From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41736) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b3Pmp-0005ac-Am for qemu-devel@nongnu.org; Thu, 19 May 2016 11:22:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b3Pmj-0000Sf-4R for qemu-devel@nongnu.org; Thu, 19 May 2016 11:22:55 -0400 From: Kevin Wolf Date: Thu, 19 May 2016 17:21:59 +0200 Message-Id: <1463671329-22655-22-git-send-email-kwolf@redhat.com> In-Reply-To: <1463671329-22655-1-git-send-email-kwolf@redhat.com> References: <1463671329-22655-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 21/31] block: Avoid bs->blk in bdrv_next() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, qemu-devel@nongnu.org We need to introduce a separate BdrvNextIterator struct that can keep more state than just the current BDS in order to avoid using the bs->blk pointer. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz --- block.c | 40 +++++++---------------- block/block-backend.c | 72 +++++++++++++++++++++++++++++------------- block/io.c | 13 ++++---- block/snapshot.c | 30 +++++++++++------- blockdev.c | 3 +- include/block/block.h | 3 +- include/sysemu/block-backend.h | 1 - migration/block.c | 4 ++- monitor.c | 6 ++-- qmp.c | 5 ++- 10 files changed, 102 insertions(+), 75 deletions(-) diff --git a/block.c b/block.c index fd4cf81..91bf431 100644 --- a/block.c +++ b/block.c @@ -2870,25 +2870,6 @@ BlockDriverState *bdrv_next_node(BlockDriverState *bs) return QTAILQ_NEXT(bs, node_list); } -/* Iterates over all top-level BlockDriverStates, i.e. BDSs that are owned by - * the monitor or attached to a BlockBackend */ -BlockDriverState *bdrv_next(BlockDriverState *bs) -{ - if (!bs || bs->blk) { - bs = blk_next_root_bs(bs); - if (bs) { - return bs; - } - } - - /* Ignore all BDSs that are attached to a BlockBackend here; they have been - * handled by the above block already */ - do { - bs = bdrv_next_monitor_owned(bs); - } while (bs && bs->blk); - return bs; -} - const char *bdrv_get_node_name(const BlockDriverState *bs) { return bs->node_name; @@ -3220,10 +3201,11 @@ void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) void bdrv_invalidate_cache_all(Error **errp) { - BlockDriverState *bs = NULL; + BlockDriverState *bs; Error *local_err = NULL; + BdrvNextIterator *it = NULL; - while ((bs = bdrv_next(bs)) != NULL) { + while ((it = bdrv_next(it, &bs)) != NULL) { AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); @@ -3265,10 +3247,11 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs, int bdrv_inactivate_all(void) { BlockDriverState *bs = NULL; + BdrvNextIterator *it = NULL; int ret = 0; int pass; - while ((bs = bdrv_next(bs)) != NULL) { + while ((it = bdrv_next(it, &bs)) != NULL) { aio_context_acquire(bdrv_get_aio_context(bs)); } @@ -3277,8 +3260,8 @@ int bdrv_inactivate_all(void) * the second pass sets the BDRV_O_INACTIVE flag so that no further write * is allowed. */ for (pass = 0; pass < 2; pass++) { - bs = NULL; - while ((bs = bdrv_next(bs)) != NULL) { + it = NULL; + while ((it = bdrv_next(it, &bs)) != NULL) { ret = bdrv_inactivate_recurse(bs, pass); if (ret < 0) { goto out; @@ -3287,8 +3270,8 @@ int bdrv_inactivate_all(void) } out: - bs = NULL; - while ((bs = bdrv_next(bs)) != NULL) { + it = NULL; + while ((it = bdrv_next(it, &bs)) != NULL) { aio_context_release(bdrv_get_aio_context(bs)); } @@ -3781,10 +3764,11 @@ bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs, */ bool bdrv_is_first_non_filter(BlockDriverState *candidate) { - BlockDriverState *bs = NULL; + BlockDriverState *bs; + BdrvNextIterator *it = NULL; /* walk down the bs forest recursively */ - while ((bs = bdrv_next(bs)) != NULL) { + while ((it = bdrv_next(it, &bs)) != NULL) { bool perm; /* try to recurse in this top level bs */ diff --git a/block/block-backend.c b/block/block-backend.c index 9dcac97..7f2eeb0 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -75,6 +75,7 @@ static const AIOCBInfo block_backend_aiocb_info = { }; static void drive_info_del(DriveInfo *dinfo); +static BlockBackend *bdrv_first_blk(BlockDriverState *bs); /* All BlockBackends */ static QTAILQ_HEAD(, BlockBackend) block_backends = @@ -286,28 +287,50 @@ BlockBackend *blk_next(BlockBackend *blk) : QTAILQ_FIRST(&monitor_block_backends); } -/* - * Iterates over all BlockDriverStates which are attached to a BlockBackend. - * This function is for use by bdrv_next(). - * - * @bs must be NULL or a BDS that is attached to a BB. - */ -BlockDriverState *blk_next_root_bs(BlockDriverState *bs) -{ +struct BdrvNextIterator { + enum { + BDRV_NEXT_BACKEND_ROOTS, + BDRV_NEXT_MONITOR_OWNED, + } phase; BlockBackend *blk; + BlockDriverState *bs; +}; - if (bs) { - assert(bs->blk); - blk = bs->blk; - } else { - blk = NULL; +/* Iterates over all top-level BlockDriverStates, i.e. BDSs that are owned by + * the monitor or attached to a BlockBackend */ +BdrvNextIterator *bdrv_next(BdrvNextIterator *it, BlockDriverState **bs) +{ + if (!it) { + it = g_new(BdrvNextIterator, 1); + *it = (BdrvNextIterator) { + .phase = BDRV_NEXT_BACKEND_ROOTS, + }; + } + + /* First, return all root nodes of BlockBackends. In order to avoid + * returning a BDS twice when multiple BBs refer to it, we only return it + * if the BB is the first one in the parent list of the BDS. */ + if (it->phase == BDRV_NEXT_BACKEND_ROOTS) { + do { + it->blk = blk_all_next(it->blk); + *bs = it->blk ? blk_bs(it->blk) : NULL; + } while (it->blk && (*bs == NULL || bdrv_first_blk(*bs) != it->blk)); + + if (*bs) { + return it; + } + it->phase = BDRV_NEXT_MONITOR_OWNED; } + /* Then return the monitor-owned BDSes without a BB attached. Ignore all + * BDSes that are attached to a BlockBackend here; they have been handled + * by the above block already */ do { - blk = blk_all_next(blk); - } while (blk && !blk->root); + it->bs = bdrv_next_monitor_owned(it->bs); + *bs = it->bs; + } while (*bs && bdrv_has_blk(*bs)); - return blk ? blk->root->bs : NULL; + return *bs ? it : NULL; } /* @@ -394,21 +417,26 @@ BlockDriverState *blk_bs(BlockBackend *blk) return blk->root ? blk->root->bs : NULL; } -/* - * Returns true if @bs has an associated BlockBackend. - */ -bool bdrv_has_blk(BlockDriverState *bs) +static BlockBackend *bdrv_first_blk(BlockDriverState *bs) { BdrvChild *child; QLIST_FOREACH(child, &bs->parents, next_parent) { if (child->role == &child_root) { assert(bs->blk); - return true; + return child->opaque; } } assert(!bs->blk); - return false; + return NULL; +} + +/* + * Returns true if @bs has an associated BlockBackend. + */ +bool bdrv_has_blk(BlockDriverState *bs) +{ + return bdrv_first_blk(bs) != NULL; } /* diff --git a/block/io.c b/block/io.c index 8a6f470..60a6bd8 100644 --- a/block/io.c +++ b/block/io.c @@ -270,10 +270,11 @@ void bdrv_drain_all(void) { /* Always run first iteration so any pending completion BHs run */ bool busy = true; - BlockDriverState *bs = NULL; + BlockDriverState *bs; + BdrvNextIterator *it = NULL; GSList *aio_ctxs = NULL, *ctx; - while ((bs = bdrv_next(bs))) { + while ((it = bdrv_next(it, &bs))) { AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); @@ -301,10 +302,10 @@ void bdrv_drain_all(void) for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) { AioContext *aio_context = ctx->data; - bs = NULL; + it = NULL; aio_context_acquire(aio_context); - while ((bs = bdrv_next(bs))) { + while ((it = bdrv_next(it, &bs))) { if (aio_context == bdrv_get_aio_context(bs)) { if (bdrv_requests_pending(bs)) { busy = true; @@ -317,8 +318,8 @@ void bdrv_drain_all(void) } } - bs = NULL; - while ((bs = bdrv_next(bs))) { + it = NULL; + while ((it = bdrv_next(it, &bs))) { AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); diff --git a/block/snapshot.c b/block/snapshot.c index e9d721d..3917ec5 100644 --- a/block/snapshot.c +++ b/block/snapshot.c @@ -373,9 +373,10 @@ int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs, bool bdrv_all_can_snapshot(BlockDriverState **first_bad_bs) { bool ok = true; - BlockDriverState *bs = NULL; + BlockDriverState *bs; + BdrvNextIterator *it = NULL; - while (ok && (bs = bdrv_next(bs))) { + while (ok && (it = bdrv_next(it, &bs))) { AioContext *ctx = bdrv_get_aio_context(bs); aio_context_acquire(ctx); @@ -393,10 +394,11 @@ int bdrv_all_delete_snapshot(const char *name, BlockDriverState **first_bad_bs, Error **err) { int ret = 0; - BlockDriverState *bs = NULL; + BlockDriverState *bs; + BdrvNextIterator *it = NULL; QEMUSnapshotInfo sn1, *snapshot = &sn1; - while (ret == 0 && (bs = bdrv_next(bs))) { + while (ret == 0 && (it = bdrv_next(it, &bs))) { AioContext *ctx = bdrv_get_aio_context(bs); aio_context_acquire(ctx); @@ -415,9 +417,10 @@ int bdrv_all_delete_snapshot(const char *name, BlockDriverState **first_bad_bs, int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs) { int err = 0; - BlockDriverState *bs = NULL; + BlockDriverState *bs; + BdrvNextIterator *it = NULL; - while (err == 0 && (bs = bdrv_next(bs))) { + while (err == 0 && (it = bdrv_next(it, &bs))) { AioContext *ctx = bdrv_get_aio_context(bs); aio_context_acquire(ctx); @@ -435,9 +438,10 @@ int bdrv_all_find_snapshot(const char *name, BlockDriverState **first_bad_bs) { QEMUSnapshotInfo sn; int err = 0; - BlockDriverState *bs = NULL; + BlockDriverState *bs; + BdrvNextIterator *it = NULL; - while (err == 0 && (bs = bdrv_next(bs))) { + while (err == 0 && (it = bdrv_next(it, &bs))) { AioContext *ctx = bdrv_get_aio_context(bs); aio_context_acquire(ctx); @@ -457,9 +461,10 @@ int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn, BlockDriverState **first_bad_bs) { int err = 0; - BlockDriverState *bs = NULL; + BlockDriverState *bs; + BdrvNextIterator *it = NULL; - while (err == 0 && (bs = bdrv_next(bs))) { + while (err == 0 && (it = bdrv_next(it, &bs))) { AioContext *ctx = bdrv_get_aio_context(bs); aio_context_acquire(ctx); @@ -480,9 +485,10 @@ int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn, BlockDriverState *bdrv_all_find_vmstate_bs(void) { bool not_found = true; - BlockDriverState *bs = NULL; + BlockDriverState *bs; + BdrvNextIterator *it = NULL; - while (not_found && (bs = bdrv_next(bs))) { + while (not_found && (it = bdrv_next(it, &bs))) { AioContext *ctx = bdrv_get_aio_context(bs); aio_context_acquire(ctx); diff --git a/blockdev.c b/blockdev.c index 03ddd3a..442ca8d 100644 --- a/blockdev.c +++ b/blockdev.c @@ -4135,8 +4135,9 @@ BlockJobInfoList *qmp_query_block_jobs(Error **errp) { BlockJobInfoList *head = NULL, **p_next = &head; BlockDriverState *bs; + BdrvNextIterator *it = NULL; - for (bs = bdrv_next(NULL); bs; bs = bdrv_next(bs)) { + while ((it = bdrv_next(it, &bs))) { AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); diff --git a/include/block/block.h b/include/block/block.h index d1f9380..a8c15e3 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -17,6 +17,7 @@ typedef struct BlockJob BlockJob; typedef struct BdrvChild BdrvChild; typedef struct BdrvChildRole BdrvChildRole; typedef struct BlockJobTxn BlockJobTxn; +typedef struct BdrvNextIterator BdrvNextIterator; typedef struct BlockDriverInfo { /* in bytes, 0 if irrelevant */ @@ -401,7 +402,7 @@ BlockDriverState *bdrv_lookup_bs(const char *device, Error **errp); bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base); BlockDriverState *bdrv_next_node(BlockDriverState *bs); -BlockDriverState *bdrv_next(BlockDriverState *bs); +BdrvNextIterator *bdrv_next(BdrvNextIterator *it, BlockDriverState **bs); BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs); int bdrv_is_encrypted(BlockDriverState *bs); int bdrv_key_required(BlockDriverState *bs); diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 44a222d..68d92b5 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -89,7 +89,6 @@ void blk_remove_all_bs(void); const char *blk_name(BlockBackend *blk); BlockBackend *blk_by_name(const char *name); BlockBackend *blk_next(BlockBackend *blk); -BlockDriverState *blk_next_root_bs(BlockDriverState *bs); bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp); void monitor_remove_blk(BlockBackend *blk); diff --git a/migration/block.c b/migration/block.c index 1743317..a7a76a0 100644 --- a/migration/block.c +++ b/migration/block.c @@ -383,6 +383,7 @@ static void init_blk_migration(QEMUFile *f) BlockDriverState *bs; BlkMigDevState *bmds; int64_t sectors; + BdrvNextIterator *it = NULL; block_mig_state.submitted = 0; block_mig_state.read_done = 0; @@ -392,7 +393,8 @@ static void init_blk_migration(QEMUFile *f) block_mig_state.bulk_completed = 0; block_mig_state.zero_blocks = migrate_zero_blocks(); - for (bs = bdrv_next(NULL); bs; bs = bdrv_next(bs)) { + + while ((it = bdrv_next(it, &bs))) { if (bdrv_is_read_only(bs)) { continue; } diff --git a/monitor.c b/monitor.c index d1c1930..2c87244 100644 --- a/monitor.c +++ b/monitor.c @@ -3427,11 +3427,13 @@ void host_net_remove_completion(ReadLineState *rs, int nb_args, const char *str) static void vm_completion(ReadLineState *rs, const char *str) { size_t len; - BlockDriverState *bs = NULL; + BlockDriverState *bs; + BdrvNextIterator *it = NULL; len = strlen(str); readline_set_completion_index(rs, len); - while ((bs = bdrv_next(bs))) { + + while ((it = bdrv_next(it, &bs))) { SnapshotInfoList *snapshots, *snapshot; AioContext *ctx = bdrv_get_aio_context(bs); bool ok = false; diff --git a/qmp.c b/qmp.c index e784a67..8f8ae3a 100644 --- a/qmp.c +++ b/qmp.c @@ -181,6 +181,7 @@ void qmp_cont(Error **errp) Error *local_err = NULL; BlockBackend *blk; BlockDriverState *bs; + BdrvNextIterator *it; /* if there is a dump in background, we should wait until the dump * finished */ @@ -199,7 +200,9 @@ void qmp_cont(Error **errp) for (blk = blk_next(NULL); blk; blk = blk_next(blk)) { blk_iostatus_reset(blk); } - for (bs = bdrv_next(NULL); bs; bs = bdrv_next(bs)) { + + it = NULL; + while ((it = bdrv_next(it, &bs))) { bdrv_add_key(bs, NULL, &local_err); if (local_err) { error_propagate(errp, local_err); -- 1.8.3.1