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RDMA/umem: Use simpler logic for ib_umem_find_best_pgsz()

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The calculation in rdma_find_pg_bit() is fairly complicated, and the
function is never called anywhere else. Inline a simpler version into
ib_umem_find_best_pgsz()

Link: https://lore.kernel.org/r/3-v2-270386b7e60b+28f4-umem_1_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Jason Gunthorpe 2020-09-04 19:41:44 -03:00
parent 10c75ccb54
commit 3361c29e92
2 changed files with 8 additions and 27 deletions
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11
drivers/infiniband/core/umem.c
View File

@ -39,6 +39,7 @@
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/count_zeros.h>
#include <rdma/ib_umem_odp.h>
#include "uverbs.h"
@ -146,7 +147,6 @@ unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
unsigned long virt)
{
struct scatterlist *sg;
unsigned int best_pg_bit;
unsigned long va, pgoff;
dma_addr_t mask;
int i;
@ -186,9 +186,14 @@ unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
mask |= va;
pgoff = 0;
}
best_pg_bit = rdma_find_pg_bit(mask, pgsz_bitmap);
return BIT_ULL(best_pg_bit);
/* The mask accumulates 1's in each position where the VA and physical
* address differ, thus the length of trailing 0 is the largest page
* size that can pass the VA through to the physical.
*/
if (mask)
pgsz_bitmap &= GENMASK(count_trailing_zeros(mask), 0);
return rounddown_pow_of_two(pgsz_bitmap);
}
EXPORT_SYMBOL(ib_umem_find_best_pgsz);

24
include/rdma/ib_verbs.h
View File

@ -3335,30 +3335,6 @@ static inline bool rdma_cap_read_inv(struct ib_device *dev, u32 port_num)
return rdma_protocol_iwarp(dev, port_num);
}
/**
* rdma_find_pg_bit - Find page bit given address and HW supported page sizes
*
* @addr: address
* @pgsz_bitmap: bitmap of HW supported page sizes
*/
static inline unsigned int rdma_find_pg_bit(unsigned long addr,
unsigned long pgsz_bitmap)
{
unsigned long align;
unsigned long pgsz;
align = addr & -addr;
/* Find page bit such that addr is aligned to the highest supported
* HW page size
*/
pgsz = pgsz_bitmap & ~(-align << 1);
if (!pgsz)
return __ffs(pgsz_bitmap);
return __fls(pgsz);
}
/**
* rdma_core_cap_opa_port - Return whether the RDMA Port is OPA or not.
* @device: Device