5 files changed, 145 insertions, 138 deletions

diff --git a/drivers/comedi/comedi_buf.c b/drivers/comedi/comedi_buf.c
index 393966c09740..002c0e76baff 100644
--- a/drivers/comedi/comedi_buf.c
+++ b/drivers/comedi/comedi_buf.c
@@ -27,14 +27,12 @@ static void comedi_buf_map_kref_release(struct kref *kref)
 
 	if (bm->page_list) {
 		if (bm->dma_dir != DMA_NONE) {
-			/*
-			 * DMA buffer was allocated as a single block.
-			 * Address is in page_list[0].
-			 */
-			buf = &bm->page_list[0];
-			dma_free_coherent(bm->dma_hw_dev,
-					  PAGE_SIZE * bm->n_pages,
-					  buf->virt_addr, buf->dma_addr);
+			for (i = 0; i < bm->n_pages; i++) {
+				buf = &bm->page_list[i];
+				dma_free_coherent(bm->dma_hw_dev, PAGE_SIZE,
+						  buf->virt_addr,
+						  buf->dma_addr);
+			}
 		} else {
 			for (i = 0; i < bm->n_pages; i++) {
 				buf = &bm->page_list[i];
@@ -56,13 +54,7 @@ static void __comedi_buf_free(struct comedi_device *dev,
 	struct comedi_buf_map *bm;
 	unsigned long flags;
 
-	if (async->prealloc_buf) {
-		if (s->async_dma_dir == DMA_NONE)
-			vunmap(async->prealloc_buf);
-		async->prealloc_buf = NULL;
-		async->prealloc_bufsz = 0;
-	}
-
+	async->prealloc_bufsz = 0;
 	spin_lock_irqsave(&s->spin_lock, flags);
 	bm = async->buf_map;
 	async->buf_map = NULL;
@@ -94,26 +86,14 @@ comedi_buf_map_alloc(struct comedi_device *dev, enum dma_data_direction dma_dir,
 		goto err;
 
 	if (bm->dma_dir != DMA_NONE) {
-		void *virt_addr;
-		dma_addr_t dma_addr;
-
-		/*
-		 * Currently, the DMA buffer needs to be allocated as a
-		 * single block so that it can be mmap()'ed.
-		 */
-		virt_addr = dma_alloc_coherent(bm->dma_hw_dev,
-					       PAGE_SIZE * n_pages, &dma_addr,
-					       GFP_KERNEL);
-		if (!virt_addr)
-			goto err;
-
 		for (i = 0; i < n_pages; i++) {
 			buf = &bm->page_list[i];
-			buf->virt_addr = virt_addr + (i << PAGE_SHIFT);
-			buf->dma_addr = dma_addr + (i << PAGE_SHIFT);
+			buf->virt_addr =
+			    dma_alloc_coherent(bm->dma_hw_dev, PAGE_SIZE,
+					       &buf->dma_addr, GFP_KERNEL);
+			if (!buf->virt_addr)
+				break;
 		}
-
-		bm->n_pages = i;
 	} else {
 		for (i = 0; i < n_pages; i++) {
 			buf = &bm->page_list[i];
@@ -123,11 +103,10 @@ comedi_buf_map_alloc(struct comedi_device *dev, enum dma_data_direction dma_dir,
 
 			SetPageReserved(virt_to_page(buf->virt_addr));
 		}
-
-		bm->n_pages = i;
-		if (i < n_pages)
-			goto err;
 	}
+	bm->n_pages = i;
+	if (i < n_pages)
+		goto err;
 
 	return bm;
 
