* [Qemu-devel] [PATCH v2 0/3] do not use aio_context_acquire/release in AIO-based drivers
@ 2017-02-22 18:07 Paolo Bonzini
2017-02-22 18:07 ` [Qemu-devel] [PATCH 1/3] curl: do not use aio_context_acquire/release Paolo Bonzini
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Paolo Bonzini @ 2017-02-22 18:07 UTC (permalink / raw)
To: qemu-devel; +Cc: stefanha, jcody, qemu-block
aio_context_acquire/release are only going away as soon as the block layer
becomes thread-safe, but we can already move away to other finer-grained
mutex whenever possible.
These three drivers don't use coroutines, hence a QemuMutex is a fine
primitive to use for protecting any per-BDS data in the libraries
they use. The QemuMutex must protect any fd handlers or bottom halves,
and also the BlockDriver callbacks which were implicitly being called
under aio_context_acquire.
Paolo
v1->v2: missing unlock in error paths (patch 2, Stefan)
Paolo Bonzini (3):
curl: do not use aio_context_acquire/release
nfs: do not use aio_context_acquire/release
iscsi: do not use aio_context_acquire/release
block/curl.c | 24 ++++++++++-------
block/iscsi.c | 83 +++++++++++++++++++++++++++++++++++++++++++++--------------
block/nfs.c | 23 ++++++++++++++---
3 files changed, 98 insertions(+), 32 deletions(-)
--
2.9.3
^ permalink raw reply [flat|nested] 6+ messages in thread* [Qemu-devel] [PATCH 1/3] curl: do not use aio_context_acquire/release 2017-02-22 18:07 [Qemu-devel] [PATCH v2 0/3] do not use aio_context_acquire/release in AIO-based drivers Paolo Bonzini @ 2017-02-22 18:07 ` Paolo Bonzini 2017-02-22 18:07 ` [Qemu-devel] [PATCH 2/3] nfs: " Paolo Bonzini ` (2 subsequent siblings) 3 siblings, 0 replies; 6+ messages in thread From: Paolo Bonzini @ 2017-02-22 18:07 UTC (permalink / raw) To: qemu-devel; +Cc: stefanha, jcody, qemu-block 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 BDRVCURLState access with a QemuMutex. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- block/curl.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/block/curl.c b/block/curl.c index 2939cc7..e83dcd8 100644 --- a/block/curl.c +++ b/block/curl.c @@ -135,6 +135,7 @@ typedef struct BDRVCURLState { char *cookie; bool accept_range; AioContext *aio_context; + QemuMutex mutex; char *username; char *password; char *proxyusername; @@ -333,6 +334,7 @@ static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len, return FIND_RET_NONE; } +/* Called with s->mutex held. */ static void curl_multi_check_completion(BDRVCURLState *s) { int msgs_in_queue; @@ -374,7 +376,9 @@ static void curl_multi_check_completion(BDRVCURLState *s) continue; } + qemu_mutex_unlock(&s->mutex); acb->common.cb(acb->common.opaque, -EPROTO); + qemu_mutex_lock(&s->mutex); qemu_aio_unref(acb); state->acb[i] = NULL; } @@ -386,6 +390,7 @@ static void curl_multi_check_completion(BDRVCURLState *s) } } +/* Called with s->mutex held. */ static void curl_multi_do_locked(CURLState *s) { CURLSocket *socket, *next_socket; @@ -409,19 +414,19 @@ static void curl_multi_do(void *arg) { CURLState *s = (CURLState *)arg; - aio_context_acquire(s->s->aio_context); + qemu_mutex_lock(&s->s->mutex); curl_multi_do_locked(s); - aio_context_release(s->s->aio_context); + qemu_mutex_unlock(&s->s->mutex); } static void curl_multi_read(void *arg) { CURLState *s = (CURLState *)arg; - aio_context_acquire(s->s->aio_context); + qemu_mutex_lock(&s->s->mutex); curl_multi_do_locked(s); curl_multi_check_completion(s->s); - aio_context_release(s->s->aio_context); + qemu_mutex_unlock(&s->s->mutex); } static void curl_multi_timeout_do(void *arg) @@ -434,11 +439,11 @@ static void curl_multi_timeout_do(void *arg) return; } - aio_context_acquire(s->aio_context); + qemu_mutex_lock(&s->mutex); curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running); curl_multi_check_completion(s); - aio_context_release(s->aio_context); + qemu_mutex_unlock(&s->mutex); #else abort(); #endif @@ -771,6 +776,7 @@ static int curl_open(BlockDriverState *bs, QDict *options, int flags, curl_easy_cleanup(state->curl); state->curl = NULL; + qemu_mutex_init(&s->mutex); curl_attach_aio_context(bs, bdrv_get_aio_context(bs)); qemu_opts_del(opts); @@ -801,12 +807,11 @@ static void curl_readv_bh_cb(void *p) CURLAIOCB *acb = p; BlockDriverState *bs = acb->common.bs; BDRVCURLState *s = bs->opaque; - AioContext *ctx = bdrv_get_aio_context(bs); size_t start = acb->sector_num * BDRV_SECTOR_SIZE; size_t end; - aio_context_acquire(ctx); + qemu_mutex_lock(&s->mutex); // In case we have the requested data already (e.g. read-ahead), // we can just call the callback and be done. @@ -854,7 +859,7 @@ static void curl_readv_bh_cb(void *p) curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running); out: - aio_context_release(ctx); + qemu_mutex_unlock(&s->mutex); if (ret != -EINPROGRESS) { acb->common.cb(acb->common.opaque, ret); qemu_aio_unref(acb); @@ -883,6 +888,7 @@ static void curl_close(BlockDriverState *bs) DPRINTF("CURL: Close\n"); curl_detach_aio_context(bs); + qemu_mutex_destroy(&s->mutex); g_free(s->cookie); g_free(s->url); -- 2.9.3 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [Qemu-devel] [PATCH 2/3] nfs: do not use aio_context_acquire/release 2017-02-22 18:07 [Qemu-devel] [PATCH v2 0/3] do not use aio_context_acquire/release in AIO-based drivers Paolo Bonzini 2017-02-22 18:07 ` [Qemu-devel] [PATCH 1/3] curl: do not use aio_context_acquire/release Paolo Bonzini @ 2017-02-22 18:07 ` Paolo Bonzini 2017-02-22 18:07 ` [Qemu-devel] [PATCH 3/3] iscsi: " Paolo Bonzini 2017-02-23 10:34 ` [Qemu-devel] [PATCH v2 0/3] do not use aio_context_acquire/release in AIO-based drivers Stefan Hajnoczi 3 siblings, 0 replies; 6+ messages in thread From: Paolo Bonzini @ 2017-02-22 18:07 UTC (permalink / raw) To: qemu-devel; +Cc: stefanha, jcody, qemu-block 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 libnfs calls with a QemuMutex. Callbacks are invoked using bottom halves, so we don't even have to drop it around callback invocations. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- block/nfs.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/block/nfs.c b/block/nfs.c index 08b43dd..3ee3275 100644 --- a/block/nfs.c +++ b/block/nfs.c @@ -54,6 +54,7 @@ typedef struct NFSClient { int events; bool has_zero_init; AioContext *aio_context; + QemuMutex mutex; blkcnt_t st_blocks; bool cache_used; NFSServer *server; @@ -191,6 +192,7 @@ static void nfs_parse_filename(const char *filename, QDict *options, static void nfs_process_read(void *arg); static void nfs_process_write(void *arg); +/* Called with QemuMutex held. */ static void nfs_set_events(NFSClient *client) { int ev = nfs_which_events(client->context); @@ -209,20 +211,20 @@ static void nfs_process_read(void *arg) { NFSClient *client = arg; - aio_context_acquire(client->aio_context); + qemu_mutex_lock(&client->mutex); nfs_service(client->context, POLLIN); nfs_set_events(client); - aio_context_release(client->aio_context); + qemu_mutex_unlock(&client->mutex); } static void nfs_process_write(void *arg) { NFSClient *client = arg; - aio_context_acquire(client->aio_context); + qemu_mutex_lock(&client->mutex); nfs_service(client->context, POLLOUT); nfs_set_events(client); - aio_context_release(client->aio_context); + qemu_mutex_unlock(&client->mutex); } static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task) @@ -242,6 +244,7 @@ static void nfs_co_generic_bh_cb(void *opaque) aio_co_wake(task->co); } +/* Called (via nfs_service) with