Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756216AbXJ0RrQ (ORCPT ); Sat, 27 Oct 2007 13:47:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755944AbXJ0Rqx (ORCPT ); Sat, 27 Oct 2007 13:46:53 -0400 Received: from ug-out-1314.google.com ([66.249.92.171]:59942 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755765AbXJ0Rqs (ORCPT ); Sat, 27 Oct 2007 13:46:48 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:date:from:to:cc:subject:message-id:references:mime-version:content-type:content-disposition:in-reply-to:user-agent; b=M664JPzxYFoD8LM+Nbr9PWOeM4joYump1BEdmf/tphnOnCQphmw/iI+xJwIT7JzoeooR8cvAnlFYNq+mZ8A1005itseZq6zv3zx5iSoyHrRRebIvxIPcMiUu5Q7uDDhh6EpRPQ9uwavkR2PpopRURY40s6N9qhhuQKUQE63PPb8= Date: Sat, 27 Oct 2007 21:46:32 +0400 From: Cyrill Gorcunov To: "Robert P. J. Day" Cc: LKML , Andrew Morton Subject: Re: [PATCH] SG: set names for numeric constants Message-ID: <20071027174632.GB7257@cvg> References: <20071027170228.GA7257@cvg> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5607 Lines: 166 [Robert P. J. Day - Sat, Oct 27, 2007 at 01:14:22PM -0400] | On Sat, 27 Oct 2007, Cyrill Gorcunov wrote: | | > | > This patch defines names for numeric constants that | > used in scatter list for more convenient code reading. | > | > Signed-off-by: Cyrill Gorcunov | ... | > @@ -73,7 +76,7 @@ static inline void sg_set_page(struct scatterlist *sg, struct page *page, | > sg->length = len; | > } | > | > -#define sg_page(sg) ((struct page *) ((sg)->page_link & ~0x3)) | > +#define sg_page(sg) ((struct page *) ((sg)->page_link & ~SG_MASK)) | > | > -#define sg_is_chain(sg) ((sg)->page_link & 0x01) | > -#define sg_is_last(sg) ((sg)->page_link & 0x02) | > +#define sg_is_chain(sg) ((sg)->page_link & SG_CHAIN) | > +#define sg_is_last(sg) ((sg)->page_link & SG_LAST) | > #define sg_chain_ptr(sg) \ | > - ((struct scatterlist *) ((sg)->page_link & ~0x03)) | > + ((struct scatterlist *) ((sg)->page_link & ~SG_MASK)) | | while you're at it, could you move all those macros to the top of the | file, rather than leaving them scattered across the first 100 lines or | so? it would just make them easier to find when you're perusing the | code. | | rday | -- | ======================================================================== | Robert P. J. Day | Linux Consulting, Training and Annoying Kernel Pedantry | Waterloo, Ontario, CANADA | | http://crashcourse.ca | ======================================================================== | This patch defines names for numeric constants that used in scatter list for more convenient code reading. Also groups all macroses on the top of the file. Signed-off-by: Cyrill Gorcunov --- Robert, what about this one? include/linux/scatterlist.h | 47 ++++++++++++++++++++++--------------------- 1 files changed, 24 insertions(+), 23 deletions(-) diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 4571231..3edd6ca 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -25,6 +25,25 @@ */ #define SG_MAGIC 0x87654321 +#define SG_CHAIN 0x1 +#define SG_LAST 0x2 +#define SG_MASK 0x3 + +/* + * We overload the LSB of the page pointer to indicate whether it's + * 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 & SG_CHAIN) +#define sg_is_last(sg) ((sg)->page_link & SG_LAST) +#define sg_chain_ptr(sg) ((struct scatterlist *)((sg)->page_link & ~SG_MASK)) +#define sg_page(sg) ((struct page *)((sg)->page_link & ~SG_MASK)) + +/* + * Loop over each sg element, following the pointer to a new list if necessary + */ +#define for_each_sg(sglist, sg, nr, __i) \ + for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg)) /** * sg_assign_page - Assign a given page to an SG entry @@ -38,13 +57,13 @@ **/ static inline void sg_assign_page(struct scatterlist *sg, struct page *page) { - unsigned long page_link = sg->page_link & 0x3; + unsigned long page_link = sg->page_link & SG_MASK; /* * In order for the low bit stealing approach to work, pages * must be aligned at a 32-bit boundary as a minimum. */ - BUG_ON((unsigned long) page & 0x03); + BUG_ON((unsigned long) page & SG_MASK); #ifdef CONFIG_DEBUG_SG BUG_ON(sg->sg_magic != SG_MAGIC); #endif @@ -73,8 +92,6 @@ static inline void sg_set_page(struct scatterlist *sg, struct page *page, sg->length = len; } -#define sg_page(sg) ((struct page *) ((sg)->page_link & ~0x3)) - /** * sg_set_buf - Set sg entry to point at given data * @sg: SG entry @@ -88,16 +105,6 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf)); } -/* - * We overload the LSB of the page pointer to indicate whether it's - * 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)) - /** * sg_next - return the next scatterlist entry in a list * @sg: The current sg entry @@ -123,12 +130,6 @@ static inline struct scatterlist *sg_next(struct scatterlist *sg) return sg; } -/* - * Loop over each sg element, following the pointer to a new list if necessary - */ -#define for_each_sg(sglist, sg, nr, __i) \ - for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg)) - /** * sg_last - return the last scatterlist entry in a list * @sgl: First entry in the scatterlist @@ -179,7 +180,7 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, #ifndef ARCH_HAS_SG_CHAIN BUG(); #endif - prv[prv_nents - 1].page_link = (unsigned long) sgl | 0x01; + prv[prv_nents - 1].page_link = (unsigned long) sgl | SG_CHAIN; } /** @@ -193,12 +194,12 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, **/ static inline void sg_mark_end(struct scatterlist *sgl, unsigned int nents) { - sgl[nents - 1].page_link = 0x02; + sgl[nents - 1].page_link = SG_LAST; } static inline void __sg_mark_end(struct scatterlist *sg) { - sg->page_link |= 0x02; + sg->page_link |= SG_LAST; } /** - 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/