Re: [PATCH 3/5] tpm: migrate tpm2_probe() to use struct tpm_buf

From: J Freyensee
Date: Thu Mar 01 2018 - 17:10:33 EST


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I'm new to this area of the kernel, but I'm not getting these lines:

+ rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0, NULL);
+ tpm_buf_destroy(&buf);
if (rc < 0)
Why is this if() check not directly after the tpm_transmit_cmd() call that sets rc? Is it correct you want to destroy buf regardless of the tpm_transmit_cmd() outcome?
return rc;
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- if (be16_to_cpu(cmd.header.out.tag) == TPM2_ST_NO_SESSIONS)
+ out = (struct tpm_output_header *)buf.data;

So buf has been destroyed, buf.data sill has something valid to assign to out?
+ if (be16_to_cpu(out->tag) == TPM2_ST_NO_SESSIONS)
chip->flags |= TPM_CHIP_FLAG_TPM2;
return 0;
Thanks,
Jay