QemuMutex held. */ static void nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data, void *private_data) @@ -273,14 +276,17 @@ static int coroutine_fn nfs_co_readv(BlockDriverState *bs, nfs_co_init_task(bs, &task); task.iov = iov; + qemu_mutex_lock(&client->mutex); if (nfs_pread_async(client->context, client->fh, sector_num * BDRV_SECTOR_SIZE, nb_sectors * BDRV_SECTOR_SIZE, nfs_co_generic_cb, &task) != 0) { + qemu_mutex_unlock(&client->mutex); return -ENOMEM; } nfs_set_events(client); + qemu_mutex_unlock(&client->mutex); while (!task.complete) { qemu_coroutine_yield(); } @@ -314,15 +320,18 @@ static int coroutine_fn nfs_co_writev(BlockDriverState *bs, qemu_iovec_to_buf(iov, 0, buf, nb_sectors * BDRV_SECTOR_SIZE); + qemu_mutex_lock(&client->mutex); if (nfs_pwrite_async(client->context, client->fh, sector_num * BDRV_SECTOR_SIZE, nb_sectors * BDRV_SECTOR_SIZE, buf, nfs_co_generic_cb, &task) != 0) { + qemu_mutex_unlock(&client->mutex); g_free(buf); return -ENOMEM; } nfs_set_events(client); + qemu_mutex_unlock(&client->mutex); while (!task.complete) { qemu_coroutine_yield(); } @@ -343,12 +352,15 @@ static int coroutine_fn nfs_co_flush(BlockDriverState *bs) nfs_co_init_task(bs, &task); + qemu_mutex_lock(&client->mutex); if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb, &task) != 0) { + qemu_mutex_unlock(&client->mutex); return -ENOMEM; } nfs_set_events(client); + qemu_mutex_unlock(&client->mutex); while (!task.complete) { qemu_coroutine_yield(); } @@ -434,6 +446,7 @@ static void nfs_file_close(BlockDriverState *bs) { NFSClient *client = bs->opaque; nfs_client_close(client); + qemu_mutex_destroy(&client->mutex); } static NFSServer *nfs_config(QDict *options, Error **errp) @@ -641,6 +654,7 @@ static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags, if (ret < 0) { return ret; } + qemu_mutex_init(&client->mutex); bs->total_sectors = ret; ret = 0; return ret; @@ -696,6 +710,7 @@ static int nfs_has_zero_init(BlockDriverState *bs) return client->has_zero_init; } +/* Called (via nfs_service) with QemuMutex held. */ static void nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data, void *private_data) -- 2.9.3 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [Qemu-devel] [PATCH 3/3] iscsi: do not use aio_context_acquire/release 2017-02-22 18:07 [Qemu-devel] [PATCH v2 0/3] do not use aio_context_acquire/release in AIO-based drivers Paolo Bonzini 2017-02-22 18:07 ` [Qemu-devel] [PATCH 1/3] curl: do not use aio_context_acquire/release Paolo Bonzini 2017-02-22 18:07 ` [Qemu-devel] [PATCH 2/3] nfs: " Paolo Bonzini @ 2017-02-22 18:07 ` Paolo Bonzini 2017-02-23 10:34 ` [Qemu-devel] [PATCH v2 0/3] do not use aio_context_acquire/release in AIO-based drivers Stefan Hajnoczi 3 siblings, 0 replies; 6+ messages in thread From: Paolo Bonzini @ 2017-02-22 18:07 UTC (permalink / raw) To: qemu-devel; +Cc: stefanha, jcody, qemu-block 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 <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- 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 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH v2 0/3] do not use aio_context_acquire/release in AIO-based drivers 2017-02-22 18:07 [Qemu-devel] [PATCH v2 0/3] do not use aio_context_acquire/release in AIO-based drivers Paolo Bonzini ` (2 preceding siblings ...) 