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Subject[PATCH 07/15] kfifo: add kfifo_dma_out_prepare_mapped()
Date
When the kfifo buffer is already dma-mapped, one cannot use the kfifo
API to fill in an SG list.

Add kfifo_dma_in_prepare_mapped() which allows exactly this. A mapped
dma_addr_t is passed and it is filled into provided sgl too. Including
the dma_len.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/kfifo.h | 37 +++++++++++++++++++++++++------------
lib/kfifo.c | 34 ++++++++++++++++++++++------------
2 files changed, 47 insertions(+), 24 deletions(-)

diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h
index 3def70e1a3e3..c7cc25b2808b 100644
--- a/include/linux/kfifo.h
+++ b/include/linux/kfifo.h
@@ -36,6 +36,7 @@
* to lock the reader.
*/

+#include <linux/dma-mapping.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
@@ -709,11 +710,12 @@ __kfifo_int_must_check_helper( \
)

/**
- * kfifo_dma_in_prepare - setup a scatterlist for DMA input
+ * kfifo_dma_in_prepare_mapped - setup a scatterlist for DMA input
* @fifo: address of the fifo to be used
* @sgl: pointer to the scatterlist array
* @nents: number of entries in the scatterlist array
* @len: number of elements to transfer
+ * @dma: mapped dma address to fill into @sgl
*
* This macro fills a scatterlist for DMA input.
* It returns the number entries in the scatterlist array.
@@ -721,7 +723,7 @@ __kfifo_int_must_check_helper( \
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these macros.
*/
-#define kfifo_dma_in_prepare(fifo, sgl, nents, len) \
+#define kfifo_dma_in_prepare_mapped(fifo, sgl, nents, len, dma) \
({ \
typeof((fifo) + 1) __tmp = (fifo); \
struct scatterlist *__sgl = (sgl); \
@@ -730,10 +732,14 @@ __kfifo_int_must_check_helper( \
const size_t __recsize = sizeof(*__tmp->rectype); \
struct __kfifo *__kfifo = &__tmp->kfifo; \
(__recsize) ? \
- __kfifo_dma_in_prepare_r(__kfifo, __sgl, __nents, __len, __recsize) : \
- __kfifo_dma_in_prepare(__kfifo, __sgl, __nents, __len); \
+ __kfifo_dma_in_prepare_r(__kfifo, __sgl, __nents, __len, __recsize, \
+ dma) : \
+ __kfifo_dma_in_prepare(__kfifo, __sgl, __nents, __len, dma); \
})

+#define kfifo_dma_in_prepare(fifo, sgl, nents, len) \
+ kfifo_dma_in_prepare_mapped(fifo, sgl, nents, len, DMA_MAPPING_ERROR)
+
/**
* kfifo_dma_in_finish - finish a DMA IN operation
* @fifo: address of the fifo to be used
@@ -758,11 +764,12 @@ __kfifo_int_must_check_helper( \
})

/**
- * kfifo_dma_out_prepare - setup a scatterlist for DMA output
+ * kfifo_dma_out_prepare_mapped - setup a scatterlist for DMA output
* @fifo: address of the fifo to be used
* @sgl: pointer to the scatterlist array
* @nents: number of entries in the scatterlist array
* @len: number of elements to transfer
+ * @dma: mapped dma address to fill into @sgl
*
* This macro fills a scatterlist for DMA output which at most @len bytes
* to transfer.
@@ -772,7 +779,7 @@ __kfifo_int_must_check_helper( \
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these macros.
*/
-#define kfifo_dma_out_prepare(fifo, sgl, nents, len) \
+#define kfifo_dma_out_prepare_mapped(fifo, sgl, nents, len, dma) \
({ \
typeof((fifo) + 1) __tmp = (fifo); \
struct scatterlist *__sgl = (sgl); \
@@ -781,10 +788,14 @@ __kfifo_int_must_check_helper( \
const size_t __recsize = sizeof(*__tmp->rectype); \
struct __kfifo *__kfifo = &__tmp->kfifo; \
(__recsize) ? \
- __kfifo_dma_out_prepare_r(__kfifo, __sgl, __nents, __len, __recsize) : \
- __kfifo_dma_out_prepare(__kfifo, __sgl, __nents, __len); \
+ __kfifo_dma_out_prepare_r(__kfifo, __sgl, __nents, __len, __recsize, \
+ dma) : \
+ __kfifo_dma_out_prepare(__kfifo, __sgl, __nents, __len, dma); \
})

