Re: [PATCH 3/4] bitmap: Introduce bitmap_size()

[Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>]

Le 02/07/2022 à 23:09, Yury Norov a écrit :
> On Sat, Jul 02, 2022 at 08:29:36PM +0200, Christophe JAILLET wrote:
> > The new bitmap_size() function returns the size, in bytes, of a bitmap.
> >
> > Remove the already existing bitmap_size() functions and macro in some
> > files.
> > These files already use the bitmap API and will use the new function
> > in bitmap.h automatically.
> >
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> >   drivers/md/dm-clone-metadata.c | 5 -----
> >   include/linux/bitmap.h         | 6 ++++++
> >   lib/math/prime_numbers.c       | 2 --
> >   3 files changed, 6 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/md/dm-clone-metadata.c b/drivers/md/dm-clone-metadata.c
> > index c43d55672bce..47c1fa7aad8b 100644
> > --- a/drivers/md/dm-clone-metadata.c
> > +++ b/drivers/md/dm-clone-metadata.c
> > @@ -465,11 +465,6 @@ static void __destroy_persistent_data_structures(struct dm_clone_metadata *cmd)
> >   
> >   /*---------------------------------------------------------------------------*/
> >   
> > -static size_t bitmap_size(unsigned long nr_bits)
> > -{
> > -	return BITS_TO_LONGS(nr_bits) * sizeof(long);
> > -}
> > -
> >   static int __dirty_map_init(struct dirty_map *dmap, unsigned long nr_words,
> >   			    unsigned long nr_regions)
> >   {
> > diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
> > index f091a1664bf1..f66fb98a4126 100644
> > --- a/include/linux/bitmap.h
> > +++ b/include/linux/bitmap.h
> > @@ -48,6 +48,7 @@ struct device;
> >    *  bitmap_equal(src1, src2, nbits)             Are *src1 and *src2 equal?
> >    *  bitmap_intersects(src1, src2, nbits)        Do *src1 and *src2 overlap?
> >    *  bitmap_subset(src1, src2, nbits)            Is *src1 a subset of *src2?
> > + *  bitmap_size(nbits)                          Size, in bytes, of a bitmap
> >    *  bitmap_empty(src, nbits)                    Are all bits zero in *src?
> >    *  bitmap_full(src, nbits)                     Are all bits set in *src?
> >    *  bitmap_weight(src, nbits)                   Hamming Weight: number set bits
> > @@ -124,6 +125,11 @@ unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node);
> >   unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node);
> >   void bitmap_free(const unsigned long *bitmap);
> >   
> > +static __always_inline size_t bitmap_size(unsigned long nbits)
> > +{
> > +	return BITS_TO_LONGS(nbits) * sizeof(unsigned long);
> > +}
> > +
> >   /* Managed variants of the above. */
> >   unsigned long *devm_bitmap_alloc(struct device *dev,
> >   				 unsigned int nbits, gfp_t flags);
> > diff --git a/lib/math/prime_numbers.c b/lib/math/prime_numbers.c
> > index d42cebf7407f..d3b64b10da1c 100644
> > --- a/lib/math/prime_numbers.c
> > +++ b/lib/math/prime_numbers.c
> > @@ -6,8 +6,6 @@
> >   #include <linux/prime_numbers.h>
> >   #include <linux/slab.h>
> >   
> > -#define bitmap_size(nbits) (BITS_TO_LONGS(nbits) * sizeof(unsigned long))
> > -
>
> This should be dropped, for sure, and kmalloc() at line 128 should be
> replaced with bitmap_alloc().

This kmalloc() is for a structure and a flexible array.

You mean re-arranging the code to allocate the structure alone at first, 
then the bitmap?

CJ

> For the driver, we need to introduce bitmap_kvmalloc/bitmap_kvfree etc.
>
> >   struct primes {
> >   	struct rcu_head rcu;
> >   	unsigned long last, sz;
> > --
> > 2.34.1

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