From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42729) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fgd8g-0005DM-GZ for qemu-devel@nongnu.org; Fri, 20 Jul 2018 17:40:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fgd8d-0005mt-9s for qemu-devel@nongnu.org; Fri, 20 Jul 2018 17:40:38 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:48090 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fgd8d-0005ln-4N for qemu-devel@nongnu.org; Fri, 20 Jul 2018 17:40:35 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3EEA9818F6E1 for ; Fri, 20 Jul 2018 21:40:34 +0000 (UTC) From: Bandan Das Date: Fri, 20 Jul 2018 17:40:18 -0400 Message-Id: <20180720214020.22897-4-bsd@redhat.com> In-Reply-To: <20180720214020.22897-1-bsd@redhat.com> References: <20180720214020.22897-1-bsd@redhat.com> Subject: [Qemu-devel] [PATCH 3/5] dev-mtp: retry write for incomplete transfers List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kraxel@redhat.com For large buffers, write may not copy the full buffer. For example, on Linux, write imposes a limit of 0x7ffff000. Note that this does not fix >4G transfers but ~>2G files will transfer successfully. Signed-off-by: Bandan Das --- hw/usb/dev-mtp.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c index 1b72603dc5..c8f6eb4e9e 100644 --- a/hw/usb/dev-mtp.c +++ b/hw/usb/dev-mtp.c @@ -1602,6 +1602,24 @@ static void utf16_to_str(uint8_t len, uint16_t *arr, char *name) g_free(wstr); } +/* Wrapper around write, returns 0 on failure */ +static uint64_t write_retry(int fd, void *buf, uint64_t size) +{ + uint64_t bytes_left = size, ret; + + while (bytes_left > 0) { + ret = write(fd, buf, bytes_left); + if ((ret == -1) && (errno != EINTR || errno != EAGAIN || + errno != EWOULDBLOCK)) { + break; + } + bytes_left -= ret; + buf += ret; + } + + return size - bytes_left; +} + static void usb_mtp_write_data(MTPState *s) { MTPData *d = s->data_out; @@ -1644,8 +1662,8 @@ static void usb_mtp_write_data(MTPState *s) goto success; } - rc = write(d->fd, d->data, s->dataset.size); - if (rc == -1) { + rc = write_retry(d->fd, d->data, s->dataset.size); + if (!rc) { usb_mtp_queue_result(s, RES_STORE_FULL, d->trans, 0, 0, 0, 0); goto done; -- 2.14.4