From ba39bd8306057fb343dfb75d93a76d824b625236 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Fri, 3 May 2019 11:44:44 +0300 Subject: [PATCH] intel_th: msu: Switch over to scatterlist Instead of using a home-grown array of pointers to the DMA pages, switch over to scatterlist data types and accessors, which has all the convenient accessors, can be used to batch-map DMA memory and is convenient for passing around between different layers, which will be useful when MSU buffer management has to cross the boundaries of the MSU driver. Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/intel_th/msu.c | 163 ++++++++++++++++++++----------- 1 file changed, 104 insertions(+), 59 deletions(-) diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c index f5d5cb862a81..0e7fbef8dee0 100644 --- a/drivers/hwtracing/intel_th/msu.c +++ b/drivers/hwtracing/intel_th/msu.c @@ -28,29 +28,19 @@ #define msc_dev(x) (&(x)->thdev->dev) -/** - * struct msc_block - multiblock mode block descriptor - * @bdesc: pointer to hardware descriptor (beginning of the block) - * @addr: physical address of the block - */ -struct msc_block { - struct msc_block_desc *bdesc; - dma_addr_t addr; -}; - /** * struct msc_window - multiblock mode window descriptor * @entry: window list linkage (msc::win_list) * @pgoff: page offset into the buffer that this window starts at * @nr_blocks: number of blocks (pages) in this window - * @block: array of block descriptors + * @sgt: array of block descriptors */ struct msc_window { struct list_head entry; unsigned long pgoff; unsigned int nr_blocks; struct msc *msc; - struct msc_block block[0]; + struct sg_table sgt; }; /** @@ -143,6 +133,24 @@ static inline bool msc_block_is_empty(struct msc_block_desc *bdesc) return false; } +static inline struct msc_block_desc * +msc_win_block(struct msc_window *win, unsigned int block) +{ + return sg_virt(&win->sgt.sgl[block]); +} + +static inline dma_addr_t +msc_win_baddr(struct msc_window *win, unsigned int block) +{ + return sg_dma_address(&win->sgt.sgl[block]); +} + +static inline unsigned long +msc_win_bpfn(struct msc_window *win, unsigned int block) +{ + return msc_win_baddr(win, block) >> PAGE_SHIFT; +} + /** * msc_oldest_window() - locate the window with oldest data * @msc: MSC device @@ -168,11 +176,11 @@ static struct msc_window *msc_oldest_window(struct msc *msc) * something like 2, in which case we're good */ list_for_each_entry(win, &msc->win_list, entry) { - if (win->block[0].addr == win_addr) + if (sg_dma_address(win->sgt.sgl) == win_addr) found++; /* skip the empty ones */ - if (msc_block_is_empty(win->block[0].bdesc)) + if (msc_block_is_empty(msc_win_block(win, 0))) continue; if (found) @@ -191,7 +199,7 @@ static struct msc_window *msc_oldest_window(struct msc *msc) static unsigned int msc_win_oldest_block(struct msc_window *win) { unsigned int blk; - struct msc_block_desc *bdesc = win->block[0].bdesc; + struct msc_block_desc *bdesc = msc_win_block(win, 0); /* without wrapping, first block is the oldest */ if (!msc_block_wrapped(bdesc)) @@ -202,7 +210,7 @@ static unsigned int msc_win_oldest_block(struct msc_window *win) * oldest data for this window. */ for (blk = 0; blk < win->nr_blocks; blk++) { - bdesc = win->block[blk].bdesc; + bdesc = msc_win_block(win, blk); if (msc_block_last_written(bdesc)) return blk; @@ -238,7 +246,7 @@ static struct msc_window *msc_next_window(struct msc_window *win) static struct msc_block_desc *msc_iter_bdesc(struct msc_iter *iter) { - return iter->win->block[iter->block].bdesc; + return msc_win_block(iter->win, iter->block); } static void msc_iter_init(struct msc_iter *iter) @@ -471,7 +479,7 @@ static void msc_buffer_clear_hw_header(struct msc *msc) offsetof(struct msc_block_desc, hw_tag); for (blk = 0; blk < win->nr_blocks; blk++) { - struct msc_block_desc *bdesc = win->block[blk].bdesc; + struct msc_block_desc *bdesc = msc_win_block(win, blk); memset(&bdesc->hw_tag, 0, hw_sz); } @@ -734,6 +742,40 @@ static struct page *msc_buffer_contig_get_page(struct msc *msc, return virt_to_page(msc->base + (pgoff << PAGE_SHIFT)); } +static int __msc_buffer_win_alloc(struct msc_window *win, + unsigned int nr_blocks) +{ + struct scatterlist *sg_ptr; + void *block; + int i, ret; + + ret = sg_alloc_table(&win->sgt, nr_blocks, GFP_KERNEL); + if (ret) + return -ENOMEM; + + for_each_sg(win->sgt.sgl, sg_ptr, nr_blocks, i) { + block = dma_alloc_coherent(msc_dev(win->msc)->parent->parent, + PAGE_SIZE, &sg_dma_address(sg_ptr), + GFP_KERNEL); + if (!block) + goto