From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ian Munsie , Michael Ellerman Subject: [PATCH 3.18 053/183] cxl: Add timeout to process element commands Date: Sun, 25 Jan 2015 10:06:15 -0800 Message-Id: <20150125180812.472760052@linuxfoundation.org> In-Reply-To: <20150125180810.160428929@linuxfoundation.org> References: <20150125180810.160428929@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Munsie commit a98e6e9f4e0224d85b4d951edc44af16dfe6094a upstream. 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. Signed-off-by: Ian Munsie Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- drivers/misc/cxl/native.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/misc/cxl/native.c +++ b/drivers/misc/cxl/native.c @@ -277,6 +277,7 @@ static int do_process_element_cmd(struct 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 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");