[Qemu-devel] [PATCH for-2.9 v2] block/file-posix.c: Fix unused variable warning on OpenBSD

[Qemu-devel] [PATCH for-2.9 v2] block/file-posix.c: Fix unused variable warning on OpenBSD

[Peter Maydell]

On OpenBSD none of the ioctls probe_logical_blocksize() tries
exist, so the variable sector_size is unused. Refactor the
code to avoid this (and reduce the duplicated code).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Jeff Cody <jcody@redhat.com>
---
v2: add (int) cast to avoid compiler warnings on some
systems when the array is empty; use 'static const'.
---
 block/file-posix.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 53febd3..db8f0a8 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -219,28 +219,28 @@ static int probe_logical_blocksize(int fd, unsigned int *sector_size_p)
 {
     unsigned int sector_size;
     bool success = false;
+    int i;
 
     errno = ENOTSUP;
-
-    /* Try a few ioctls to get the right size */
+    static const unsigned long ioctl_list[] = {
 #ifdef BLKSSZGET
-    if (ioctl(fd, BLKSSZGET, &sector_size) >= 0) {
-        *sector_size_p = sector_size;
-        success = true;
-    }
+        BLKSSZGET,
 #endif
 #ifdef DKIOCGETBLOCKSIZE
-    if (ioctl(fd, DKIOCGETBLOCKSIZE, &sector_size) >= 0) {
-        *sector_size_p = sector_size;
-        success = true;
-    }
+        DKIOCGETBLOCKSIZE,
 #endif
 #ifdef DIOCGSECTORSIZE
-    if (ioctl(fd, DIOCGSECTORSIZE, &sector_size) >= 0) {
-        *sector_size_p = sector_size;
-        success = true;
-    }
+        DIOCGSECTORSIZE,
 #endif
+    };
+
+    /* Try a few ioctls to get the right size */
+    for (i = 0; i < (int)ARRAY_SIZE(ioctl_list); i++) {
+        if (ioctl(fd, ioctl_list[i], &sector_size) >= 0) {
+            *sector_size_p = sector_size;
+            success = true;
+        }
+    }
 
     return success ? 0 : -errno;
 }
-- 
2.7.4

Re: [Qemu-devel] [PATCH for-2.9 v2] block/file-posix.c: Fix unused variable warning on OpenBSD

[Max Reitz]

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On 23.03.2017 15:36, Peter Maydell wrote:
> On OpenBSD none of the ioctls probe_logical_blocksize() tries
> exist, so the variable sector_size is unused. Refactor the
> code to avoid this (and reduce the duplicated code).
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Reviewed-by: Jeff Cody <jcody@redhat.com>
> ---
> v2: add (int) cast to avoid compiler warnings on some
> systems when the array is empty; use 'static const'.
> ---
>  block/file-posix.c | 28 ++++++++++++++--------------
>  1 file changed, 14 insertions(+), 14 deletions(-)

Thanks, applied to my block branch for 2.9:

https://github.com/XanClic/qemu/commits/block

Max


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