kernel/linux.git/include/rdma/ib_umem.h, branch linux-7.0.y

RDMA/umem: Use consistent DMA attributes when unmapping entries

2026-05-23T11:09:11+00:00

[ Upstream commit 179b32095854d44749dd535502f05d95bbf43775 ] The DMA API expects that mapping and unmapping use the same DMA attributes. The RDMA umem code did not meet this requirement, so fix the mismatch. Fixes: f03d9fadfe13 ("RDMA/core: Add weak ordering dma attr to dma mapping") Signed-off-by: Leon Romanovsky Signed-off-by: Sasha Levin

RDMA/core: Add umem "is_contiguous" and "start_dma_addr" helpers

2025-07-13T08:00:34+00:00

In some cases drivers may need to check if a given umem is contiguous. Add a helper function in core code so that drivers don't need to deal with umem or scatter-gather lists structure. Additionally add a helper for getting umem's start DMA address and use it in other helper functions that open code it. Signed-off-by: Michael Margolin Link: https://patch.msgid.link/20250708202308.24783-3-mrgolin@amazon.com Reviewed-by: Jason Gunthorpe Signed-off-by: Leon Romanovsky

RDMA/umem: Introduce an option to revoke DMABUF umem

2024-08-11T08:12:49+00:00

Introduce an option to revoke DMABUF umem. This option will retain the umem allocation while revoking its DMA mapping. Furthermore, any subsequent attempts to map the pages should fail once the umem has been revoked. This functionality will be utilized in the upcoming patches in the series, where we aim to delay umem deallocation until the mkey deregistration. However, we must unmap its pages immediately. Signed-off-by: Yishai Hadas Link: https://patch.msgid.link/a38270f2fe4a194868ca2312f4c1c760e51bcbff.1722512548.git.leon@kernel.org Signed-off-by: Leon Romanovsky

RDMA/umem: Add support for creating pinned DMABUF umem with a given dma device

2024-08-11T08:12:49+00:00

Add support for creating pinned DMABUF umem with a specified DMA device instead of the DMA device of the given IB device. This API will be utilized in the upcoming patches of the series when multiple path DMAs are implemented. Signed-off-by: Yishai Hadas Link: https://patch.msgid.link/038aad36a43797e5591b20ba81051fc5758124f9.1722512548.git.leon@kernel.org Signed-off-by: Leon Romanovsky

RDMA/core: Fix umem iterator when PAGE_SIZE is greater then HCA pgsz

2023-12-05T00:02:41+00:00

64k pages introduce the situation in this diagram when the HCA 4k page size is being used: +-------------------------------------------+ <--- 64k aligned VA | | | HCA 4k page | | | +-------------------------------------------+ | o | | | | o | | | | o | +-------------------------------------------+ | | | HCA 4k page | | | +-------------------------------------------+ <--- Live HCA page |OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO| <--- offset | | <--- VA | MR data | +-------------------------------------------+ | | | HCA 4k page | | | +-------------------------------------------+ | o | | | | o | | | | o | +-------------------------------------------+ | | | HCA 4k page | | | +-------------------------------------------+ The VA addresses are coming from rdma-core in this diagram can be arbitrary, but for 64k pages, the VA may be offset by some number of HCA 4k pages and followed by some number of HCA 4k pages. The current iterator doesn't account for either the preceding 4k pages or the following 4k pages. Fix the issue by extending the ib_block_iter to contain the number of DMA pages like comment [1] says and by using __sg_advance to start the iterator at the first live HCA page. The changes are contained in a parallel set of iterator start and next functions that are umem aware and specific to umem since there is one user of the rdma_for_each_block() without umem. These two fixes prevents the extra pages before and after the user MR data. Fix the preceding pages by using the __sq_advance field to start at the first 4k page containing MR data. Fix the following pages by saving the number of pgsz blocks in the iterator state and downcounting on each next. This fix allows for the elimination of the small page crutch noted in the Fixes. Fixes: 10c75ccb54e4 ("RDMA/umem: Prevent small pages from being returned by ib_umem_find_best_pgsz()") Link: https://lore.kernel.org/r/20231129202143.1434-2-shiraz.saleem@intel.com Signed-off-by: Mike Marciniszyn Signed-off-by: Shiraz Saleem Reviewed-by: Jason Gunthorpe Signed-off-by: Jason Gunthorpe

RDMA/umem: Remove unused 'work' member from struct ib_umem

2023-02-12T18:25:25+00:00

It is not used now. Fixes: b95df5e3e459 ("drivers/IB,core: reduce scope of mmap_sem") Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/r/0-v1-22a2667fa089+a3-umem_work_jgg@nvidia.com Reviewed-by: Devesh Sharma Signed-off-by: Leon Romanovsky

RDMA/umem: Allow pinned dmabuf umem usage

2021-10-28T11:58:26+00:00

Introduce ib_umem_dmabuf_get_pinned() which allows the driver to get a dmabuf umem which is pinned and does not require move_notify callback implementation. The returned umem is pinned and DMA mapped like standard cpu umems, and is released through ib_umem_release() (incl. unpinning and unmapping). Link: https://lore.kernel.org/r/20211012120903.96933-3-galpress@amazon.com Signed-off-by: Gal Pressman Signed-off-by: Jason Gunthorpe

RDMA: Use the sg_table directly and remove the opencoded version from umem

2021-08-24T22:52:40+00:00

This allows using the normal sg_table APIs and makes all the code cleaner. Remove sgt, nents and nmapd from ib_umem. Link: https://lore.kernel.org/r/20210824142531.3877007-4-maorg@nvidia.com Signed-off-by: Maor Gottlieb Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe

lib/scatterlist: Fix wrong update of orig_nents

2021-08-24T22:52:40+00:00

orig_nents should represent the number of entries with pages, but __sg_alloc_table_from_pages sets orig_nents as the number of total entries in the table. This is wrong when the API is used for dynamic allocation where not all the table entries are mapped with pages. It wasn't observed until now, since RDMA umem who uses this API in the dynamic form doesn't use orig_nents implicit or explicit by the scatterlist APIs. Fix it by changing the append API to track the SG append table state and have an API to free the append table according to the total number of entries in the table. Now all APIs set orig_nents as number of enries with pages. Fixes: 07da1223ec93 ("lib/scatterlist: Add support in dynamic allocation of SG table from pages") Link: https://lore.kernel.org/r/20210824142531.3877007-3-maorg@nvidia.com Signed-off-by: Maor Gottlieb Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe

RDMA/umem: Support importing dma-buf as user memory region

2021-01-20T20:07:52+00:00

Dma-buf is a standard cross-driver buffer sharing mechanism that can be used to support peer-to-peer access from RDMA devices. Device memory exported via dma-buf is associated with a file descriptor. This is passed to the user space as a property associated with the buffer allocation. When the buffer is registered as a memory region, the file descriptor is passed to the RDMA driver along with other parameters. Implement the common code for importing dma-buf object and mapping dma-buf pages. Link: https://lore.kernel.org/r/1608067636-98073-2-git-send-email-jianxin.xiong@intel.com Signed-off-by: Jianxin Xiong Reviewed-by: Sean Hefty Acked-by: Michael J. Ruhl Acked-by: Christian Koenig Acked-by: Daniel Vetter Signed-off-by: Jason Gunthorpe