| Message ID | 20170314023050.32756-1-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 03/13/2017 09:30 PM, Fam Zheng wrote: > bdrv_child_set_perm alone is not very usable because the caller must > call bdrv_child_check_perm first. This is already encapsulated > conveniently in bdrv_child_try_set_perm, so remove the other prototypes > from the header and fix the one wrong caller, block/mirror.c. > > Signed-off-by: Fam Zheng <famz@redhat.com> > --- > block.c | 13 +++++++++---- > block/mirror.c | 6 ++++-- > include/block/block_int.h | 4 ---- > 3 files changed, 13 insertions(+), 10 deletions(-) > > diff --git a/block.c b/block.c > index cb57370..a77e8a0 100644 > --- a/block.c > +++ b/block.c > @@ -1393,6 +1393,11 @@ static int bdrv_fill_options(QDict **options, const char *filename, > return 0; > } > > +static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared, > + GSList *ignore_children, Error **errp); > +static void bdrv_child_abort_perm_update(BdrvChild *c); > +static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); > + Now that you have static prototypes, is it worth rearranging the file (in a followup) to sort the function implementations into topological order so that a prototype is not necessary? [In general, I try to code so that static prototypes are only necessary if I am implementing mutually-referencing recursive code. But it's not a strict requirement] Reviewed-by: Eric Blake <eblake@redhat.com>
On Tue, 03/14 08:28, Eric Blake wrote: > On 03/13/2017 09:30 PM, Fam Zheng wrote: > > bdrv_child_set_perm alone is not very usable because the caller must > > call bdrv_child_check_perm first. This is already encapsulated > > conveniently in bdrv_child_try_set_perm, so remove the other prototypes > > from the header and fix the one wrong caller, block/mirror.c. > > > > Signed-off-by: Fam Zheng <famz@redhat.com> > > --- > > block.c | 13 +++++++++---- > > block/mirror.c | 6 ++++-- > > include/block/block_int.h | 4 ---- > > 3 files changed, 13 insertions(+), 10 deletions(-) > > > > diff --git a/block.c b/block.c > > index cb57370..a77e8a0 100644 > > --- a/block.c > > +++ b/block.c > > @@ -1393,6 +1393,11 @@ static int bdrv_fill_options(QDict **options, const char *filename, > > return 0; > > } > > > > +static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared, > > + GSList *ignore_children, Error **errp); > > +static void bdrv_child_abort_perm_update(BdrvChild *c); > > +static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); > > + > > Now that you have static prototypes, is it worth rearranging the file > (in a followup) to sort the function implementations into topological > order so that a prototype is not necessary? [In general, I try to code > so that static prototypes are only necessary if I am implementing > mutually-referencing recursive code. But it's not a strict requirement] Yes, thanks for pointing out, but it does have a recursion here: bdrv_check_update_perm -> bdrv_check_perm -> bdrv_child_check_perm -> bdrv_check_update_perm Fam > > Reviewed-by: Eric Blake <eblake@redhat.com> > > -- > Eric Blake eblake redhat com +1-919-301-3266 > Libvirt virtualization library http://libvirt.org >
Am 14.03.2017 um 03:30 hat Fam Zheng geschrieben: > bdrv_child_set_perm alone is not very usable because the caller must > call bdrv_child_check_perm first. Well, you can imagine use cases where you want to check multiple children first and then set or abort all of them, but apparently we haven't found such a case yet, so I'm fine with making the functions private for now. If we ever need it, making them public again is trivial. > This is already encapsulated > conveniently in bdrv_child_try_set_perm, so remove the other prototypes > from the header and fix the one wrong caller, block/mirror.c. > > Signed-off-by: Fam Zheng <famz@redhat.com> Thanks, applied to the block branch. Kevin
On Wed, 03/15 11:52, Kevin Wolf wrote: > Am 14.03.2017 um 03:30 hat Fam Zheng geschrieben: > > bdrv_child_set_perm alone is not very usable because the caller must > > call bdrv_child_check_perm first. > > Well, you can imagine use cases where you want to check multiple > children first and then set or abort all of them, but apparently we > haven't found such a case yet, so I'm fine with making the functions > private for now. If we ever need it, making them public again is > trivial. Yes, no problem with that use case but by then I suppose we should also add an assertion about the calling sequence: e.g. in image locking, raw_set_perm goes nut if not preceded by `raw_check_perm. > > > This is already encapsulated > > conveniently in bdrv_child_try_set_perm, so remove the other prototypes > > from the header and fix the one wrong caller, block/mirror.c. > > > > Signed-off-by: Fam Zheng <famz@redhat.com> > > Thanks, applied to the block branch. Thanks! Fam > > Kevin
