Toss4 cleanup (LLNL#166)

* Replaces #define around msr_devnode with _Generic The type of (((struct class *)0)->devnode) has changed at least twice in the mainline kernel. Coding based on mainline kernel versions has repeatedly run into the problem of distros backporting features to older kernels. Solved here using _Generic and multiple function definitions. * Continuing to versionproof use of devnode. * Fixes more nodedev issues. * Last of the devnode issues. * Fixes copyright year and formatting issues. Per Stephanie's comments. * minor code formatting - add new lines between function definitions - use 4 instead of 8 spaces for indents --------- Co-authored-by: Barry <[email protected]> Co-authored-by: Stephanie Brink <[email protected]>
rountree · Sep 23, 2024 · d9fd51a · d9fd51a
1 parent 465f56e
commit d9fd51a
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Showing 4 changed files with 91 additions and 40 deletions.
diff --git a/msr_allowlist.c b/msr_allowlist.c
@@ -361,15 +361,25 @@ static int parse_next_allowlist_entry(char *inbuf, char **nextinbuf, struct allo
     return *nextinbuf - inbuf;
 }
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,39)
-static char *msr_allowlist_nodename(struct device *dev, mode_t *mode)
-#else
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(6,2,0)
-static char *msr_allowlist_nodename(struct device *dev, umode_t *mode)
-#else
-static char *msr_allowlist_nodename(const struct device *dev, umode_t *mode)
-#endif
-#endif
+
+#define msr_allowlist_nodename_selector _Generic(\
+    (((struct class *)0)->devnode),\
+    char* (*) (struct device *,       mode_t  *) : msr_allowlist_nodename1,\
+    char* (*) (struct device *,       umode_t *) : msr_allowlist_nodename2,\
+    char* (*) (const struct device *, umode_t *) : msr_allowlist_nodename3 \
+    )
+
+static char *msr_allowlist_nodename1(struct device *dev, mode_t *mode)
+{
+    return kasprintf(GFP_KERNEL, "cpu/msr_allowlist");
+}
+
+static char *msr_allowlist_nodename2(struct device *dev, umode_t *mode)
+{
+    return kasprintf(GFP_KERNEL, "cpu/msr_allowlist");
+}
+
+static char *msr_allowlist_nodename3(const struct device *dev, umode_t *mode)
 {
     return kasprintf(GFP_KERNEL, "cpu/msr_allowlist");
 }
@@ -429,7 +439,7 @@ int msr_allowlist_init(int *majordev)
     }
     cdev_class_created = 1;
 
-    cdev_class->devnode = msr_allowlist_nodename;
+    cdev_class->devnode = msr_allowlist_nodename_selector;
 
     dev = device_create(cdev_class, NULL, MKDEV(*majordev, 0), NULL, "msr_allowlist");
     if (IS_ERR(dev))

diff --git a/msr_batch.c b/msr_batch.c
@@ -179,15 +179,24 @@ void msrbatch_cleanup(int majordev)
     }
 }
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,39)
-static char *msrbatch_nodename(struct device *dev, mode_t *mode)
-#else
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(6,2,0)
-static char *msrbatch_nodename(struct device *dev, umode_t *mode)
-#else
-static char *msrbatch_nodename(const struct device *dev, umode_t *mode)
-#endif
-#endif
+#define msrbatch_nodename_selector _Generic(\
+    (((struct class *)0)->devnode),\
+    char* (*) (      struct device *,  mode_t *) : msrbatch_nodename1,\
+    char* (*) (      struct device *, umode_t *) : msrbatch_nodename2,\
+    char* (*) (const struct device *, umode_t *) : msrbatch_nodename3 \
+    )
+
+static char *msrbatch_nodename1(struct device *dev, mode_t *mode)
+{
+    return kasprintf(GFP_KERNEL, "cpu/msr_batch");
+}
+
+static char *msrbatch_nodename2(struct device *dev, umode_t *mode)
+{
+    return kasprintf(GFP_KERNEL, "cpu/msr_batch");
+}
+
+static char *msrbatch_nodename3(const struct device *dev, umode_t *mode)
 {
     return kasprintf(GFP_KERNEL, "cpu/msr_batch");
 }
@@ -223,7 +232,7 @@ int msrbatch_init(int *majordev)
     }
     cdev_class_created = 1;
 
