  pci/0000:af:00.1/nvm-flash: size 10485760 snapshot [] max 1
  pci/0000:af:00.1/device-caps: size 4096 snapshot [] max 10

This information enables users to understand why a new region command
may fail due to having too many existing snapshots.

Reported-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/devlink/devlink-region.rst b/Documentation/networking/devlink/devlink-region.rst
index 58fe95e..f06dca9 100644 (file)
--- a/Documentation/networking/devlink/devlink-region.rst
+++ b/Documentation/networking/devlink/devlink-region.rst
@@ -44,8 +44,8 @@ example usage
 
     # Show all of the exposed regions with region sizes:
     $ devlink region show
-    pci/0000:00:05.0/cr-space: size 1048576 snapshot [1 2]
-    pci/0000:00:05.0/fw-health: size 64 snapshot [1 2]
+    pci/0000:00:05.0/cr-space: size 1048576 snapshot [1 2] max 8
+    pci/0000:00:05.0/fw-health: size 64 snapshot [1 2] max 8
 
     # Delete a snapshot using:
     $ devlink region del pci/0000:00:05.0/cr-space snapshot 1

diff --git a/Documentation/networking/devlink/ice.rst b/Documentation/networking/devlink/ice.rst
index a432dc4..32aea1f 100644 (file)
--- a/Documentation/networking/devlink/ice.rst
+++ b/Documentation/networking/devlink/ice.rst
@@ -141,6 +141,10 @@ Users can request an immediate capture of a snapshot via the
 
 .. code:: shell
 
+    $ devlink region show
+    pci/0000:01:00.0/nvm-flash: size 10485760 snapshot [] max 1
+    pci/0000:01:00.0/device-caps: size 4096 snapshot [] max 10
+
     $ devlink region new pci/0000:01:00.0/nvm-flash snapshot 1
     $ devlink region dump pci/0000:01:00.0/nvm-flash snapshot 1
 

diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 32f53a0..b897b80 100644 (file)
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -551,6 +551,8 @@ enum devlink_attr {
        DEVLINK_ATTR_RATE_NODE_NAME,            /* string */
        DEVLINK_ATTR_RATE_PARENT_NODE_NAME,     /* string */
 
+       DEVLINK_ATTR_REGION_MAX_SNAPSHOTS,      /* u32 */
+
        /* add new attributes above here, update the policy in devlink.c */
 
        __DEVLINK_ATTR_MAX,

diff --git a/net/core/devlink.c b/net/core/devlink.c
index b643030..4917112 100644 (file)
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -5078,6 +5078,11 @@ static int devlink_nl_region_fill(struct sk_buff *msg, struct devlink *devlink,
        if (err)
                goto nla_put_failure;
 
+       err = nla_put_u32(msg, DEVLINK_ATTR_REGION_MAX_SNAPSHOTS,
+                         region->max_snapshots);
+       if (err)
+               goto nla_put_failure;
+
        err = devlink_nl_region_snapshots_id_put(msg, devlink, region);
        if (err)
                goto nla_put_failure;