From: Gabriel Krisman Bertazi <krisman@collabora.com>
Date: Tue, 17 Mar 2020 00:45:07 +0000 (-0400)
Subject: um: ubd: Retry buffer read on any kind of error
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e355b2f55efc4633409ada14125c9e28ad2de012;p=linux.git

um: ubd: Retry buffer read on any kind of error

Should bulk_req_safe_read return an error, we want to retry the read,
otherwise, even though no IO will be done, os_write_file might still end
up writing garbage to the pipe.

Cc: Martyn Welch <martyn.welch@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index eca45ad2166c9..eae8c83364f71 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1592,11 +1592,11 @@ int io_thread(void *arg)
 			&io_remainder_size,
 			UBD_REQ_BUFFER_SIZE
 		);
-		if (n < 0) {
-			if (n == -EAGAIN) {
+		if (n <= 0) {
+			if (n == -EAGAIN)
 				ubd_read_poll(-1);
-				continue;
-			}
+
+			continue;
 		}
 
 		for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {