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[Qemu-block] [PATCH 3/3] iscsi: do not use aio_context_acquire/release
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From: |
Paolo Bonzini |
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Subject: |
[Qemu-block] [PATCH 3/3] iscsi: do not use aio_context_acquire/release |
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Date: |
Wed, 22 Feb 2017 19:07:25 +0100 |
Now that all bottom halves and callbacks take care of taking the
AioContext lock, we can migrate some users away from it and to a
specific QemuMutex or CoMutex.
Protect libiscsi calls with a QemuMutex. Callbacks are invoked
using bottom halves, so we don't even have to drop it around
callback invocations.
Reviewed-by: Stefan Hajnoczi <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
block/iscsi.c | 83 +++++++++++++++++++++++++++++++++++++++++++++--------------
1 file changed, 64 insertions(+), 19 deletions(-)
diff --git a/block/iscsi.c b/block/iscsi.c
index 2561be9..e483f6d 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -58,6 +58,7 @@ typedef struct IscsiLun {
int events;
QEMUTimer *nop_timer;
QEMUTimer *event_timer;
+ QemuMutex mutex;
struct scsi_inquiry_logical_block_provisioning lbp;
struct scsi_inquiry_block_limits bl;
unsigned char *zeroblock;
@@ -252,6 +253,7 @@ static int iscsi_translate_sense(struct scsi_sense *sense)
return ret;
}
+/* Called (via iscsi_service) with QemuMutex held. */
static void
iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
void *command_data, void *opaque)
@@ -352,6 +354,7 @@ static const AIOCBInfo iscsi_aiocb_info = {
static void iscsi_process_read(void *arg);
static void iscsi_process_write(void *arg);
+/* Called with QemuMutex held. */
static void
iscsi_set_events(IscsiLun *iscsilun)
{
@@ -395,10 +398,10 @@ iscsi_process_read(void *arg)
IscsiLun *iscsilun = arg;
struct iscsi_context *iscsi = iscsilun->iscsi;
- aio_context_acquire(iscsilun->aio_context);
+ qemu_mutex_lock(&iscsilun->mutex);
iscsi_service(iscsi, POLLIN);
iscsi_set_events(iscsilun);
- aio_context_release(iscsilun->aio_context);
+ qemu_mutex_unlock(&iscsilun->mutex);
}
static void
@@ -407,10 +410,10 @@ iscsi_process_write(void *arg)
IscsiLun *iscsilun = arg;
struct iscsi_context *iscsi = iscsilun->iscsi;
- aio_context_acquire(iscsilun->aio_context);
+ qemu_mutex_lock(&iscsilun->mutex);
iscsi_service(iscsi, POLLOUT);
iscsi_set_events(iscsilun);
- aio_context_release(iscsilun->aio_context);
+ qemu_mutex_unlock(&iscsilun->mutex);
}
static int64_t sector_lun2qemu(int64_t sector, IscsiLun *iscsilun)
@@ -589,6 +592,7 @@ iscsi_co_writev_flags(BlockDriverState *bs, int64_t
sector_num, int nb_sectors,
uint64_t lba;
uint32_t num_sectors;
bool fua = flags & BDRV_REQ_FUA;
+ int r = 0;
if (fua) {
assert(iscsilun->dpofua);
@@ -604,6 +608,7 @@ iscsi_co_writev_flags(BlockDriverState *bs, int64_t
sector_num, int nb_sectors,
lba = sector_qemu2lun(sector_num, iscsilun);
num_sectors = sector_qemu2lun(nb_sectors, iscsilun);
iscsi_co_init_iscsitask(iscsilun, &iTask);
+ qemu_mutex_lock(&iscsilun->mutex);
retry:
if (iscsilun->use_16_for_rw) {
#if LIBISCSI_API_VERSION >= (20160603)
@@ -640,7 +645,9 @@ retry:
#endif
while (!iTask.complete) {
iscsi_set_events(iscsilun);
+ qemu_mutex_unlock(&iscsilun->mutex);
qemu_coroutine_yield();
+ qemu_mutex_lock(&iscsilun->mutex);
}
if (iTask.task != NULL) {
@@ -655,12 +662,15 @@ retry:
if (iTask.status != SCSI_STATUS_GOOD) {
iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors);
- return iTask.err_code;
+ r = iTask.err_code;
+ goto out_unlock;
}
iscsi_allocmap_set_allocated(iscsilun, sector_num, nb_sectors);
- return 0;
+out_unlock:
+ qemu_mutex_unlock(&iscsilun->mutex);