2017-02-22 18:07 ` [Qemu-devel] [PATCH 3/3] iscsi: " Paolo Bonzini @ 2017-02-23 10:34 ` Stefan Hajnoczi 3 siblings, 0 replies; 6+ messages in thread From: Stefan Hajnoczi @ 2017-02-23 10:34 UTC (permalink / raw) To: Paolo Bonzini; +Cc: qemu-devel, jcody, qemu-block [-- Attachment #1: Type: text/plain, Size: 1165 bytes --] On Wed, Feb 22, 2017 at 07:07:22PM +0100, Paolo Bonzini wrote: > aio_context_acquire/release are only going away as soon as the block layer > becomes thread-safe, but we can already move away to other finer-grained > mutex whenever possible. > > These three drivers don't use coroutines, hence a QemuMutex is a fine > primitive to use for protecting any per-BDS data in the libraries > they use. The QemuMutex must protect any fd handlers or bottom halves, > and also the BlockDriver callbacks which were implicitly being called > under aio_context_acquire. > > Paolo > > v1->v2: missing unlock in error paths (patch 2, Stefan) > > Paolo Bonzini (3): > curl: do not use aio_context_acquire/release > nfs: do not use aio_context_acquire/release > iscsi: do not use aio_context_acquire/release > > block/curl.c | 24 ++++++++++------- > block/iscsi.c | 83 +++++++++++++++++++++++++++++++++++++++++++++-------------- > block/nfs.c | 23 ++++++++++++++--- > 3 files changed, 98 insertions(+), 32 deletions(-) > > -- > 2.9.3 > Thanks, applied to my block tree: https://github.com/stefanha/qemu/commits/block Stefan [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 455 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Qemu-devel] [PATCH 0/3] do not use aio_context_acquire/release in AIO-based drivers @ 2017-02-17 19:40 Paolo Bonzini 2017-02-17 19:40 ` [Qemu-devel] [PATCH 3/3] iscsi: do not use aio_context_acquire/release Paolo Bonzini 0 siblings, 1 reply; 6+ messages in thread From: Paolo Bonzini @ 2017-02-17 19:40 UTC (permalink / raw) To: qemu-devel; +Cc: qemu-block, jcody aio_context_acquire/release are only going away as soon as the block layer becomes thread-safe, but we can already move away to other finer-grained mutex whenever possible. These three drivers don't use coroutines, hence a QemuMutex is a fine primitive to use for protecting any per-BDS data in the libraries they use. The QemuMutex must protect any fd handlers or bottom halves, and also the BlockDriver callbacks which were implicitly being called under aio_context_acquire. Paolo Paolo Bonzini (3): curl: do not use aio_context_acquire/release nfs: do not use aio_context_acquire/release iscsi: do not use aio_context_acquire/release block/curl.c | 24 ++++++++++------- block/iscsi.c | 83 +++++++++++++++++++++++++++++++++++++++++++++-------------- block/nfs.c | 20 +++++++++++--- 3 files changed, 95 insertions(+), 32 deletions(-) -- 2.9.3 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Qemu-devel] [PATCH 3/3] iscsi: do not use aio_context_acquire/release 2017-02-17 19:40 [Qemu-devel] [PATCH " Paolo Bonzini @ 2017-02-17 19:40 ` Paolo Bonzini 0 siblings, 0 replies; 6+ messages in thread From: Paolo Bonzini @ 2017-02-17 19:40 UTC (permalink / raw) To: qemu-devel; +Cc: qemu-block, jcody 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. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- 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 ^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-02-23 10:34 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2017-02-22 18:07 [Qemu-devel] [PATCH v2 0/3] do not use aio_context_acquire/release in AIO-based drivers Paolo Bonzini 2017-02-22 18:07 ` [Qemu-devel] [PATCH 1/3] curl: do not use aio_context_acquire/release Paolo Bonzini 2017-02-22 18:07 ` [Qemu-devel] [PATCH 2/3] nfs: " Paolo Bonzini 2017-02-22 18:07 ` [Qemu-devel] [PATCH 3/3] iscsi: " Paolo Bonzini 2017-02-23 10:34 ` [Qemu-devel] [PATCH v2 0/3] do not use aio_context_acquire/release in AIO-based drivers Stefan Hajnoczi -- strict thread matches above, loose matches on Subject: below -- 2017-02-17 19:40 [Qemu-devel] [PATCH " Paolo Bonzini 2017-02-17 19:40 ` [Qemu-devel] [PATCH 3/3] iscsi: do not use aio_context_acquire/release Paolo Bonzini
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