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Re: [Qemu-devel] [PATCH 6/7] curl: convert readv to coroutines
From: |
Jeff Cody |
Subject: |
Re: [Qemu-devel] [PATCH 6/7] curl: convert readv to coroutines |
Date: |
Fri, 12 May 2017 17:40:39 -0400 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Wed, May 10, 2017 at 04:32:04PM +0200, Paolo Bonzini wrote:
> This is pretty simple. The bottom half goes away because, unlike
> bdrv_aio_readv, coroutine-based read can return immediately without
> yielding. However, for simplicity I kept the former bottom half
> handler in a separate function.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
> block/curl.c | 94
> ++++++++++++++++++++++++------------------------------------
> 1 file changed, 38 insertions(+), 56 deletions(-)
>
> diff --git a/block/curl.c b/block/curl.c
> index 3e288f2bc7..80870bd60c 100644
> --- a/block/curl.c
> +++ b/block/curl.c
> @@ -76,10 +76,6 @@ static CURLMcode __curl_multi_socket_action(CURLM
> *multi_handle,
> #define CURL_TIMEOUT_DEFAULT 5
> #define CURL_TIMEOUT_MAX 10000
>
> -#define FIND_RET_NONE 0
> -#define FIND_RET_OK 1
> -#define FIND_RET_WAIT 2
> -
> #define CURL_BLOCK_OPT_URL "url"
> #define CURL_BLOCK_OPT_READAHEAD "readahead"
> #define CURL_BLOCK_OPT_SSLVERIFY "sslverify"
> @@ -93,11 +89,12 @@ static CURLMcode __curl_multi_socket_action(CURLM
> *multi_handle,
> struct BDRVCURLState;
>
> typedef struct CURLAIOCB {
> - BlockAIOCB common;
> + Coroutine *co;
> QEMUIOVector *qiov;
>
> uint64_t offset;
> uint64_t bytes;
> + int ret;
>
> size_t start;
> size_t end;
> @@ -268,11 +265,11 @@ static size_t curl_read_cb(void *ptr, size_t size,
> size_t nmemb, void *opaque)
> request_length - offset);
> }
>
> + acb->ret = 0;
> + s->acb[i] = NULL;
> qemu_mutex_unlock(&s->s->mutex);
> - acb->common.cb(acb->common.opaque, 0);
> + aio_co_wake(acb->co);
> qemu_mutex_lock(&s->s->mutex);
> - qemu_aio_unref(acb);
> - s->acb[i] = NULL;
> }
> }
>
> @@ -282,8 +279,8 @@ read_end:
> }
>
> /* Called with s->mutex held. */
> -static int curl_find_buf(BDRVCURLState *s, uint64_t start, uint64_t len,
> - CURLAIOCB *acb)
> +static bool curl_find_buf(BDRVCURLState *s, uint64_t start, uint64_t len,
> + CURLAIOCB *acb)
> {
> int i;
> uint64_t end = start + len;
> @@ -312,7 +309,8 @@ static int curl_find_buf(BDRVCURLState *s, uint64_t
> start, uint64_t len,
> if (clamped_len < len) {
> qemu_iovec_memset(acb->qiov, clamped_len, 0, len -
> clamped_len);
> }
> - return FIND_RET_OK;
> + acb->ret = 0;
> + return true;
> }
>
> // Wait for unfinished chunks
> @@ -330,13 +328,13 @@ static int curl_find_buf(BDRVCURLState *s, uint64_t
> start, uint64_t len,
> for (j=0; j<CURL_NUM_ACB; j++) {
> if (!state->acb[j]) {
> state->acb[j] = acb;
> - return FIND_RET_WAIT;
> + return true;
> }
> }
> }
> }
>
> - return FIND_RET_NONE;
> + return false;
> }
>
> /* Called with s->mutex held. */
> @@ -381,11 +379,11 @@ static void curl_multi_check_completion(BDRVCURLState
> *s)
> continue;
> }
>
> + acb->ret = -EIO;
> + state->acb[i] = NULL;
> qemu_mutex_unlock(&s->mutex);
> - acb->common.cb(acb->common.opaque, -EIO);
> + aio_co_wake(acb->co);
> qemu_mutex_lock(&s->mutex);
> - qemu_aio_unref(acb);
> - state->acb[i] = NULL;
> }
> }
>
> @@ -821,19 +819,11 @@ out_noclean:
> return -EINVAL;
> }
>
> -static const AIOCBInfo curl_aiocb_info = {
> - .aiocb_size = sizeof(CURLAIOCB),
> -};
> -
> -
> -static void curl_readv_bh_cb(void *p)
> +static void curl_setup_preadv(BlockDriverState *bs, CURLAIOCB *acb)
> {
> CURLState *state;
> int running;
> - int ret = -EINPROGRESS;
>
> - CURLAIOCB *acb = p;
> - BlockDriverState *bs = acb->common.bs;
> BDRVCURLState *s = bs->opaque;
>
> uint64_t start = acb->offset;
> @@ -843,14 +833,8 @@ static void curl_readv_bh_cb(void *p)
>
> // In case we have the requested data already (e.g. read-ahead),
> // we can just call the callback and be done.