err_nomem; + + sg_set_buf(sg_ptr, block, PAGE_SIZE); + } + + return nr_blocks; + +err_nomem: + for (i--; i >= 0; i--) + dma_free_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE, + msc_win_block(win, i), + msc_win_baddr(win, i)); + + sg_free_table(&win->sgt); + + return -ENOMEM; +} + /** * msc_buffer_win_alloc() - alloc a window for a multiblock mode * @msc: MSC device @@ -747,45 +789,48 @@ static struct page *msc_buffer_contig_get_page(struct msc *msc, static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks) { struct msc_window *win; - unsigned long size = PAGE_SIZE; - int i, ret = -ENOMEM; + int ret = -ENOMEM, i; if (!nr_blocks) return 0; - win = kzalloc(offsetof(struct msc_window, block[nr_blocks]), - GFP_KERNEL); + /* + * This limitation hold as long as we need random access to the + * block. When that changes, this can go away. + */ + if (nr_blocks > SG_MAX_SINGLE_ALLOC) + return -EINVAL; + + win = kzalloc(sizeof(*win), GFP_KERNEL); if (!win) return -ENOMEM; + win->msc = msc; + if (!list_empty(&msc->win_list)) { struct msc_window *prev = list_last_entry(&msc->win_list, struct msc_window, entry); + /* This works as long as blocks are page-sized */ win->pgoff = prev->pgoff + prev->nr_blocks; } - for (i = 0; i < nr_blocks; i++) { - win->block[i].bdesc = - dma_alloc_coherent(msc_dev(msc)->parent->parent, size, - &win->block[i].addr, GFP_KERNEL); - - if (!win->block[i].bdesc) - goto err_nomem; + ret = __msc_buffer_win_alloc(win, nr_blocks); + if (ret < 0) + goto err_nomem; #ifdef CONFIG_X86 + for (i = 0; i < ret; i++) /* Set the page as uncached */ - set_memory_uc((unsigned long)win->block[i].bdesc, 1); + set_memory_uc((unsigned long)msc_win_block(win, i), 1); #endif - } - win->msc = msc; - win->nr_blocks = nr_blocks; + win->nr_blocks = ret; if (list_empty(&msc->win_list)) { - msc->base = win->block[0].bdesc; - msc->base_addr = win->block[0].addr; + msc->base = msc_win_block(win, 0); + msc->base_addr = msc_win_baddr(win, 0); } list_add_tail(&win->entry, &msc->win_list); @@ -794,19 +839,25 @@ static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks) return 0; err_nomem: - for (i--; i >= 0; i--) { -#ifdef CONFIG_X86 - /* Reset the page to write-back before releasing */ - set_memory_wb((unsigned long)win->block[i].bdesc, 1); -#endif - dma_free_coherent(msc_dev(msc)->parent->parent, size, - win->block[i].bdesc, win->block[i].addr); - } kfree(win); return ret; } +static void __msc_buffer_win_free(struct msc *msc, struct msc_window *win) +{ + int i; + + for (i = 0; i < win->nr_blocks; i++) { + struct page *page = sg_page(&win->sgt.sgl[i]); + + page->mapping = NULL; + dma_free_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE, + msc_win_block(win, i), msc_win_baddr(win, i)); + } + sg_free_table(&win->sgt); +} + /** * msc_buffer_win_free() - free a window from MSC's window list * @msc: MSC device @@ -827,17 +878,13 @@ static void msc_buffer_win_free(struct msc *msc, struct msc_window *win) msc->base_addr = 0; } - for (i = 0; i < win->nr_blocks; i++) { - struct page *page = virt_to_page(win->block[i].bdesc); - - page->mapping = NULL; #ifdef CONFIG_X86 - /* Reset the page to write-back before releasing */ - set_memory_wb((unsigned long)win->block[i].bdesc, 1); + for (i = 0; i < win->nr_blocks; i++) + /* Reset the page to write-back */ + set_memory_wb((unsigned long)msc_win_block(win, i), 1); #endif - dma_free_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE, - win->block[i].bdesc, win->block[i].addr); - } + + __msc_buffer_win_free(msc, win); kfree(win); } @@ -871,11 +918,11 @@ static void msc_buffer_relink(struct msc *msc) } for (blk = 0; blk < win->nr_blocks; blk++) { - struct msc_block_desc *bdesc = win->block[blk].bdesc; + struct msc_block_desc *bdesc = msc_win_block(win, blk); memset(bdesc, 0, sizeof(*bdesc)); - bdesc->next_win = next_win->block[0].addr >> PAGE_SHIFT; + bdesc->next_win = msc_win_bpfn(next_win, 0); /* * Similarly to last window, last block should point @@ -883,11 +930,9 @@ static void msc_buffer_relink(struct msc *msc) */ if (blk == win->nr_blocks - 1) { sw_tag |= MSC_SW_TAG_LASTBLK; - bdesc->next_blk = - win->block[0].addr >> PAGE_SHIFT; + bdesc->next_blk = msc_win_bpfn(win, 0); } else { - bdesc->next_blk = - win->block[blk + 1].addr >> PAGE_SHIFT; + bdesc->next_blk = msc_win_bpfn(win, blk + 1); } bdesc->sw_tag = sw_tag; @@ -1062,7 +1107,7 @@ static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff) found: pgoff -= win->pgoff; - return virt_to_page(win->block[pgoff].bdesc); + return sg_page(&win->sgt.sgl[pgoff]); } /**