Commit 4cfb44df authored by Benjamin Berg's avatar Benjamin Berg Committed by Johannes Berg
Browse files

um: chan_user: retry partial writes 



In the next commit, we are going to set the output FD to be blocking.
Once that is done, the write() may be short if an interrupt happens
while it is writing out data. As such, to properly catch an EINTR error,
we need to retry the write.

Signed-off-by: default avatarBenjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20231018123643.1255813-3-benjamin@sipsolutions.net


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent c6c4cbaa

arch/um/drivers/chan_user.c

+15 −3
Original line number Diff line number Diff line
@@ -37,11 +37,23 @@ int generic_read(int fd, __u8 *c_out, void *unused) 


int generic_write(int fd, const __u8 *buf, size_t n, void *unused)

{

	int written = 0;

	int err;



	CATCH_EINTR(err = write(fd, buf, n));

	if (err > 0)

		return err;

	/* The FD may be in blocking mode, as such, need to retry short writes,

	 * they may have been interrupted by a signal.

	 */

	do {

		errno = 0;

		err = write(fd, buf + written, n - written);

		if (err > 0) {

			written += err;

			continue;

		}

	} while (err < 0 && errno == EINTR);



	if (written > 0)

		return written;

	else if (errno == EAGAIN)

		return 0;

	else if (err == 0)