From: Will Deacon <will@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: Will Deacon <will@kernel.org>, Kees Cook <keescook@chromium.org>,
Ingo Molnar <mingo@kernel.org>,
Elena Reshetova <elena.reshetova@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Hanjun Guo <guohanjun@huawei.com>,
Jan Glauber <jglauber@marvell.com>
Subject: [PATCH v3 03/10] lib/refcount: Remove unused refcount_*_checked() variants
Date: Mon, 7 Oct 2019 16:46:56 +0100 [thread overview]
Message-ID: <20191007154703.5574-4-will@kernel.org> (raw)
In-Reply-To: <20191007154703.5574-1-will@kernel.org>
The full-fat refcount implementation is exposed via a set of functions
suffixed with "_checked()", the idea being that code can choose to use
the more expensive, yet more secure implementation on a case-by-case
basis.
In reality, this hasn't happened, so with a grand total of zero users,
let's remove the checked variants for now by simply dropping the suffix
and predicating the out-of-line functions on CONFIG_REFCOUNT_FULL=y.
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
include/linux/refcount.h | 25 ++++++-------------
lib/refcount.c | 54 +++++++++++++++++++++-------------------
2 files changed, 36 insertions(+), 43 deletions(-)
diff --git a/include/linux/refcount.h b/include/linux/refcount.h
index 89066a1471dd..edd505d1a23b 100644
--- a/include/linux/refcount.h
+++ b/include/linux/refcount.h
@@ -44,32 +44,21 @@ static inline unsigned int refcount_read(const refcount_t *r)
return atomic_read(&r->refs);
}
-extern __must_check bool refcount_add_not_zero_checked(int i, refcount_t *r);
-extern void refcount_add_checked(int i, refcount_t *r);
-
-extern __must_check bool refcount_inc_not_zero_checked(refcount_t *r);
-extern void refcount_inc_checked(refcount_t *r);
-
-extern __must_check bool refcount_sub_and_test_checked(int i, refcount_t *r);
-
-extern __must_check bool refcount_dec_and_test_checked(refcount_t *r);
-extern void refcount_dec_checked(refcount_t *r);
-
#ifdef CONFIG_REFCOUNT_FULL
#define REFCOUNT_MAX (UINT_MAX - 1)
#define REFCOUNT_SATURATED UINT_MAX
-#define refcount_add_not_zero refcount_add_not_zero_checked
-#define refcount_add refcount_add_checked
+extern __must_check bool refcount_add_not_zero(int i, refcount_t *r);
+extern void refcount_add(int i, refcount_t *r);
-#define refcount_inc_not_zero refcount_inc_not_zero_checked
-#define refcount_inc refcount_inc_checked
+extern __must_check bool refcount_inc_not_zero(refcount_t *r);
+extern void refcount_inc(refcount_t *r);
-#define refcount_sub_and_test refcount_sub_and_test_checked
+extern __must_check bool refcount_sub_and_test(int i, refcount_t *r);
-#define refcount_dec_and_test refcount_dec_and_test_checked
-#define refcount_dec refcount_dec_checked
+extern __must_check bool refcount_dec_and_test(refcount_t *r);
+extern void refcount_dec(refcount_t *r);
#else
diff --git a/lib/refcount.c b/lib/refcount.c
index 719b0bc42ab1..a2f670998cee 100644
--- a/lib/refcount.c
+++ b/lib/refcount.c
@@ -43,8 +43,10 @@
#include <linux/spinlock.h>
#include <linux/bug.h>
+#ifdef CONFIG_REFCOUNT_FULL
+
/**
- * refcount_add_not_zero_checked - add a value to a refcount unless it is 0
+ * refcount_add_not_zero - add a value to a refcount unless it is 0
* @i: the value to add to the refcount
* @r: the refcount
*
@@ -61,7 +63,7 @@
*
* Return: false if the passed refcount is 0, true otherwise
*/
-bool refcount_add_not_zero_checked(int i, refcount_t *r)
+bool refcount_add_not_zero(int i, refcount_t *r)
{
unsigned int new, val = atomic_read(&r->refs);
@@ -83,10 +85,10 @@ bool refcount_add_not_zero_checked(int i, refcount_t *r)
return true;
}
-EXPORT_SYMBOL(refcount_add_not_zero_checked);
+EXPORT_SYMBOL(refcount_add_not_zero);
/**
- * refcount_add_checked - add a value to a refcount
+ * refcount_add - add a value to a refcount
* @i: the value to add to the refcount
* @r: the refcount
*
@@ -101,14 +103,14 @@ EXPORT_SYMBOL(refcount_add_not_zero_checked);
* cases, refcount_inc(), or one of its variants, should instead be used to
* increment a reference count.
