From fa52b3fe5e9383022f83382f5ffcb386b9b11b4f Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Thu, 27 Jun 2019 15:51:45 +0300 Subject: intel_th: msu: Support multipage blocks Now that the MSU is using scatterlist, we can support multipage blocks. At the moment, the code assumes that all blocks are page-sized, but in larger buffers it may make sense to chunk together larger blocks of memory. One place where one-to-many relationship needs to be handled is the MSU buffer's mmap path. Get rid of the implicit assumption that all blocks are page-sized. Signed-off-by: Alexander Shishkin Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20190627125152.54905-3-alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/intel_th/msu.c | 56 +++++++++++++++++++++++++++------------- 1 file changed, 38 insertions(+), 18 deletions(-) (limited to 'drivers') diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c index cfd48c81b9d9..c9c29f56d093 100644 --- a/drivers/hwtracing/intel_th/msu.c +++ b/drivers/hwtracing/intel_th/msu.c @@ -33,12 +33,14 @@ * @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 + * @nr_segs: number of segments in this window (<= @nr_blocks) * @sgt: array of block descriptors */ struct msc_window { struct list_head entry; unsigned long pgoff; unsigned int nr_blocks; + unsigned int nr_segs; struct msc *msc; struct sg_table sgt; }; @@ -141,6 +143,12 @@ msc_win_block(struct msc_window *win, unsigned int block) return sg_virt(&win->sgt.sgl[block]); } +static inline size_t +msc_win_actual_bsz(struct msc_window *win, unsigned int block) +{ + return win->sgt.sgl[block].length; +} + static inline dma_addr_t msc_win_baddr(struct msc_window *win, unsigned int block) { @@ -234,7 +242,7 @@ static unsigned int msc_win_oldest_block(struct msc_window *win) * with wrapping, last written block contains both the newest and the * oldest data for this window. */ - for (blk = 0; blk < win->nr_blocks; blk++) { + for (blk = 0; blk < win->nr_segs; blk++) { bdesc = msc_win_block(win, blk); if (msc_block_last_written(bdesc)) @@ -366,7 +374,7 @@ static int msc_iter_block_advance(struct msc_iter *iter) return msc_iter_win_advance(iter); /* block advance */ - if (++iter->block == iter->win->nr_blocks) + if (++iter->block == iter->win->nr_segs) iter->block = 0; /* no wrapping, sanity check in case there is no last written block */ @@ -478,7 +486,7 @@ static void msc_buffer_clear_hw_header(struct msc *msc) size_t hw_sz = sizeof(struct msc_block_desc) - offsetof(struct msc_block_desc, hw_tag); - for (blk = 0; blk < win->nr_blocks; blk++) { + for (blk = 0; blk < win->nr_segs; blk++) { struct msc_block_desc *bdesc = msc_win_block(win, blk); memset(&bdesc->hw_tag, 0, hw_sz); @@ -734,17 +742,17 @@ static struct page *msc_buffer_contig_get_page(struct msc *msc, } static int __msc_buffer_win_alloc(struct msc_window *win, - unsigned int nr_blocks) + unsigned int nr_segs) { struct scatterlist *sg_ptr; void *block; int i, ret; - ret = sg_alloc_table(&win->sgt, nr_blocks, GFP_KERNEL); + ret = sg_alloc_table(&win->sgt, nr_segs, GFP_KERNEL); if (ret) return -ENOMEM; - for_each_sg(win->sgt.sgl, sg_ptr, nr_blocks, i) { + for_each_sg(win->sgt.sgl, sg_ptr, nr_segs, i) { block = dma_alloc_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE, &sg_dma_address(sg_ptr), GFP_KERNEL); @@ -754,7 +762,7 @@ static int __msc_buffer_win_alloc(struct msc_window *win, sg_set_buf(sg_ptr, block, PAGE_SIZE); } - return nr_blocks; + return nr_segs; err_nomem: for (i--; i >= 0; i--) @@ -768,11 +776,11 @@ err_nomem: } #ifdef CONFIG_X86 -static void msc_buffer_set_uc(struct msc_window *win, unsigned int nr_blocks) +static void msc_buffer_set_uc(struct msc_window *win, unsigned int nr_segs) { int i; - for (i = 0; i < nr_blocks; i++) + for (i = 0; i < nr_segs; i++) /* Set the page as uncached */ set_memory_uc((unsigned long)msc_win_block(win, i), 1); } @@ -781,13 +789,13 @@ static void msc_buffer_set_wb(struct msc_window *win) { int i; - for (i = 0; i < win->nr_blocks; i++) + for (i = 0; i < win->nr_segs; i++) /* Reset the page to write-back */ set_memory_wb((unsigned long)msc_win_block(win, i), 1); } #else /* !X86 */ static inline void -msc_buffer_set_uc(struct msc_window *win, unsigned int nr_blocks) {} +msc_buffer_set_uc(struct msc_window *win, unsigned int nr_segs) {} static inline void msc_buffer_set_wb(struct msc_window *win) {} #endif /* CONFIG_X86 */ @@ -827,7 +835,6 @@ static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks) struct msc_window, entry); - /* This works as long as blocks are page-sized */ win->pgoff = prev->pgoff + prev->nr_blocks; } @@ -837,7 +844,8 @@ static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks) msc_buffer_set_uc(win, ret); - win->nr_blocks = ret; + win->nr_segs = ret; + win->nr_blocks = nr_blocks; if (list_empty(&msc->win_list)) { msc->base = msc_win_block(win, 0); @@ -860,7 +868,7 @@ static void __msc_buffer_win_free(struct msc *msc, struct msc_window *win) { int i; - for (i = 0; i < win->nr_blocks; i++) { + for (i = 0; i < win->nr_segs; i++) { struct page *page = sg_page(&win->sgt.sgl[i]); page->mapping = NULL; @@ -923,7 +931,7 @@ static void msc_buffer_relink(struct msc *msc) next_win = list_next_entry(win, entry); } - for (blk = 0; blk < win->nr_blocks; blk++) { + for (blk = 0; blk < win->nr_segs; blk++) { struct msc_block_desc *bdesc = msc_win_block(win, blk); memset(bdesc, 0, sizeof(*bdesc)); @@ -934,7 +942,7 @@ static void msc_buffer_relink(struct msc *msc) * Similarly to last window, last block should point * to the first one. */ - if (blk == win->nr_blocks - 1) { + if (blk == win->nr_segs - 1) { sw_tag |= MSC_SW_TAG_LASTBLK; bdesc->next_blk = msc_win_bpfn(win, 0); } else { @@ -942,7 +950,7 @@ static void msc_buffer_relink(struct msc *msc) } bdesc->sw_tag = sw_tag; - bdesc->block_sz = PAGE_SIZE / 64; + bdesc->block_sz = msc_win_actual_bsz(win, blk) / 64; } } @@ -1101,6 +1109,7 @@ static int msc_buffer_free_unless_used(struct msc *msc) static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff) { struct msc_window *win; + unsigned int blk; if (msc->mode == MSC_MODE_SINGLE) return msc_buffer_contig_get_page(msc, pgoff); @@ -1113,7 +1122,18 @@ static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff) found: pgoff -= win->pgoff; - return sg_page(&win->sgt.sgl[pgoff]); + + for (blk = 0; blk < win->nr_segs; blk++) { + struct page *page = sg_page(&win->sgt.sgl[blk]); + size_t pgsz = PFN_DOWN(msc_win_actual_bsz(win, blk)); + + if (pgoff < pgsz) + return page + pgoff; + + pgoff -= pgsz; + } + + return NULL; } /** -- cgit v1.2.3