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[Qemu-devel] [PULL 5/7] dev-mtp: retry write for incomplete transfers
From: |
Gerd Hoffmann |
Subject: |
[Qemu-devel] [PULL 5/7] dev-mtp: retry write for incomplete transfers |
Date: |
Tue, 21 Aug 2018 11:11:46 +0200 |
From: Bandan Das <address@hidden>
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 <address@hidden>
Message-id: address@hidden
Signed-off-by: Gerd Hoffmann <address@hidden>
---
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;
--
2.9.3
- [Qemu-devel] [PULL 0/7] Usb 20180821 patches, Gerd Hoffmann, 2018/08/21
- [Qemu-devel] [PULL 1/7] docs/usb2.txt: ehci has six ports, Gerd Hoffmann, 2018/08/21
- [Qemu-devel] [PULL 2/7] ohci: Clear the interrupt counter for erroneous transfers, Gerd Hoffmann, 2018/08/21
- [Qemu-devel] [PULL 3/7] dev-mtp: add support for canceling transaction, Gerd Hoffmann, 2018/08/21
- [Qemu-devel] [PULL 7/7] dev-mtp: rename x-root to rootdir, Gerd Hoffmann, 2018/08/21
- [Qemu-devel] [PULL 4/7] dev-mtp: fix buffer allocation for writing file contents, Gerd Hoffmann, 2018/08/21
- [Qemu-devel] [PULL 6/7] dev-mtp: Add support for > 4GB file transfers, Gerd Hoffmann, 2018/08/21
- [Qemu-devel] [PULL 5/7] dev-mtp: retry write for incomplete transfers,
Gerd Hoffmann <=
- Re: [Qemu-devel] [PULL 0/7] Usb 20180821 patches, Peter Maydell, 2018/08/23