*/
-void refcount_add_checked(int i, refcount_t *r)
+void refcount_add(int i, refcount_t *r)
{
- WARN_ONCE(!refcount_add_not_zero_checked(i, r), "refcount_t: addition on 0; use-after-free.\n");
+ WARN_ONCE(!refcount_add_not_zero(i, r), "refcount_t: addition on 0; use-after-free.\n");
}
-EXPORT_SYMBOL(refcount_add_checked);
+EXPORT_SYMBOL(refcount_add);
/**
- * refcount_inc_not_zero_checked - increment a refcount unless it is 0
+ * refcount_inc_not_zero - increment a refcount unless it is 0
* @r: the refcount to increment
*
* Similar to atomic_inc_not_zero(), but will saturate at REFCOUNT_SATURATED
@@ -120,7 +122,7 @@ EXPORT_SYMBOL(refcount_add_checked);
*
* Return: true if the increment was successful, false otherwise
*/
-bool refcount_inc_not_zero_checked(refcount_t *r)
+bool refcount_inc_not_zero(refcount_t *r)
{
unsigned int new, val = atomic_read(&r->refs);
@@ -140,10 +142,10 @@ bool refcount_inc_not_zero_checked(refcount_t *r)
return true;
}
-EXPORT_SYMBOL(refcount_inc_not_zero_checked);
+EXPORT_SYMBOL(refcount_inc_not_zero);
/**
- * refcount_inc_checked - increment a refcount
+ * refcount_inc - increment a refcount
* @r: the refcount to increment
*
* Similar to atomic_inc(), but will saturate at REFCOUNT_SATURATED and WARN.
@@ -154,14 +156,14 @@ EXPORT_SYMBOL(refcount_inc_not_zero_checked);
* Will WARN if the refcount is 0, as this represents a possible use-after-free
* condition.
*/
-void refcount_inc_checked(refcount_t *r)
+void refcount_inc(refcount_t *r)
{
- WARN_ONCE(!refcount_inc_not_zero_checked(r), "refcount_t: increment on 0; use-after-free.\n");
+ WARN_ONCE(!refcount_inc_not_zero(r), "refcount_t: increment on 0; use-after-free.\n");
}
-EXPORT_SYMBOL(refcount_inc_checked);
+EXPORT_SYMBOL(refcount_inc);
/**
- * refcount_sub_and_test_checked - subtract from a refcount and test if it is 0
+ * refcount_sub_and_test - subtract from a refcount and test if it is 0
* @i: amount to subtract from the refcount
* @r: the refcount
*
@@ -180,7 +182,7 @@ EXPORT_SYMBOL(refcount_inc_checked);
*
* Return: true if the resulting refcount is 0, false otherwise
*/
-bool refcount_sub_and_test_checked(int i, refcount_t *r)
+bool refcount_sub_and_test(int i, refcount_t *r)
{
unsigned int new, val = atomic_read(&r->refs);
@@ -203,10 +205,10 @@ bool refcount_sub_and_test_checked(int i, refcount_t *r)
return false;
}
-EXPORT_SYMBOL(refcount_sub_and_test_checked);
+EXPORT_SYMBOL(refcount_sub_and_test);
/**
- * refcount_dec_and_test_checked - decrement a refcount and test if it is 0
+ * refcount_dec_and_test - decrement a refcount and test if it is 0
* @r: the refcount
*
* Similar to atomic_dec_and_test(), it will WARN on underflow and fail to
@@ -218,14 +220,14 @@ EXPORT_SYMBOL(refcount_sub_and_test_checked);
*
* Return: true if the resulting refcount is 0, false otherwise
*/
-bool refcount_dec_and_test_checked(refcount_t *r)
+bool refcount_dec_and_test(refcount_t *r)
{
- return refcount_sub_and_test_checked(1, r);
+ return refcount_sub_and_test(1, r);
}
-EXPORT_SYMBOL(refcount_dec_and_test_checked);
+EXPORT_SYMBOL(refcount_dec_and_test);
/**
- * refcount_dec_checked - decrement a refcount
+ * refcount_dec - decrement a refcount
* @r: the refcount
*
* Similar to atomic_dec(), it will WARN on underflow and fail to decrement
@@ -234,11 +236,13 @@ EXPORT_SYMBOL(refcount_dec_and_test_checked);
* Provides release memory ordering, such that prior loads and stores are done
* before.
