ANDROID: goldfish_pipe: bugfixes and performance improvements.

Combine following patches from android-goldfish-3.18 branch:

c0f015a [pipe] Fix the pipe driver for x64 platform + correct pages count
48e6bf5 [pipe] Use get_use_pages_fast() which is possibly faster
fb20f13 [goldfish] More pages in goldfish pipe
f180e6d goldfish_pipe: Return from read_write on signal and EIO
3dec3b7 [pipe] Fix a minor leak in setup_access_params_addr()

Change-Id: I1041fd65d7faaec123e6cedd3dbbc5a2fbb86c4d

1 files changed, 75 insertions, 44 deletions

diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index 3215a33cf4fe..55929ed58ea3 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -109,6 +109,16 @@
 #define PIPE_WAKE_READ         (1 << 1)  /* pipe can now be read from */
 #define PIPE_WAKE_WRITE        (1 << 2)  /* pipe can now be written to */
 
+#define MAX_PAGES_TO_GRAB 32
+
+#define DEBUG 0
+
+#if DEBUG
+#define DPRINT(...) { printk(KERN_ERR __VA_ARGS__); }
+#else
+#define DPRINT(...)
+#endif
+
 struct access_params {
 	unsigned long channel;
 	u32 size;
@@ -231,8 +241,10 @@ static int setup_access_params_addr(struct platform_device *pdev,
 	if (valid_batchbuffer_addr(dev, aps)) {
 		dev->aps = aps;
 		return 0;
-	} else
+	} else {
+		devm_kfree(&pdev->dev, aps);
 		return -1;
+	}
 }
 
 /* A value that will not be set by qemu emulator */
@@ -269,6 +281,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 	struct goldfish_pipe *pipe = filp->private_data;
 	struct goldfish_pipe_dev *dev = pipe->dev;
 	unsigned long address, address_end;
+	struct page* pages[MAX_PAGES_TO_GRAB] = {};
 	int count = 0, ret = -EINVAL;
 
 	/* If the emulator already closed the pipe, no need to go further */
@@ -292,45 +305,59 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 	address_end = address + bufflen;
 
 	while (address < address_end) {
-		unsigned long  page_end = (address & PAGE_MASK) + PAGE_SIZE;
-		unsigned long  next     = page_end < address_end ? page_end
-								 : address_end;
-		unsigned long  avail    = next - address;
-		int status, wakeBit;
-
-		struct page *page;
-
-		/* Either vaddr or paddr depending on the device version */
-		unsigned long xaddr;
+		unsigned long page_end = (address & PAGE_MASK) + PAGE_SIZE;
+		unsigned long next, avail;
+		int status, wakeBit, page_i, num_contiguous_pages;
+		long first_page, last_page, requested_pages;
+		unsigned long xaddr, xaddr_prev, xaddr_i;
 
 		/*
-		 * We grab the pages on a page-by-page basis in case user
-		 * space gives us a potentially huge buffer but the read only
-		 * returns a small amount, then there's no need to pin that
-		 * much memory to the process.
+		 * Attempt to grab multiple physically contiguous pages.
 		 */
-		down_read(&current->mm->mmap_sem);
-		ret = get_user_pages(current, current->mm, address, 1,
-				     !is_write, 0, &page, NULL);
-		up_read(&current->mm->mmap_sem);
-		if (ret < 0)
+		first_page = address & PAGE_MASK;
+		last_page = (address_end - 1) & PAGE_MASK;
+		requested_pages = ((last_page - first_page) >> PAGE_SHIFT) + 1;
+		if (requested_pages > MAX_PAGES_TO_GRAB) {
+			requested_pages = MAX_PAGES_TO_GRAB;
+		}
+		ret = get_user_pages_fast(first_page, requested_pages,
+				!is_write, pages);
+
+		DPRINT("%s: requested pages: %d %d\n", __FUNCTION__, ret, requested_pages);
+		if (ret == 0) {
+			DPRINT("%s: error: (requested pages == 0) (wanted %d)\n",
+					__FUNCTION__, requested_pages);
+			return ret;
+		}
+		if (ret < 0) {
+			DPRINT("%s: (requested pages < 0) %d \n",
+				 	__FUNCTION__, requested_pages);
 			return ret;
+		}
 
-		if (dev->version) {
-			/* Device version 1 or newer (qemu-android) expects the
-			 * physical address. */
-			xaddr = page_to_phys(page) | (address & ~PAGE_MASK);
-		} else {
-			/* Device version 0 (classic emulator) expects the
-			 * virtual address. */
-			xaddr = address;
+		xaddr = page_to_phys(pages[0]) | (address & ~PAGE_MASK);
+		xaddr_prev = xaddr;
+		num_contiguous_pages = ret == 0 ? 0 : 1;
+		for (page_i = 1; page_i < ret; page_i++) {
+			xaddr_i = page_to_phys(pages[page_i]) | (address & ~PAGE_MASK);
+			if (xaddr_i == xaddr_prev + PAGE_SIZE) {
+				page_end += PAGE_SIZE;
+				xaddr_prev = xaddr_i;
+				num_contiguous_pages++;
+			} else {
+				DPRINT("%s: discontinuous page boundary: %d pages instead\n",
+						__FUNCTION__, page_i);
+				break;
+			}
 		}
+		next = page_end < address_end ? page_end : address_end;
+		avail = next - address;
 
