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cxl: Add timeout to process element commands

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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 <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Ian Munsie 2014-12-08 19:17:56 +11:00 committed by Michael Ellerman
parent ee41d11d53
commit a98e6e9f4e
1 changed files with 5 additions and 0 deletions
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5
drivers/misc/cxl/native.c
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@ -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");