[PATCH v1 1/3] tools: allocate bitmaps in units of unsigned long

[PATCH v1 1/3] tools: allocate bitmaps in units of unsigned long

[Olaf Hering]

Allocate enough memory so that the returned pointer can be safely
accessed as an array of unsigned long.

The actual bitmap size in units of bytes, as returned by bitmap_size,
remains unchanged.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 tools/libs/ctrl/xc_bitops.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/libs/ctrl/xc_bitops.h b/tools/libs/ctrl/xc_bitops.h
index 3d3a09772a..d6c5ea5138 100644
--- a/tools/libs/ctrl/xc_bitops.h
+++ b/tools/libs/ctrl/xc_bitops.h
@@ -21,7 +21,10 @@ static inline unsigned long bitmap_size(unsigned long nr_bits)
 
 static inline void *bitmap_alloc(unsigned long nr_bits)
 {
-    return calloc(1, bitmap_size(nr_bits));
+    unsigned long longs;
+
+    longs = (nr_bits + BITS_PER_LONG - 1) / BITS_PER_LONG;
+    return calloc(longs, sizeof(unsigned long));
 }
 
 static inline void bitmap_set(void *addr, unsigned long nr_bits)

[PATCH v1 2/3] tools: remove unused ORDER_LONG

[Olaf Hering]

There are no users left, xenpaging has its own variant.
The last user was removed with commit 11d0044a168994de85b9b328452292852aedc871

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 tools/libs/ctrl/xc_bitops.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tools/libs/ctrl/xc_bitops.h b/tools/libs/ctrl/xc_bitops.h
index d6c5ea5138..f0bac4a071 100644
--- a/tools/libs/ctrl/xc_bitops.h
+++ b/tools/libs/ctrl/xc_bitops.h
@@ -6,9 +6,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-/* Needed by several includees, but no longer used for bitops. */
 #define BITS_PER_LONG (sizeof(unsigned long) * 8)
-#define ORDER_LONG (sizeof(unsigned long) == 4 ? 5 : 6)
 
 #define BITMAP_ENTRY(_nr,_bmap) ((_bmap))[(_nr) / 8]
 #define BITMAP_SHIFT(_nr) ((_nr) % 8)

[PATCH v1 3/3] tools: add API to work with sevaral bits at once

[Olaf Hering]

Introduce new API to test if a fixed number of bits is clear or set,
and clear or set them all at once.

The caller has to make sure the input bitnumber is a multiply of BITS_PER_LONG.

This API avoids the loop over each bit in a known range just to see
if all of them are either clear or set.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 tools/libs/ctrl/xc_bitops.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/tools/libs/ctrl/xc_bitops.h b/tools/libs/ctrl/xc_bitops.h
index f0bac4a071..92f38872fb 100644
--- a/tools/libs/ctrl/xc_bitops.h
+++ b/tools/libs/ctrl/xc_bitops.h
@@ -77,4 +77,29 @@ static inline void bitmap_or(void *_dst, const void *_other,
         dst[i] |= other[i];
 }
 
+static inline int test_bit_long_set(unsigned long nr_base, const void *_addr)
+{
+    const unsigned long *addr = _addr;
+    unsigned long val = addr[nr_base / BITS_PER_LONG];
+    return val == ~0;
+}
+
+static inline int test_bit_long_clear(unsigned long nr_base, const void *_addr)
+{
+    const unsigned long *addr = _addr;
+    unsigned long val = addr[nr_base / BITS_PER_LONG];
+    return val == 0;
+}
+
+static inline void clear_bit_long(unsigned long nr_base, void *_addr)
+{
+    unsigned long *addr = _addr;
+    addr[nr_base / BITS_PER_LONG] = 0;
+}
+
+static inline void set_bit_long(unsigned long nr_base, void *_addr)
+{
+    unsigned long *addr = _addr;
+    addr[nr_base / BITS_PER_LONG] = ~0;
+}
 #endif  /* XC_BITOPS_H */

Re: [PATCH v1 1/3] tools: allocate bitmaps in units of unsigned long

[Wei Liu]

On Wed, Dec 09, 2020 at 04:54:49PM +0100, Olaf Hering wrote:
> Allocate enough memory so that the returned pointer can be safely
> accessed as an array of unsigned long.
> 
> The actual bitmap size in units of bytes, as returned by bitmap_size,
> remains unchanged.
> 
> Signed-off-by: Olaf Hering <olaf@aepfle.de>

Acked-by: Wei Liu <wl@xen.org>

I can see where you're coming from. This (internal) API's returned
pointer is being assigned to unsigned long *.

