Re: [PATCH v4] page_io: zswap: do not crash the kernel on decompression failure

[Matthew Wilcox <willy@infradead.org>]

On Mon, May 12, 2025 at 03:49:29PM -0400, Nhat Pham wrote:
> Not a bad idea, just no usecase yet. From the POV of
> zswap_decompress()'s callers, any decompression failure is handled the
> same way, no matter the cause.
> 
> Where it might be useful is the debug print statement right below
> this. However, zstd and lz4 only return 0 or -EINVAL, I think - not
> super useful.
> 
> https://github.com/torvalds/linux/blob/master/crypto/zstd.c#L163-L165
> https://github.com/torvalds/linux/blob/master/crypto/lz4.c#L61
> 
> Not sure about other compressors.

OK, fair enough.  If there's no better information to return, then
this way is fine.

> > (also i really dislike the chained approach:
> >
> >         decomp_ret = crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait);
> >
> > that's much harder to understand than the two lines i have above)
> 
> I can send a style fix sometimes if people dislike this - no big deal :)
> 
> BTW, hopefully you don't mind the Suggested-by: tag. I know it
> deviated a bit from your original suggestion, but the main spirit of
> that suggestion remains, so I feel like I should credit you and Yosry.

The Suggested-by is appropriate, I think.