[PATCH] lib: Fix some sparse warnings in devres.c

[PATCH] lib: Fix some sparse warnings in devres.c

[Steven Rostedt]

Having a discussion about sparse warnings in the kernel, and that we
should clean them up, I decided to pick a random file to do so. This
happened to be devres.c which gives the following warnings:

  CHECK   lib/devres.c
lib/devres.c:83:9: warning: cast removes address space of expression
lib/devres.c:117:31: warning: incorrect type in return expression (different address spaces)
lib/devres.c:117:31:    expected void [noderef] <asn:2>*
lib/devres.c:117:31:    got void *
lib/devres.c:125:31: warning: incorrect type in return expression (different address spaces)
lib/devres.c:125:31:    expected void [noderef] <asn:2>*
lib/devres.c:125:31:    got void *
lib/devres.c:136:26: warning: incorrect type in assignment (different address spaces)
lib/devres.c:136:26:    expected void [noderef] <asn:2>*[assigned] dest_ptr
lib/devres.c:136:26:    got void *
lib/devres.c:226:9: warning: cast removes address space of expression

Mostly it's just the use of typecasting to void * without adding
__force, or returning ERR_PTR(-ESOMEERR) without typecasting to a
__iomem type.

I added a helper macro IOMEM_ERR_PTR() that does the typecast to make
the code a little nicer than adding ugly typecasts to the code.

This is applied against linux-next.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/lib/devres.c b/lib/devres.c
index 8235331..48cb3c7 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -81,11 +81,13 @@ EXPORT_SYMBOL(devm_ioremap_nocache);
 void devm_iounmap(struct device *dev, void __iomem *addr)
 {
 	WARN_ON(devres_destroy(dev, devm_ioremap_release, devm_ioremap_match,
-			       (void *)addr));
+			       (__force void *)addr));
 	iounmap(addr);
 }
 EXPORT_SYMBOL(devm_iounmap);
 
+#define IOMEM_ERR_PTR(err) (__force void __iomem *)ERR_PTR(err)
+
 /**
  * devm_ioremap_resource() - check, request region, and ioremap resource
  * @dev: generic device to handle the resource for
@@ -114,7 +116,7 @@ void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res)
 
 	if (!res || resource_type(res) != IORESOURCE_MEM) {
 		dev_err(dev, "invalid resource\n");
-		return ERR_PTR(-EINVAL);
+		return IOMEM_ERR_PTR(-EINVAL);
 	}
 
 	size = resource_size(res);
@@ -122,7 +124,7 @@ void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res)
 
 	if (!devm_request_mem_region(dev, res->start, size, name)) {
 		dev_err(dev, "can't request region for resource %pR\n", res);
-		return ERR_PTR(-EBUSY);
+		return IOMEM_ERR_PTR(-EBUSY);
 	}
 
 	if (res->flags & IORESOURCE_CACHEABLE)
@@ -133,7 +135,7 @@ void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res)
 	if (!dest_ptr) {
 		dev_err(dev, "ioremap failed for resource %pR\n", res);
 		devm_release_mem_region(dev, res->start, size);
-		dest_ptr = ERR_PTR(-ENOMEM);
+		dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
 	}
 
 	return dest_ptr;
@@ -224,7 +226,7 @@ void devm_ioport_unmap(struct device *dev, void __iomem *addr)
 {
 	ioport_unmap(addr);
 	WARN_ON(devres_destroy(dev, devm_ioport_map_release,
-			       devm_ioport_map_match, (void *)addr));
+			       devm_ioport_map_match, (__force void *)addr));
 }
 EXPORT_SYMBOL(devm_ioport_unmap);
 #endif /* CONFIG_HAS_IOPORT */

[PATCH] sched/wait: suppress sparse 'variable shadowing' warning

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

This warning seems to show up a lot now, since ___wait_event()
is (indirectly) used inside wait_event_timeout(), which also
has a variable called __ret. Rename the one in ___wait_event()
to ___ret (another leading underscore) to suppress the warning.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/linux/wait.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 559044c..c55ea5c 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -195,7 +195,7 @@ wait_queue_head_t *bit_waitqueue(void *, int);
 ({									\
 	__label__ __out;						\
 	wait_queue_t __wait;						\
-	long __ret = ret;						\
+	long ___ret = ret;						\
 									\
 	INIT_LIST_HEAD(&__wait.task_list);				\
 	if (exclusive)							\
@@ -210,7 +210,7 @@ wait_queue_head_t *bit_waitqueue(void *, int);
 			break;						\
 									\
 		if (___wait_is_interruptible(state) && __int) {		\
-			__ret = __int;					\
+			___ret = __int;					\
 			if (exclusive) {				\
 				abort_exclusive_wait(&wq, &__wait,	\
 						     state, NULL);	\
@@ -222,7 +222,7 @@ wait_queue_head_t *bit_waitqueue(void *, int);
 		cmd;							\
 	}								\
 	finish_wait(&wq, &__wait);					\
-__out:	__ret;								\
+__out:	___ret;								\
 })
 
 #define __wait_event(wq, condition)					\
-- 
1.8.5.3

Re: [PATCH] sched/wait: suppress sparse 'variable shadowing' warning

[Peter Zijlstra]

On Thu, Feb 06, 2014 at 05:28:41PM +0100, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@intel.com>
> 
> This warning seems to show up a lot now, since ___wait_event()
> is (indirectly) used inside wait_event_timeout(), which also
> has a variable called __ret. Rename the one in ___wait_event()
> to ___ret (another leading underscore) to suppress the warning.
> 
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Thanks!

