mirror of https://gitee.com/openkylin/linux.git
f7c6a7b5d5
Export ib_umem_get()/ib_umem_release() and put low-level drivers in
control of when to call ib_umem_get() to pin and DMA map userspace,
rather than always calling it in ib_uverbs_reg_mr() before calling the
low-level driver's reg_user_mr method.
Also move these functions to be in the ib_core module instead of
ib_uverbs, so that driver modules using them do not depend on
ib_uverbs.
This has a number of advantages:
- It is better design from the standpoint of making generic code a
library that can be used or overridden by device-specific code as
the details of specific devices dictate.
- Drivers that do not need to pin userspace memory regions do not
need to take the performance hit of calling ib_mem_get(). For
example, although I have not tried to implement it in this patch,
the ipath driver should be able to avoid pinning memory and just
use copy_{to,from}_user() to access userspace memory regions.
- Buffers that need special mapping treatment can be identified by
the low-level driver. For example, it may be possible to solve
some Altix-specific memory ordering issues with mthca CQs in
userspace by mapping CQ buffers with extra flags.
- Drivers that need to pin and DMA map userspace memory for things
other than memory regions can use ib_umem_get() directly, instead
of hacks using extra parameters to their reg_phys_mr method. For
example, the mlx4 driver that is pending being merged needs to pin
and DMA map QP and CQ buffers, but it does not need to create a
memory key for these buffers. So the cleanest solution is for mlx4
to call ib_umem_get() in the create_qp and create_cq methods.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
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| .. | ||
| Kconfig | ||
| Makefile | ||
| cxio_dbg.c | ||
| cxio_hal.c | ||
| cxio_hal.h | ||
| cxio_resource.c | ||
| cxio_resource.h | ||
| cxio_wr.h | ||
| iwch.c | ||
| iwch.h | ||
| iwch_cm.c | ||
| iwch_cm.h | ||
| iwch_cq.c | ||
| iwch_ev.c | ||
| iwch_mem.c | ||
| iwch_provider.c | ||
| iwch_provider.h | ||
| iwch_qp.c | ||
| iwch_user.h | ||
| tcb.h | ||