From d33e3e4bf8df7a7f1bd538bc19d17c8c21f14df2 Mon Sep 17 00:00:00 2001 From: Bandan Das Date: Fri, 20 Jul 2018 17:40:18 -0400 Subject: [PATCH] dev-mtp: retry write for incomplete transfers 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 Message-id: 20180720214020.22897-4-bsd@redhat.com Signed-off-by: Gerd Hoffmann --- 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; -- 2.11.0