Re: [Qemu-devel] [PATCH 1/4] blockdev: Disentangle BlockDriverState and DriveInfo creation
Benoît Canet writes: > The Friday 12 Sep 2014 à 21:26:21 (+0200), Markus Armbruster wrote : >> blockdev_init() mixes up BlockDriverState and DriveInfo initialization >> Finish the BlockDriverState job before starting to mess with >> DriveInfo. Easier on the eyes. >> >> Signed-off-by: Markus Armbruster >> --- >> blockdev.c | 43 +++ >> 1 file changed, 23 insertions(+), 20 deletions(-) >> >> diff --git a/blockdev.c b/blockdev.c >> index b361fbb..5ec4635 100644 >> --- a/blockdev.c >> +++ b/blockdev.c >> @@ -301,6 +301,7 @@ static DriveInfo *blockdev_init(const char *file, QDict >> *bs_opts, >> int ro = 0; >> int bdrv_flags = 0; >> int on_read_error, on_write_error; >> +BlockDriverState *bs; >> DriveInfo *dinfo; >> ThrottleConfig cfg; >> int snapshot = 0; >> @@ -456,26 +457,27 @@ static DriveInfo *blockdev_init(const char *file, >> QDict *bs_opts, >> } >> >> /* init */ >> +bs = bdrv_new(qemu_opts_id(opts), errp); >> +if (!bs) { >> +goto early_err; >> +} >> +bs->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0; >> +bs->read_only = ro; >> +bs->detect_zeroes = detect_zeroes; >> + >> +bdrv_set_on_error(bs, on_read_error, on_write_error); >> + >> +/* disk I/O throttling */ >> +if (throttle_enabled(&cfg)) { >> +bdrv_io_limits_enable(bs); >> +bdrv_set_io_limits(bs, &cfg); >> +} >> + >> dinfo = g_malloc0(sizeof(*dinfo)); >> dinfo->id = g_strdup(qemu_opts_id(opts)); >> -dinfo->bdrv = bdrv_new(dinfo->id, &error); >> -if (error) { >> -error_propagate(errp, error); >> -goto bdrv_new_err; >> -} >> -dinfo->bdrv->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0; >> -dinfo->bdrv->read_only = ro; >> -dinfo->bdrv->detect_zeroes = detect_zeroes; >> +dinfo->bdrv = bs; >> QTAILQ_INSERT_TAIL(&drives, dinfo, next); >> >> -bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error); >> - >> -/* disk I/O throttling */ >> -if (throttle_enabled(&cfg)) { >> -bdrv_io_limits_enable(dinfo->bdrv); >> -bdrv_set_io_limits(dinfo->bdrv, &cfg); >> -} >> - >> if (!file || !*file) { >> if (has_driver_specific_opts) { >> file = NULL; >> @@ -502,7 +504,8 @@ static DriveInfo *blockdev_init(const char *file, QDict >> *bs_opts, >> bdrv_flags |= ro ? 0 : BDRV_O_RDWR; >> >> QINCREF(bs_opts); >> -ret = bdrv_open(&dinfo->bdrv, file, NULL, bs_opts, bdrv_flags, drv, >> &error); >> +ret = bdrv_open(&bs, file, NULL, bs_opts, bdrv_flags, drv, &error); >> +assert(bs == dinfo->bdrv); >> >> if (ret < 0) { >> error_setg(errp, "could not open disk image %s: %s", >> @@ -511,8 +514,9 @@ static DriveInfo *blockdev_init(const char *file, QDict >> *bs_opts, >> goto err; >> } >> >> -if (bdrv_key_required(dinfo->bdrv)) >> +if (bdrv_key_required(bs)) { >> autostart = 0; >> +} >> >> QDECREF(bs_opts); >> qemu_opts_del(opts); >> @@ -520,9 +524,8 @@ static DriveInfo *blockdev_init(const char *file, QDict >> *bs_opts, >> return dinfo; >> >> err: >> -bdrv_unref(dinfo->bdrv); > >> +bdrv_unref(bs); > I would have moved this. > >> QTAILQ_REMOVE(&drives, dinfo, next); >> -bdrv_new_err: >> g_free(dinfo->id); >> g_free(dinfo); > > To Here. > > No functional difference but it would reflect it's goto chain role: > being in the reverse order of the allocations. You're right. In the BlockBackend series, this becomes just err: blk_unref(blk); early_err: so the disorder is just temporary. I'll change it anyway if I have to respin for some other reason. >> early_err: >> -- >> 1.9.3 > > Reviewed-by: Benoît Canet Thanks!
