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[2/7] ashmem: Implement read(2) in ashmem driver

Message ID 1324428595-9253-3-git-send-email-john.stultz@linaro.org
State Accepted
Headers show

Commit Message

John Stultz Dec. 21, 2011, 12:49 a.m. UTC 
From: Bjorn Bringert <bringert@android.com>

Bug: 2595601
Change-Id: I47c0016f594f9354fb8658ccb26e3d395bcb137b
Signed-off-by: Bjorn Bringert <bringert@android.com>
[jstultz: Tweaked commit subject]
CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
CC: Greg KH <greg@kroah.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 drivers/staging/android/ashmem.c |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)
diff mbox

Patch

diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
index 5775c6c..6f1a0bb 100644
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -211,6 +211,32 @@  static int ashmem_release(struct inode *ignored, struct file *file)
 	return 0;
 }
 
+static ssize_t ashmem_read(struct file *file, char __user *buf,
+			   size_t len, loff_t *pos)
+{
+	struct ashmem_area *asma = file->private_data;
+	int ret = 0;
+
+	mutex_lock(&ashmem_mutex);
+
+	/* If size is not set, or set to 0, always return EOF. */
+	if (asma->size == 0) {
+		goto out;
+        }
+
+	if (!asma->file) {
+		ret = -EBADF;
+		goto out;
+	}
+
+	ret = asma->file->f_op->read(asma->file, buf, len, pos);
+
+out:
+	mutex_unlock(&ashmem_mutex);
+	return ret;
+}
+
+
 static int ashmem_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct ashmem_area *asma = file->private_data;
@@ -612,6 +638,7 @@  static struct file_operations ashmem_fops = {
 	.owner = THIS_MODULE,
 	.open = ashmem_open,
 	.release = ashmem_release,
+        .read = ashmem_read,
 	.mmap = ashmem_mmap,
 	.unlocked_ioctl = ashmem_ioctl,
 	.compat_ioctl = ashmem_ioctl,