Type conversion for align type promotion in P2ALIGN

In P2ALIGN, the result would be incorrect when align is unsigned integer and x is larger than max value of the type of align. In that case, -(align) would be a positive integer, which means high bits would be zero and finally stay zero after '&' when align is converted to a larger integer type. Signed-off-by: Qiuhao Chen <[email protected]>
openzfs · Feb 29, 2024 · d8312e4 · d8312e4
1 parent 8f2f6cd
commit d8312e4
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Showing 4 changed files with 8 additions and 4 deletions.
diff --git a/include/os/freebsd/spl/sys/ccompile.h b/include/os/freebsd/spl/sys/ccompile.h
@@ -138,7 +138,8 @@ typedef int enum_t;
 #define	readdir64 readdir
 #define	dirent64 dirent
 #endif
-#define	P2ALIGN(x, align)		((x) & -(align))
+#define	P2ALIGN(x, align) \
+	((x) & -((sizeof (x) > sizeof (align))?(typeof(x))(align):(align)))
 #define	P2CROSS(x, y, align)	(((x) ^ (y)) > (align) - 1)
 #define	P2ROUNDUP(x, align)		((((x) - 1) | ((align) - 1)) + 1)
 #define	P2PHASE(x, align)		((x) & ((align) - 1))

diff --git a/include/os/freebsd/spl/sys/sysmacros.h b/include/os/freebsd/spl/sys/sysmacros.h
@@ -191,7 +191,8 @@ extern unsigned char bcd_to_byte[256];
  * eg, P2ALIGN(0x1234, 0x100) == 0x1200 (0x12*align)
  * eg, P2ALIGN(0x5600, 0x100) == 0x5600 (0x56*align)
  */
-#define	P2ALIGN(x, align)		((x) & -(align))
+#define	P2ALIGN(x, align) \
+	((x) & -((sizeof (x) > sizeof (align))?(typeof(x))(align):(align)))
 
 /*
  * return x % (mod) align

diff --git a/include/os/linux/spl/sys/sysmacros.h b/include/os/linux/spl/sys/sysmacros.h
@@ -159,7 +159,8 @@ makedev(unsigned int major, unsigned int minor)
 /*
  * Compatibility macros/typedefs needed for Solaris -> Linux port
  */
-#define	P2ALIGN(x, align)	((x) & -(align))
+#define	P2ALIGN(x, align) \
+	((x) & -((sizeof (x) > sizeof (align))?(typeof(x))(align):(align)))
 #define	P2CROSS(x, y, align)	(((x) ^ (y)) > (align) - 1)
 #define	P2ROUNDUP(x, align)	((((x) - 1) | ((align) - 1)) + 1)
 #define	P2PHASE(x, align)	((x) & ((align) - 1))

diff --git a/lib/libspl/include/os/linux/sys/sysmacros.h b/lib/libspl/include/os/linux/sys/sysmacros.h
@@ -52,7 +52,8 @@
 /*
  * Compatibility macros/typedefs needed for Solaris -> Linux port
  */
-#define	P2ALIGN(x, align)	((x) & -(align))
+#define	P2ALIGN(x, align) \
+	((x) & -((sizeof (x) > sizeof (align))?(typeof(x))(align):(align)))
 #define	P2CROSS(x, y, align)	(((x) ^ (y)) > (align) - 1)
 #define	P2ROUNDUP(x, align)	((((x) - 1) | ((align) - 1)) + 1)
 #define	P2BOUNDARY(off, len, align) \