Re: [Qemu-devel] [PATCH 1/4] blockdev: Disentangle BlockDriverState and DriveInfo creation
The Friday 12 Sep 2014 à 21:26:21 (+0200), Markus Armbruster wrote : > blockdev_init() mixes up BlockDriverState and DriveInfo initialization > Finish the BlockDriverState job before starting to mess with > DriveInfo. Easier on the eyes. > > Signed-off-by: Markus Armbruster > --- > blockdev.c | 43 +++ > 1 file changed, 23 insertions(+), 20 deletions(-) > > diff --git a/blockdev.c b/blockdev.c > index b361fbb..5ec4635 100644 > --- a/blockdev.c > +++ b/blockdev.c > @@ -301,6 +301,7 @@ static DriveInfo *blockdev_init(const char *file, QDict > *bs_opts, > int ro = 0; > int bdrv_flags = 0; > int on_read_error, on_write_error; > +BlockDriverState *bs; > DriveInfo *dinfo; > ThrottleConfig cfg; > int snapshot = 0; > @@ -456,26 +457,27 @@ static DriveInfo *blockdev_init(const char *file, QDict > *bs_opts, > } > > /* init */ > +bs = bdrv_new(qemu_opts_id(opts), errp); > +if (!bs) { > +goto early_err; > +} > +bs->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0; > +bs->read_only = ro; > +bs->detect_zeroes = detect_zeroes; > + > +bdrv_set_on_error(bs, on_read_error, on_write_error); > + > +/* disk I/O throttling */ > +if (throttle_enabled(&cfg)) { > +bdrv_io_limits_enable(bs); > +bdrv_set_io_limits(bs, &cfg); > +} > + > dinfo = g_malloc0(sizeof(*dinfo)); > dinfo->id = g_strdup(qemu_opts_id(opts)); > -dinfo->bdrv = bdrv_new(dinfo->id, &error); > -if (error) { > -error_propagate(errp, error); > -goto bdrv_new_err; > -} > -dinfo->bdrv->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0; > -dinfo->bdrv->read_only = ro; > -dinfo->bdrv->detect_zeroes = detect_zeroes; > +dinfo->bdrv = bs; > QTAILQ_INSERT_TAIL(&drives, dinfo, next); > > -bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error); > - > -/* disk I/O throttling */ > -if (throttle_enabled(&cfg)) { > -bdrv_io_limits_enable(dinfo->bdrv); > -bdrv_set_io_limits(dinfo->bdrv, &cfg); > -} > - > if (!file || !*file) { > if (has_driver_specific_opts) { > file = NULL; > @@ -502,7 +504,8 @@ static DriveInfo *blockdev_init(const char *file, QDict > *bs_opts, > bdrv_flags |= ro ? 0 : BDRV_O_RDWR; > > QINCREF(bs_opts); > -ret = bdrv_open(&dinfo->bdrv, file, NULL, bs_opts, bdrv_flags, drv, > &error); > +ret = bdrv_open(&bs, file, NULL, bs_opts, bdrv_flags, drv, &error); > +assert(bs == dinfo->bdrv); > > if (ret < 0) { > error_setg(errp, "could not open disk image %s: %s", > @@ -511,8 +514,9 @@ static DriveInfo *blockdev_init(const char *file, QDict > *bs_opts, > goto err; > } > > -if (bdrv_key_required(dinfo->bdrv)) > +if (bdrv_key_required(bs)) { > autostart = 0; > +} > > QDECREF(bs_opts); > qemu_opts_del(opts); > @@ -520,9 +524,8 @@ static DriveInfo *blockdev_init(const char *file, QDict > *bs_opts, > return dinfo; > > err: > -bdrv_unref(dinfo->bdrv); > +bdrv_unref(bs); I would have moved this. > QTAILQ_REMOVE(&drives, dinfo, next); > -bdrv_new_err: > g_free(dinfo->id); > g_free(dinfo); To Here. No functional difference but it would reflect it's goto chain role: being in the reverse order of the allocations. > early_err: > -- > 1.9.3 Reviewed-by: Benoît Canet >
Re: [Qemu-devel] [PATCH 1/4] blockdev: Disentangle BlockDriverState and DriveInfo creation
