From 3794afbeb177ed0932d166d30bb2af9d9859dff9 Mon Sep 17 00:00:00 2001 From: Konsta Holtta Date: Tue, 13 Nov 2018 15:36:19 +0200 Subject: gpu: nvgpu: add safe channel id lookup Add gk20a_channel_from_id() to retrieve a channel, given a raw channel ID, with a reference taken (or NULL if the channel was dead). This makes it harder to mistakenly use a channel that's dead and thus uncovers bugs sooner. Convert code to use the new lookup when applicable; work remains to convert complex uses where a ref should have been taken but hasn't. The channel ID is also validated against FIFO_INVAL_CHANNEL_ID; NULL is returned for such IDs. This is often useful and does not hurt when unnecessary. However, this does not prevent the case where a channel would be closed and reopened again when someone would hold a stale channel number. In all such conditions the caller should hold a reference already. The only conditions where a channel can be safely looked up by an id and used without taking a ref are when initializing or deinitializing the list of channels. Jira NVGPU-1460 Change-Id: I0a30968d17c1e0784d315a676bbe69c03a73481c Signed-off-by: Konsta Holtta Reviewed-on: https://git-master.nvidia.com/r/1955400 Signed-off-by: Debarshi Dutta (cherry picked from commit 7df3d587502c2de997dfbe8ea8ddc114d0a0481e in dev-kernel) Reviewed-on: https://git-master.nvidia.com/r/2008515 Reviewed-by: mobile promotions Tested-by: mobile promotions --- drivers/gpu/nvgpu/gk20a/gr_gk20a.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'drivers/gpu/nvgpu/gk20a/gr_gk20a.c') diff --git a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c index 8cb66279..928d80cb 100644 --- a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c +++ b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c @@ -5581,15 +5581,16 @@ static struct channel_gk20a *gk20a_gr_get_channel_from_ctx( if (gr->chid_tlb[i].curr_ctx == curr_ctx) { chid = gr->chid_tlb[i].chid; tsgid = gr->chid_tlb[i].tsgid; - ret = gk20a_channel_get(&f->channel[chid]); + ret = gk20a_channel_from_id(g, chid); goto unlock; } } /* slow path */ for (chid = 0; chid < f->num_channels; chid++) { - struct channel_gk20a *ch = &f->channel[chid]; - if (gk20a_channel_get(ch) == NULL) { + struct channel_gk20a *ch = gk20a_channel_from_id(g, chid); + + if (ch == NULL) { continue; } -- cgit v1.2.2