[media] dvb_ringbuffer.h: Document all functions
There are several functions there there weren't properly documented. Add documentation for them. While here, make checkpatch.pl happier. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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Mauro Carvalho Chehab
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Коммит
ff54c19d8e
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@ -18,10 +18,6 @@
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifndef _DVB_RINGBUFFER_H_
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@ -30,6 +26,18 @@
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#include <linux/spinlock.h>
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#include <linux/wait.h>
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/**
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* struct dvb_ringbuffer - Describes a ring buffer used at DVB framework
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*
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* @data: Area were the ringbuffer data is written
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* @size: size of the ringbuffer
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* @pread: next position to read
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* @pwrite: next position to write
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* @error: used by ringbuffer clients to indicate that an error happened.
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* @queue: Wait queue used by ringbuffer clients to indicate when buffer
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* was filled
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* @lock: Spinlock used to protect the ringbuffer
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*/
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struct dvb_ringbuffer {
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u8 *data;
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ssize_t size;
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@ -43,7 +51,21 @@ struct dvb_ringbuffer {
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#define DVB_RINGBUFFER_PKTHDRSIZE 3
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/**
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* dvb_ringbuffer_init - initialize ring buffer, lock and queue
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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* @data: pointer to the buffer where the data will be stored
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* @len: bytes from ring buffer into @buf
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*/
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extern void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data,
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size_t len);
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/**
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* dvb_ringbuffer_empty - test whether buffer is empty
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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*/
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/*
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* Notes:
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* ------
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@ -72,67 +94,131 @@ struct dvb_ringbuffer {
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* Resetting the buffer counts as a read and write operation.
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* Two or more writers must be locked against each other.
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*/
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/* initialize ring buffer, lock and queue */
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extern void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len);
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/* test whether buffer is empty */
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extern int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf);
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/* return the number of free bytes in the buffer */
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/**
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* dvb_ringbuffer_free - returns the number of free bytes in the buffer
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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*
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* Return: number of free bytes in the buffer
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*/
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extern ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf);
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/* return the number of bytes waiting in the buffer */
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/**
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* dvb_ringbuffer_avail - returns the number of bytes waiting in the buffer
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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*
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* Return: number of bytes waiting in the buffer
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*/
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extern ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf);
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/*
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* Reset the read and write pointers to zero and flush the buffer
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/**
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* dvb_ringbuffer_reset - resets the ringbuffer to initial state
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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*
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* Resets the read and write pointers to zero and flush the buffer.
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*
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* This counts as a read and write operation
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*/
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extern void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf);
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/* read routines & macros */
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/* ---------------------- */
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/* flush buffer */
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/*
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* read routines & macros
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*/
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/**
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* dvb_ringbuffer_flush - flush buffer
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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*/
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extern void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf);
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/* flush buffer protected by spinlock and wake-up waiting task(s) */
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/**
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* dvb_ringbuffer_flush_spinlock_wakeup- flush buffer protected by spinlock
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* and wake-up waiting task(s)
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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*/
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extern void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf);
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/* peek at byte @offs: in the buffer */
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#define DVB_RINGBUFFER_PEEK(rbuf,offs) \
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(rbuf)->data[((rbuf)->pread+(offs))%(rbuf)->size]
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/* DVB_RINGBUFFER_PEEK - peek at byte @offs: in the buffer */
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#define DVB_RINGBUFFER_PEEK(rbuf, offs) \
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(rbuf)->data[((rbuf)->pread + (offs)) % (rbuf)->size]
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/* advance read ptr by @num: bytes */
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#define DVB_RINGBUFFER_SKIP(rbuf,num) \
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(rbuf)->pread=((rbuf)->pread+(num))%(rbuf)->size
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#define DVB_RINGBUFFER_SKIP(rbuf, num) {\
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(rbuf)->pread = ((rbuf)->pread + (num)) % (rbuf)->size;\
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}
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/*
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* read @len: bytes from ring buffer into @buf:
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* @usermem: specifies whether @buf: resides in user space
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* returns number of bytes transferred or -EFAULT
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/**
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* dvb_ringbuffer_read_user - Reads a buffer into an user pointer
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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* @buf: pointer to the buffer where the data will be stored
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* @len: bytes from ring buffer into @buf
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*
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* This variant assumes that the buffer is a memory at the userspace. So,
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* it will internally call copy_to_user().
