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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Sean Paul" <seanpaul@chromium.org>,
        "Nicholas Mc Guire" <hofrat@osadl.org>
Date:   Sun, 11 Nov 2018 19:49:05 +0000
Message-ID: <lsq.1541965745.625280545@decadent.org.uk>
Subject: [PATCH 3.16 260/366] drm: re-enable error handling
In-Reply-To: <lsq.1541965744.387173642@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Nicholas Mc Guire <hofrat@osadl.org>

commit d530b5f1ca0bb66958a2b714bebe40a1248b9c15 upstream.

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")
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1531571532-22733-1-git-send-email-hofrat@osadl.org
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/gpu/drm/drm_context.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/drm_context.c
+++ b/drivers/gpu/drm/drm_context.c
@@ -316,7 +316,7 @@ int drm_addctx(struct drm_device *dev, v
 		ctx->handle = drm_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;