+ return r;
}
@@ -693,18 +703,21 @@ static int64_t coroutine_fn
iscsi_co_get_block_status(BlockDriverState *bs,
goto out;
}
+ qemu_mutex_lock(&iscsilun->mutex);
retry:
if (iscsi_get_lba_status_task(iscsilun->iscsi, iscsilun->lun,
sector_qemu2lun(sector_num, iscsilun),
8 + 16, iscsi_co_generic_cb,
&iTask) == NULL) {
ret = -ENOMEM;
- goto out;
+ goto out_unlock;
}
while (!iTask.complete) {
iscsi_set_events(iscsilun);
+ qemu_mutex_unlock(&iscsilun->mutex);
qemu_coroutine_yield();
+ qemu_mutex_lock(&iscsilun->mutex);
}
if (iTask.do_retry) {
@@ -721,20 +734,20 @@ retry:
* because the device is busy or the cmd is not
* supported) we pretend all blocks are allocated
* for backwards compatibility */
- goto out;
+ goto out_unlock;
}
lbas = scsi_datain_unmarshall(iTask.task);
if (lbas == NULL) {
ret = -EIO;
- goto out;
+ goto out_unlock;
}
lbasd = &lbas->descriptors[0];
if (sector_qemu2lun(sector_num, iscsilun) != lbasd->lba) {
ret = -EIO;
- goto out;
+ goto out_unlock;
}
*pnum = sector_lun2qemu(lbasd->num_blocks, iscsilun);
@@ -756,6 +769,8 @@ retry:
if (*pnum > nb_sectors) {
*pnum = nb_sectors;
}
+out_unlock:
+ qemu_mutex_unlock(&iscsilun->mutex);
out:
if (iTask.task != NULL) {
scsi_free_scsi_task(iTask.task);
@@ -818,6 +833,7 @@ static int coroutine_fn iscsi_co_readv(BlockDriverState *bs,
num_sectors = sector_qemu2lun(nb_sectors, iscsilun);
iscsi_co_init_iscsitask(iscsilun, &iTask);
+ qemu_mutex_lock(&iscsilun->mutex);
retry:
if (iscsilun->use_16_for_rw) {
#if LIBISCSI_API_VERSION >= (20160603)
@@ -855,7 +871,9 @@ retry:
#endif
while (!iTask.complete) {
iscsi_set_events(iscsilun);
+ qemu_mutex_unlock(&iscsilun->mutex);
qemu_coroutine_yield();
+ qemu_mutex_lock(&iscsilun->mutex);
}
if (iTask.task != NULL) {
@@ -867,6 +885,7 @@ retry:
iTask.complete = 0;
goto retry;
}
+ qemu_mutex_unlock(&iscsilun->mutex);
if (iTask.status != SCSI_STATUS_GOOD) {
return iTask.err_code;
@@ -881,6 +900,7 @@ static int coroutine_fn iscsi_co_flush(BlockDriverState *bs)
struct IscsiTask iTask;
iscsi_co_init_iscsitask(iscsilun, &iTask);
+ qemu_mutex_lock(&iscsilun->mutex);
retry:
if (iscsi_synchronizecache10_task(iscsilun->iscsi, iscsilun->lun, 0, 0, 0,
0, iscsi_co_generic_cb, &iTask) == NULL)
{
@@ -889,7 +909,9 @@ retry:
while (!iTask.complete) {
iscsi_set_events(iscsilun);
+ qemu_mutex_unlock(&iscsilun->mutex);
qemu_coroutine_yield();
+ qemu_mutex_lock(&iscsilun->mutex);
}
if (iTask.task != NULL) {
@@ -901,6 +923,7 @@ retry:
iTask.complete = 0;
goto retry;
}
+ qemu_mutex_unlock(&iscsilun->mutex);
if (iTask.status != SCSI_STATUS_GOOD) {
return iTask.err_code;
@@ -910,6 +933,7 @@ retry:
}
#ifdef __linux__
+/* Called (via iscsi_service) with QemuMutex held. */
static void
iscsi_aio_ioctl_cb(struct iscsi_context *iscsi, int status,
void *command_data, void *opaque)
@@ -1034,6 +1058,7 @@ static BlockAIOCB *iscsi_aio_ioctl(BlockDriverState *bs,
acb->task->expxferlen = acb->ioh->dxfer_len;
data.size = 0;
+ qemu_mutex_lock(&iscsilun->mutex);
if (acb->task->xfer_dir == SCSI_XFER_WRITE) {
if (acb->ioh->iovec_count == 0) {
data.data = acb->ioh->dxferp;
@@ -1049,6 +1074,7 @@ static BlockAIOCB *iscsi_aio_ioctl(BlockDriverState *bs,
iscsi_aio_ioctl_cb,
(data.size > 0) ? &data : NULL,
acb) != 0) {
+ qemu_mutex_unlock(&iscsilun->mutex);
scsi_free_scsi_task(acb->task);
qemu_aio_unref(acb);
return NULL;
@@ -1068,6 +1094,7 @@ static BlockAIOCB *iscsi_aio_ioctl(BlockDriverState *bs,
}
iscsi_set_events(iscsilun);
+ qemu_mutex_unlock(&iscsilun->mutex);
return &acb->common;
}
@@ -1092,6 +1119,7 @@ coroutine_fn iscsi_co_pdiscard(BlockDriverState *bs,
int64_t offset, int count)
IscsiLun *iscsilun = bs->opaque;
struct IscsiTask iTask;
struct unmap_list list;
+ int r = 0;
