From: Jack Steiner Fix a bug in the assignment of GRU contexts used for kernel functions. If a sleep occurs on the wait for a semaphore, the thread could switch cpus and allocate resources on the wrong blade. Signed-off-by: Jack Steiner --- drivers/misc/sgi-gru/grukservices.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) Index: linux/drivers/misc/sgi-gru/grukservices.c =================================================================== --- linux.orig/drivers/misc/sgi-gru/grukservices.c 2009-11-20 09:32:35.000000000 -0600 +++ linux/drivers/misc/sgi-gru/grukservices.c 2009-11-20 09:32:37.000000000 -0600 @@ -221,13 +221,21 @@ static int gru_free_kernel_contexts(void static struct gru_blade_state *gru_lock_kernel_context(int blade_id) { struct gru_blade_state *bs; + int bid; STAT(lock_kernel_context); - bs = gru_base[blade_id]; +again: + bid = blade_id < 0 ? uv_numa_blade_id() : blade_id; + bs = gru_base[bid]; + /* Handle the case where migration occured while waiting for the sema */ down_read(&bs->bs_kgts_sema); + if (blade_id < 0 && bid != uv_numa_blade_id()) { + up_read(&bs->bs_kgts_sema); + goto again; + } if (!bs->bs_kgts || !bs->bs_kgts->ts_gru) - gru_load_kernel_context(bs, blade_id); + gru_load_kernel_context(bs, bid); return bs; } @@ -256,7 +264,7 @@ static int gru_get_cpu_resources(int dsr BUG_ON(dsr_bytes > GRU_NUM_KERNEL_DSR_BYTES); preempt_disable(); - bs = gru_lock_kernel_context(uv_numa_blade_id()); + bs = gru_lock_kernel_context(-1); lcpu = uv_blade_processor_id(); *cb = bs->kernel_cb + lcpu * GRU_HANDLE_STRIDE; *dsr = bs->kernel_dsr + lcpu * GRU_NUM_KERNEL_DSR_BYTES; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/