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>
79 lines
2.5 KiB
C
79 lines
2.5 KiB
C
/*
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* Copyright (c) 2007 Cisco Systems. All rights reserved.
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*
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* This software is available to you under a choice of one of two
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* licenses. You may choose to be licensed under the terms of the GNU
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* General Public License (GPL) Version 2, available from the file
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* COPYING in the main directory of this source tree, or the
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* OpenIB.org BSD license below:
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* - Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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*
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* - Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#ifndef IB_UMEM_H
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#define IB_UMEM_H
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#include <linux/list.h>
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#include <linux/scatterlist.h>
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struct ib_ucontext;
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struct ib_umem {
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struct ib_ucontext *context;
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size_t length;
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int offset;
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int page_size;
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int writable;
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struct list_head chunk_list;
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};
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struct ib_umem_chunk {
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struct list_head list;
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int nents;
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int nmap;
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struct scatterlist page_list[0];
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};
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#ifdef CONFIG_INFINIBAND_USER_MEM
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struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
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size_t size, int access);
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void ib_umem_release(struct ib_umem *umem);
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int ib_umem_page_count(struct ib_umem *umem);
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#else /* CONFIG_INFINIBAND_USER_MEM */
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#include <linux/err.h>
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static inline struct ib_umem *ib_umem_get(struct ib_ucontext *context,
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unsigned long addr, size_t size,
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int access) {
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return ERR_PTR(-EINVAL);
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}
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static inline void ib_umem_release(struct ib_umem *umem) { }
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static inline int ib_umem_page_count(struct ib_umem *umem) { return 0; }
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#endif /* CONFIG_INFINIBAND_USER_MEM */
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#endif /* IB_UMEM_H */
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