@@ -141,11 +120,8 @@ static void __comedi_buf_alloc(struct comedi_device *dev,
 			       unsigned int n_pages)
 {
 	struct comedi_async *async = s->async;
-	struct page **pages = NULL;
 	struct comedi_buf_map *bm;
-	struct comedi_buf_page *buf;
 	unsigned long flags;
-	unsigned int i;
 
 	if (!IS_ENABLED(CONFIG_HAS_DMA) && s->async_dma_dir != DMA_NONE) {
 		dev_err(dev->class_dev,
@@ -160,30 +136,7 @@ static void __comedi_buf_alloc(struct comedi_device *dev,
 	spin_lock_irqsave(&s->spin_lock, flags);
 	async->buf_map = bm;
 	spin_unlock_irqrestore(&s->spin_lock, flags);
-
-	if (bm->dma_dir != DMA_NONE) {
-		/*
-		 * DMA buffer was allocated as a single block.
-		 * Address is in page_list[0].
-		 */
-		buf = &bm->page_list[0];
-		async->prealloc_buf = buf->virt_addr;
-	} else {
-		pages = vmalloc(sizeof(struct page *) * n_pages);
-		if (!pages)
-			return;
-
-		for (i = 0; i < n_pages; i++) {
-			buf = &bm->page_list[i];
-			pages[i] = virt_to_page(buf->virt_addr);
-		}
-
-		/* vmap the pages to prealloc_buf */
-		async->prealloc_buf = vmap(pages, n_pages, VM_MAP,
-					   COMEDI_PAGE_PROTECTION);
-
-		vfree(pages);
-	}
+	async->prealloc_bufsz = n_pages << PAGE_SHIFT;
 }
 
 void comedi_buf_map_get(struct comedi_buf_map *bm)
@@ -264,7 +217,7 @@ int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
 	new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
 
 	/* if no change is required, do nothing */
-	if (async->prealloc_buf && async->prealloc_bufsz == new_size)
+	if (async->prealloc_bufsz == new_size)
 		return 0;
 
 	/* deallocate old buffer */
@@ -275,14 +228,9 @@ int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
 		unsigned int n_pages = new_size >> PAGE_SHIFT;
 
 		__comedi_buf_alloc(dev, s, n_pages);
-
-		if (!async->prealloc_buf) {
-			/* allocation failed */
-			__comedi_buf_free(dev, s);
+		if (!async->prealloc_bufsz)
 			return -ENOMEM;
-		}
 	}
-	async->prealloc_bufsz = new_size;
 
 	return 0;
 }
@@ -365,6 +313,7 @@ static unsigned int comedi_buf_munge(struct comedi_subdevice *s,
 				     unsigned int num_bytes)
 {
 	struct comedi_async *async = s->async;
+	struct comedi_buf_page *buf_page_list = async->buf_map->page_list;
 	unsigned int count = 0;
 	const unsigned int num_sample_bytes = comedi_bytes_per_sample(s);
 
@@ -376,15 +325,16 @@ static unsigned int comedi_buf_munge(struct comedi_subdevice *s,
 	/* don't munge partial samples */
 	num_bytes -= num_bytes % num_sample_bytes;
 	while (count < num_bytes) {
-		int block_size = num_bytes - count;
-		unsigned int buf_end;
-
-		buf_end = async->prealloc_bufsz - async->munge_ptr;
-		if (block_size > buf_end)
-			block_size = buf_end;
+		/*
+		 * Do not munge beyond page boundary.
+		 * Note: prealloc_bufsz is a multiple of PAGE_SIZE.
+		 */
+		unsigned int page = async->munge_ptr >> PAGE_SHIFT;
+		unsigned int offset = offset_in_page(async->munge_ptr);
+		unsigned int block_size =
+			     min(num_bytes - count, PAGE_SIZE - offset);
 
-		s->munge(s->device, s,
-			 async->prealloc_buf + async->munge_ptr,
+		s->munge(s->device, s, buf_page_list[page].virt_addr + offset,
 			 block_size, async->munge_chan);
 
 		/*
@@ -397,7 +347,8 @@ static unsigned int comedi_buf_munge(struct comedi_subdevice *s,
 		async->munge_chan %= async->cmd.chanlist_len;
 		async->munge_count += block_size;
 		async->munge_ptr += block_size;
-		async->munge_ptr %= async->prealloc_bufsz;
+		if (async->munge_ptr == async->prealloc_bufsz)
+			async->munge_ptr = 0;
 		count += block_size;
 	}
 
