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dev-mtp: retry write for incomplete transfers

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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 <bsd@redhat.com>
Message-id: 20180720214020.22897-4-bsd@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Bandan Das 2018-07-20 17:40:18 -04:00 committed by Gerd Hoffmann
parent 406f35d7fc
commit d33e3e4bf8
1 changed files with 20 additions and 2 deletions
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22
hw/usb/dev-mtp.c
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@ -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;