From ff2aeb1eb64c8a4770a6304f9addbae9f9828646 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 5 Dec 2007 16:43:11 +0900 Subject: libata: convert to chained sg libata used private sg iterator to handle padding sg. Now that sg can be chained, padding can be handled using standard sg ops. Convert to chained sg. * s/qc->__sg/qc->sg/ * s/qc->pad_sgent/qc->extra_sg[]/. Because chaining consumes one sg entry. There need to be two extra sg entries. The renaming is also for future addition of other extra sg entries. * Padding setup is moved into ata_sg_setup_extra() which is organized in a way that future addition of other extra sg entries is easy. * qc->orig_n_elem is unused and removed. * qc->n_elem now contains the number of sg entries that LLDs should map. qc->mapped_n_elem is added to carry the original number of mapped sgs for unmapping. * The last sg of the original sg list is used to chain to extra sg list. The original last sg is pointed to by qc->last_sg and the content is stored in qc->saved_last_sg. It's restored during ata_sg_clean(). * All sg walking code has been updated. Unnecessary assertions and checks for conditions the core layer already guarantees are removed. Signed-off-by: Tejun Heo Cc: Jens Axboe Signed-off-by: Jeff Garzik --- include/linux/libata.h | 42 ++++++++---------------------------------- 1 file changed, 8 insertions(+), 34 deletions(-) (limited to 'include/linux') diff --git a/include/linux/libata.h b/include/linux/libata.h index acd90ad78417..162f8b5509ac 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -458,7 +458,7 @@ struct ata_queued_cmd { unsigned int tag; unsigned int n_elem; unsigned int n_iter; - unsigned int orig_n_elem; + unsigned int mapped_n_elem; int dma_dir; @@ -471,11 +471,12 @@ struct ata_queued_cmd { struct scatterlist *cursg; unsigned int cursg_ofs; + struct scatterlist *last_sg; + struct scatterlist saved_last_sg; struct scatterlist sgent; - struct scatterlist pad_sgent; + struct scatterlist extra_sg[2]; - /* DO NOT iterate over __sg manually, use ata_for_each_sg() */ - struct scatterlist *__sg; + struct scatterlist *sg; unsigned int err_mask; struct ata_taskfile result_tf; @@ -1123,35 +1124,6 @@ extern void ata_port_pbar_desc(struct ata_port *ap, int bar, ssize_t offset, const char *name); #endif -/* - * qc helpers - */ -static inline struct scatterlist * -ata_qc_first_sg(struct ata_queued_cmd *qc) -{ - qc->n_iter = 0; - if (qc->n_elem) - return qc->__sg; - if (qc->pad_len) - return &qc->pad_sgent; - return NULL; -} - -static inline struct scatterlist * -ata_qc_next_sg(struct scatterlist *sg, struct ata_queued_cmd *qc) -{ - if (sg == &qc->pad_sgent) - return NULL; - if (++qc->n_iter < qc->n_elem) - return sg_next(sg); - if (qc->pad_len) - return &qc->pad_sgent; - return NULL; -} - -#define ata_for_each_sg(sg, qc) \ - for (sg = ata_qc_first_sg(qc); sg; sg = ata_qc_next_sg(sg, qc)) - static inline unsigned int ata_tag_valid(unsigned int tag) { return (tag < ATA_MAX_QUEUE) ? 1 : 0; @@ -1386,15 +1358,17 @@ static inline void ata_tf_init(struct ata_device *dev, struct ata_taskfile *tf) static inline void ata_qc_reinit(struct ata_queued_cmd *qc) { qc->dma_dir = DMA_NONE; - qc->__sg = NULL; + qc->sg = NULL; qc->flags = 0; qc->cursg = NULL; qc->cursg_ofs = 0; qc->nbytes = qc->curbytes = 0; qc->n_elem = 0; + qc->mapped_n_elem = 0; qc->n_iter = 0; qc->err_mask = 0; qc->pad_len = 0; + qc->last_sg = NULL; qc->sect_size = ATA_SECT_SIZE; ata_tf_init(qc->dev, &qc->tf); -- cgit v1.2.2