@@ -558,46 +509,52 @@ static void comedi_buf_memcpy_to(struct comedi_subdevice *s,
 				 const void *data, unsigned int num_bytes)
 {
 	struct comedi_async *async = s->async;
+	struct comedi_buf_page *buf_page_list = async->buf_map->page_list;
 	unsigned int write_ptr = async->buf_write_ptr;
 
 	while (num_bytes) {
-		unsigned int block_size;
-
-		if (write_ptr + num_bytes > async->prealloc_bufsz)
-			block_size = async->prealloc_bufsz - write_ptr;
-		else
-			block_size = num_bytes;
+		/*
+		 * Do not copy beyond page boundary.
+		 * Note: prealloc_bufsz is a multiple of PAGE_SIZE.
+		 */
+		unsigned int page = write_ptr >> PAGE_SHIFT;
+		unsigned int offset = offset_in_page(write_ptr);
+		unsigned int block_size = min(num_bytes, PAGE_SIZE - offset);
 
-		memcpy(async->prealloc_buf + write_ptr, data, block_size);
+		memcpy(buf_page_list[page].virt_addr + offset,
+		       data, block_size);
 
 		data += block_size;
 		num_bytes -= block_size;
-
-		write_ptr = 0;
+		write_ptr += block_size;
+		if (write_ptr == async->prealloc_bufsz)
+			write_ptr = 0;
 	}
 }
 
 static void comedi_buf_memcpy_from(struct comedi_subdevice *s,
 				   void *dest, unsigned int nbytes)
 {
-	void *src;
 	struct comedi_async *async = s->async;
+	struct comedi_buf_page *buf_page_list = async->buf_map->page_list;
 	unsigned int read_ptr = async->buf_read_ptr;
 
 	while (nbytes) {
-		unsigned int block_size;
-
-		src = async->prealloc_buf + read_ptr;
-
-		if (nbytes >= async->prealloc_bufsz - read_ptr)
-			block_size = async->prealloc_bufsz - read_ptr;
-		else
-			block_size = nbytes;
+		/*
+		 * Do not copy beyond page boundary.
+		 * Note: prealloc_bufsz is a multiple of PAGE_SIZE.
+		 */
+		unsigned int page = read_ptr >> PAGE_SHIFT;
+		unsigned int offset = offset_in_page(read_ptr);
+		unsigned int block_size = min(nbytes, PAGE_SIZE - offset);
 
-		memcpy(dest, src, block_size);
+		memcpy(dest, buf_page_list[page].virt_addr + offset,
+		       block_size);
 		nbytes -= block_size;
 		dest += block_size;
-		read_ptr = 0;
+		read_ptr += block_size;
+		if (read_ptr == async->prealloc_bufsz)
+			read_ptr = 0;
 	}
 }
 
diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c
index b9df9b19d4bd..3383a7ce27ff 100644
--- a/drivers/comedi/comedi_fops.c
+++ b/drivers/comedi/comedi_fops.c
@@ -2387,13 +2387,27 @@ static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
 		goto done;
 	}
 	if (bm->dma_dir != DMA_NONE) {
+		unsigned long vm_start = vma->vm_start;
+		unsigned long vm_end = vma->vm_end;
+
 		/*
-		 * DMA buffer was allocated as a single block.
-		 * Address is in page_list[0].
+		 * Buffer pages are not contiguous, so temporarily modify VMA
+		 * start and end addresses for each buffer page.
 		 */
-		buf = &bm->page_list[0];
-		retval = dma_mmap_coherent(bm->dma_hw_dev, vma, buf->virt_addr,
-					   buf->dma_addr, n_pages * PAGE_SIZE);
+		for (i = 0; i < n_pages; ++i) {
+			buf = &bm->page_list[i];
+			vma->vm_start = start;
+			vma->vm_end = start + PAGE_SIZE;
+			retval = dma_mmap_coherent(bm->dma_hw_dev, vma,
+						   buf->virt_addr,
+						   buf->dma_addr, PAGE_SIZE);
+			if (retval)
+				break;
+
+			start += PAGE_SIZE;
+		}
+		vma->vm_start = vm_start;
+		vma->vm_end = vm_end;
 	} else {
 		for (i = 0; i < n_pages; ++i) {
 			unsigned long pfn;
@@ -2407,19 +2421,18 @@ static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
 
