| Message ID | 1542974495-12387-1-git-send-email-hofrat@osadl.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/omap: dss: do not allow devm_kasprintf() to fail | expand |
Hello Nicholas, On Friday, 23 November 2018 14:01:35 EET Nicholas Mc Guire wrote: > omapdss_display_init() is called by multiple drivers and does not expect > a return value so without changing all call-sites the low-probability > failure of devm_kasprintf() can not be reported up the call stack. As > the amount allocated here is very small (<= 16 bytes) and it is an > initialization function that most likely will be called during system > initialization it should be OK to use __GFP_NOFAIL here to prevent > devm_kasprintf() from returning NULL. > > Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> > Fixes: 36c61ae2b755 ("drm/omap: dss: Remove display ordering from > dss/display.c") > --- > > Problem located with experimental coccinelle script > > While the use of __GFP_NOFAIL is to be limited (small infrequent > allocations) this case does seems suitable as it is rare and small > (initialization) .As all the current drivers using > omapdss_display_init() currently seem not to initialize dssdev->name > prior to calling omapdss_display_init() and the unlikely failure > case can not be reasonably responded (returns void) not allowing > a allocation failure here should be acceptable. Given that my plan is to eventually drop omapdss_display_init(), this looks fine to me. Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > Patch was compile tested with: omap2plus_defconfig (implies OMAP_DSS_BASE=m) > > Patch is against 4.20-rc3 (localversion-next is next-20181123) > > drivers/gpu/drm/omapdrm/dss/display.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/omapdrm/dss/display.c > b/drivers/gpu/drm/omapdrm/dss/display.c index 34b2a4e..7dbe874 100644 > --- a/drivers/gpu/drm/omapdrm/dss/display.c > +++ b/drivers/gpu/drm/omapdrm/dss/display.c > @@ -45,7 +45,8 @@ void omapdss_display_init(struct omap_dss_device *dssdev) > of_property_read_string(dssdev->dev->of_node, "label", &dssdev->name); > > if (dssdev->name == NULL) > - dssdev->name = devm_kasprintf(dssdev->dev, GFP_KERNEL, > + dssdev->name = devm_kasprintf(dssdev->dev, > + GFP_KERNEL | __GFP_NOFAIL, > "display%u", id); > } > EXPORT_SYMBOL_GPL(omapdss_display_init);
diff --git a/drivers/gpu/drm/omapdrm/dss/display.c b/drivers/gpu/drm/omapdrm/dss/display.c index 34b2a4e..7dbe874 100644 --- a/drivers/gpu/drm/omapdrm/dss/display.c +++ b/drivers/gpu/drm/omapdrm/dss/display.c @@ -45,7 +45,8 @@ void omapdss_display_init(struct omap_dss_device *dssdev) of_property_read_string(dssdev->dev->of_node, "label", &dssdev->name); if (dssdev->name == NULL) - dssdev->name = devm_kasprintf(dssdev->dev, GFP_KERNEL, + dssdev->name = devm_kasprintf(dssdev->dev, + GFP_KERNEL | __GFP_NOFAIL, "display%u", id); } EXPORT_SYMBOL_GPL(omapdss_display_init);
omapdss_display_init() is called by multiple drivers and does not expect a return value so without changing all call-sites the low-probability failure of devm_kasprintf() can not be reported up the call stack. As the amount allocated here is very small (<= 16 bytes) and it is an initialization function that most likely will be called during system initialization it should be OK to use __GFP_NOFAIL here to prevent devm_kasprintf() from returning NULL. Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Fixes: 36c61ae2b755 ("drm/omap: dss: Remove display ordering from dss/display.c") --- Problem located with experimental coccinelle script While the use of __GFP_NOFAIL is to be limited (small infrequent allocations) this case does seems suitable as it is rare and small (initialization) .As all the current drivers using omapdss_display_init() currently seem not to initialize dssdev->name prior to calling omapdss_display_init() and the unlikely failure case can not be reasonably responded (returns void) not allowing a allocation failure here should be acceptable. Patch was compile tested with: omap2plus_defconfig (implies OMAP_DSS_BASE=m) Patch is against 4.20-rc3 (localversion-next is next-20181123) drivers/gpu/drm/omapdrm/dss/display.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)