Commit fa52b3fe authored by Alexander Shishkin's avatar Alexander Shishkin Committed by Greg Kroah-Hartman
Browse files

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: default avatarAlexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190627125152.54905-3-alexander.shishkin@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4aa5aed2

drivers/hwtracing/intel_th/msu.c

+38 −18
Original line number Diff line number Diff line
@@ -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;

}



/**

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