[Qemu-devel] [PATCH v2 0/3] vmdk: Move descriptor buffers to heap

[Qemu-devel] [PATCH v2 0/3] vmdk: Move descriptor buffers to heap

[Fam Zheng]

All three functions are not in hot path (all run once for the BDS lifecycle),
so it's okay to convert to g_malloc0.

Fam


Fam Zheng (3):
  vmdk: Switch to heap arrays for vmdk_write_cid
  vmdk: Switch to heap arrays for vmdk_read_cid
  vmdk: Switch to heap arrays for vmdk_parent_open

 block/vmdk.c | 47 +++++++++++++++++++++++++++++------------------
 1 file changed, 29 insertions(+), 18 deletions(-)

-- 
2.4.3

[Qemu-devel] [PATCH v2 1/3] vmdk: Switch to heap arrays for vmdk_write_cid

[Fam Zheng]

It is only called once for each opened image, so we can do it the easy
way.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/vmdk.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index a8db5d9..1ec2452 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -274,36 +274,39 @@ static uint32_t vmdk_read_cid(BlockDriverState *bs, int parent)
 
 static int vmdk_write_cid(BlockDriverState *bs, uint32_t cid)
 {
-    char desc[DESC_SIZE], tmp_desc[DESC_SIZE];
+    char *desc, *tmp_desc;
     char *p_name, *tmp_str;
     BDRVVmdkState *s = bs->opaque;
-    int ret;
+    int ret = 0;
 
+    desc = g_malloc0(DESC_SIZE);
+    tmp_desc = g_malloc0(DESC_SIZE);
     ret = bdrv_pread(bs->file->bs, s->desc_offset, desc, DESC_SIZE);
     if (ret < 0) {
-        return ret;
+        goto out;
     }
 
     desc[DESC_SIZE - 1] = '\0';
     tmp_str = strstr(desc, "parentCID");
     if (tmp_str == NULL) {
-        return -EINVAL;
+        ret = -EINVAL;
+        goto out;
     }
 
-    pstrcpy(tmp_desc, sizeof(tmp_desc), tmp_str);
+    pstrcpy(tmp_desc, DESC_SIZE, tmp_str);
     p_name = strstr(desc, "CID");
     if (p_name != NULL) {
         p_name += sizeof("CID");
-        snprintf(p_name, sizeof(desc) - (p_name - desc), "%" PRIx32 "\n", cid);
-        pstrcat(desc, sizeof(desc), tmp_desc);
+        snprintf(p_name, DESC_SIZE - (p_name - desc), "%" PRIx32 "\n", cid);
+        pstrcat(desc, DESC_SIZE, tmp_desc);
     }
 
     ret = bdrv_pwrite_sync(bs->file->bs, s->desc_offset, desc, DESC_SIZE);
-    if (ret < 0) {
-        return ret;
-    }
 
-    return 0;
+out:
+    g_free(desc);
+    g_free(tmp_desc);
+    return ret;
 }
 
 static int vmdk_is_cid_valid(BlockDriverState *bs)
-- 
2.4.3

[Qemu-devel] [PATCH v2 2/3] vmdk: Switch to heap arrays for vmdk_read_cid

[Fam Zheng]

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/vmdk.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index 1ec2452..c68f456 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -242,15 +242,17 @@ static void vmdk_free_last_extent(BlockDriverState *bs)
 
 static uint32_t vmdk_read_cid(BlockDriverState *bs, int parent)
 {
-    char desc[DESC_SIZE];
+    char *desc;
     uint32_t cid = 0xffffffff;
     const char *p_name, *cid_str;
     size_t cid_str_size;
     BDRVVmdkState *s = bs->opaque;
     int ret;
 
+    desc = g_malloc0(DESC_SIZE);
     ret = bdrv_pread(bs->file->bs, s->desc_offset, desc, DESC_SIZE);
     if (ret < 0) {
+        g_free(desc);
         return 0;
     }
 
