Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932765AbbFEVWo (ORCPT ); Fri, 5 Jun 2015 17:22:44 -0400 Received: from mga03.intel.com ([134.134.136.65]:35732 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932737AbbFEVWd (ORCPT ); Fri, 5 Jun 2015 17:22:33 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,560,1427785200"; d="scan'208";a="706138801" Subject: [PATCH v4 8/9] scatterlist: convert to __pfn_t From: Dan Williams To: linux-kernel@vger.kernel.org Cc: axboe@kernel.dk, boaz@plexistor.com, david@fromorbit.com, linux-arch@vger.kernel.org, arnd@arndb.de, ross.zwisler@linux.intel.com, linux-nvdimm@ml01.01.org, benh@kernel.crashing.org, linux-fsdevel@vger.kernel.org, heiko.carstens@de.ibm.com, hch@lst.de, tj@kernel.org, paulus@samba.org, hpa@zytor.com, schwidefsky@de.ibm.com, willy@linux.intel.com, akpm@linux-foundation.org, torvalds@linux-foundation.org, mingo@kernel.org Date: Fri, 05 Jun 2015 17:19:49 -0400 Message-ID: <20150605211949.20751.59262.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <20150605205052.20751.77149.stgit@dwillia2-desk3.amr.corp.intel.com> References: <20150605205052.20751.77149.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-8-g92dd MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8541 Lines: 273 __pfn_t replaces the struct page reference in struct scatterlist. Given __pfn_t implements the same bits at the same bit positions for denoting sg_is_chain() + sg_is_last() this conversion is binary identical to the previous state. Signed-off-by: Dan Williams --- include/asm-generic/pfn.h | 9 ++++ include/linux/scatterlist.h | 103 ++++++++++++++++++++++++++++++------------- samples/kfifo/dma-example.c | 8 ++- 3 files changed, 86 insertions(+), 34 deletions(-) diff --git a/include/asm-generic/pfn.h b/include/asm-generic/pfn.h index e9fed20d606a..f826c50ed025 100644 --- a/include/asm-generic/pfn.h +++ b/include/asm-generic/pfn.h @@ -108,4 +108,13 @@ static inline __pfn_t page_to_pfn_t(struct page *page) return pfn; } + +static inline __pfn_t nth_pfn(__pfn_t pfn, unsigned int n) +{ + __pfn_t ret; + + ret.data = (__pfn_t_to_pfn(pfn) + n) << PFN_SHIFT + | (pfn.data & PFN_MASK); + return ret; +} #endif /* __ASM_PFN_H */ diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index eca1ec93775c..49054374646e 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -11,7 +11,7 @@ struct scatterlist { #ifdef CONFIG_DEBUG_SG unsigned long sg_magic; #endif - unsigned long page_link; + __pfn_t pfn; unsigned int offset; unsigned int length; dma_addr_t dma_address; @@ -44,14 +44,14 @@ struct sg_table { /* * Notes on SG table design. * - * We use the unsigned long page_link field in the scatterlist struct to place + * We use the __pfn_t pfn field in the scatterlist struct to place * the page pointer AND encode information about the sg table as well. The two * lower bits are reserved for this information. * - * If bit 0 is set, then the page_link contains a pointer to the next sg + * If PFN_SG_CHAIN is set, then the pfn contains a pointer to the next sg * table list. Otherwise the next entry is at sg + 1. * - * If bit 1 is set, then this sg entry is the last element in a list. + * If PFN_SG_LAST is set, then this sg entry is the last element in a list. * * See sg_next(). * @@ -64,10 +64,30 @@ struct sg_table { * a valid sg entry, or whether it points to the start of a new scatterlist. * Those low bits are there for everyone! (thanks mason :-) */ -#define sg_is_chain(sg) ((sg)->page_link & 0x01) -#define sg_is_last(sg) ((sg)->page_link & 0x02) -#define sg_chain_ptr(sg) \ - ((struct scatterlist *) ((sg)->page_link & ~0x03)) +static inline bool sg_is_chain(struct scatterlist *sg) +{ + return (sg->pfn.data & PFN_MASK) == PFN_SG_CHAIN; +} + +static inline bool sg_is_last(struct scatterlist *sg) +{ + return (sg->pfn.data & PFN_MASK) == PFN_SG_LAST; +} + +static inline struct scatterlist *sg_chain_ptr(struct scatterlist *sg) +{ + return (struct scatterlist *) (sg->pfn.data & ~PFN_MASK); +} + +static inline void sg_assign_pfn(struct scatterlist *sg, __pfn_t pfn) +{ +#ifdef CONFIG_DEBUG_SG + BUG_ON(sg->sg_magic != SG_MAGIC); + BUG_ON(sg_is_chain(sg)); +#endif + pfn.data &= ~PFN_SG_LAST; + sg->pfn.data = (sg->pfn.data & PFN_SG_LAST) | pfn.data; +} /** * sg_assign_page - Assign a given page to an SG entry @@ -81,18 +101,23 @@ struct sg_table { **/ static inline void sg_assign_page(struct scatterlist *sg, struct page *page) { - unsigned long page_link = sg->page_link & 0x3; + __pfn_t pfn = page_to_pfn_t(page); /* * In order for the low bit stealing approach to work, pages - * must be aligned at a 32-bit boundary as a