linux-kernel - [PATCH] firmware: request_firmware() should propagate -ERESTARTSYS

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Date:   Tue, 23 May 2017 15:16:07 +0200
From:   Martin Fuzzey <mfuzzey@...keon.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Luis R. Rodriguez" <mcgrof@...nel.org>
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH] firmware: request_firmware() should propagate -ERESTARTSYS

When -ERESTARTSYS is returned by wait_* due to a signal this should
be returned from request_firmware() so that the syscall may be
restarted if necessary.

Without this it is not possible to distinguish the case of
request_firmware() failing due to a timeout with that due to a signal.

In my particular case request_firmware() was being called from
a sysfs .store() callback and the writing process was the
Android init process which received a SIGCHLD causing
request_firmware() to fail.

Signed-off-by: Martin Fuzzey <mfuzzey@...keon.com>
---
 drivers/base/firmware_class.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index b616bf7..13ed62f 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -1023,9 +1023,10 @@ static int _request_firmware_load(struct firmware_priv *fw_priv,
 		mutex_unlock(&fw_lock);
 	}

-	if (fw_state_is_aborted(&buf->fw_st))
-		retval = -EAGAIN;
-	else if (buf->is_paged_buf && !buf->data)
+	if (fw_state_is_aborted(&buf->fw_st)) {
+		if (retval != -ERESTARTSYS)
+			retval = -EAGAIN;
+	} else if (buf->is_paged_buf && !buf->data)
 		retval = -ENOMEM;

 	device_del(f_dev);