OpenE2K/qemu-e2k
13
4
Fork 0
Code Issues 4 Pull Requests Projects 2 Releases Activity

ide/atapi: make PIO read requests async

Browse Source 
PIO read requests on the ATAPI interface used to be sync blk requests.
This has two significant drawbacks. First the main loop hangs util an
I/O request is completed and secondly if the I/O request does not
complete (e.g. due to an unresponsive storage) Qemu hangs completely.

Note: Due to possible race conditions requests during an ongoing
elementary transfer are still sync.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1447345846-15624-2-git-send-email-pl@kamp.de
Signed-off-by: John Snow <jsnow@redhat.com>
This commit is contained in:
Peter Lieven 2015-11-17 14:59:52 -05:00 committed by John Snow
parent c27e9014d5
commit 5f81724d80
1 changed files with 82 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

95
hw/ide/atapi.c
View File

@ -105,20 +105,27 @@ static void cd_data_to_raw(uint8_t *buf, int lba)
memset(buf, 0, 288);
}
static int cd_read_sector(IDEState *s, int lba, uint8_t *buf, int sector_size)
static int
cd_read_sector_sync(IDEState *s)
{
int ret;
block_acct_start(blk_get_stats(s->blk), &s->acct,
4 * BDRV_SECTOR_SIZE, BLOCK_ACCT_READ);
switch(sector_size) {
#ifdef DEBUG_IDE_ATAPI
printf("cd_read_sector_sync: lba=%d\n", s->lba);
#endif
switch (s->cd_sector_size) {
case 2048:
ret = blk_read(s->blk, (int64_t)lba << 2, buf, 4);
ret = blk_read(s->blk, (int64_t)s->lba << 2,
s->io_buffer, 4);
break;
case 2352:
ret = blk_read(s->blk, (int64_t)lba << 2, buf + 16, 4);
ret = blk_read(s->blk, (int64_t)s->lba << 2,
s->io_buffer + 16, 4);
if (ret >= 0) {
cd_data_to_raw(buf, lba);
cd_data_to_raw(s->io_buffer, s->lba);
}
break;
default:
@ -130,11 +137,65 @@ static int cd_read_sector(IDEState *s, int lba, uint8_t *buf, int sector_size)
block_acct_failed(blk_get_stats(s->blk), &s->acct);
} else {
block_acct_done(blk_get_stats(s->blk), &s->acct);
s->lba++;
s->io_buffer_index = 0;
}
return ret;
}
static void cd_read_sector_cb(void *opaque, int ret)
{
IDEState *s = opaque;
block_acct_done(blk_get_stats(s->blk), &s->acct);
#ifdef DEBUG_IDE_ATAPI
printf("cd_read_sector_cb: lba=%d ret=%d\n", s->lba, ret);
#endif
if (ret < 0) {
ide_atapi_io_error(s, ret);
return;
}
if (s->cd_sector_size == 2352) {
cd_data_to_raw(s->io_buffer, s->lba);
}
s->lba++;
s->io_buffer_index = 0;
s->status &= ~BUSY_STAT;
ide_atapi_cmd_reply_end(s);
}
static int cd_read_sector(IDEState *s)
{
if (s->cd_sector_size != 2048 && s->cd_sector_size != 2352) {
return -EINVAL;
}
s->iov.iov_base = (s->cd_sector_size == 2352) ?
s->io_buffer + 16 : s->io_buffer;
s->iov.iov_len = 4 * BDRV_SECTOR_SIZE;
qemu_iovec_init_external(&s->qiov, &s->iov, 1);
#ifdef DEBUG_IDE_ATAPI
printf("cd_read_sector: lba=%d\n", s->lba);
#endif
block_acct_start(blk_get_stats(s->blk), &s->acct,
4 * BDRV_SECTOR_SIZE, BLOCK_ACCT_READ);
blk_aio_readv(s->blk, (int64_t)s->lba << 2, &s->qiov, 4,
cd_read_sector_cb, s);
s->status |= BUSY_STAT;
return 0;
}
void ide_atapi_cmd_ok(IDEState *s)
{
s->error = 0;
@ -196,18 +257,27 @@ void ide_atapi_cmd_reply_end(IDEState *s)
ide_atapi_cmd_ok(s);
ide_set_irq(s->bus);
#ifdef DEBUG_IDE_ATAPI
printf("status=0x%x\n", s->status);
printf("end of transfer, status=0x%x\n", s->status);
#endif
} else {
/* see if a new sector must be read */
if (s->lba != -1 && s->io_buffer_index >= s->cd_sector_size) {
ret = cd_read_sector(s, s->lba, s->io_buffer, s->cd_sector_size);
if (ret < 0) {
ide_atapi_io_error(s, ret);
if (!s->elementary_transfer_size) {
ret = cd_read_sector(s);
if (ret < 0) {
ide_atapi_io_error(s, ret);
}
return;
} else {
/* rebuffering within an elementary transfer is
* only possible with a sync request because we
* end up with a race condition otherwise */
ret = cd_read_sector_sync(s);
if (ret < 0) {
ide_atapi_io_error(s, ret);
return;
}
}
s->lba++;
s->io_buffer_index = 0;
}
if (s->elementary_transfer_size > 0) {
/* there are some data left to transmit in this elementary
@ -287,7 +357,6 @@ static void ide_atapi_cmd_read_pio(IDEState *s, int lba, int nb_sectors,
s->io_buffer_index = sector_size;
s->cd_sector_size = sector_size;
s->status = READY_STAT | SEEK_STAT;
ide_atapi_cmd_reply_end(s);
}
@ -372,7 +441,7 @@ eot:
if (ret < 0) {
block_acct_failed(blk_get_stats(s->blk), &s->acct);
} else {
block_acct_done(blk_get_stats(s->blk), &s->acct);
block_acct_done(blk_get_stats(s->blk), &s->acct);
}
ide_set_inactive(s, false);
}