> - switch (curl_find_buf(s, start, acb->bytes, acb)) {
> - case FIND_RET_OK:
> - ret = 0;
> - goto out;
> - case FIND_RET_WAIT:
> - goto out;
> - default:
> - break;
> + if (curl_find_buf(s, start, acb->bytes, acb)) {
> + goto out;
> }
>
> // No cache found, so let's start a new request
> @@ -866,7 +850,7 @@ static void curl_readv_bh_cb(void *p)
>
> if (curl_init_state(s, state) < 0) {
> curl_clean_state(state);
> - ret = -EIO;
> + acb->ret = -EIO;
> goto out;
> }
>
> @@ -881,7 +865,7 @@ static void curl_readv_bh_cb(void *p)
> state->orig_buf = g_try_malloc(state->buf_len);
> if (state->buf_len && state->orig_buf == NULL) {
> curl_clean_state(state);
> - ret = -ENOMEM;
> + acb->ret = -ENOMEM;
> goto out;
> }
> state->acb[0] = acb;
> @@ -898,26 +882,24 @@ static void curl_readv_bh_cb(void *p)
>
> out:
> qemu_mutex_unlock(&s->mutex);
> - if (ret != -EINPROGRESS) {
> - acb->common.cb(acb->common.opaque, ret);
> - qemu_aio_unref(acb);
> - }
> }
>
> -static BlockAIOCB *curl_aio_readv(BlockDriverState *bs,
> - int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
> - BlockCompletionFunc *cb, void *opaque)
> +static int coroutine_fn curl_co_preadv(BlockDriverState *bs,
> + uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)
> {
> - CURLAIOCB *acb;
> -
> - acb = qemu_aio_get(&curl_aiocb_info, bs, cb, opaque);
> -
> - acb->qiov = qiov;
> - acb->offset = sector_num * BDRV_SECTOR_SIZE;
> - acb->bytes = nb_sectors * BDRV_SECTOR_SIZE;
> -
> - aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), curl_readv_bh_cb, acb);
> - return &acb->common;
> + CURLAIOCB acb = {
> + .co = qemu_coroutine_self(),
> + .ret = -EINPROGRESS,
> + .qiov = qiov,
> + .offset = offset,
> + .bytes = bytes
> + };
> +
> + curl_setup_preadv(bs, &acb);
> + while (acb.ret == -EINPROGRESS) {
> + qemu_coroutine_yield();
> + }
> + return acb.ret;
> }
>
> static void curl_close(BlockDriverState *bs)
> @@ -948,7 +930,7 @@ static BlockDriver bdrv_http = {
> .bdrv_close = curl_close,
> .bdrv_getlength = curl_getlength,
>
> - .bdrv_aio_readv = curl_aio_readv,
> + .bdrv_co_preadv = curl_co_preadv,
>
> .bdrv_detach_aio_context = curl_detach_aio_context,
> .bdrv_attach_aio_context = curl_attach_aio_context,
> @@ -964,7 +946,7 @@ static BlockDriver bdrv_https = {
> .bdrv_close = curl_close,
> .bdrv_getlength = curl_getlength,
>
> - .bdrv_aio_readv = curl_aio_readv,
> + .bdrv_co_preadv = curl_co_preadv,
>
> .bdrv_detach_aio_context = curl_detach_aio_context,
> .bdrv_attach_aio_context = curl_attach_aio_context,
> @@ -980,7 +962,7 @@ static BlockDriver bdrv_ftp = {
> .bdrv_close = curl_close,
> .bdrv_getlength = curl_getlength,
>
> - .bdrv_aio_readv = curl_aio_readv,
> + .bdrv_co_preadv = curl_co_preadv,
>
> .bdrv_detach_aio_context = curl_detach_aio_context,
> .bdrv_attach_aio_context = curl_attach_aio_context,
> @@ -996,7 +978,7 @@ static BlockDriver bdrv_ftps = {
> .bdrv_close = curl_close,
> .bdrv_getlength = curl_getlength,
>
> - .bdrv_aio_readv = curl_aio_readv,
> + .bdrv_co_preadv = curl_co_preadv,
>
> .bdrv_detach_aio_context = curl_detach_aio_context,
> .bdrv_attach_aio_context = curl_attach_aio_context,
> --
> 2.12.2
>
>
Reviewed-by: Jeff Cody <address@hidden>
- Re: [Qemu-devel] [PATCH 4/7] curl: split curl_find_state/curl_init_state, (continued)
- [Qemu-devel] [PATCH 7/7] curl: do not do aio_poll when waiting for a free CURLState, Paolo Bonzini, 2017/05/10
- [Qemu-devel] [PATCH 5/7] curl: convert CURLAIOCB to byte values, Paolo Bonzini, 2017/05/10
- [Qemu-devel] [PATCH 6/7] curl: convert readv to coroutines, Paolo Bonzini, 2017/05/10
- Re: [Qemu-devel] [PATCH 6/7] curl: convert readv to coroutines,
Jeff Cody <=
- Re: [Qemu-devel] [PATCH v2 0/7] curl: locking cleanups/fixes, coroutine conversion, remove aio_poll, no-reply, 2017/05/10
- Re: [Qemu-devel] [PATCH v2 0/7] curl: locking cleanups/fixes, coroutine conversion, remove aio_poll, Richard W.M. Jones, 2017/05/10