Re: [Virtio-fs] [PATCH v2 1/7] virtiofsd: Changed allocations of fuse_req to GLib functions

From: Mahmoud Mandour <ma.mandourr@gmail.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: "open list:virtiofs" <virtio-fs@redhat.com>, qemu-devel@nongnu.org
Subject: Re: [Virtio-fs] [PATCH v2 1/7] virtiofsd: Changed allocations of fuse_req to GLib functions
Date: Wed, 21 Apr 2021 02:39:00 +0200	[thread overview]
Message-ID: <CAD-LL6jeKzfY5ehBU_D6Bnpm53jNneecWLvYs_seGTOmZ=Am6Q@mail.gmail.com> (raw)
In-Reply-To: <20210420190334.GE1529659@redhat.com>

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On Tue, Apr 20, 2021 at 9:03 PM Vivek Goyal <vgoyal@redhat.com> wrote:

> On Tue, Apr 20, 2021 at 05:46:36PM +0200, Mahmoud Mandour wrote:
> > Replaced the allocation and deallocation of fuse_req structs
> > using calloc()/free() call pairs to a GLib's g_try_new0()
> > and g_free().
>
> Hi,
>
> What's the context of these patches. I see all of them are switching
> to glib functions. Why to do that? What's the advantage.
>
> Vivek
>
> >
> > Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
> > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  tools/virtiofsd/fuse_lowlevel.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/virtiofsd/fuse_lowlevel.c
> b/tools/virtiofsd/fuse_lowlevel.c
> > index 58e32fc963..812cef6ef6 100644
> > --- a/tools/virtiofsd/fuse_lowlevel.c
> > +++ b/tools/virtiofsd/fuse_lowlevel.c
> > @@ -106,7 +106,7 @@ static void list_add_req(struct fuse_req *req,
> struct fuse_req *next)
> >  static void destroy_req(fuse_req_t req)
> >  {
> >      pthread_mutex_destroy(&req->lock);
> > -    free(req);
> > +    g_free(req);
> >  }
> >
> >  void fuse_free_req(fuse_req_t req)
> > @@ -130,7 +130,7 @@ static struct fuse_req *fuse_ll_alloc_req(struct
> fuse_session *se)
> >  {
> >      struct fuse_req *req;
> >
> > -    req = (struct fuse_req *)calloc(1, sizeof(struct fuse_req));
> > +    req = g_try_new0(struct fuse_req, 1);
> >      if (req == NULL) {
> >          fuse_log(FUSE_LOG_ERR, "fuse: failed to allocate request\n");
> >      } else {
> > @@ -1684,7 +1684,7 @@ static struct fuse_req *check_interrupt(struct
> fuse_session *se,
> >          if (curr->u.i.unique == req->unique) {
> >              req->interrupted = 1;
> >              list_del_req(curr);
> > -            free(curr);
> > +            g_free(curr);
> >              return NULL;
> >          }
> >      }
> > --
> > 2.25.1
> >
> > _______________________________________________
> > Virtio-fs mailing list
> > Virtio-fs@redhat.com
> > https://listman.redhat.com/mailman/listinfo/virtio-fs
>
>
Hello Vivek,

Taken from the Qemu Coding Style document in the documentation:
"Use of the malloc/free/realloc/calloc/valloc/memalign/posix_memalign APIs
is not allowed in the QEMU codebase. Instead of these routines, use the
GLib memory allocation routines
g_malloc/g_malloc0/g_new/g_new0/g_realloc/g_free or QEMU’s
qemu_memalign/qemu_blockalign/qemu_vfree APIs."
It's also in the bite-sized contributions page as a task.

Thanks,
Mahmoud

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