Re: CONFIG_PREEMPT and JFFS2 oops

Joakim Tjernlund
2012-01-28T14:42:57Z

Paul Walmsley <paul@pwsan.com> wrote on 2012/01/28 10:51:26:
>
> On Thu, 26 Jan 2012, Joakim Tjernlund wrote:
>
> > .. and you should delay the second allocation to when it is needed. After swapping ptrs, test if
> > tmp_buf is NULL and kmalloc if so.
>
> Hmm. You are thinking of a GFP_ATOMIC allocation? Seems best to avoid
> those?

No, just stick the kmalloc after the unlock:

spin_unlock(&jffs2_compressor_list_lock);
if (!tmp_buf) {
tmp_buf = kmalloc(...);
<error handling if still NULL>
}
*datalen = orig_slen;
*cdatalen = orig_dlen;
compr_ret = this->compress(data_in, tmp_buf, datalen, cdatalen, NULL);

That way you also skip a second kmalloc if the list only holds one compressor and
you don't need GFP_ATOMIC

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