+#define kfifo_dma_out_prepare(fifo, sgl, nents, len) \
+ kfifo_dma_out_prepare_mapped(fifo, sgl, nents, len, DMA_MAPPING_ERROR)
+
/**
* kfifo_dma_out_finish - finish a DMA OUT operation
* @fifo: address of the fifo to be used
@@ -905,10 +916,10 @@ extern int __kfifo_to_user(struct __kfifo *fifo,
void __user *to, unsigned long len, unsigned int *copied);

extern unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
- struct scatterlist *sgl, int nents, unsigned int len);
+ struct scatterlist *sgl, int nents, unsigned int len, dma_addr_t dma);

extern unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
- struct scatterlist *sgl, int nents, unsigned int len);
+ struct scatterlist *sgl, int nents, unsigned int len, dma_addr_t dma);

extern unsigned int __kfifo_out_peek(struct __kfifo *fifo,
void *buf, unsigned int len);
@@ -930,13 +941,15 @@ extern int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
unsigned long len, unsigned int *copied, size_t recsize);

extern unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
- struct scatterlist *sgl, int nents, unsigned int len, size_t recsize);
+ struct scatterlist *sgl, int nents, unsigned int len, size_t recsize,
+ dma_addr_t dma);

extern void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
unsigned int len, size_t recsize);

extern unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
- struct scatterlist *sgl, int nents, unsigned int len, size_t recsize);
+ struct scatterlist *sgl, int nents, unsigned int len, size_t recsize,
+ dma_addr_t dma);

extern unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize);

diff --git a/lib/kfifo.c b/lib/kfifo.c
index 3a249ce4f281..75ce9225548a 100644
--- a/lib/kfifo.c
+++ b/lib/kfifo.c
@@ -6,6 +6,7 @@
*/

#include <linux/kernel.h>
+#include <linux/dma-mapping.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/err.h>
@@ -307,7 +308,7 @@ EXPORT_SYMBOL(__kfifo_to_user);

static unsigned int setup_sgl_buf(struct __kfifo *fifo, struct scatterlist *sgl,
unsigned int data_offset, int nents,
- unsigned int len)
+ unsigned int len, dma_addr_t dma)
{
const void *buf = fifo->data + data_offset;

@@ -316,11 +317,16 @@ static unsigned int setup_sgl_buf(struct __kfifo *fifo, struct scatterlist *sgl,

sg_set_buf(sgl, buf, len);

+ if (dma != DMA_MAPPING_ERROR) {
+ sg_dma_address(sgl) = dma + data_offset;
+ sg_dma_len(sgl) = len;
+ }
+
return 1;
}

static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl,
- int nents, unsigned int len, unsigned int off)
+ int nents, unsigned int len, unsigned int off, dma_addr_t dma)
{
unsigned int size = fifo->mask + 1;
unsigned int esize = fifo->esize;
@@ -335,14 +341,15 @@ static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl,
}
len_to_end = min(len, size - off);

- n = setup_sgl_buf(fifo, sgl, off, nents, len_to_end);
- n += setup_sgl_buf(fifo, sgl + n, 0, nents - n, len - len_to_end);
+ n = setup_sgl_buf(fifo, sgl, off, nents, len_to_end, dma);
+ n += setup_sgl_buf(fifo, sgl + n, 0, nents - n, len - len_to_end, dma);

return n;
}

unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
- struct scatterlist *sgl, int nents, unsigned int len)
+ struct scatterlist *sgl, int nents, unsigned int len,
+ dma_addr_t dma)
{
unsigned int l;

@@ -350,12 +357,13 @@ unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
if (len > l)
len = l;

- return setup_sgl(fifo, sgl, nents, len, fifo->in);
+ return setup_sgl(fifo, sgl, nents, len, fifo->in, dma);
}
EXPORT_SYMBOL(__kfifo_dma_in_prepare);

unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
- struct scatterlist *sgl, int nents, unsigned int len)
+ struct scatterlist *sgl, int nents, unsigned int len,
+ dma_addr_t dma)
{
unsigned int l;

@@ -363,7 +371,7 @@ unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
if (len > l)
len = l;

- return setup_sgl(fifo, sgl, nents, len, fifo->out);
+ return setup_sgl(fifo, sgl, nents, len, fifo->out, dma);
}
EXPORT_SYMBOL(__kfifo_dma_out_prepare);

@@ -547,7 +555,8 @@ int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
EXPORT_SYMBOL(__kfifo_to_user_r);

unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
- struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
+ struct scatterlist *sgl, int nents, unsigned int len, size_t recsize,
+ dma_addr_t dma)
{
BUG_ON(!nents);

@@ -556,7 +565,7 @@ unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
if (len + recsize > kfifo_unused(fifo))
return 0;

- return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize);
+ return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize, dma);
}
EXPORT_SYMBOL(__kfifo_dma_in_prepare_r);

@@ -570,7 +579,8 @@ void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
EXPORT_SYMBOL(__kfifo_dma_in_finish_r);

unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
- struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
+ struct scatterlist *sgl, int nents, unsigned int len, size_t recsize,
+ dma_addr_t dma)
{
BUG_ON(!nents);

@@ -579,7 +589,7 @@ unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
if (len + recsize > fifo->in - fifo->out)
return 0;

- return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize);
+ return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize, dma);
}
EXPORT_SYMBOL(__kfifo_dma_out_prepare_r);

--
2.44.0

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