thanks. done in v8 I am sending right now.
On Mon, Feb 8, 2016 at 3:36 PM, Andrew Morton [off-list ref] wrote:
On Sun, 7 Feb 2016 17:08:45 -0800 David Decotigny [off-list ref] wrote:
quoted
From: David Decotigny <redacted>
Aimed at transferring bitmaps to/from user-space in a 32/64-bit agnostic
way.
Tested:
unit tests (next patch) on qemu i386, x86_64, ppc, ppc64 BE and LE,
ARM.
@@ -1060,6 +1062,90 @@ int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
EXPORT_SYMBOL(bitmap_allocate_region);
/**
+ * bitmap_from_u32array - copy the contents of a u32 array of bits to bitmap
+ * @bitmap: array of unsigned longs, the destination bitmap, non NULL
+ * @nbits: number of bits in @bitmap
+ * @buf: array of u32 (in host byte order), the source bitmap, non NULL
+ * @nwords: number of u32 words in @buf
+ *
+ * copy min(nbits, 32*nwords) bits from @buf to @bitmap, remaining
+ * bits between nword and nbits in @bitmap (if any) are cleared. In
+ * last word of @bitmap, the bits beyond nbits (if any) are kept
+ * unchanged.
+ */
This will leave the caller not knowing how many valid bits are actually
present in the resulting bitmap. To determine that, the caller will
need to perform (duplicated) math on `nbits' and `nwords'.
quoted
+void bitmap_from_u32array(unsigned long *bitmap, unsigned int nbits,
+ const u32 *buf, unsigned int nwords)
So how about we make this return the number of valid bits in *bitmap?
quoted
+/**
+ * bitmap_to_u32array - copy the contents of bitmap to a u32 array of bits
+ * @buf: array of u32 (in host byte order), the dest bitmap, non NULL
+ * @nwords: number of u32 words in @buf
+ * @bitmap: array of unsigned longs, the source bitmap, non NULL
+ * @nbits: number of bits in @bitmap
+ *
+ * copy min(nbits, 32*nwords) bits from @bitmap to @buf. Remaining
+ * bits after nbits in @buf (if any) are cleared.
+ */
+void bitmap_to_u32array(u32 *buf, unsigned int nwords,
+ const unsigned long *bitmap, unsigned int nbits)
Ditto.