We are seeing a lot of sg_alloc_table allocation failures using the new drm prime infrastructure. We isolated the cause to code in __sg_alloc_table that was re-writing the gfp_flags.

There is a comment in the code that suggest that there is an assumption about the allocation coming from a memory pool. This was likely true when sg lists were primarily used for disk I/O.

Change-Id: I459169f56e4a9aa859661b22ec9d4e6925f99e85 Signed-off-by: Mandeep Singh Baines msb@chromium.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: Jens Axboe axboe@kernel.dk Cc: Paul Gortmaker paul.gortmaker@windriver.com Cc: Cong Wang amwang@redhat.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Rob Clark rob.clark@linaro.org Cc: Sumit Semwal sumit.semwal@linaro.org Cc: Inki Dae inki.dae@samsung.com Cc: Dave Airlie airlied@redhat.com Cc: Sonny Rao sonnyrao@chromium.org Cc: Olof Johansson olofj@chromium.org --- lib/scatterlist.c | 8 -------- 1 files changed, 0 insertions(+), 8 deletions(-)

diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 6096e89..d09bdd8 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -279,14 +279,6 @@ int __sg_alloc_table(struct sg_table *table, unsigned int nents, if (!left) sg_mark_end(&sg[sg_size - 1]);

- /* - * only really needed for mempool backed sg allocations (like - * SCSI), a possible improvement here would be to pass the - * table pointer into the allocator and let that clear these - * flags - */ - gfp_mask &= ~__GFP_WAIT; - gfp_mask |= __GFP_HIGH; prv = sg; } while (left);