mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-22 17:01:14 +00:00
![Dan Williams](/assets/img/avatar_default.png)
Back in 2011, Russell pointed out that the "async_tx channel switch" capability was violating expectations of the dma mapping api [1]. At the time the existing uses were reviewed as still usable, but that longer term we needed a rework of the raid offload implementation. While some of the framework for a fixed implementation was introduced in 2012 [2], the wider rewrite never materialized. There continues to be interest in raid offload with new dma/raid engine drivers being submitted. Those drivers must not build on top of the broken channel switching capability. Prevent async_tx from using an offload engine if the channel switching capability is enabled. This still allows the engine to be used for other purposes, but the broken way async_tx uses these engines for raid will be disabled. For configurations where this causes a performance regression the only solution is to start the work of eliminating the async_tx api and moving channel management into the raid code directly where it can manage marshalling an operation stream between multiple dma channels. [1]: http://lists.infradead.org/pipermail/linux-arm-kernel/2011-January/036753.html [2]: https://lkml.org/lkml/2012/12/6/71 Cc: Anatolij Gustschin <agust@denx.de> Cc: Anup Patel <anup.patel@broadcom.com> Cc: Rameshwar Prasad Sahu <rsahu@apm.com> Cc: Saeed Bishara <saeed.bishara@gmail.com> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Reported-by: Russell King <linux@armlinux.org.uk> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
208 lines
6.8 KiB
C
208 lines
6.8 KiB
C
/*
|
|
* Copyright © 2006, Intel Corporation.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms and conditions of the GNU General Public License,
|
|
* version 2, as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
|
* more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along with
|
|
* this program; if not, write to the Free Software Foundation, Inc.,
|
|
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*
|
|
*/
|
|
#ifndef _ASYNC_TX_H_
|
|
#define _ASYNC_TX_H_
|
|
#include <linux/dmaengine.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/interrupt.h>
|
|
|
|
/* on architectures without dma-mapping capabilities we need to ensure
|
|
* that the asynchronous path compiles away
|
|
*/
|
|
#ifdef CONFIG_HAS_DMA
|
|
#define __async_inline
|
|
#else
|
|
#define __async_inline __always_inline
|
|
#endif
|
|
|
|
/**
|
|
* dma_chan_ref - object used to manage dma channels received from the
|
|
* dmaengine core.
|
|
* @chan - the channel being tracked
|
|
* @node - node for the channel to be placed on async_tx_master_list
|
|
* @rcu - for list_del_rcu
|
|
* @count - number of times this channel is listed in the pool
|
|
* (for channels with multiple capabiities)
|
|
*/
|
|
struct dma_chan_ref {
|
|
struct dma_chan *chan;
|
|
struct list_head node;
|
|
struct rcu_head rcu;
|
|
atomic_t count;
|
|
};
|
|
|
|
/**
|
|
* async_tx_flags - modifiers for the async_* calls
|
|
* @ASYNC_TX_XOR_ZERO_DST: this flag must be used for xor operations where the
|
|
* the destination address is not a source. The asynchronous case handles this
|
|
* implicitly, the synchronous case needs to zero the destination block.
|
|
* @ASYNC_TX_XOR_DROP_DST: this flag must be used if the destination address is
|
|
* also one of the source addresses. In the synchronous case the destination
|
|
* address is an implied source, whereas the asynchronous case it must be listed
|
|
* as a source. The destination address must be the first address in the source
|
|
* array.
|
|
* @ASYNC_TX_ACK: immediately ack the descriptor, precludes setting up a
|
|
* dependency chain
|
|
* @ASYNC_TX_FENCE: specify that the next operation in the dependency
|
|
* chain uses this operation's result as an input
|
|
* @ASYNC_TX_PQ_XOR_DST: do not overwrite the syndrome but XOR it with the
|
|
* input data. Required for rmw case.
|
|
*/
|
|
enum async_tx_flags {
|
|
ASYNC_TX_XOR_ZERO_DST = (1 << 0),
|
|
ASYNC_TX_XOR_DROP_DST = (1 << 1),
|
|
ASYNC_TX_ACK = (1 << 2),
|
|
ASYNC_TX_FENCE = (1 << 3),
|
|
ASYNC_TX_PQ_XOR_DST = (1 << 4),
|
|
};
|
|
|
|
/**
|
|
* struct async_submit_ctl - async_tx submission/completion modifiers
|
|
* @flags: submission modifiers
|
|
* @depend_tx: parent dependency of the current operation being submitted
|
|
* @cb_fn: callback routine to run at operation completion
|
|
* @cb_param: parameter for the callback routine
|
|
* @scribble: caller provided space for dma/page address conversions
|
|
*/
|
|
struct async_submit_ctl {
|
|
enum async_tx_flags flags;
|
|
struct dma_async_tx_descriptor *depend_tx;
|
|
dma_async_tx_callback cb_fn;
|
|
void *cb_param;
|
|
void *scribble;
|
|
};
|
|
|
|
#if defined(CONFIG_DMA_ENGINE) && !defined(CONFIG_ASYNC_TX_CHANNEL_SWITCH)
|
|
#define async_tx_issue_pending_all dma_issue_pending_all
|
|
|
|
/**
|
|
* async_tx_issue_pending - send pending descriptor to the hardware channel
|
|
* @tx: descriptor handle to retrieve hardware context
|
|
*
|
|
* Note: any dependent operations will have already been issued by
|
|
* async_tx_channel_switch, or (in the case of no channel switch) will
|
|
* be already pending on this channel.