 			start += PAGE_SIZE;
 		}
+	}
 
 #ifdef CONFIG_MMU
-		/*
-		 * Leaving behind a partial mapping of a buffer we're about to
-		 * drop is unsafe, see remap_pfn_range_notrack().
-		 * We need to zap the range here ourselves instead of relying
-		 * on the automatic zapping in remap_pfn_range() because we call
-		 * remap_pfn_range() in a loop.
-		 */
-		if (retval)
-			zap_vma_ptes(vma, vma->vm_start, size);
+	/*
+	 * Leaving behind a partial mapping of a buffer we're about to drop is
+	 * unsafe, see remap_pfn_range_notrack().  We need to zap the range
+	 * here ourselves instead of relying on the automatic zapping in
+	 * remap_pfn_range() because we call remap_pfn_range() in a loop.
+	 */
+	if (retval)
+		zap_vma_ptes(vma, vma->vm_start, size);
 #endif
-	}
 
 	if (retval == 0) {
 		vma->vm_ops = &comedi_vm_ops;
@@ -2475,6 +2488,62 @@ done:
 	return mask;
 }
 
+static unsigned int comedi_buf_copy_to_user(struct comedi_subdevice *s,
+	void __user *dest, unsigned int src_offset, unsigned int n)
+{
+	struct comedi_buf_map *bm = s->async->buf_map;
+	struct comedi_buf_page *buf_page_list = bm->page_list;
+	unsigned int page = src_offset >> PAGE_SHIFT;
+	unsigned int offset = offset_in_page(src_offset);
+
+	while (n) {
+		unsigned int copy_amount = min(n, PAGE_SIZE - offset);
+		unsigned int uncopied;
+
+		uncopied = copy_to_user(dest, buf_page_list[page].virt_addr +
+					offset, copy_amount);
+		copy_amount -= uncopied;
+		n -= copy_amount;
+		if (uncopied)
+			break;
+
+		dest += copy_amount;
+		page++;
+		if (page == bm->n_pages)
+			page = 0;	/* buffer wraparound */
+		offset = 0;
+	}
+	return n;
+}
+
+static unsigned int comedi_buf_copy_from_user(struct comedi_subdevice *s,
+	unsigned int dst_offset, const void __user *src, unsigned int n)
+{
+	struct comedi_buf_map *bm = s->async->buf_map;
+	struct comedi_buf_page *buf_page_list = bm->page_list;
+	unsigned int page = dst_offset >> PAGE_SHIFT;
+	unsigned int offset = offset_in_page(dst_offset);
+
+	while (n) {
+		unsigned int copy_amount = min(n, PAGE_SIZE - offset);
+		unsigned int uncopied;
+
+		uncopied = copy_from_user(buf_page_list[page].virt_addr +
+					  offset, src, copy_amount);
+		copy_amount -= uncopied;
+		n -= copy_amount;
+		if (uncopied)
+			break;
+
+		src += copy_amount;
+		page++;
+		if (page == bm->n_pages)
+			page = 0;	/* buffer wraparound */
+		offset = 0;
+	}
+	return n;
+}
+
 static ssize_t comedi_write(struct file *file, const char __user *buf,
 			    size_t nbytes, loff_t *offset)
 {
@@ -2516,7 +2585,6 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
 	add_wait_queue(&async->wait_head, &wait);
 	while (count == 0 && !retval) {
 		unsigned int runflags;
-		unsigned int wp, n1, n2;
 
 		set_current_state(TASK_INTERRUPTIBLE);
 