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*
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* Return: number of bytes transferred or -EFAULT
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*/
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extern ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf,
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u8 __user *buf, size_t len);
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/**
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* dvb_ringbuffer_read - Reads a buffer into a pointer
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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* @buf: pointer to the buffer where the data will be stored
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* @len: bytes from ring buffer into @buf
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*
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* This variant assumes that the buffer is a memory at the Kernel space
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*
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* Return: number of bytes transferred or -EFAULT
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*/
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extern void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf,
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u8 *buf, size_t len);
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/* write routines & macros */
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/* ----------------------- */
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/* write single byte to ring buffer */
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#define DVB_RINGBUFFER_WRITE_BYTE(rbuf,byte) \
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{ (rbuf)->data[(rbuf)->pwrite]=(byte); \
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(rbuf)->pwrite=((rbuf)->pwrite+1)%(rbuf)->size; }
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/*
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* write @len: bytes to ring buffer
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* @usermem: specifies whether @buf: resides in user space
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* returns number of bytes transferred or -EFAULT
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*/
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* write routines & macros
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*/
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/* write single byte to ring buffer */
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#define DVB_RINGBUFFER_WRITE_BYTE(rbuf, byte) \
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{ (rbuf)->data[(rbuf)->pwrite] = (byte); \
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(rbuf)->pwrite = ((rbuf)->pwrite + 1) % (rbuf)->size; }
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/**
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* dvb_ringbuffer_write - Writes a buffer into the ringbuffer
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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* @buf: pointer to the buffer where the data will be read
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* @len: bytes from ring buffer into @buf
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*
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* This variant assumes that the buffer is a memory at the Kernel space
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*
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* return: number of bytes transferred or -EFAULT
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*/
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extern ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf,
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size_t len);
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/**
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* dvb_ringbuffer_writeuser - Writes a buffer received via an user pointer
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*
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* @rbuf: pointer to struct dvb_ringbuffer
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* @buf: pointer to the buffer where the data will be read
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* @len: bytes from ring buffer into @buf
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*
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* This variant assumes that the buffer is a memory at the userspace. So,
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* it will internally call copy_from_user().
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*
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* Return: number of bytes transferred or -EFAULT
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*/
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extern ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
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const u8 __user *buf, size_t len);
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@ -143,9 +229,10 @@ extern ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
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* @rbuf: Ringbuffer to write to.
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* @buf: Buffer to write.
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* @len: Length of buffer (currently limited to 65535 bytes max).
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* returns Number of bytes written, or -EFAULT, -ENOMEM, -EVINAL.
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*
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* Return: Number of bytes written, or -EFAULT, -ENOMEM, -EVINAL.
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*/
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extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf,
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extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8 *buf,
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size_t len);
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/**
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@ -157,7 +244,7 @@ extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf,
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* @buf: Destination buffer for data.
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* @len: Size of destination buffer.
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*
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* returns Number of bytes read, or -EFAULT.
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* Return: Number of bytes read, or -EFAULT.
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*
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* .. note::
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*
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@ -181,7 +268,7 @@ extern ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf,
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* @buf: Destination buffer for data.
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* @len: Size of destination buffer.
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*
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* returns Number of bytes read, or -EFAULT.
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* Return: Number of bytes read, or -EFAULT.
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*/
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extern ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
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int offset, u8 *buf, size_t len);
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@ -199,10 +286,12 @@ extern void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx);
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*
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* @rbuf: Ringbuffer concerned.
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* @idx: Previous packet index, or -1 to return the first packet index.
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* @pktlen: On success, will be updated to contain the length of the packet in bytes.
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* @pktlen: On success, will be updated to contain the length of the packet
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* in bytes.
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* returns Packet index (if >=0), or -1 if no packets available.
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*/
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extern ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen);
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extern ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf,
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size_t idx, size_t *pktlen);
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#endif /* _DVB_RINGBUFFER_H_ */
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