Merge tag 'docs-6.5' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "It's been a relatively calm cycle in docsland. We do have:

   - Some initial page-table documentation from Linus (the other Linus)

   - Regression-handling documentation improvements from Thorsten

   - Addition of kerneldoc documentation for the ERR_PTR() and related
     macros from James Seo

  ... and the usual collection of fixes and updates"

* tag 'docs-6.5' of git://git.lwn.net/linux:
  docs: consolidate storage interfaces
  Documentation: update git configuration for Link: tag
  Documentation: KVM: make corrections to vcpu-requests.rst
  Documentation: KVM: make corrections to ppc-pv.rst
  Documentation: KVM: make corrections to locking.rst
  Documentation: KVM: make corrections to halt-polling.rst
  Documentation: virt: correct location of haltpoll module params
  Documentation/mm: Initial page table documentation
  docs: crypto: async-tx-api: fix typo in struct name
  docs/doc-guide: Clarify how to write tables
  docs: handling-regressions: rework section about fixing procedures
  docs: process: fix a typoed cross-reference
  docs: submitting-patches: Discuss interleaved replies
  MAINTAINERS: direct process doc changes to a dedicated ML
  Documentation: core-api: Add error pointer functions to kernel-api
  err.h: Add missing kerneldocs for error pointer functions
  Documentation: conf.py: Add __force to c_id_attributes
  docs: clarify KVM related kernel parameters' descriptions
  docs: consolidate human interface subsystems
  docs: admin-guide: Add information about intel_pstate active mode

1 files changed, 48 insertions, 0 deletions

diff --git a/include/linux/err.h b/include/linux/err.h
index a139c64aef2a..b5d9bb2a2349 100644
--- a/include/linux/err.h
+++ b/include/linux/err.h
@@ -19,23 +19,54 @@
 
 #ifndef __ASSEMBLY__
 
+/**
+ * IS_ERR_VALUE - Detect an error pointer.
+ * @x: The pointer to check.
+ *
+ * Like IS_ERR(), but does not generate a compiler warning if result is unused.
+ */
 #define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO)
 
+/**
+ * ERR_PTR - Create an error pointer.
+ * @error: A negative error code.
+ *
+ * Encodes @error into a pointer value. Users should consider the result
+ * opaque and not assume anything about how the error is encoded.
+ *
+ * Return: A pointer with @error encoded within its value.
+ */
 static inline void * __must_check ERR_PTR(long error)
 {
 	return (void *) error;
 }
 
+/**
+ * PTR_ERR - Extract the error code from an error pointer.
+ * @ptr: An error pointer.
+ * Return: The error code within @ptr.
+ */
 static inline long __must_check PTR_ERR(__force const void *ptr)
 {
 	return (long) ptr;
 }
 
+/**
+ * IS_ERR - Detect an error pointer.
+ * @ptr: The pointer to check.
+ * Return: true if @ptr is an error pointer, false otherwise.
+ */
 static inline bool __must_check IS_ERR(__force const void *ptr)
 {
 	return IS_ERR_VALUE((unsigned long)ptr);
 }
 
+/**
+ * IS_ERR_OR_NULL - Detect an error pointer or a null pointer.
+ * @ptr: The pointer to check.
+ *
+ * Like IS_ERR(), but also returns true for a null pointer.
+ */
 static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
 {
 	return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
@@ -54,6 +85,23 @@ static inline void * __must_check ERR_CAST(__force const void *ptr)
 	return (void *) ptr;
 }
 
+/**
+ * PTR_ERR_OR_ZERO - Extract the error code from a pointer if it has one.
+ * @ptr: A potential error pointer.
+ *
+ * Convenience function that can be used inside a function that returns
+ * an error code to propagate errors received as error pointers.
+ * For example, ``return PTR_ERR_OR_ZERO(ptr);`` replaces:
+ *
+ * .. code-block:: c
+ *
+ *	if (IS_ERR(ptr))
+ *		return PTR_ERR(ptr);
+ *	else
+ *		return 0;
+ *
+ * Return: The error code within @ptr if it is an error pointer; 0 otherwise.
+ */
 static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
 {
 	if (IS_ERR(ptr))