minimum. + * must be aligned at a sizeof(unsigned long) boundary. */ - BUG_ON((unsigned long) page & 0x03); -#ifdef CONFIG_DEBUG_SG - BUG_ON(sg->sg_magic != SG_MAGIC); - BUG_ON(sg_is_chain(sg)); -#endif - sg->page_link = page_link | (unsigned long) page; + BUG_ON(pfn.data & PFN_MASK); + + sg_assign_pfn(sg, pfn); +} + +static inline void sg_set_pfn(struct scatterlist *sg, __pfn_t pfn, + unsigned int len, unsigned int offset) +{ + sg_assign_pfn(sg, pfn); + sg->offset = offset; + sg->length = len; } /** @@ -112,18 +137,30 @@ static inline void sg_assign_page(struct scatterlist *sg, struct page *page) static inline void sg_set_page(struct scatterlist *sg, struct page *page, unsigned int len, unsigned int offset) { - sg_assign_page(sg, page); - sg->offset = offset; - sg->length = len; + sg_set_pfn(sg, page_to_pfn_t(page), len, offset); } static inline struct page *sg_page(struct scatterlist *sg) { + __pfn_t pfn = sg->pfn; + struct page *page; + #ifdef CONFIG_DEBUG_SG BUG_ON(sg->sg_magic != SG_MAGIC); BUG_ON(sg_is_chain(sg)); #endif - return (struct page *)((sg)->page_link & ~0x3); + + pfn.data &= ~PFN_SG_LAST; + page = __pfn_t_to_page(pfn); + + /* don't use sg_page() on non linear-mapped memory */ + BUG_ON(!page); + return page; +} + +static inline unsigned long sg_pfn(struct scatterlist *sg) +{ + return __pfn_t_to_pfn(sg->pfn); } /** @@ -175,7 +212,8 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, * Set lowest bit to indicate a link pointer, and make sure to clear * the termination bit if it happens to be set. */ - prv[prv_nents - 1].page_link = ((unsigned long) sgl | 0x01) & ~0x02; + prv[prv_nents - 1].pfn.data = ((unsigned long) sgl | PFN_SG_CHAIN) + & ~PFN_SG_LAST; } /** @@ -195,8 +233,8 @@ static inline void sg_mark_end(struct scatterlist *sg) /* * Set termination bit, clear potential chain bit */ - sg->page_link |= 0x02; - sg->page_link &= ~0x01; + sg->pfn.data |= PFN_SG_LAST; + sg->pfn.data &= ~PFN_SG_CHAIN; } /** @@ -212,7 +250,7 @@ static inline void sg_unmark_end(struct scatterlist *sg) #ifdef CONFIG_DEBUG_SG BUG_ON(sg->sg_magic != SG_MAGIC); #endif - sg->page_link &= ~0x02; + sg->pfn.data &= ~PFN_SG_LAST; } /** @@ -220,14 +258,13 @@ static inline void sg_unmark_end(struct scatterlist *sg) * @sg: SG entry * * Description: - * This calls page_to_phys() on the page in this sg entry, and adds the - * sg offset. The caller must know that it is legal to call page_to_phys() - * on the sg page. + * This calls __pfn_t_to_phys() on the pfn in this sg entry, and adds the + * sg offset. * **/ static inline dma_addr_t sg_phys(struct scatterlist *sg) { - return page_to_phys(sg_page(sg)) + sg->offset; + return __pfn_t_to_phys(sg->pfn) + sg->offset; } /** @@ -281,7 +318,7 @@ size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, #define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) /* - * sg page iterator + * sg page / pfn iterator * * Iterates over sg entries page-by-page. On each successful iteration, * you can call sg_page_iter_page(@piter) and sg_page_iter_dma_address(@piter) @@ -304,13 +341,19 @@ bool __sg_page_iter_next(struct sg_page_iter *piter); void __sg_page_iter_start(struct sg_page_iter *piter, struct scatterlist *sglist, unsigned int nents, unsigned long pgoffset); + +static inline __pfn_t sg_page_iter_pfn(struct sg_page_iter *piter) +{ + return nth_pfn(piter->sg->pfn, piter->sg_pgoffset); +} + /** * sg_page_iter_page - get the current page held by the page iterator * @piter: page iterator holding the page */ static inline struct page *sg_page_iter_page(struct sg_page_iter *piter) { - return nth_page(sg_page(piter->sg), piter->sg_pgoffset); + return __pfn_t_to_page(sg_page_iter_pfn(piter)); } /** diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c index aa243db93f01..3eeff9a56e0e 100644 --- a/samples/kfifo/dma-example.c +++ b/samples/kfifo/dma-example.c @@ -75,8 +75,8 @@ static int __init example_init(void) for (i = 0; i < nents; i++) { printk(KERN_INFO "sg[%d] -> " - "page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n", - i, sg[i].page_link, sg[i].offset, sg[i].length); + "pfn_data 0x%.8lx offset 0x%.8x length 0x%.8x\n", + i, sg[i].pfn.data, sg[i].offset, sg[i].length); if (sg_is_last(&sg[i])) break; @@ -104,8 +104,8 @@ static int __init example_init(void) for (i = 0; i < nents; i++) { printk(KERN_INFO "sg[%d] -> " - "page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n", - i, sg[i].page_link, sg[i].offset, sg[i].length); + "pfn_data 0x%.8lx offset 0x%.8x length 0x%.8x\n", + i, sg[i].pfn.data, sg[i].offset, sg[i].length); if (sg_is_last(&sg[i])) break; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/