Re: [PATCH 27/27] ... and the intel_rdt driver

David Howells
2017-06-14T22:31:36Z

This also needs the attached addition to fix the intel_rdt driver.

David
---
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index f5af0cc7eb0d..d026701894fd 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -35,6 +35,11 @@
#include <asm/intel_rdt.h>
#include <asm/intel_rdt_common.h>

+struct rdt_fs_context {
+ struct kernfs_fs_context kfc;
+ bool enable_cdp;
+};
+
DEFINE_STATIC_KEY_FALSE(rdt_enable_key);
struct kernfs_root *rdt_root;
struct rdtgroup rdtgroup_default;
@@ -743,22 +748,6 @@ static void cdp_disable(void)
}
}

-static int parse_rdtgroupfs_options(char *data)
-{
- char *token, *o = data;
- int ret = 0;
-
- while ((token = strsep(&o, ",")) != NULL) {
- if (!*token)
- return -EINVAL;
-
- if (!strcmp(token, "cdp"))
- ret = cdp_enable();
- }
-
- return ret;
-}
-
/*
* We don't allow rdtgroup directories to be created anywhere
* except the root directory. Thus when looking for the rdtgroup
@@ -823,11 +812,9 @@ void rdtgroup_kn_unlock(struct kernfs_node *kn)
}
}

-static struct dentry *rdt_mount(struct file_system_type *fs_type,
- int flags, const char *unused_dev_name,
- void *data)
+static int rdt_get_tree(struct fs_context *fc)
{
- struct dentry *dentry;
+ struct rdt_fs_context *ctx = container_of(fc, struct rdt_fs_context, kfc.fc);
int ret;

mutex_lock(&rdtgroup_mutex);
@@ -835,27 +822,25 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
* resctrl file system can only be mounted once.
*/
if (static_branch_unlikely(&rdt_enable_key)) {
- dentry = ERR_PTR(-EBUSY);
+ errorf("intel_rdt: Can only mount once");
+ ret = -EBUSY;
goto out;
}

- ret = parse_rdtgroupfs_options(data);
- if (ret) {
- dentry = ERR_PTR(ret);
- goto out_cdp;
+ if (ctx->enable_cdp) {
+ ret = cdp_enable();
+ if (ret < 0)
+ goto out_cdp;
}

closid_init();

ret = rdtgroup_create_info_dir(rdtgroup_default.kn);
- if (ret) {
- dentry = ERR_PTR(ret);
+ if (ret < 0)
goto out_cdp;
- }

- dentry = kernfs_mount(fs_type, flags, rdt_root,
- RDTGROUP_SUPER_MAGIC, NULL);
- if (IS_ERR(dentry))
+ ret = kernfs_get_tree(&ctx->kfc);
+ if (ret < 0)
goto out_cdp;

static_branch_enable(&rdt_enable_key);
@@ -865,8 +850,42 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
cdp_disable();
out:
mutex_unlock(&rdtgroup_mutex);
+ return ret;
+}
+
+static int rdt_parse_option(struct fs_context *fc, char *p)
+{
+ struct rdt_fs_context *ctx = container_of(fc, struct rdt_fs_context, kfc.fc);

- return dentry;
+ if (strcmp(p, "cdp") == 0) {
+ ctx->enable_cdp = true;
+ return 0;
+ }
+
+ return invalf("intel_rdt: Unknown option");
+}
+
+static void rdt_fs_context_free(struct fs_context *fc)
+{
+ struct rdt_fs_context *ctx = container_of(fc, struct rdt_fs_context, kfc.fc);
+
+ kernfs_free_fs_context(&ctx->kfc);
+}
+
+static const struct fs_context_operations rdt_fs_context_ops = {
+ .free = rdt_fs_context_free,
+ .parse_option = rdt_parse_option,
+ .get_tree = rdt_get_tree,
+};
+
+static int rdt_init_fs_context(struct fs_context *fc, struct super_block *src_sb)
+{
+ struct rdt_fs_context *ctx = container_of(fc, struct rdt_fs_context, kfc.fc);
+
+ ctx->kfc.root = rdt_root;
+ ctx->kfc.magic = RDTGROUP_SUPER_MAGIC;
+ ctx->kfc.fc.ops = &rdt_fs_context_ops;
+ return 0;
}

static int reset_all_ctrls(struct rdt_resource *r)
@@ -994,9 +1013,10 @@ static void rdt_kill_sb(struct super_block *sb)
}

static struct file_system_type rdt_fs_type = {
- .name = "resctrl",
- .mount = rdt_mount,
- .kill_sb = rdt_kill_sb,
+ .name = "resctrl",
+ .fs_context_size = sizeof(struct rdt_fs_context),
+ .init_fs_context = rdt_init_fs_context,
+ .kill_sb = rdt_kill_sb,
};

static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name,