| Message ID | 20230403154800.215924-5-paul@crapouillou.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: new DMABUF based API, v3 | expand |
On Mon, 3 Apr 2023 17:47:53 +0200 Paul Cercueil <paul@crapouillou.net> wrote: > Adding write support to the buffer-dma code is easy - the write() > function basically needs to do the exact same thing as the read() > function: dequeue a block, read or write the data, enqueue the block > when entirely processed. > > Therefore, the iio_buffer_dma_read() and the new iio_buffer_dma_write() > now both call a function iio_buffer_dma_io(), which will perform this > task. > > The .space_available() callback can return the exact same value as the > .data_available() callback for input buffers, since in both cases we > count the exact same thing (the number of bytes in each available > block). As they are doing the same thing, I'd like that to be visible down where the callback is set. As such, do we need a wrapper to provide the space available version? Perhaps just give the data_available version a more generic name to make it seem appropriate for both usecases? Otherwise LGTM. Jonathan > > Note that we preemptively reset block->bytes_used to the buffer's size > in iio_dma_buffer_request_update(), as in the future the > iio_dma_buffer_enqueue() function won't reset it. > > Signed-off-by: Paul Cercueil <paul@crapouillou.net> > Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com> > > --- > v2: - Fix block->state not being reset in > iio_dma_buffer_request_update() for output buffers. > - Only update block->bytes_used once and add a comment about why we > update it. > - Add a comment about why we're setting a different state for output > buffers in iio_dma_buffer_request_update() > - Remove useless cast to bool (!!) in iio_dma_buffer_io() > > v3: - Reorganize arguments to iio_dma_buffer_io() > - Change 'is_write' argument to 'is_from_user' > - Change (__force char *) to (__force __user char *), in > iio_dma_buffer_write(), since we only want to drop the "const". > --- > drivers/iio/buffer/industrialio-buffer-dma.c | 89 ++++++++++++++++---- > include/linux/iio/buffer-dma.h | 7 ++ > 2 files changed, 80 insertions(+), 16 deletions(-) > > diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c > index 1fc91467d1aa..86eced458236 100644 > --- a/drivers/iio/buffer/industrialio-buffer-dma.c > +++ b/drivers/iio/buffer/industrialio-buffer-dma.c > @@ -195,6 +195,18 @@ static void _iio_dma_buffer_block_done(struct iio_dma_buffer_block *block) > block->state = IIO_BLOCK_STATE_DONE; > } > > +static void iio_dma_buffer_queue_wake(struct iio_dma_buffer_queue *queue) > +{ > + __poll_t flags; > + > + if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) > + flags = EPOLLIN | EPOLLRDNORM; > + else > + flags = EPOLLOUT | EPOLLWRNORM; > + > + wake_up_interruptible_poll(&queue->buffer.pollq, flags); > +} > + > /** > * iio_dma_buffer_block_done() - Indicate that a block has been completed > * @block: The completed block > @@ -212,7 +224,7 @@ void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block) > spin_unlock_irqrestore(&queue->list_lock, flags); > > iio_buffer_block_put_atomic(block); > - wake_up_interruptible_poll(&queue->buffer.pollq, EPOLLIN | EPOLLRDNORM); > + iio_dma_buffer_queue_wake(queue); > } > EXPORT_SYMBOL_GPL(iio_dma_buffer_block_done); > > @@ -241,7 +253,7 @@ void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue, > } > spin_unlock_irqrestore(&queue->list_lock, flags); > > - wake_up_interruptible_poll(&queue->buffer.pollq, EPOLLIN | EPOLLRDNORM); > + iio_dma_buffer_queue_wake(queue); > } > EXPORT_SYMBOL_GPL(iio_dma_buffer_block_list_abort); > > @@ -335,8 +347,24 @@ int iio_dma_buffer_request_update(struct iio_buffer *buffer) > queue->fileio.blocks[i] = block; > } > > - block->state = IIO_BLOCK_STATE_QUEUED; > - list_add_tail(&block->head, &queue->incoming); > + /* > + * block->bytes_used may have been modified previously, e.g. by > + * iio_dma_buffer_block_list_abort(). Reset it here to the > + * block's so that iio_dma_buffer_io() will work. > + */ > + block->bytes_used = block->size; > + > + /* > + * If it's an input buffer, mark the block as queued, and > + * iio_dma_buffer_enable() will submit it. Otherwise mark it as > + * done, which means it's ready to be dequeued. > + */ > + if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) { > + block->state = IIO_BLOCK_STATE_QUEUED; > + list_add_tail(&block->head, &queue->incoming); > + } else { > + block->state = IIO_BLOCK_STATE_DONE; > + } > } > > out_unlock: > @@ -465,20 +493,12 @@ static struct iio_dma_buffer_block *iio_dma_buffer_dequeue( > return block; > } > > -/** > - * iio_dma_buffer_read() - DMA buffer read callback > - * @buffer: Buffer to read form > - * @n: Number of bytes to read > - * @user_buffer: Userspace buffer to copy the data to > - * > - * Should be used as the read callback for iio_buffer_access_ops > - * struct for DMA buffers. > - */ > -int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, > - char __user *user_buffer) > +static int iio_dma_buffer_io(struct iio_buffer *buffer, size_t n, > + char __user *user_buffer, bool is_from_user) > { > struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); > struct iio_dma_buffer_block *block; > + void *addr; > int ret; > > if (n < buffer->bytes_per_datum) > @@ -501,8 +521,13 @@ int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, > n = rounddown(n, buffer->bytes_per_datum); > if (n > block->bytes_used - queue->fileio.pos) > n = block->bytes_used - queue->fileio.pos; > + addr = block->vaddr + queue->fileio.pos; > > - if (copy_to_user(user_buffer, block->vaddr + queue->fileio.pos, n)) { > + if (is_from_user) > + ret = copy_from_user(addr, user_buffer, n); > + else > + ret = copy_to_user(user_buffer, addr, n); > + if (ret) { > ret = -EFAULT; > goto out_unlock; > } > @@ -521,8 +546,40 @@ int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, > > return ret; > } > + > +/** > + * iio_dma_buffer_read() - DMA buffer read callback > + * @buffer: Buffer to read form > + * @n: Number of bytes to read > + * @user_buffer: Userspace buffer to copy the data to > + * > + * Should be used as the read callback for iio_buffer_access_ops > + * struct for DMA buffers. > + */ > +int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, > + char __user *user_buffer) > +{ > + return iio_dma_buffer_io(buffer, n, user_buffer, false); > +} > EXPORT_SYMBOL_GPL(iio_dma_buffer_read); > > +/** > + * iio_dma_buffer_write() - DMA buffer write callback > + * @buffer: Buffer to read form > + * @n: Number of bytes to read > + * @user_buffer: Userspace buffer to copy the data from > + * > + * Should be used as the write callback for iio_buffer_access_ops > + * struct for DMA buffers. > + */ > +int iio_dma_buffer_write(struct iio_buffer *buffer, size_t n, > + const char __user *user_buffer) > +{ > + return iio_dma_buffer_io(buffer, n, > + (__force __user char *)user_buffer, true); > +} > +EXPORT_SYMBOL_GPL(iio_dma_buffer_write); > + > /** > * iio_dma_buffer_data_available() - DMA buffer data_available callback > * @buf: Buffer to check for data availability > diff --git a/include/linux/iio/buffer-dma.h b/include/linux/iio/buffer-dma.h > index 18d3702fa95d..490b93f76fa8 100644 > --- a/include/linux/iio/buffer-dma.h > +++ b/include/linux/iio/buffer-dma.h > @@ -132,6 +132,8 @@ int iio_dma_buffer_disable(struct iio_buffer *buffer, > struct iio_dev *indio_dev); > int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, > char __user *user_buffer); > +int iio_dma_buffer_write(struct iio_buffer *buffer, size_t n, > + const char __user *user_buffer); > size_t iio_dma_buffer_data_available(struct iio_buffer *buffer); > int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd); > int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length); > @@ -142,4 +144,9 @@ int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue, > void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue); > void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue); > > +static inline size_t iio_dma_buffer_space_available(struct iio_buffer *buffer) > +{ > + return iio_dma_buffer_data_available(buffer); As mentioned above, I don't see having this trivial wrapper as beneficial. > +} > + > #endif
diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c index 1fc91467d1aa..86eced458236 100644 --- a/drivers/iio/buffer/industrialio-buffer-dma.c +++ b/drivers/iio/buffer/industrialio-buffer-dma.c @@ -195,6 +195,18 @@ static void _iio_dma_buffer_block_done(struct iio_dma_buffer_block *block) block->state = IIO_BLOCK_STATE_DONE; } +static void iio_dma_buffer_queue_wake(struct iio_dma_buffer_queue *queue) +{ + __poll_t flags; + + if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) + flags = EPOLLIN | EPOLLRDNORM; + else + flags = EPOLLOUT | EPOLLWRNORM; + + wake_up_interruptible_poll(&queue->buffer.pollq, flags); +} + /** * iio_dma_buffer_block_done() - Indicate that a block has been completed * @block: The completed block @@ -212,7 +224,7 @@ void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block) spin_unlock_irqrestore(&queue->list_lock, flags); iio_buffer_block_put_atomic(block); - wake_up_interruptible_poll(&queue->buffer.pollq, EPOLLIN | EPOLLRDNORM); + iio_dma_buffer_queue_wake(queue); } EXPORT_SYMBOL_GPL(iio_dma_buffer_block_done); @@ -241,7 +253,7 @@ void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue, } spin_unlock_irqrestore(&queue->list_lock, flags); - wake_up_interruptible_poll(&queue->buffer.pollq, EPOLLIN | EPOLLRDNORM); + iio_dma_buffer_queue_wake(queue); } EXPORT_SYMBOL_GPL(iio_dma_buffer_block_list_abort); @@ -335,8 +347,24 @@ int iio_dma_buffer_request_update(struct iio_buffer *buffer) queue->fileio.blocks[i] = block; } - block->state = IIO_BLOCK_STATE_QUEUED; - list_add_tail(&block->head, &queue->incoming); + /* + * block->bytes_used may have been modified previously, e.g. by + * iio_dma_buffer_block_list_abort(). Reset it here to the + * block's so that iio_dma_buffer_io() will work. + */ + block->bytes_used = block->size; + + /* + * If it's an input buffer, mark the block as queued, and + * iio_dma_buffer_enable() will submit it. Otherwise mark it as + * done, which means it's ready to be dequeued. + */ + if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) { + block->state = IIO_BLOCK_STATE_QUEUED; + list_add_tail(&block->head, &queue->incoming); + } else { + block->state = IIO_BLOCK_STATE_DONE; + } } out_unlock: @@ -465,20 +493,12 @@ static struct iio_dma_buffer_block *iio_dma_buffer_dequeue( return block; } -/** - * iio_dma_buffer_read() - DMA buffer read callback - * @buffer: Buffer to read form - * @n: Number of bytes to read - * @user_buffer: Userspace buffer to copy the data to - * - * Should be used as the read callback for iio_buffer_access_ops - * struct for DMA buffers. - */ -int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, - char __user *user_buffer) +static int iio_dma_buffer_io(struct iio_buffer *buffer, size_t n, + char __user *user_buffer, bool is_from_user) { struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); struct iio_dma_buffer_block *block; + void *addr; int ret; if (n < buffer->bytes_per_datum) @@ -501,8 +521,13 @@ int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, n = rounddown(n, buffer->bytes_per_datum); if (n > block->bytes_used - queue->fileio.pos) n = block->bytes_used - queue->fileio.pos; + addr = block->vaddr + queue->fileio.pos; - if (copy_to_user(user_buffer, block->vaddr + queue->fileio.pos, n)) { + if (is_from_user) + ret = copy_from_user(addr, user_buffer, n); + else + ret = copy_to_user(user_buffer, addr, n); + if (ret) { ret = -EFAULT; goto out_unlock; } @@ -521,8 +546,40 @@ int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, return ret; } + +/** + * iio_dma_buffer_read() - DMA buffer read callback + * @buffer: Buffer to read form + * @n: Number of bytes to read + * @user_buffer: Userspace buffer to copy the data to + * + * Should be used as the read callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, + char __user *user_buffer) +{ + return iio_dma_buffer_io(buffer, n, user_buffer, false); +} EXPORT_SYMBOL_GPL(iio_dma_buffer_read); +/** + * iio_dma_buffer_write() - DMA buffer write callback + * @buffer: Buffer to read form + * @n: Number of bytes to read + * @user_buffer: Userspace buffer to copy the data from + * + * Should be used as the write callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_write(struct iio_buffer *buffer, size_t n, + const char __user *user_buffer) +{ + return iio_dma_buffer_io(buffer, n, + (__force __user char *)user_buffer, true); +} +EXPORT_SYMBOL_GPL(iio_dma_buffer_write); + /** * iio_dma_buffer_data_available() - DMA buffer data_available callback * @buf: Buffer to check for data availability diff --git a/include/linux/iio/buffer-dma.h b/include/linux/iio/buffer-dma.h index 18d3702fa95d..490b93f76fa8 100644 --- a/include/linux/iio/buffer-dma.h +++ b/include/linux/iio/buffer-dma.h @@ -132,6 +132,8 @@ int iio_dma_buffer_disable(struct iio_buffer *buffer, struct iio_dev *indio_dev); int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, char __user *user_buffer); +int iio_dma_buffer_write(struct iio_buffer *buffer, size_t n, + const char __user *user_buffer); size_t iio_dma_buffer_data_available(struct iio_buffer *buffer); int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd); int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length); @@ -142,4 +144,9 @@ int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue, void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue); void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue); +static inline size_t iio_dma_buffer_space_available(struct iio_buffer *buffer) +{ + return iio_dma_buffer_data_available(buffer); +} + #endif