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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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|---|---|---|
| .. | ||
| ipath_common.h | ||
| ipath_cq.c | ||
| ipath_debug.h | ||
| ipath_diag.c | ||
| ipath_dma.c | ||
| ipath_driver.c | ||
| ipath_eeprom.c | ||
| ipath_file_ops.c | ||
| ipath_fs.c | ||
| ipath_iba6110.c | ||
| ipath_iba6120.c | ||
| ipath_init_chip.c | ||
| ipath_intr.c | ||
| ipath_kernel.h | ||
| ipath_keys.c | ||
| ipath_layer.c | ||
| ipath_layer.h | ||
| ipath_mad.c | ||
| ipath_mmap.c | ||
| ipath_mr.c | ||
| ipath_qp.c | ||
| ipath_rc.c | ||
| ipath_registers.h | ||
| ipath_ruc.c | ||
| ipath_srq.c | ||
| ipath_stats.c | ||
| ipath_sysfs.c | ||
| ipath_uc.c | ||
| ipath_ud.c | ||
| ipath_user_pages.c | ||
| ipath_verbs.c | ||
| ipath_verbs.h | ||
| ipath_verbs_mcast.c | ||
| ipath_wc_ppc64.c | ||
| ipath_wc_x86_64.c | ||
| Kconfig | ||
| Makefile | ||