[RESEND] IB/uverbs: fix gcc-7 type warning

Message ID 20170906134558.3279199-1-arnd@arndb.de
State New
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  • [RESEND] IB/uverbs: fix gcc-7 type warning
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Commit Message

Arnd Bergmann Sept. 6, 2017, 1:45 p.m.
We get a harmless warning about the fact that we use the result of a
multiplication as a condition:

drivers/infiniband/core/uverbs_main.c: In function 'ib_uverbs_write':
drivers/infiniband/core/uverbs_main.c:787:40: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]
drivers/infiniband/core/uverbs_main.c:787:117: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]
drivers/infiniband/core/uverbs_main.c:790:50: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]
drivers/infiniband/core/uverbs_main.c:790:151: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]

This changes the macro to explicitly check the number for a positive
length, which avoids the warning.

Fixes: a96e4e2ffe43 ("IB/uverbs: New macro to set pointers to NULL if length is 0 in INIT_UDATA()")
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
Originally submitted on July 14, but this patch is still pending.
I modified the change text this time, as the first version incorrectly
stated that it only happens with ccache.
---
 drivers/infiniband/core/uverbs.h | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

-- 
2.9.0

Comments

Christoph Hellwig Sept. 6, 2017, 1:58 p.m. | #1
On Wed, Sep 06, 2017 at 03:45:31PM +0200, Arnd Bergmann wrote:
> We get a harmless warning about the fact that we use the result of a

> multiplication as a condition:


Please just turn the thing into a function while you're at it.
I'm not even sure it needs to be inline..
Arnd Bergmann Sept. 6, 2017, 8:43 p.m. | #2
On Wed, Sep 6, 2017 at 3:58 PM, Christoph Hellwig <hch@infradead.org> wrote:
> On Wed, Sep 06, 2017 at 03:45:31PM +0200, Arnd Bergmann wrote:

>> We get a harmless warning about the fact that we use the result of a

>> multiplication as a condition:

>

> Please just turn the thing into a function while you're at it.

> I'm not even sure it needs to be inline..


Ok, the patch gets quite big once I also modify INIT_UDATA the same way,
but it seems like a good cleanup anyway. INIT_UDATA (renamed to
ib_uverbs_init_udata()) should definitely remain inline, so I'm leaving
both that way.

        Arnd

Patch

diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h
index 37c8903e7fd0..986a8a66ebbe 100644
--- a/drivers/infiniband/core/uverbs.h
+++ b/drivers/infiniband/core/uverbs.h
@@ -55,12 +55,14 @@ 
 		(udata)->outlen = (olen);				\
 	} while (0)
 
-#define INIT_UDATA_BUF_OR_NULL(udata, ibuf, obuf, ilen, olen)			\
-	do {									\
-		(udata)->inbuf  = (ilen) ? (const void __user *) (ibuf) : NULL;	\
-		(udata)->outbuf = (olen) ? (void __user *) (obuf) : NULL;	\
-		(udata)->inlen  = (ilen);					\
-		(udata)->outlen = (olen);					\
+#define INIT_UDATA_BUF_OR_NULL(udata, ibuf, obuf, ilen, olen)		\
+	do {								\
+		(udata)->inbuf  = (ilen) > 0 ?				\
+				  (const void __user *) (ibuf) : NULL;	\
+		(udata)->outbuf = (olen) > 0 ?				\
+				  (void __user *) (obuf) : NULL;	\
+		(udata)->inlen  = (ilen);				\
+		(udata)->outlen = (olen);				\
 	} while (0)
 
 /*