@@ -269,6 +271,7 @@ static uint32_t vmdk_read_cid(BlockDriverState *bs, int parent)
         sscanf(p_name, "%" SCNx32, &cid);
     }
 
+    g_free(desc);
     return cid;
 }
 
-- 
2.4.3

[Qemu-devel] [PATCH v2 3/3] vmdk: Switch to heap arrays for vmdk_parent_open

[Fam Zheng]

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/vmdk.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index c68f456..03be7f0 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -343,15 +343,16 @@ static int vmdk_reopen_prepare(BDRVReopenState *state,
 static int vmdk_parent_open(BlockDriverState *bs)
 {
     char *p_name;
-    char desc[DESC_SIZE + 1];
+    char *desc;
     BDRVVmdkState *s = bs->opaque;
     int ret;
 
-    desc[DESC_SIZE] = '\0';
+    desc = g_malloc0(DESC_SIZE + 1);
     ret = bdrv_pread(bs->file->bs, s->desc_offset, desc, DESC_SIZE);
     if (ret < 0) {
-        return ret;
+        goto out;
     }
+    ret = 0;
 
     p_name = strstr(desc, "parentFileNameHint");
     if (p_name != NULL) {
@@ -360,16 +361,20 @@ static int vmdk_parent_open(BlockDriverState *bs)
         p_name += sizeof("parentFileNameHint") + 1;
         end_name = strchr(p_name, '\"');
         if (end_name == NULL) {
-            return -EINVAL;
+            ret = -EINVAL;
+            goto out;
         }
         if ((end_name - p_name) > sizeof(bs->backing_file) - 1) {
-            return -EINVAL;
+            ret = -EINVAL;
+            goto out;
         }
 
         pstrcpy(bs->backing_file, end_name - p_name + 1, p_name);
     }
 
-    return 0;
+out:
+    g_free(desc);
+    return ret;
 }
 
 /* Create and append extent to the extent array. Return the added VmdkExtent
-- 
2.4.3

Re: [Qemu-devel] [PATCH v2 3/3] vmdk: Switch to heap arrays for vmdk_parent_open

[Fam Zheng]

On Tue, 03/08 16:24, Fam Zheng wrote:
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block/vmdk.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/block/vmdk.c b/block/vmdk.c
> index c68f456..03be7f0 100644
> --- a/block/vmdk.c
> +++ b/block/vmdk.c
> @@ -343,15 +343,16 @@ static int vmdk_reopen_prepare(BDRVReopenState *state,
>  static int vmdk_parent_open(BlockDriverState *bs)
>  {
>      char *p_name;
> -    char desc[DESC_SIZE + 1];
> +    char *desc;
>      BDRVVmdkState *s = bs->opaque;
>      int ret;
>  
> -    desc[DESC_SIZE] = '\0';
> +    desc = g_malloc0(DESC_SIZE + 1);
>      ret = bdrv_pread(bs->file->bs, s->desc_offset, desc, DESC_SIZE);
>      if (ret < 0) {
> -        return ret;
> +        goto out;
>      }
> +    ret = 0;

Kevin, were you referring to this "ret = 0" in the cover letter? If so, it is
not useless, because ret was set to DESC_SIZE by bdrv_pread. :)

Fam

Re: [Qemu-devel] [PATCH v2 3/3] vmdk: Switch to heap arrays for vmdk_parent_open

[Kevin Wolf]