-    cdev_class->devnode = msrbatch_nodename;
+    cdev_class->devnode = msrbatch_nodename_selector;
 
     dev = device_create(cdev_class, NULL, MKDEV(*majordev, 0), NULL, "msr_batch");
     if (IS_ERR(dev))

diff --git a/msr_entry.c b/msr_entry.c
@@ -254,15 +254,30 @@ static struct notifier_block __refdata msr_class_cpu_notifier =
 };
 #endif
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,39)
-static char *msr_devnode(struct device *dev, mode_t *mode)
-#else
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(6,2,0)
-static char *msr_devnode(struct device *dev, umode_t *mode)
-#else
-static char *msr_devnode(const struct device *dev, umode_t *mode)
-#endif
-#endif
+/* The type of (((struct class *)0)->devnode) has changed at least
+ * twice in the mainline linux kernel.  Trying to pin these changes
+ * to specific mainline kernel versions runs into the problem of
+ * distros backporting features to older kernels.  Instead, we are
+ * now keying off of the change in the parameter types.*/
+
+#define msr_devnode_selector _Generic(\
+    (((struct class *)0)->devnode),\
+    char * (*) (struct device *, mode_t *) : msr_devnode1,\
+    char * (*) (struct device *, umode_t *) : msr_devnode2,\
+    char * (*) (const struct device *, umode_t *) : msr_devnode3\
+    )
+
+static char *msr_devnode1(struct device *dev, mode_t *mode)
+{
+    return kasprintf(GFP_KERNEL, "cpu/%u/msr_safe", MINOR(dev->devt));
+}
+
+static char *msr_devnode2(struct device *dev, umode_t *mode)
+{
+    return kasprintf(GFP_KERNEL, "cpu/%u/msr_safe", MINOR(dev->devt));
+}
+
+static char *msr_devnode3(const struct device *dev, umode_t *mode)
 {
     return kasprintf(GFP_KERNEL, "cpu/%u/msr_safe", MINOR(dev->devt));
 }
@@ -329,7 +344,7 @@ static int __init msr_init(void)
         err = PTR_ERR(msr_class);
         goto out_chrdev;
     }
-    msr_class->devnode = msr_devnode;
+    msr_class->devnode = msr_devnode_selector;
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4,10,0)
     i = 0;

diff --git a/msr_version.c b/msr_version.c
@@ -52,15 +52,32 @@ static const struct file_operations fops =
     .open = open_version
 };
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,39)
-static char *msr_version_nodename(struct device *dev, mode_t *mode)
-#else
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(6,2,0)
-static char *msr_version_nodename(struct device *dev, umode_t *mode)
-#else
-static char *msr_version_nodename(const struct device *dev, umode_t *mode)
-#endif
-#endif
+#define msr_version_nodename_selector _Generic(\
+    (((struct class *)0)->devnode),\
+    char * (*) (      struct device *,  mode_t *) : msr_version_nodename1,\
+    char * (*) (      struct device *, umode_t *) : msr_version_nodename2,\
+    char * (*) (const struct device *, umode_t *) : msr_version_nodename3 \
+    )
+
+static char *msr_version_nodename1(struct device *dev, mode_t *mode)
+{
+    if (mode)
+    {
+        *mode = 0400;   // read-only
+    }
+    return kasprintf(GFP_KERNEL, "cpu/msr_safe_version");
+}
+
+static char *msr_version_nodename2(struct device *dev, umode_t *mode)
+{
+    if (mode)
+    {
+        *mode = 0400;   // read-only
+    }
+    return kasprintf(GFP_KERNEL, "cpu/msr_safe_version");
+}
+
+static char *msr_version_nodename3(const struct device *dev, umode_t *mode)
 {
     if (mode)
     {
@@ -122,7 +139,7 @@ int msr_version_init(int *majordev)
     }
     cdev_class_created = 1;
 
-    cdev_class->devnode = msr_version_nodename;
+    cdev_class->devnode = msr_version_nodename_selector;
 
     dev = device_create(cdev_class, NULL, MKDEV(*majordev, 0), NULL, "msr_safe_version");
     if (IS_ERR(dev))