@@ -2555,14 +2623,7 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
 		}
 
 		set_current_state(TASK_RUNNING);
-		wp = async->buf_write_ptr;
-		n1 = min(n, async->prealloc_bufsz - wp);
-		n2 = n - n1;
-		m = copy_from_user(async->prealloc_buf + wp, buf, n1);
-		if (m)
-			m += n2;
-		else if (n2)
-			m = copy_from_user(async->prealloc_buf, buf + n1, n2);
+		m = comedi_buf_copy_from_user(s, async->buf_write_ptr, buf, n);
 		if (m) {
 			n -= m;
 			retval = -EFAULT;
@@ -2651,8 +2712,6 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
 
 	add_wait_queue(&async->wait_head, &wait);
 	while (count == 0 && !retval) {
-		unsigned int rp, n1, n2;
-
 		set_current_state(TASK_INTERRUPTIBLE);
 
 		m = comedi_buf_read_n_available(s);
@@ -2689,14 +2748,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
 		}
 
 		set_current_state(TASK_RUNNING);
-		rp = async->buf_read_ptr;
-		n1 = min(n, async->prealloc_bufsz - rp);
-		n2 = n - n1;
-		m = copy_to_user(buf, async->prealloc_buf + rp, n1);
-		if (m)
-			m += n2;
-		else if (n2)
-			m = copy_to_user(buf + n1, async->prealloc_buf, n2);
+		m = comedi_buf_copy_to_user(s, buf, async->buf_read_ptr, n);
 		if (m) {
 			n -= m;
 			retval = -EFAULT;
diff --git a/drivers/comedi/drivers/adl_pci9118.c b/drivers/comedi/drivers/adl_pci9118.c
index a76e2666d583..67c663892e48 100644
--- a/drivers/comedi/drivers/adl_pci9118.c
+++ b/drivers/comedi/drivers/adl_pci9118.c
@@ -32,7 +32,7 @@
  * ranges).
  *
  * There are some hardware limitations:
- * a) You cann't use mixture of unipolar/bipoar ranges or differencial/single
+ * a) You can't use mixture of unipolar/bipolar ranges or differential/single
  *  ended inputs.
  * b) DMA transfers must have the length aligned to two samples (32 bit),
  *  so there is some problems if cmd->chanlist_len is odd. This driver tries
@@ -227,7 +227,7 @@ struct pci9118_private {
 	struct pci9118_dmabuf dmabuf[2];
 	int softsshdelay;		/*
 					 * >0 use software S&H,
-					 * numer is requested delay in ns
+					 * number is requested delay in ns
 					 */
 	unsigned char softsshsample;	/*
 					 * polarity of S&H signal
diff --git a/drivers/comedi/drivers/ni_atmio.c b/drivers/comedi/drivers/ni_atmio.c
index 330ae1c58800..b4e759e5703f 100644
--- a/drivers/comedi/drivers/ni_atmio.c
+++ b/drivers/comedi/drivers/ni_atmio.c
@@ -215,7 +215,7 @@ static const int ni_irqpin[] = {
 
 #include "ni_mio_common.c"
 
-static const struct pnp_device_id device_ids[] = {
+static const struct pnp_device_id __maybe_unused device_ids[] = {
 	{.id = "NIC1900", .driver_data = 0},
 	{.id = "NIC2400", .driver_data = 0},
 	{.id = "NIC2500", .driver_data = 0},
diff --git a/drivers/comedi/drivers/ni_pcidio.c b/drivers/comedi/drivers/ni_pcidio.c
index 2d58e83420e8..2c7bb9c1ea5b 100644
--- a/drivers/comedi/drivers/ni_pcidio.c
+++ b/drivers/comedi/drivers/ni_pcidio.c
@@ -747,8 +747,6 @@ static int ni_pcidio_change(struct comedi_device *dev,
 	if (ret < 0)
 		return ret;
 
-	memset(s->async->prealloc_buf, 0xaa, s->async->prealloc_bufsz);
-
 	return 0;
 }