 		/* Now, try to transfer the bytes in the current page */
 		spin_lock_irqsave(&dev->lock, irq_flags);
 		if (access_with_param(dev,
-				      is_write ? CMD_WRITE_BUFFER : CMD_READ_BUFFER,
-				      xaddr, avail, pipe, &status)) {
+					is_write ? CMD_WRITE_BUFFER : CMD_READ_BUFFER,
+					xaddr, avail, pipe, &status)) {
 			gf_write_ptr(pipe, dev->base + PIPE_REG_CHANNEL,
 				     dev->base + PIPE_REG_CHANNEL_HIGH);
 			writel(avail, dev->base + PIPE_REG_SIZE);
@@ -343,9 +370,13 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 		}
 		spin_unlock_irqrestore(&dev->lock, irq_flags);
 
-		if (status > 0 && !is_write)
-			set_page_dirty(page);
-		put_page(page);
+		for (page_i = 0; page_i < ret; page_i++) {
+			if (status > 0 && !is_write &&
+				page_i < num_contiguous_pages) {
+				set_page_dirty(pages[page_i]);
+			}
+			put_page(pages[page_i]);
+		}
 
 		if (status > 0) { /* Correct transfer */
 			count += status;
@@ -367,7 +398,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 			 */
 			if (status != PIPE_ERROR_AGAIN)
 				pr_info_ratelimited("goldfish_pipe: backend returned error %d on %s\n",
-					    status, is_write ? "write" : "read");
+						status, is_write ? "write" : "read");
 			ret = 0;
 			break;
 		}
@@ -377,7 +408,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 		 * non-blocking mode, just return the error code.
 		 */
 		if (status != PIPE_ERROR_AGAIN ||
-			(filp->f_flags & O_NONBLOCK) != 0) {
+				(filp->f_flags & O_NONBLOCK) != 0) {
 			ret = goldfish_pipe_error_convert(status);
 			break;
 		}
@@ -391,7 +422,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 
 		/* Tell the emulator we're going to wait for a wake event */
 		goldfish_cmd(pipe,
-			     is_write ? CMD_WAKE_ON_WRITE : CMD_WAKE_ON_READ);
+				is_write ? CMD_WAKE_ON_WRITE : CMD_WAKE_ON_READ);
 
 		/* Unlock the pipe, then wait for the wake signal */
 		mutex_unlock(&pipe->lock);
@@ -399,15 +430,11 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 		while (test_bit(wakeBit, &pipe->flags)) {
 			if (wait_event_interruptible(
 					pipe->wake_queue,
-					!test_bit(wakeBit, &pipe->flags))) {
-				ret = -ERESTARTSYS;
-				break;
-			}
+					!test_bit(wakeBit, &pipe->flags)))
+				return -ERESTARTSYS;
 
-			if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)) {
-				ret = -EIO;
-				break;
-			}
+			if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
+				return -EIO;
 		}
 
 		/* Try to re-acquire the lock */
@@ -543,6 +570,8 @@ static int goldfish_pipe_open(struct inode *inode, struct file *file)
 
 	pipe->dev = dev;
 	mutex_init(&pipe->lock);
+	DPRINT("%s: call. pipe_dev pipe_dev=0x%lx new_pipe_addr=0x%lx file=0x%lx\n", __FUNCTION__, pipe_dev, pipe, file);
+	// spin lock init, write head of list, i guess
 	init_waitqueue_head(&pipe->wake_queue);
 
 	/*
@@ -565,6 +594,7 @@ static int goldfish_pipe_release(struct inode *inode, struct file *filp)
 {
 	struct goldfish_pipe *pipe = filp->private_data;
 
+	DPRINT("%s: call. pipe=0x%lx file=0x%lx\n", __FUNCTION__, pipe, filp);
 	/* The guest is closing the channel, so tell the emulator right now */
 	goldfish_cmd(pipe, CMD_CLOSE);
 	kfree(pipe);
@@ -589,6 +619,7 @@ static struct miscdevice goldfish_pipe_device = {
 
 static int goldfish_pipe_probe(struct platform_device *pdev)
 {
+	DPRINT("%s: call. platform_device=0x%lx\n", __FUNCTION__, pdev);
 	int err;
 	struct resource *r;
 	struct goldfish_pipe_dev *dev = pipe_dev;