Re: [PATCH] sched/wait: suppress sparse 'variable shadowing' warning

[Steven Rostedt]

On Thu, 6 Feb 2014 17:45:58 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, Feb 06, 2014 at 05:28:41PM +0100, Johannes Berg wrote:
> > From: Johannes Berg <johannes.berg@intel.com>
> > 
> > This warning seems to show up a lot now, since ___wait_event()
> > is (indirectly) used inside wait_event_timeout(), which also
> > has a variable called __ret. Rename the one in ___wait_event()
> > to ___ret (another leading underscore) to suppress the warning.
> > 
> > Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> 
> Thanks!

Tag, you're it!

Now you need to submit a patch to fix one sparse warning this week ;-)

Yeah, yeah, I know. Like you have time.

This could be a cool drinking game. Every time you fix someone else's
sparse error, they have to drink a pint :-)

-- Steve

Re: [PATCH] sched/wait: suppress sparse 'variable shadowing' warning

[Ingo Molnar]

* Steven Rostedt <rostedt@goodmis.org> wrote:

> On Thu, 6 Feb 2014 17:45:58 +0100
> Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > On Thu, Feb 06, 2014 at 05:28:41PM +0100, Johannes Berg wrote:
> > > From: Johannes Berg <johannes.berg@intel.com>
> > > 
> > > This warning seems to show up a lot now, since ___wait_event()
> > > is (indirectly) used inside wait_event_timeout(), which also
> > > has a variable called __ret. Rename the one in ___wait_event()
> > > to ___ret (another leading underscore) to suppress the warning.
> > > 
> > > Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> > 
> > Thanks!
> 
> Tag, you're it!
> 
> Now you need to submit a patch to fix one sparse warning this week ;-)
> 
> Yeah, yeah, I know. Like you have time.
> 
> This could be a cool drinking game. Every time you fix someone else's
> sparse error, they have to drink a pint :-)

... which game would result in a heightened mood amongst developers 
and even more Sparse errors, resulting in more fixes from PeterZ and 
more pints downed, creating a nice feedback loop. Sounds like fun for 
everyone, except Peter? ;-)

Thanks,

	Ingo

[tip:core/locking] sched/wait: Suppress Sparse ' variable shadowing' warning

[tip-bot for Johannes Berg]

Commit-ID:  980f88e414418bf65569a3b62b08b07e6fc2f4c6
Gitweb:     http://git.kernel.org/tip/980f88e414418bf65569a3b62b08b07e6fc2f4c6
Author:     Johannes Berg <johannes.berg@intel.com>
AuthorDate: Thu, 6 Feb 2014 17:28:41 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Sun, 9 Feb 2014 13:11:49 +0100

sched/wait: Suppress Sparse 'variable shadowing' warning

This warning seems to show up a lot now, since ___wait_event()
is (indirectly) used inside wait_event_timeout(), which also
has a variable called __ret. Rename the one in ___wait_event()
to ___ret (another leading underscore) to suppress the warning.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1391704121.12789.20.camel@jlt4.sipsolutions.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 include/linux/wait.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 559044c..c55ea5c 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -195,7 +195,7 @@ wait_queue_head_t *bit_waitqueue(void *, int);
 ({									\
 	__label__ __out;						\
 	wait_queue_t __wait;						\
-	long __ret = ret;						\
+	long ___ret = ret;						\
 									\
 	INIT_LIST_HEAD(&__wait.task_list);				\
 	if (exclusive)							\
@@ -210,7 +210,7 @@ wait_queue_head_t *bit_waitqueue(void *, int);
 			break;						\
 									\
 		if (___wait_is_interruptible(state) && __int) {		\
-			__ret = __int;					\
+			___ret = __int;					\
 			if (exclusive) {				\
 				abort_exclusive_wait(&wq, &__wait,	\
 						     state, NULL);	\
@@ -222,7 +222,7 @@ wait_queue_head_t *bit_waitqueue(void *, int);
 		cmd;							\
 	}								\
 	finish_wait(&wq, &__wait);					\
-__out:	__ret;								\
+__out:	___ret;								\
 })
 
 #define __wait_event(wq, condition)					\

Re: [PATCH] lib: Fix some sparse warnings in devres.c

[Greg Kroah-Hartman]

On Thu, Feb 06, 2014 at 11:13:46AM -0500, Steven Rostedt wrote:
> Having a discussion about sparse warnings in the kernel, and that we
> should clean them up, I decided to pick a random file to do so. This
> happened to be devres.c which gives the following warnings:
> 
>   CHECK   lib/devres.c
> lib/devres.c:83:9: warning: cast removes address space of expression
> lib/devres.c:117:31: warning: incorrect type in return expression (different address spaces)
> lib/devres.c:117:31:    expected void [noderef] <asn:2>*
> lib/devres.c:117:31:    got void *
> lib/devres.c:125:31: warning: incorrect type in return expression (different address spaces)
> lib/devres.c:125:31:    expected void [noderef] <asn:2>*
> lib/devres.c:125:31:    got void *
> lib/devres.c:136:26: warning: incorrect type in assignment (different address spaces)
> lib/devres.c:136:26:    expected void [noderef] <asn:2>*[assigned] dest_ptr
> lib/devres.c:136:26:    got void *
> lib/devres.c:226:9: warning: cast removes address space of expression
> 
> Mostly it's just the use of typecasting to void * without adding
> __force, or returning ERR_PTR(-ESOMEERR) without typecasting to a
> __iomem type.
> 
> I added a helper macro IOMEM_ERR_PTR() that does the typecast to make
> the code a little nicer than adding ugly typecasts to the code.
> 
> This is applied against linux-next.
> 
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>