linux-kernel - [PATCH 2/2] um: ubd: Retry buffer read on any kind of error

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Message-Id: <20200317004507.1513370-3-krisman@collabora.com>
Date:   Mon, 16 Mar 2020 20:45:07 -0400
From:   Gabriel Krisman Bertazi <krisman@...labora.com>
To:     jdike@...toit.com
Cc:     richard@....at, anton.ivanov@...bridgegreys.com,
        linux-um@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Gabriel Krisman Bertazi <krisman@...labora.com>,
        kernel@...labora.com, Martyn Welch <martyn.welch@...labora.com>
Subject: [PATCH 2/2] 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@...labora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
---
 arch/um/drivers/ubd_kern.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 0f5d0a699a49..d259f0728003 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1591,11 +1591,11 @@ 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++) {
-- 
2.25.0