Re: [patch V3 01/10] rslib: Add GFP aware init function

From: Stephen Rothwell
Date: Tue Apr 24 2018 - 21:17:50 EST


Hi Thomas,

On Sun, 22 Apr 2018 18:23:46 +0200 Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> The rslib usage in dm/verity_fec is broken because init_rs() can nest in
> GFP_NOIO mempool allocations as init_rs() is invoked from the mempool alloc
> callback.
>
> Provide a variant which takes gfp_t flags as argument.
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
> Cc: Alasdair Kergon <agk@xxxxxxxxxx>
> Cc: Neil Brown <neilb@xxxxxxxx>
> ---
> include/linux/rslib.h | 26 +++++++++++++++++++++++---
> lib/reed_solomon/reed_solomon.c | 36 ++++++++++++++++++++----------------
> 2 files changed, 43 insertions(+), 19 deletions(-)
>
> --- a/include/linux/rslib.h
> +++ b/include/linux/rslib.h
> @@ -77,10 +77,30 @@ int decode_rs16(struct rs_control *rs, u
> #endif
>
> /* Create or get a matching rs control structure */
> -struct rs_control *init_rs(int symsize, int gfpoly, int fcr, int prim,
> - int nroots);
> +struct rs_control *init_rs_gfp(int symsize, int gfpoly, int fcr, int prim,
> + int nroots, gfp_t gfp);
> +
> +/**
> + * init_rs - Create a RS control struct and initialize it
> + * @symsize: the symbol size (number of bits)
> + * @gfpoly: the extended Galois field generator polynomial coefficients,
> + * with the 0th coefficient in the low order bit. The polynomial
> + * must be primitive;
> + * @fcr: the first consecutive root of the rs code generator polynomial
> + * in index form
> + * @prim: primitive element to generate polynomial roots
> + * @nroots: RS code generator polynomial degree (number of roots)
> + *
> + * Allocations use GFP_KERNEL.
> + */
> +static inline struct rs_control *init_rs(int symsize, int gfpoly, int fcr,
> + int prim, int nroots)
> +{
> + return init_rs_gfp(symsize, gfpoly, fcr, prim, nroots, GFP_KERNEL);
> +}
> +

The version of this patch that Kees has committed to his kspp tree in linux-next has

#include <linux/slab.h>

why not just

#include <linux/types.h> /* for gpf_t */
#include <linux/gpf.h> /* for GFP_KERNEL */

?
--
Cheers,
Stephen Rothwell

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