linux-kernel - [PATCH v2 1/2] idr: Document calling context for IDA APIs mustn't use locks

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Message-Id: <20190730212048.164657-1-swboyd@chromium.org>
Date:   Tue, 30 Jul 2019 14:20:47 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     linux-kernel@...r.kernel.org, Greg KH <gregkh@...uxfoundation.org>,
        Tri Vo <trong@...roid.com>, Jonathan Corbet <corbet@....net>,
        linux-doc@...r.kernel.org
Subject: [PATCH v2 1/2] idr: Document calling context for IDA APIs mustn't use locks

The documentation for these functions indicates that callers don't need
to hold a lock while calling them, but that documentation is only in one
place under "IDA Usage". Let's state the same information on each IDA
function so that it's clear what the calling context requires.
Furthermore, let's document ida_simple_get() with the same information
so that callers know how this API works.

Cc: Greg KH <gregkh@...uxfoundation.org>
Cc: Tri Vo <trong@...roid.com>
Cc: Jonathan Corbet <corbet@....net>
Cc: linux-doc@...r.kernel.org
Signed-off-by: Stephen Boyd <swboyd@...omium.org>
---
 include/linux/idr.h | 9 ++++++---
 lib/idr.c           | 9 ++++++---
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/include/linux/idr.h b/include/linux/idr.h
index 4ec8986e5dfb..5bb026007044 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -263,7 +263,8 @@ void ida_destroy(struct ida *ida);
  *
  * Allocate an ID between 0 and %INT_MAX, inclusive.
  *
- * Context: Any context.
+ * Context: Any context. It is safe to call this function without
+ * locking in your code.
  * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
  * or %-ENOSPC if there are no free IDs.
  */
@@ -280,7 +281,8 @@ static inline int ida_alloc(struct ida *ida, gfp_t gfp)
  *
  * Allocate an ID between @min and %INT_MAX, inclusive.
  *
- * Context: Any context.
+ * Context: Any context. It is safe to call this function without
+ * locking in your code.
  * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
  * or %-ENOSPC if there are no free IDs.
  */
@@ -297,7 +299,8 @@ static inline int ida_alloc_min(struct ida *ida, unsigned int min, gfp_t gfp)
  *
  * Allocate an ID between 0 and @max, inclusive.
  *
- * Context: Any context.
+ * Context: Any context. It is safe to call this function without
+ * locking in your code.
  * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
  * or %-ENOSPC if there are no free IDs.
  */
diff --git a/lib/idr.c b/lib/idr.c
index 66a374892482..dbd25696162e 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -381,7 +381,8 @@ EXPORT_SYMBOL(idr_replace);
  * Allocate an ID between @min and @max, inclusive.  The allocated ID will
  * not exceed %INT_MAX, even if @max is larger.
  *
- * Context: Any context.
+ * Context: Any context. It is safe to call this function without
+ * locking in your code.
  * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
  * or %-ENOSPC if there are no free IDs.
  */
@@ -488,7 +489,8 @@ EXPORT_SYMBOL(ida_alloc_range);
  * @ida: IDA handle.
  * @id: Previously allocated ID.
  *
- * Context: Any context.
+ * Context: Any context. It is safe to call this function without
+ * locking in your code.
  */
 void ida_free(struct ida *ida, unsigned int id)
 {
@@ -540,7 +542,8 @@ EXPORT_SYMBOL(ida_free);
  * or freed.  If the IDA is already empty, there is no need to call this
  * function.
  *
- * Context: Any context.
+ * Context: Any context. It is safe to call this function without
+ * locking in your code.
  */
 void ida_destroy(struct ida *ida)
 {
-- 
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