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Date: Thu, 27 Jun 2019 15:51:45 +0300
From: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-kernel@...r.kernel.org,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [GIT PULL 2/9] 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 <alexander.shishkin@...ux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
drivers/hwtracing/intel_th/msu.c | 56 ++++++++++++++++++++++----------
1 file changed, 38 insertions(+), 18 deletions(-)
diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c
index 8c568b5c8920..45af29af2473 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 @@ static int __msc_buffer_win_alloc(struct msc_window *win,
}
#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;
}
/**
--
2.20.1
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