*/
-void refcount_dec_checked(refcount_t *r)
+void refcount_dec(refcount_t *r)
{
- WARN_ONCE(refcount_dec_and_test_checked(r), "refcount_t: decrement hit 0; leaking memory.\n");
+ WARN_ONCE(refcount_dec_and_test(r), "refcount_t: decrement hit 0; leaking memory.\n");
}
-EXPORT_SYMBOL(refcount_dec_checked);
+EXPORT_SYMBOL(refcount_dec);
+
+#endif /* CONFIG_REFCOUNT_FULL */
/**
* refcount_dec_if_one - decrement a refcount if it is 1
--
2.23.0.581.g78d2f28ef7-goog
next prev parent reply other threads:[~2019-10-07 15:47 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 15:46 [PATCH v3 00/10] Rework REFCOUNT_FULL using atomic_fetch_* operations Will Deacon
2019-10-07 15:46 ` [PATCH v3 01/10] lib/refcount: Define constants for saturation and max refcount values Will Deacon
2019-10-07 15:46 ` [PATCH v3 02/10] lib/refcount: Ensure integer operands are treated as signed Will Deacon
2019-10-07 15:46 ` Will Deacon [this message]
2019-10-07 15:46 ` [PATCH v3 04/10] lib/refcount: Move bulk of REFCOUNT_FULL implementation into header Will Deacon
2019-10-07 15:46 ` [PATCH v3 05/10] lib/refcount: Improve performance of generic REFCOUNT_FULL code Will Deacon
2019-10-09 9:25 ` Peter Zijlstra
2019-10-09 11:35 ` Peter Zijlstra
2019-10-09 16:44 ` Will Deacon
2019-10-09 17:41 ` Peter Zijlstra
2019-10-07 15:46 ` [PATCH v3 06/10] lib/refcount: Move saturation warnings out of line Will Deacon
2019-10-10 20:48 ` Kees Cook
2019-10-11 12:09 ` Will Deacon
2019-10-07 15:47 ` [PATCH v3 07/10] lib/refcount: Consolidate REFCOUNT_{MAX,SATURATED} definitions Will Deacon
2019-10-07 15:47 ` [PATCH v3 08/10] refcount: Consolidate implementations of refcount_t Will Deacon
2019-10-10 20:49 ` Kees Cook
2019-10-07 15:47 ` [PATCH v3 09/10] lib/refcount: Remove unused 'refcount_error_report()' function Will Deacon
2019-10-10 20:50 ` Kees Cook
2019-10-11 12:12 ` Will Deacon
2019-10-07 15:47 ` [PATCH v3 10/10] drivers/lkdtm: Remove references to CONFIG_REFCOUNT_FULL Will Deacon
2019-10-10 20:50 ` Kees Cook
2019-10-09 10:01 ` [PATCH v3 00/10] Rework REFCOUNT_FULL using atomic_fetch_* operations Hanjun Guo
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