|
|
*/
|
|
static inline void async_tx_issue_pending(struct dma_async_tx_descriptor *tx)
|
|
{
|
|
if (likely(tx)) {
|
|
struct dma_chan *chan = tx->chan;
|
|
struct dma_device *dma = chan->device;
|
|
|
|
dma->device_issue_pending(chan);
|
|
}
|
|
}
|
|
#ifdef CONFIG_ARCH_HAS_ASYNC_TX_FIND_CHANNEL
|
|
#include <asm/async_tx.h>
|
|
#else
|
|
#define async_tx_find_channel(dep, type, dst, dst_count, src, src_count, len) \
|
|
__async_tx_find_channel(dep, type)
|
|
struct dma_chan *
|
|
__async_tx_find_channel(struct async_submit_ctl *submit,
|
|
enum dma_transaction_type tx_type);
|
|
#endif /* CONFIG_ARCH_HAS_ASYNC_TX_FIND_CHANNEL */
|
|
#else
|
|
static inline void async_tx_issue_pending_all(void)
|
|
{
|
|
do { } while (0);
|
|
}
|
|
|
|
static inline void async_tx_issue_pending(struct dma_async_tx_descriptor *tx)
|
|
{
|
|
do { } while (0);
|
|
}
|
|
|
|
static inline struct dma_chan *
|
|
async_tx_find_channel(struct async_submit_ctl *submit,
|
|
enum dma_transaction_type tx_type, struct page **dst,
|
|
int dst_count, struct page **src, int src_count,
|
|
size_t len)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* async_tx_sync_epilog - actions to take if an operation is run synchronously
|
|
* @cb_fn: function to call when the transaction completes
|
|
* @cb_fn_param: parameter to pass to the callback routine
|
|
*/
|
|
static inline void
|
|
async_tx_sync_epilog(struct async_submit_ctl *submit)
|
|
{
|
|
if (submit->cb_fn)
|
|
submit->cb_fn(submit->cb_param);
|
|
}
|
|
|
|
typedef union {
|
|
unsigned long addr;
|
|
struct page *page;
|
|
dma_addr_t dma;
|
|
} addr_conv_t;
|
|
|
|
static inline void
|
|
init_async_submit(struct async_submit_ctl *args, enum async_tx_flags flags,
|
|
struct dma_async_tx_descriptor *tx,
|
|
dma_async_tx_callback cb_fn, void *cb_param,
|
|
addr_conv_t *scribble)
|
|
{
|
|
args->flags = flags;
|
|
args->depend_tx = tx;
|
|
args->cb_fn = cb_fn;
|
|
args->cb_param = cb_param;
|
|
args->scribble = scribble;
|
|
}
|
|
|
|
void async_tx_submit(struct dma_chan *chan, struct dma_async_tx_descriptor *tx,
|
|
struct async_submit_ctl *submit);
|
|
|
|
struct dma_async_tx_descriptor *
|
|
async_xor(struct page *dest, struct page **src_list, unsigned int offset,
|
|
int src_cnt, size_t len, struct async_submit_ctl *submit);
|
|
|
|
struct dma_async_tx_descriptor *
|
|
async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
|
|
int src_cnt, size_t len, enum sum_check_flags *result,
|
|
struct async_submit_ctl *submit);
|
|
|
|
struct dma_async_tx_descriptor *
|
|
async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
|
|
unsigned int src_offset, size_t len,
|
|
struct async_submit_ctl *submit);
|
|
|
|
struct dma_async_tx_descriptor *async_trigger_callback(struct async_submit_ctl *submit);
|
|
|
|
struct dma_async_tx_descriptor *
|
|
async_gen_syndrome(struct page **blocks, unsigned int offset, int src_cnt,
|
|
size_t len, struct async_submit_ctl *submit);
|
|
|
|
struct dma_async_tx_descriptor *
|
|
async_syndrome_val(struct page **blocks, unsigned int offset, int src_cnt,
|
|
size_t len, enum sum_check_flags *pqres, struct page *spare,
|
|
struct async_submit_ctl *submit);
|
|
|
|
struct dma_async_tx_descriptor *
|
|
async_raid6_2data_recov(int src_num, size_t bytes, int faila, int failb,
|
|
struct page **ptrs, struct async_submit_ctl *submit);
|
|
|
|
struct dma_async_tx_descriptor *
|
|
async_raid6_datap_recov(int src_num, size_t bytes, int faila,
|
|
struct page **ptrs, struct async_submit_ctl *submit);
|
|
|
|
void async_tx_quiesce(struct dma_async_tx_descriptor **tx);
|
|
#endif /* _ASYNC_TX_H_ */
|