diff options
| author |   Jason Gunthorpe <jgg@nvidia.com> | 2020-09-04 19:41:42 -0300 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2020-09-09 15:33:17 -0300 |
| commit | a40c20dabdf9045270767c75918feb67f0727c89 (patch) | |
| tree | 18d950f161029c7eb29da0f5a31c9d89da64b71d /drivers | |
| parent | RDMA: Make counters destroy symmetrical (diff) | |
| download | linux-dev-a40c20dabdf9045270767c75918feb67f0727c89.tar.xz linux-dev-a40c20dabdf9045270767c75918feb67f0727c89.zip | |
RDMA/umem: Fix ib_umem_find_best_pgsz() for mappings that cross a page boundary
It is possible for a single SGL to span an aligned boundary, eg if the SGL
is
61440 -> 90112
Then the length is 28672, which currently limits the block size to
32k. With a 32k page size the two covering blocks will be:
32768->65536 and 65536->98304
However, the correct answer is a 128K block size which will span the whole
28672 bytes in a single block.
Instead of limiting based on length figure out which high IOVA bits don't
change between the start and end addresses. That is the highest useful
page size.
Fixes: 4a35339958f1 ("RDMA/umem: Add API to find best driver supported page size in an MR")
Link: https://lore.kernel.org/r/1-v2-270386b7e60b+28f4-umem_1_jgg@nvidia.com
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/infiniband/core/umem.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index 831bff8d52e5..09539dd764ec 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -156,8 +156,13 @@ unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem, return 0; va = virt; - /* max page size not to exceed MR length */ - mask = roundup_pow_of_two(umem->length); + /* The best result is the smallest page size that results in the minimum + * number of required pages. Compute the largest page size that could + * work based on VA address bits that don't change. + */ + mask = pgsz_bitmap & + GENMASK(BITS_PER_LONG - 1, + bits_per((umem->length - 1 + virt) ^ virt)); /* offset into first SGL */ pgoff = umem->address & ~PAGE_MASK; |