[PATCH ndctl v2 03/10] daxctl: add resize support in reconfigure-device

[Joao Martins]

Add the ability to change the size of an inactive dax
device. Uses of this includes adjusting existing devices
or enterily freeing the region device to make the space
available.

        $ daxctl disable-device dax0.0
        disabled 1 device
        $ daxctl reconfigure-device -s 0 dax0.0
        reconfigured 1 device
        $ daxctl reconfigure-device -s 4G dax0.0
        reconfigured 1 device

@size (-s) and @mode (-m) are mutually exclusive as the latter relates
to assigning memory to System-RAM through kmem as opposed
to reconfiguring dynamic dax devices.

Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
 Documentation/daxctl/daxctl-reconfigure-device.txt | 16 +++++++++++
 daxctl/device.c                                    | 32 ++++++++++++++++++++--
 2 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/Documentation/daxctl/daxctl-reconfigure-device.txt 
b/Documentation/daxctl/daxctl-reconfigure-device.txt
index cb28fed24e52..8caae436faae 100644
--- a/Documentation/daxctl/daxctl-reconfigure-device.txt
+++ b/Documentation/daxctl/daxctl-reconfigure-device.txt
@@ -75,6 +75,14 @@ daxctl_dev_get_target_node() or 'daxctl list')
 # numactl --cpunodebind=0-1 --membind=2 -- some-service --opt1 --opt2
 ----
 
+* Change the size of a dax device
+----
+# daxctl reconfigure-device dax0.1 -s 16G
+reconfigured 1 device
+# daxctl reconfigure-device dax0.1 -s 0
+reconfigured 1 device
+----
+
 DESCRIPTION
 -----------
 
@@ -120,6 +128,14 @@ OPTIONS
        more /dev/daxX.Y devices, where X is the region id and Y is the device
        instance id.
 
+-s::
+--size=::
+       For regions that support dax device creation, change the device size
+       in bytes. This option supports the suffixes "k" or "K" for KiB, "m" or
+       "M" for MiB, "g" or "G" for GiB and "t" or "T" for TiB.
+
+       The size must be a multiple of the region alignment.
+
 -m::
 --mode=::
        Specify the mode to which the dax device(s) should be reconfigured.
diff --git a/daxctl/device.c b/daxctl/device.c
index 705f1f8ff7f6..033e098eafe0 100644
--- a/daxctl/device.c
+++ b/daxctl/device.c
@@ -9,6 +9,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/sysmacros.h>
+#include <util/size.h>
 #include <util/json.h>
 #include <util/filter.h>
 #include <json-c/json.h>
@@ -20,6 +21,7 @@ static struct {
        const char *dev;
        const char *mode;
        const char *region;
+       const char *size;
        bool no_online;
        bool no_movable;
        bool force;
@@ -34,6 +36,7 @@ enum dev_mode {
 };
 
 static enum dev_mode reconfig_mode = DAXCTL_DEV_MODE_UNKNOWN;
+static long long size = -1;
 static unsigned long flags;
 
 enum memory_zone {
@@ -60,12 +63,16 @@ OPT_BOOLEAN('N', "no-online", &param.no_online, \
 OPT_BOOLEAN('f', "force", &param.force, \
                "attempt to offline memory sections before reconfiguration")
 
+#define CREATE_OPTIONS() \
+OPT_STRING('s', "size", &param.size, "size", "size to switch the device to")
+
 #define ZONE_OPTIONS() \
 OPT_BOOLEAN('\0', "no-movable", &param.no_movable, \
                "online memory in ZONE_NORMAL")
 
 static const struct option reconfig_options[] = {
        BASE_OPTIONS(),
+       CREATE_OPTIONS(),
        RECONFIG_OPTIONS(),
        ZONE_OPTIONS(),
        OPT_END(),
@@ -90,6 +97,7 @@ static const char *parse_device_options(int argc, const char 
**argv,
                usage,
                NULL
        };
+       unsigned long long units = 1;
        int i, rc = 0;
 
        argc = parse_options(argc, argv, options, u, 0);
@@ -135,12 +143,14 @@ static const char *parse_device_options(int argc, const 
char **argv,
        /* Handle action-specific options */
        switch (action) {
        case ACTION_RECONFIG:
-               if (!param.mode) {
-                       fprintf(stderr, "error: a 'mode' option is required\n");
+               if (!param.size && !param.mode) {
+                       fprintf(stderr, "error: a 'mode' or 'size' option is 
required\n");
                        usage_with_options(u, reconfig_options);
                        rc = -EINVAL;
                }
-               if (strcmp(param.mode, "system-ram") == 0) {
+               if (param.size) {
+                       size = __parse_size64(param.size, &units);
+               } else if (strcmp(param.mode, "system-ram") == 0) {
                        reconfig_mode = DAXCTL_DEV_MODE_RAM;
                        if (param.no_movable)
                                mem_zone = MEM_ZONE_NORMAL;
@@ -309,6 +319,17 @@ static int dev_offline_memory(struct daxctl_dev *dev)
        return 0;
 }
 
+static int dev_resize(struct daxctl_dev *dev, unsigned long long val)
+{
+       int rc;
+
+       rc = daxctl_dev_set_size(dev, val);
+       if (rc < 0)
+               return rc;
+
+       return 0;
+}
+
 static int disable_devdax_device(struct daxctl_dev *dev)
 {
        struct daxctl_memory *mem = daxctl_dev_get_memory(dev);
@@ -418,6 +439,11 @@ static int do_reconfig(struct daxctl_dev *dev, enum 
dev_mode mode,
        struct json_object *jdev;
        int rc = 0;
 
+       if (size >= 0) {
+               rc = dev_resize(dev, size);
+               return rc;
+       }
+
        switch (mode) {
        case DAXCTL_DEV_MODE_RAM:
                rc = reconfig_mode_system_ram(dev);
-- 
1.8.3.1
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