cxl: Fix afu_read() not doing finish_wait() on signal or non-blocking
If afu_read() returned due to a signal or the AFU file descriptor being
opened non-blocking it would not call finish_wait() before returning,
which could lead to a crash later when something else wakes up the wait
queue.
This patch restructures the wait logic to ensure that the cleanup is
done correctly.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index 847b7e6..378b099 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -273,6 +273,7 @@
struct cxl_context *ctx = file->private_data;
struct cxl_event event;
unsigned long flags;
+ int rc;
DEFINE_WAIT(wait);
if (count < CXL_READ_MIN_SIZE)
@@ -285,13 +286,17 @@
if (ctx_event_pending(ctx))
break;
+ if (file->f_flags & O_NONBLOCK) {
+ rc = -EAGAIN;
+ goto out;
+ }
+
+ if (signal_pending(current)) {
+ rc = -ERESTARTSYS;
+ goto out;
+ }
+
spin_unlock_irqrestore(&ctx->lock, flags);
- if (file->f_flags & O_NONBLOCK)
- return -EAGAIN;
-
- if (signal_pending(current))
- return -ERESTARTSYS;
-
pr_devel("afu_read going to sleep...\n");
schedule();
pr_devel("afu_read woken up\n");
@@ -336,6 +341,11 @@
if (copy_to_user(buf, &event, event.header.size))
return -EFAULT;
return event.header.size;
+
+out:
+ finish_wait(&ctx->wq, &wait);
+ spin_unlock_irqrestore(&ctx->lock, flags);
+ return rc;
}
static const struct file_operations afu_fops = {