> ---
>  tools/libs/ctrl/xc_bitops.h | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/libs/ctrl/xc_bitops.h b/tools/libs/ctrl/xc_bitops.h
> index 3d3a09772a..d6c5ea5138 100644
> --- a/tools/libs/ctrl/xc_bitops.h
> +++ b/tools/libs/ctrl/xc_bitops.h
> @@ -21,7 +21,10 @@ static inline unsigned long bitmap_size(unsigned long nr_bits)
>  
>  static inline void *bitmap_alloc(unsigned long nr_bits)
>  {
> -    return calloc(1, bitmap_size(nr_bits));
> +    unsigned long longs;
> +
> +    longs = (nr_bits + BITS_PER_LONG - 1) / BITS_PER_LONG;
> +    return calloc(longs, sizeof(unsigned long));
>  }
>  
>  static inline void bitmap_set(void *addr, unsigned long nr_bits)

Re: [PATCH v1 2/3] tools: remove unused ORDER_LONG

[Wei Liu]

On Wed, Dec 09, 2020 at 04:54:50PM +0100, Olaf Hering wrote:
> There are no users left, xenpaging has its own variant.
> The last user was removed with commit 11d0044a168994de85b9b328452292852aedc871
> 
> Signed-off-by: Olaf Hering <olaf@aepfle.de>

Acked-by: Wei Liu <wl@xen.org>

Re: [PATCH v1 3/3] tools: add API to work with sevaral bits at once

[Wei Liu]

On Wed, Dec 09, 2020 at 04:54:51PM +0100, Olaf Hering wrote:
> Introduce new API to test if a fixed number of bits is clear or set,
> and clear or set them all at once.
> 
> The caller has to make sure the input bitnumber is a multiply of BITS_PER_LONG.
> 
> This API avoids the loop over each bit in a known range just to see
> if all of them are either clear or set.
> 
> Signed-off-by: Olaf Hering <olaf@aepfle.de>

I would rather these be introduced along side their callers.

> ---
>  tools/libs/ctrl/xc_bitops.h | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/tools/libs/ctrl/xc_bitops.h b/tools/libs/ctrl/xc_bitops.h
> index f0bac4a071..92f38872fb 100644
> --- a/tools/libs/ctrl/xc_bitops.h
> +++ b/tools/libs/ctrl/xc_bitops.h
> @@ -77,4 +77,29 @@ static inline void bitmap_or(void *_dst, const void *_other,
>          dst[i] |= other[i];
>  }
>  
> +static inline int test_bit_long_set(unsigned long nr_base, const void *_addr)

What's wrong with requiring the input addr be const unsigned long *?

Re: [PATCH v1 3/3] tools: add API to work with sevaral bits at once

[Olaf Hering]

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Am Tue, 15 Dec 2020 16:22:44 +0000
schrieb Wei Liu <wl@xen.org>:

> What's wrong with requiring the input addr be const unsigned long *?

Probably nothing. In the end I just borrowed the prototypes from the other functions in this file.

I will resend with this change once I have the consumers ready.

Olaf

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Re: [PATCH v1 3/3] tools: add API to work with sevaral bits at once

[Wei Liu]

On Tue, Dec 15, 2020 at 05:29:17PM +0100, Olaf Hering wrote:
> Am Tue, 15 Dec 2020 16:22:44 +0000
> schrieb Wei Liu <wl@xen.org>:
> 
> > What's wrong with requiring the input addr be const unsigned long *?
> 
> Probably nothing. In the end I just borrowed the prototypes from the other functions in this file.
> 
> I will resend with this change once I have the consumers ready.

Okay.

I will push the first two shortly.

Wei.

> 
> Olaf