Max Reitz writes: > On 12.09.2014 21:26, Markus Armbruster wrote: >> blockdev_init() mixes up BlockDriverState and DriveInfo initialization >> Finish the BlockDriverState job before starting to mess with >> DriveInfo. Easier on the eyes. >> >> Signed-off-by: Markus Armbruster >> --- >> blockdev.c | 43 +++ >> 1 file changed, 23 insertions(+), 20 deletions(-) >> >> diff --git a/blockdev.c b/blockdev.c >> index b361fbb..5ec4635 100644 >> --- a/blockdev.c >> +++ b/blockdev.c >> @@ -301,6 +301,7 @@ static DriveInfo *blockdev_init(const char *file, QDict >> *bs_opts, >> int ro = 0; >> int bdrv_flags = 0; >> int on_read_error, on_write_error; >> +BlockDriverState *bs; >> DriveInfo *dinfo; >> ThrottleConfig cfg; >> int snapshot = 0; >> @@ -456,26 +457,27 @@ static DriveInfo *blockdev_init(const char *file, >> QDict *bs_opts, >> } >> /* init */ >> +bs = bdrv_new(qemu_opts_id(opts), errp); >> +if (!bs) { >> +goto early_err; >> +} >> +bs->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0; >> +bs->read_only = ro; >> +bs->detect_zeroes = detect_zeroes; >> + >> +bdrv_set_on_error(bs, on_read_error, on_write_error); >> + >> +/* disk I/O throttling */ >> +if (throttle_enabled(&cfg)) { >> +bdrv_io_limits_enable(bs); >> +bdrv_set_io_limits(bs, &cfg); >> +} >> + >> dinfo = g_malloc0(sizeof(*dinfo)); > > Could've changed this to g_new0 in the process, but you're the expert > for that, so I'll leave it up to you. ;-) When I made block use g_new() & friends, I only converted patterns like p = g_malloc(sizeof(T)), not patterns like p = g_malloc(sizeof(*p)). In the former case, p = g_new(T) is a clear improvement, because now the compiler checks T matches typeof(*p). In the latter case, we trade some visible obviousness for type safety. Matter of taste. If we agree to prefer type safety in block land, I'll gladly do the conversion work. >> dinfo->id = g_strdup(qemu_opts_id(opts)); >> -dinfo->bdrv = bdrv_new(dinfo->id, &error); >> -if (error) { >> -error_propagate(errp, error); >> -goto bdrv_new_err; >> -} >> -dinfo->bdrv->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0; >> -dinfo->bdrv->read_only = ro; >> -dinfo->bdrv->detect_zeroes = detect_zeroes; >> +dinfo->bdrv = bs; >> QTAILQ_INSERT_TAIL(&drives, dinfo, next); >> -bdrv_set_on_error(dinfo->bdrv, on_read_error, >> on_write_error); >> - >> -/* disk I/O throttling */ >> -if (throttle_enabled(&cfg)) { >> -bdrv_io_limits_enable(dinfo->bdrv); >> -bdrv_set_io_limits(dinfo->bdrv, &cfg); >> -} >> - >> if (!file || !*file) { >> if (has_driver_specific_opts) { >> file = NULL; >> @@ -502,7 +504,8 @@ static DriveInfo *blockdev_init(const char *file, QDict >> *bs_opts, >> bdrv_flags |= ro ? 0 : BDRV_O_RDWR; >> QINCREF(bs_opts); >> -ret = bdrv_open(&dinfo->bdrv, file, NULL, bs_opts, bdrv_flags, drv, >> &error); >> +ret = bdrv_open(&bs, file, NULL, bs_opts, bdrv_flags, drv, &error); >> +assert(bs == dinfo->bdrv); > > Well, this is guaranteed by bdrv_open(), but of course better having > too many assertions than too few. Indeed. bdrv_open() is in another file, and its function comment doesn't quite spell out this part of its contract. Assertions do double-duty: they check assumptions are valid, and they remind the reader of assumptions. The second part can be useful even when the first part is trivial. > With or without g_new0: > > Reviewed-by: Max Reitz Thanks!
