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Commit a98e6e9f authored by Ian Munsie's avatar Ian Munsie Committed by Michael Ellerman
Browse files

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: default avatarIan Munsie <imunsie@au1.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent ee41d11d

drivers/misc/cxl/native.c

+5 −0
Original line number Diff line number Diff line
@@ -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");