Message ID | 20161021173535.100245-1-andriy.shevchenko@linux.intel.com (mailing list archive) |
---|---|
State | Changes Requested |
Headers | show |
On Fri, Oct 21, 2016 at 08:35:26PM +0300, Andy Shevchenko wrote: > +int sg_nents_for_dma(struct scatterlist *sgl, unsigned int sglen, size_t len) > +{ > + struct scatterlist *sg; > + int i, nents = 0; > + > + for_each_sg(sgl, sg, sglen, i) > + nents += DIV_ROUND_UP(sg_dma_len(sg), len); > + return nents; > +} Should we have this in a global one as it is DMAengine specfic stuff..?
On Mon, Nov 14, 2016 at 5:13 AM, Vinod Koul <vinod.koul@intel.com> wrote: > On Fri, Oct 21, 2016 at 08:35:26PM +0300, Andy Shevchenko wrote: > >> +int sg_nents_for_dma(struct scatterlist *sgl, unsigned int sglen, size_t len) >> +{ >> + struct scatterlist *sg; >> + int i, nents = 0; >> + >> + for_each_sg(sgl, sg, sglen, i) >> + nents += DIV_ROUND_UP(sg_dma_len(sg), len); >> + return nents; >> +} > > Should we have this in a global one as it is DMAengine specfic stuff..? I think we may start as global for DMA engine. Anyway, I have to fix the kbuild bot warnings, meanwhile I move the stuff to local dmaengine.h.
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index cb3c8fe..d199667 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -243,6 +243,7 @@ static inline void *sg_virt(struct scatterlist *sg) int sg_nents(struct scatterlist *sg); int sg_nents_for_len(struct scatterlist *sg, u64 len); +int sg_nents_for_dma(struct scatterlist *sgl, unsigned int sglen, size_t len); struct scatterlist *sg_next(struct scatterlist *); struct scatterlist *sg_last(struct scatterlist *s, unsigned int); void sg_init_table(struct scatterlist *, unsigned int); diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 004fc70..5b75a21 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -90,6 +90,31 @@ int sg_nents_for_len(struct scatterlist *sg, u64 len) EXPORT_SYMBOL(sg_nents_for_len); /** + * sg_nents_for_dma - return count of DMA-capable entries in scatterlist + * @sgl: The scatterlist + * @sglen: The current number of entries + * @len: The maximum length of DMA-capable block + * + * Description: + * Determines the number of entries in @sgl which would be permitted in + * DMA-capable transfer if list had been split accordingly, taking into + * account chaining as well. + * + * Returns: + * the number of sgl entries needed + * + **/ +int sg_nents_for_dma(struct scatterlist *sgl, unsigned int sglen, size_t len) +{ + struct scatterlist *sg; + int i, nents = 0; + + for_each_sg(sgl, sg, sglen, i) + nents += DIV_ROUND_UP(sg_dma_len(sg), len); + return nents; +} + +/** * sg_last - return the last scatterlist entry in a list * @sgl: First entry in the scatterlist * @nents: Number of entries in the scatterlist