Re:The Linux Kernel, CDDL and Related Issues
by mioelnir on Friday February 26, 2016 @09:14PM
(#11185728)
So, because it supports more than one KBI it is a derived work, whereas if it had one static KBI to only work on one specific version it would not be derived?
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Re:The Linux Kernel, CDDL and Related Issues
by jepler on Saturday February 27, 2016 @09:19AM
(#11187134)
Not necessarily. But let's look at one specific instance of adapting to a different "KBI", as you call it. I picked HAVE_VFS_ITERATE, just because it sounded interesting. What's the story?
Well, in May 2013, Al Viro committed code to Linux to add several new "KBIs", dir_emit and related functions (in include/linux/fs.h, which does not have a license block):
commit 5f99f4e79abc64ed9d93a4b0158b21c64ff7f478
Author: Al Viro <[email protected]>
AuthorDate: Wed May 15 20:23:06 2013 -0400
Commit: Al Viro <[email protected]>
CommitDate: Sat Jun 29 12:46:48 2013 +0400
[readdir] switch dcache_readdir() users to ->iterate()
new helpers - dir_emit_dot(file, ctx, dentry), dir_emit_dotdot(file, ctx),
dir_emit_dots(file, ctx).
Signed-off-by: Al Viro <[email protected]>
...
+static inline bool dir_emit(struct dir_context *ctx,
+ const char *name, int namelen,
+ u64 ino, unsigned type)
+{
+ return ctx->actor(ctx, name, namelen, ctx->pos, ino, type) == 0;
+}
+static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
+{
+ return ctx->actor(ctx, ".", 1, ctx->pos,
+ file->f_path.dentry->d_inode->i_ino, DT_DIR) == 0;
+}
+static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
+{
+ return ctx->actor(ctx, "..", 2, ctx->pos,
+ parent_ino(file->f_path.dentry), DT_DIR) == 0;
+}
+static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
+{
+ if (ctx->pos == 0) {
+ if (!dir_emit_dot(file, ctx))
+ return false;
+ ctx->pos = 1;
+ }
+ if (ctx->pos == 1) {
+ if (!dir_emit_dotdot(file, ctx))
+ return false;
+ ctx->pos = 2;
+ }
+ return true;
+}
commit 0f37d0c8bed442dd0d2c1b1dddd68653fa6eec66
Author: Richard Yao <[email protected]>
AuthorDate: Wed Aug 7 08:53:45 2013 -0400
Commit: Brian Behlendorf <[email protected]>
CommitDate: Thu Aug 15 16:19:07 2013 -0700
Linux 3.11 compat: fops->iterate()
...
Compatibility with older kernels was accomplished by adding
versions of the trivial dir_emit* helper functions.
...
+static inline bool
+dir_emit(struct dir_context *ctx, const char *name, int namelen,
+ uint64_t ino, unsigned type)
+{
+ return ctx->actor(ctx->dirent, name, namelen, ctx->pos, ino, type) == 0;
+}
+
+static inline bool
+dir_emit_dot(struct file *file, struct dir_context *ctx)
+{
+ return ctx->actor(ctx->dirent, ".", 1, ctx->pos,
+ file->f_path.dentry->d_inode->i_ino, DT_DIR) == 0;
+}
+
+static inline bool
+dir_emit_dotdot(struct file *file, struct dir_context *ctx)
+{
+ return ctx->actor(ctx->dirent, "..", 2, ctx->pos,
+ parent_ino(file->f_path.dentry), DT_DIR) == 0;
+}
+
+static inline bool
+dir_emit_dots(struct file *file, struct dir_context *ctx)
+{
+ if (ctx->pos == 0) {
+ if (!dir_emit_dot(file, ctx))
+ return false;
+ ctx->pos = 1;
+ }
+ if (ctx->pos == 1) {
+ if (!dir_emit_dotdot(file, ctx))
+ return false;
+ ctx->pos = 2;
+ }
+ return true;
+}