On 03/14/2017 10:06 PM, Fam Zheng wrote: >>> +static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared, >>> + GSList *ignore_children, Error **errp); >>> +static void bdrv_child_abort_perm_update(BdrvChild *c); >>> +static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); >>> + >> >> Now that you have static prototypes, is it worth rearranging the file >> (in a followup) to sort the function implementations into topological >> order so that a prototype is not necessary? [In general, I try to code >> so that static prototypes are only necessary if I am implementing >> mutually-referencing recursive code. But it's not a strict requirement] > > Yes, thanks for pointing out, but it does have a recursion here: > > bdrv_check_update_perm > -> bdrv_check_perm > -> bdrv_child_check_perm > -> bdrv_check_update_perm > So you're right, topological sorting is not possible. Carry on, nothing to see here :)
Am 15.03.2017 um 12:09 hat Fam Zheng geschrieben: > On Wed, 03/15 11:52, Kevin Wolf wrote: > > Am 14.03.2017 um 03:30 hat Fam Zheng geschrieben: > > > bdrv_child_set_perm alone is not very usable because the caller must > > > call bdrv_child_check_perm first. > > > > Well, you can imagine use cases where you want to check multiple > > children first and then set or abort all of them, but apparently we > > haven't found such a case yet, so I'm fine with making the functions > > private for now. If we ever need it, making them public again is > > trivial. > > Yes, no problem with that use case but by then I suppose we should also add an > assertion about the calling sequence: e.g. in image locking, raw_set_perm goes > nut if not preceded by `raw_check_perm. Yes, that makes sense. Kevin
diff --git a/block.c b/block.c index cb57370..a77e8a0 100644 --- a/block.c +++ b/block.c @@ -1393,6 +1393,11 @@ static int bdrv_fill_options(QDict **options, const char *filename, return 0; } +static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared, + GSList *ignore_children, Error **errp); +static void bdrv_child_abort_perm_update(BdrvChild *c); +static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); + /* * Check whether permissions on this node can be changed in a way that * @cumulative_perms and @cumulative_shared_perms are the new cumulative @@ -1615,8 +1620,8 @@ static int bdrv_check_update_perm(BlockDriverState *bs, uint64_t new_used_perm, /* Needs to be followed by a call to either bdrv_child_set_perm() or * bdrv_child_abort_perm_update(). */ -int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared, - GSList *ignore_children, Error **errp) +static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared, + GSList *ignore_children, Error **errp) { int ret; @@ -1627,7 +1632,7 @@ int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared, return ret; } -void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared) +static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared) { uint64_t cumulative_perms, cumulative_shared_perms; @@ -1639,7 +1644,7 @@ void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared) bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms); } -void bdrv_child_abort_perm_update(BdrvChild *c) +static void bdrv_child_abort_perm_update(BdrvChild *c) { bdrv_abort_perm_update(c->bs); } diff --git a/block/mirror.c b/block/mirror.c index 4f3a5cb..ca4baa5 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -574,7 +574,8 @@ static void mirror_exit(BlockJob *job, void *opaque) * valid. Also give up permissions on mirror_top_bs->backing, which might * block the removal. */ block_job_remove_all_bdrv(job); - bdrv_child_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL); + bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, + &error_abort); bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort); /* We just changed the BDS the job BB refers to (with either or both of the @@ -1245,7 +1246,8 @@ fail: block_job_unref(&s->common); } - bdrv_child_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL); + bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, + &error_abort); bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort); } diff --git a/include/block/block_int.h b/include/block/block_int.h index 6c699ac..59400bd 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -889,10 +889,6 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, void *opaque, Error **errp); void bdrv_root_unref_child(BdrvChild *child); -int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared, - GSList *ignore_children, Error **errp); -void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); -void bdrv_child_abort_perm_update(BdrvChild *c); int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, Error **errp);
bdrv_child_set_perm alone is not very usable because the caller must call bdrv_child_check_perm first. This is already encapsulated conveniently in bdrv_child_try_set_perm, so remove the other prototypes from the header and fix the one wrong caller, block/mirror.c. Signed-off-by: Fam Zheng <famz@redhat.com> --- block.c | 13 +++++++++---- block/mirror.c | 6 ++++-- include/block/block_int.h | 4 ---- 3 files changed, 13 insertions(+), 10 deletions(-)