Commit d045c466 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Stefan Hajnoczi
Browse files

iscsi: do not use aio_context_acquire/release 



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: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20170222180725.28611-4-pbonzini@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 37d1e4d9

block/iscsi.c

+64 −19
Original line number Diff line number Diff line
@@ -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 apply_chap(struct iscsi_context *iscsi, QemuOpts *opts,
@@ -1331,7 +1374,7 @@ 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;
@@ -1344,7 +1387,7 @@ 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)
@@ -1890,6 +1933,7 @@ 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
@@ -1935,6 +1979,7 @@ 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));

}