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Message-ID: <20061214064430.GM4587@ftp.linux.org.uk>
Date: Thu, 14 Dec 2006 06:44:30 +0000
From: Al Viro <viro@....linux.org.uk>
To: Ben Collins <ben.collins@...ntu.com>
Cc: Linus Torvalds <torvalds@...l.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2.6.20-rc1] ib_verbs: Use explicit if-else statements to avoid errors with do-while macros
On Wed, Dec 13, 2006 at 10:10:05PM -0500, Ben Collins wrote:
> At least on PPC, the "op ? op : dma" construct causes a compile failure
> because the dma_* is a do{}while(0) macro.
>
> This turns all of them into proper if/else to avoid this problem.
NAK.
Proper fix is to kill stupid do { } while (0) mess. It's supposed
to behave like a function returning void, so it should be ((void)0).
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
diff --git a/include/asm-alpha/dma-mapping.h b/include/asm-alpha/dma-mapping.h
index 57e09f5..ce759ea 100644
--- a/include/asm-alpha/dma-mapping.h
+++ b/include/asm-alpha/dma-mapping.h
@@ -41,9 +41,9 @@ #define dma_supported(dev, mask) (mask
#define dma_map_single(dev, va, size, dir) virt_to_phys(va)
#define dma_map_page(dev, page, off, size, dir) (page_to_pa(page) + off)
-#define dma_unmap_single(dev, addr, size, dir) do { } while (0)
-#define dma_unmap_page(dev, addr, size, dir) do { } while (0)
-#define dma_unmap_sg(dev, sg, nents, dir) do { } while (0)
+#define dma_unmap_single(dev, addr, size, dir) ((void)0)
+#define dma_unmap_page(dev, addr, size, dir) ((void)0)
+#define dma_unmap_sg(dev, sg, nents, dir) ((void)0)
#define dma_mapping_error(addr) (0)
@@ -55,12 +55,12 @@ #define dma_is_consistent(d, h) (1)
int dma_set_mask(struct device *dev, u64 mask);
-#define dma_sync_single_for_cpu(dev, addr, size, dir) do { } while (0)
-#define dma_sync_single_for_device(dev, addr, size, dir) do { } while (0)
-#define dma_sync_single_range(dev, addr, off, size, dir) do { } while (0)
-#define dma_sync_sg_for_cpu(dev, sg, nents, dir) do { } while (0)
-#define dma_sync_sg_for_device(dev, sg, nents, dir) do { } while (0)
-#define dma_cache_sync(dev, va, size, dir) do { } while (0)
+#define dma_sync_single_for_cpu(dev, addr, size, dir) ((void)0)
+#define dma_sync_single_for_device(dev, addr, size, dir) ((void)0)
+#define dma_sync_single_range(dev, addr, off, size, dir) ((void)0)
+#define dma_sync_sg_for_cpu(dev, sg, nents, dir) ((void)0)
+#define dma_sync_sg_for_device(dev, sg, nents, dir) ((void)0)
+#define dma_cache_sync(dev, va, size, dir) ((void)0)
#define dma_get_cache_alignment() L1_CACHE_BYTES
diff --git a/include/asm-powerpc/dma-mapping.h b/include/asm-powerpc/dma-mapping.h
index 7c7de87..a19a6f1 100644
--- a/include/asm-powerpc/dma-mapping.h
+++ b/include/asm-powerpc/dma-mapping.h
@@ -37,9 +37,9 @@ #else /* ! CONFIG_NOT_COHERENT_CACHE */
*/
#define __dma_alloc_coherent(gfp, size, handle) NULL
-#define __dma_free_coherent(size, addr) do { } while (0)
-#define __dma_sync(addr, size, rw) do { } while (0)
-#define __dma_sync_page(pg, off, sz, rw) do { } while (0)
+#define __dma_free_coherent(size, addr) ((void)0)
+#define __dma_sync(addr, size, rw) ((void)0)
+#define __dma_sync_page(pg, off, sz, rw) ((void)0)
#endif /* ! CONFIG_NOT_COHERENT_CACHE */
@@ -251,7 +251,7 @@ dma_map_single(struct device *dev, void
}
/* We do nothing. */
-#define dma_unmap_single(dev, addr, size, dir) do { } while (0)
+#define dma_unmap_single(dev, addr, size, dir) ((void)0)
static inline dma_addr_t
dma_map_page(struct device *dev, struct page *page,
@@ -266,7 +266,7 @@ dma_map_page(struct device *dev, struct
}
/* We do nothing. */
-#define dma_unmap_page(dev, handle, size, dir) do { } while (0)
+#define dma_unmap_page(dev, handle, size, dir) ((void)0)
static inline int
dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
@@ -286,7 +286,7 @@ dma_map_sg(struct device *dev, struct sc
}
/* We don't do anything here. */
-#define dma_unmap_sg(dev, sg, nents, dir) do { } while (0)
+#define dma_unmap_sg(dev, sg, nents, dir) ((void)0)
#endif /* CONFIG_PPC64 */
-
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