Merge tag 'v3.10.23' into linux-linaro-lsk

[firefly-linux-kernel-4.4.55.git] / drivers / gator / gator_annotate.c

diff --git a/drivers/gator/gator_annotate.c b/drivers/gator/gator_annotate.c
index ad9f3091235e11e4edaf27ca2163333df80e5ec0..5b9399bea230c7cccd982bc81ba49216786175af 100644 (file)
--- a/drivers/gator/gator_annotate.c
+++ b/drivers/gator/gator_annotate.c
@@ -39,14 +39,17 @@ static int annotate_copy(struct file *file, char const __user *buf, size_t count
 static ssize_t annotate_write(struct file *file, char const __user *buf, size_t count_orig, loff_t *offset)
 {
        int pid, cpu, header_size, available, contiguous, length1, length2, size, count = count_orig & 0x7fffffff;
+       bool interrupt_context;
 
        if (*offset) {
                return -EINVAL;
        }
 
-       // Annotations are not supported in interrupt context
-       if (in_interrupt()) {
-               printk(KERN_WARNING "gator: Annotations are not supported in interrupt context\n");
+       interrupt_context = in_interrupt();
+       // Annotations are not supported in interrupt context, but may work if you comment out the the next four lines of code.
+       //   By doing so, annotations in interrupt context can result in deadlocks and lost data.
+       if (interrupt_context) {
+               printk(KERN_WARNING "gator: Annotations are not supported in interrupt context. Edit gator_annotate.c in the gator driver to enable annotations in interrupt context.\n");
                return -EINVAL;
        }
 
@@ -77,7 +80,19 @@ static ssize_t annotate_write(struct file *file, char const __user *buf, size_t
        if (size <= 0) {
                // Buffer is full, wait until space is available
                spin_unlock(&annotate_lock);
+
+               // Drop the annotation as blocking is not allowed in interrupt context
+               if (interrupt_context) {
+                       return -EINVAL;
+               }
+
                wait_event_interruptible(gator_annotate_wait, buffer_bytes_available(cpu, ANNOTATE_BUF) > header_size || !collect_annotations);
+
+               // Check to see if a signal is pending
+               if (signal_pending(current)) {
+                       return -EINTR;
+               }
+
                goto retry;
        }