From a98e6e9f4e0224d85b4d951edc44af16dfe6094a Mon Sep 17 00:00:00 2001 From: Ian Munsie Date: Mon, 8 Dec 2014 19:17:56 +1100 Subject: [PATCH] cxl: Add timeout to process element commands In the event that something goes wrong in the hardware and it is unable to complete a process element comment we would end up polling forever, effectively making the associated process unkillable. This patch adds a timeout to the process element command code path, so that we will give up if the hardware does not respond in a reasonable time. Cc: stable@vger.kernel.org Signed-off-by: Ian Munsie Signed-off-by: Michael Ellerman --- drivers/misc/cxl/native.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c index 1001cf49af94..f2b37b41a0da 100644 --- a/drivers/misc/cxl/native.c +++ b/drivers/misc/cxl/native.c @@ -277,6 +277,7 @@ static int do_process_element_cmd(struct cxl_context *ctx, u64 cmd, u64 pe_state) { u64 state; + unsigned long timeout = jiffies + (HZ * CXL_TIMEOUT); WARN_ON(!ctx->afu->enabled); @@ -286,6 +287,10 @@ static int do_process_element_cmd(struct cxl_context *ctx, smp_mb(); cxl_p1n_write(ctx->afu, CXL_PSL_LLCMD_An, cmd | ctx->pe); while (1) { + if (time_after_eq(jiffies, timeout)) { + dev_warn(&ctx->afu->dev, "WARNING: Process Element Command timed out!\n"); + return -EBUSY; + } state = be64_to_cpup(ctx->afu->sw_command_status); if (state == ~0ULL) { pr_err("cxl: Error adding process element to AFU\n"); -- 2.20.1