Am 09.03.2016 um 01:43 hat Fam Zheng geschrieben:
> On Tue, 03/08 16:24, Fam Zheng wrote:
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > ---
> >  block/vmdk.c | 17 +++++++++++------
> >  1 file changed, 11 insertions(+), 6 deletions(-)
> > 
> > diff --git a/block/vmdk.c b/block/vmdk.c
> > index c68f456..03be7f0 100644
> > --- a/block/vmdk.c
> > +++ b/block/vmdk.c
> > @@ -343,15 +343,16 @@ static int vmdk_reopen_prepare(BDRVReopenState *state,
> >  static int vmdk_parent_open(BlockDriverState *bs)
> >  {
> >      char *p_name;
> > -    char desc[DESC_SIZE + 1];
> > +    char *desc;
> >      BDRVVmdkState *s = bs->opaque;
> >      int ret;
> >  
> > -    desc[DESC_SIZE] = '\0';
> > +    desc = g_malloc0(DESC_SIZE + 1);
> >      ret = bdrv_pread(bs->file->bs, s->desc_offset, desc, DESC_SIZE);
> >      if (ret < 0) {
> > -        return ret;
> > +        goto out;
> >      }
> > +    ret = 0;
> 
> Kevin, were you referring to this "ret = 0" in the cover letter? If so, it is
> not useless, because ret was set to DESC_SIZE by bdrv_pread. :)

Nope, I meant the initialisation in patch 1.

Kevin

Re: [Qemu-devel] [PATCH v2 3/3] vmdk: Switch to heap arrays for vmdk_parent_open

[Fam Zheng]

On Wed, 03/09 10:50, Kevin Wolf wrote:
> Am 09.03.2016 um 01:43 hat Fam Zheng geschrieben:
> > On Tue, 03/08 16:24, Fam Zheng wrote:
> > > Signed-off-by: Fam Zheng <famz@redhat.com>
> > > ---
> > >  block/vmdk.c | 17 +++++++++++------
> > >  1 file changed, 11 insertions(+), 6 deletions(-)
> > > 
> > > diff --git a/block/vmdk.c b/block/vmdk.c
> > > index c68f456..03be7f0 100644
> > > --- a/block/vmdk.c
> > > +++ b/block/vmdk.c
> > > @@ -343,15 +343,16 @@ static int vmdk_reopen_prepare(BDRVReopenState *state,
> > >  static int vmdk_parent_open(BlockDriverState *bs)
> > >  {
> > >      char *p_name;
> > > -    char desc[DESC_SIZE + 1];
> > > +    char *desc;
> > >      BDRVVmdkState *s = bs->opaque;
> > >      int ret;
> > >  
> > > -    desc[DESC_SIZE] = '\0';
> > > +    desc = g_malloc0(DESC_SIZE + 1);
> > >      ret = bdrv_pread(bs->file->bs, s->desc_offset, desc, DESC_SIZE);
> > >      if (ret < 0) {
> > > -        return ret;
> > > +        goto out;
> > >      }
> > > +    ret = 0;
> > 
> > Kevin, were you referring to this "ret = 0" in the cover letter? If so, it is
> > not useless, because ret was set to DESC_SIZE by bdrv_pread. :)
> 
> Nope, I meant the initialisation in patch 1.

You're right.

Fam

Re: [Qemu-devel] [PATCH v2 0/3] vmdk: Move descriptor buffers to heap

[Paolo Bonzini]

On 08/03/2016 09:24, Fam Zheng wrote:
> All three functions are not in hot path (all run once for the BDS lifecycle),
> so it's okay to convert to g_malloc0.
> 
> Fam
> 
> 
> Fam Zheng (3):
>   vmdk: Switch to heap arrays for vmdk_write_cid
>   vmdk: Switch to heap arrays for vmdk_read_cid
>   vmdk: Switch to heap arrays for vmdk_parent_open
> 
>  block/vmdk.c | 47 +++++++++++++++++++++++++++++------------------
>  1 file changed, 29 insertions(+), 18 deletions(-)
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Re: [Qemu-devel] [PATCH v2 0/3] vmdk: Move descriptor buffers to heap

[Kevin Wolf]

Am 08.03.2016 um 09:24 hat Fam Zheng geschrieben:
> All three functions are not in hot path (all run once for the BDS lifecycle),
> so it's okay to convert to g_malloc0.

Yeah, it's okay, but still kind of useless to memset the whole buffer
before you overwrite it anyway. There's also a useless ret = 0 somewhere.
I'd prefer not to do that in the next series.

Anyway, thanks, applied to the block branch.

Kevin