Re: [Qemu-devel] [PATCH 1/4] blockdev: Disentangle BlockDriverState and DriveInfo creation
On 12.09.2014 21:26, Markus Armbruster wrote: blockdev_init() mixes up BlockDriverState and DriveInfo initialization Finish the BlockDriverState job before starting to mess with DriveInfo. Easier on the eyes. Signed-off-by: Markus Armbruster --- blockdev.c | 43 +++ 1 file changed, 23 insertions(+), 20 deletions(-) diff --git a/blockdev.c b/blockdev.c index b361fbb..5ec4635 100644 --- a/blockdev.c +++ b/blockdev.c @@ -301,6 +301,7 @@ static DriveInfo *blockdev_init(const char *file, QDict *bs_opts, int ro = 0; int bdrv_flags = 0; int on_read_error, on_write_error; +BlockDriverState *bs; DriveInfo *dinfo; ThrottleConfig cfg; int snapshot = 0; @@ -456,26 +457,27 @@ static DriveInfo *blockdev_init(const char *file, QDict *bs_opts, } /* init */ +bs = bdrv_new(qemu_opts_id(opts), errp); +if (!bs) { +goto early_err; +} +bs->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0; +bs->read_only = ro; +bs->detect_zeroes = detect_zeroes; + +bdrv_set_on_error(bs, on_read_error, on_write_error); + +/* disk I/O throttling */ +if (throttle_enabled(&cfg)) { +bdrv_io_limits_enable(bs); +bdrv_set_io_limits(bs, &cfg); +} + dinfo = g_malloc0(sizeof(*dinfo)); Could've changed this to g_new0 in the process, but you're the expert for that, so I'll leave it up to you. ;-) dinfo->id = g_strdup(qemu_opts_id(opts)); -dinfo->bdrv = bdrv_new(dinfo->id, &error); -if (error) { -error_propagate(errp, error); -goto bdrv_new_err; -} -dinfo->bdrv->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0; -dinfo->bdrv->read_only = ro; -dinfo->bdrv->detect_zeroes = detect_zeroes; +dinfo->bdrv = bs; QTAILQ_INSERT_TAIL(&drives, dinfo, next); -bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error); - -/* disk I/O throttling */ -if (throttle_enabled(&cfg)) { -bdrv_io_limits_enable(dinfo->bdrv); -bdrv_set_io_limits(dinfo->bdrv, &cfg); -} - if (!file || !*file) { if (has_driver_specific_opts) { file = NULL; @@ -502,7 +504,8 @@ static DriveInfo *blockdev_init(const char *file, QDict *bs_opts, bdrv_flags |= ro ? 0 : BDRV_O_RDWR; QINCREF(bs_opts); -ret = bdrv_open(&dinfo->bdrv, file, NULL, bs_opts, bdrv_flags, drv, &error); +ret = bdrv_open(&bs, file, NULL, bs_opts, bdrv_flags, drv, &error); +assert(bs == dinfo->bdrv); Well, this is guaranteed by bdrv_open(), but of course better having too many assertions than too few. With or without g_new0: Reviewed-by: Max Reitz