| Message ID | 20190523144019.GA28932@embeddedor (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | usbip: usbip_host_common: Use struct_size() in realloc() | expand |
Hi all, Sorry, please, drop this patch. Thanks -- Gustavo On 5/23/19 9:40 AM, Gustavo A. R. Silva wrote: > One of the more common cases of allocation size calculations is finding > the size of a structure that has a zero-sized array at the end, along > with memory for some number of elements for that array. For example: > > struct foo { > int stuff; > struct boo entry[]; > }; > > size = sizeof(struct foo) + count * sizeof(struct boo); > instance = realloc(instance, size); > > Instead of leaving these open-coded and prone to type mistakes, we can > now use the new struct_size() helper: > > size = struct_size(instance, entry, count); > > or > > instance = realloc(instance, struct_size(instance, entry, count)); > > Notice that, in this case, variable size is not necessary, > hence it is removed. > > This code was detected with the help of Coccinelle. > > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> > --- > > Notice that checkpatch reports the following warning: > > WARNING: line over 80 characters > #57: FILE: tools/usb/usbip/libsrc/usbip_host_common.c:90: > + edev = realloc(edev, struct_size(edev, uinf, edev->udev.bNumInterfaces)); > > The line above is 81-character long. So, I think we should be fine > with that, instead of split it into two lines like: > > edev = realloc(edev, > struct_size(edev, uinf, edev->udev.bNumInterfaces)); > > Thanks > -- > Gustavo > > tools/usb/usbip/libsrc/usbip_host_common.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c > index 2813aa821c82..1645d02a52af 100644 > --- a/tools/usb/usbip/libsrc/usbip_host_common.c > +++ b/tools/usb/usbip/libsrc/usbip_host_common.c > @@ -67,7 +67,6 @@ struct usbip_exported_device *usbip_exported_device_new( > { > struct usbip_exported_device *edev = NULL; > struct usbip_exported_device *edev_old; > - size_t size; > int i; > > edev = calloc(1, sizeof(struct usbip_exported_device)); > @@ -87,11 +86,8 @@ struct usbip_exported_device *usbip_exported_device_new( > goto err; > > /* reallocate buffer to include usb interface data */ > - size = sizeof(struct usbip_exported_device) + > - edev->udev.bNumInterfaces * sizeof(struct usbip_usb_interface); > - > edev_old = edev; > - edev = realloc(edev, size); > + edev = realloc(edev, struct_size(edev, uinf, edev->udev.bNumInterfaces)); > if (!edev) { > edev = edev_old; > dbg("realloc failed"); >
diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c index 2813aa821c82..1645d02a52af 100644 --- a/tools/usb/usbip/libsrc/usbip_host_common.c +++ b/tools/usb/usbip/libsrc/usbip_host_common.c @@ -67,7 +67,6 @@ struct usbip_exported_device *usbip_exported_device_new( { struct usbip_exported_device *edev = NULL; struct usbip_exported_device *edev_old; - size_t size; int i; edev = calloc(1, sizeof(struct usbip_exported_device)); @@ -87,11 +86,8 @@ struct usbip_exported_device *usbip_exported_device_new( goto err; /* reallocate buffer to include usb interface data */ - size = sizeof(struct usbip_exported_device) + - edev->udev.bNumInterfaces * sizeof(struct usbip_usb_interface); - edev_old = edev; - edev = realloc(edev, size); + edev = realloc(edev, struct_size(edev, uinf, edev->udev.bNumInterfaces)); if (!edev) { edev = edev_old; dbg("realloc failed");
One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; struct boo entry[]; }; size = sizeof(struct foo) + count * sizeof(struct boo); instance = realloc(instance, size); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: size = struct_size(instance, entry, count); or instance = realloc(instance, struct_size(instance, entry, count)); Notice that, in this case, variable size is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- Notice that checkpatch reports the following warning: WARNING: line over 80 characters #57: FILE: tools/usb/usbip/libsrc/usbip_host_common.c:90: + edev = realloc(edev, struct_size(edev, uinf, edev->udev.bNumInterfaces)); The line above is 81-character long. So, I think we should be fine with that, instead of split it into two lines like: edev = realloc(edev, struct_size(edev, uinf, edev->udev.bNumInterfaces)); Thanks -- Gustavo tools/usb/usbip/libsrc/usbip_host_common.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)