| Message ID | 1531571532-22733-1-git-send-email-hofrat@osadl.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, Jul 14, 2018 at 02:32:12PM +0200, Nicholas Mc Guire wrote: > drm_legacy_ctxbitmap_next() returns idr_alloc() which can return > -ENOMEM, -EINVAL or -ENOSPC none of which are -1 . but the call sites > of drm_legacy_ctxbitmap_next() seem to be assuming that the error case > would be -1 (original return of drm_ctxbitmap_next() prior to 2.6.23 > was actually -1). Thus reenable error handling by checking for < 0. > > Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Thanks for your patch, I've applied it to drm-misc-fixes. Sean > Fixes: 62968144e673 ("drm: convert drm context code to use Linux idr") > --- > > Problem located with experimental coccinelle script > > The noted Fixes tag is one of the commits that removed the -1 return > value in 2.6.23 in drm_ctxbitmap_next() but thats not the only change > that must have taken place to invalidate the error check. > > Patch was compile tested with: x86_64_defconfig > > Patch is against 4.18-rc4 (localversion-next is next-20180713) > > drivers/gpu/drm/drm_context.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_context.c b/drivers/gpu/drm/drm_context.c > index 3c4000f..f973d28 100644 > --- a/drivers/gpu/drm/drm_context.c > +++ b/drivers/gpu/drm/drm_context.c > @@ -372,7 +372,7 @@ int drm_legacy_addctx(struct drm_device *dev, void *data, > ctx->handle = drm_legacy_ctxbitmap_next(dev); > } > DRM_DEBUG("%d\n", ctx->handle); > - if (ctx->handle == -1) { > + if (ctx->handle < 0) { > DRM_DEBUG("Not enough free contexts.\n"); > /* Should this return -EBUSY instead? */ > return -ENOMEM; > -- > 2.1.4 >
diff --git a/drivers/gpu/drm/drm_context.c b/drivers/gpu/drm/drm_context.c index 3c4000f..f973d28 100644 --- a/drivers/gpu/drm/drm_context.c +++ b/drivers/gpu/drm/drm_context.c @@ -372,7 +372,7 @@ int drm_legacy_addctx(struct drm_device *dev, void *data, ctx->handle = drm_legacy_ctxbitmap_next(dev); } DRM_DEBUG("%d\n", ctx->handle); - if (ctx->handle == -1) { + if (ctx->handle < 0) { DRM_DEBUG("Not enough free contexts.\n"); /* Should this return -EBUSY instead? */ return -ENOMEM;
drm_legacy_ctxbitmap_next() returns idr_alloc() which can return -ENOMEM, -EINVAL or -ENOSPC none of which are -1 . but the call sites of drm_legacy_ctxbitmap_next() seem to be assuming that the error case would be -1 (original return of drm_ctxbitmap_next() prior to 2.6.23 was actually -1). Thus reenable error handling by checking for < 0. Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Fixes: 62968144e673 ("drm: convert drm context code to use Linux idr") --- Problem located with experimental coccinelle script The noted Fixes tag is one of the commits that removed the -1 return value in 2.6.23 in drm_ctxbitmap_next() but thats not the only change that must have taken place to invalidate the error check. Patch was compile tested with: x86_64_defconfig Patch is against 4.18-rc4 (localversion-next is next-20180713) drivers/gpu/drm/drm_context.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)