From dce6d406669b56506192e726ffbb238e409a7120 Mon Sep 17 00:00:00 2001 From: Georgi Djakov Date: Wed, 16 Jan 2019 18:11:03 +0200 Subject: [PATCH] interconnect: Revert to previous config if any request fails When consumers report their bandwidth needs with icc_set_bw(), it's possible that the requested amount of bandwidth is not available or just the new configuration fails to apply on some path. In this case revert to the previous configuration and propagate the error back to the consumers to let them know that bandwidth is not available, hardware is busy or whatever error is returned by the interconnect platform driver. Signed-off-by: Georgi Djakov Signed-off-by: Greg Kroah-Hartman --- drivers/interconnect/core.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c index 8091d998549a..6005a1c189f6 100644 --- a/drivers/interconnect/core.c +++ b/drivers/interconnect/core.c @@ -414,14 +414,18 @@ EXPORT_SYMBOL_GPL(of_icc_get); int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw) { struct icc_node *node; + u32 old_avg, old_peak; size_t i; int ret; - if (!path) + if (!path || !path->num_nodes) return 0; mutex_lock(&icc_lock); + old_avg = path->reqs[0].avg_bw; + old_peak = path->reqs[0].peak_bw; + for (i = 0; i < path->num_nodes; i++) { node = path->reqs[i].node; @@ -434,10 +438,19 @@ int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw) } ret = apply_constraints(path); - if (ret) + if (ret) { pr_debug("interconnect: error applying constraints (%d)\n", ret); + for (i = 0; i < path->num_nodes; i++) { + node = path->reqs[i].node; + path->reqs[i].avg_bw = old_avg; + path->reqs[i].peak_bw = old_peak; + aggregate_requests(node); + } + apply_constraints(path); + } + mutex_unlock(&icc_lock); return ret;