Revision 30f92d62e5b41a94de2d0bbd677a6ea2fcfed74f authored by Akinobu Mita on 06 September 2017, 10:15:31 UTC, committed by Christoph Hellwig on 11 September 2017, 16:29:38 UTC
The initial chunk size for host memory buffer allocation is currently PAGE_SIZE << MAX_ORDER. MAX_ORDER order allocation is usually failed without CONFIG_DMA_CMA. So the HMB allocation is retried with chunk size PAGE_SIZE << (MAX_ORDER - 1) in general, but there is no problem if the retry allocation works correctly. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> [hch: rebased] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Cc: stable@vger.kernel.org
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reciprocal_div.c
#include <linux/kernel.h>
#include <asm/div64.h>
#include <linux/reciprocal_div.h>
#include <linux/export.h>
/*
* For a description of the algorithm please have a look at
* include/linux/reciprocal_div.h
*/
struct reciprocal_value reciprocal_value(u32 d)
{
struct reciprocal_value R;
u64 m;
int l;
l = fls(d - 1);
m = ((1ULL << 32) * ((1ULL << l) - d));
do_div(m, d);
++m;
R.m = (u32)m;
R.sh1 = min(l, 1);
R.sh2 = max(l - 1, 0);
return R;
}
EXPORT_SYMBOL(reciprocal_value);
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