if (!is_byte_request_lun_aligned(offset, count, iscsilun)) {
return -ENOTSUP;
@@ -1106,15 +1134,19 @@ coroutine_fn iscsi_co_pdiscard(BlockDriverState *bs,
int64_t offset, int count)
list.num = count / iscsilun->block_size;
iscsi_co_init_iscsitask(iscsilun, &iTask);
+ qemu_mutex_lock(&iscsilun->mutex);
retry:
if (iscsi_unmap_task(iscsilun->iscsi, iscsilun->lun, 0, 0, &list, 1,
iscsi_co_generic_cb, &iTask) == NULL) {
- return -ENOMEM;
+ r = -ENOMEM;
+ goto out_unlock;
}
while (!iTask.complete) {
iscsi_set_events(iscsilun);
+ qemu_mutex_unlock(&iscsilun->mutex);
qemu_coroutine_yield();
+ qemu_mutex_lock(&iscsilun->mutex);
}
if (iTask.task != NULL) {
@@ -1131,17 +1163,20 @@ retry:
/* the target might fail with a check condition if it
is not happy with the alignment of the UNMAP request
we silently fail in this case */
- return 0;
+ goto out_unlock;
}
if (iTask.status != SCSI_STATUS_GOOD) {
- return iTask.err_code;
+ r = iTask.err_code;
+ goto out_unlock;
}
iscsi_allocmap_set_invalid(iscsilun, offset >> BDRV_SECTOR_BITS,
count >> BDRV_SECTOR_BITS);
- return 0;
+out_unlock:
+ qemu_mutex_unlock(&iscsilun->mutex);
+ return r;
}
static int
@@ -1153,6 +1188,7 @@ coroutine_fn iscsi_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset,
uint64_t lba;
uint32_t nb_blocks;
bool use_16_for_ws = iscsilun->use_16_for_rw;
+ int r = 0;
if (!is_byte_request_lun_aligned(offset, count, iscsilun)) {
return -ENOTSUP;
@@ -1186,6 +1222,7 @@ coroutine_fn iscsi_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset,
}
}
+ qemu_mutex_lock(&iscsilun->mutex);
iscsi_co_init_iscsitask(iscsilun, &iTask);
retry:
if (use_16_for_ws) {
@@ -1205,7 +1242,9 @@ retry:
while (!iTask.complete) {
iscsi_set_events(iscsilun);
+ qemu_mutex_unlock(&iscsilun->mutex);
qemu_coroutine_yield();
+ qemu_mutex_lock(&iscsilun->mutex);
}
if (iTask.status == SCSI_STATUS_CHECK_CONDITION &&
@@ -1215,7 +1254,8 @@ retry:
/* WRITE SAME is not supported by the target */
iscsilun->has_write_same = false;
scsi_free_scsi_task(iTask.task);
- return -ENOTSUP;
+ r = -ENOTSUP;
+ goto out_unlock;
}
if (iTask.task != NULL) {
@@ -1231,7 +1271,8 @@ retry:
if (iTask.status != SCSI_STATUS_GOOD) {
iscsi_allocmap_set_invalid(iscsilun, offset >> BDRV_SECTOR_BITS,
count >> BDRV_SECTOR_BITS);
- return iTask.err_code;
+ r = iTask.err_code;
+ goto out_unlock;
}
if (flags & BDRV_REQ_MAY_UNMAP) {
@@ -1242,7 +1283,9 @@ retry:
count >> BDRV_SECTOR_BITS);
}
- return 0;
+out_unlock:
+ qemu_mutex_unlock(&iscsilun->mutex);
+ return r;
}
static void parse_chap(struct iscsi_context *iscsi, const char *target,
@@ -1397,7 +1440,7 @@ static void iscsi_nop_timed_event(void *opaque)
{
IscsiLun *iscsilun = opaque;
- aio_context_acquire(iscsilun->aio_context);
+ qemu_mutex_lock(&iscsilun->mutex);
if (iscsi_get_nops_in_flight(iscsilun->iscsi) >= MAX_NOP_FAILURES) {
error_report("iSCSI: NOP timeout. Reconnecting...");
iscsilun->request_timed_out = true;
@@ -1410,7 +1453,7 @@ static void iscsi_nop_timed_event(void *opaque)
iscsi_set_events(iscsilun);
out:
- aio_context_release(iscsilun->aio_context);
+ qemu_mutex_unlock(&iscsilun->mutex);
}
static void iscsi_readcapacity_sync(IscsiLun *iscsilun, Error **errp)
@@ -1812,6 +1855,7 @@ static int iscsi_open(BlockDriverState *bs, QDict
*options, int flags,
scsi_free_scsi_task(task);
task = NULL;
+ qemu_mutex_init(&iscsilun->mutex);
iscsi_attach_aio_context(bs, iscsilun->aio_context);
/* Guess the internal cluster (page) size of the iscsi target by the means
@@ -1860,6 +1904,7 @@ static void iscsi_close(BlockDriverState *bs)
iscsi_destroy_context(iscsi);
g_free(iscsilun->zeroblock);
iscsi_allocmap_free(iscsilun);
+ qemu_mutex_destroy(&iscsilun->mutex);
memset(iscsilun, 0, sizeof(IscsiLun));
}
--
2.9.3