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Message-Id: <20190503084455.23436-13-alexander.shishkin@linux.intel.com>
Date: Fri, 3 May 2019 11:44:45 +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>
Subject: [GIT PULL 12/22] 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>
---
drivers/hwtracing/intel_th/msu.c | 48 ++++++++++++++++++++++----------
1 file changed, 34 insertions(+), 14 deletions(-)
diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c
index 0e7fbef8dee0..a4f7a5b21d48 100644
--- a/drivers/hwtracing/intel_th/msu.c
+++ b/drivers/hwtracing/intel_th/msu.c
@@ -32,13 +32,15 @@
* 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
+ * @nr_blocks: number of blocks in this window (<= @nr_pages)
+ * @nr_pages: number of pages in this window
* @sgt: array of block descriptors
*/
struct msc_window {
struct list_head entry;
unsigned long pgoff;
unsigned int nr_blocks;
+ unsigned int nr_pages;
struct msc *msc;
struct sg_table sgt;
};
@@ -139,6 +141,12 @@ 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)
{
@@ -779,26 +787,26 @@ static int __msc_buffer_win_alloc(struct msc_window *win,
/**
* msc_buffer_win_alloc() - alloc a window for a multiblock mode
* @msc: MSC device
- * @nr_blocks: number of pages in this window
+ * @nr_pages: number of pages in this window
*
* This modifies msc::win_list and msc::base, which requires msc::buf_mutex
* to serialize, so the caller is expected to hold it.
*
* Return: 0 on success, -errno otherwise.
*/
-static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
+static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_pages)
{
struct msc_window *win;
int ret = -ENOMEM, i;
- if (!nr_blocks)
+ if (!nr_pages)
return 0;
/*
* 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)
+ if (nr_pages > SG_MAX_SINGLE_ALLOC)
return -EINVAL;
win = kzalloc(sizeof(*win), GFP_KERNEL);
@@ -812,11 +820,10 @@ 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;
+ win->pgoff = prev->pgoff + prev->nr_pages;
}
- ret = __msc_buffer_win_alloc(win, nr_blocks);
+ ret = __msc_buffer_win_alloc(win, nr_pages);
if (ret < 0)
goto err_nomem;
@@ -827,6 +834,7 @@ static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
#endif
win->nr_blocks = ret;
+ win->nr_pages = nr_pages;
if (list_empty(&msc->win_list)) {
msc->base = msc_win_block(win, 0);
@@ -834,7 +842,7 @@ static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
}
list_add_tail(&win->entry, &msc->win_list);
- msc->nr_pages += nr_blocks;
+ msc->nr_pages += nr_pages;
return 0;
@@ -870,7 +878,7 @@ static void msc_buffer_win_free(struct msc *msc, struct msc_window *win)
{
int i;
- msc->nr_pages -= win->nr_blocks;
+ msc->nr_pages -= win->nr_pages;
list_del(&win->entry);
if (list_empty(&msc->win_list)) {
@@ -936,7 +944,7 @@ 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;
}
}
@@ -1095,19 +1103,31 @@ 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);
list_for_each_entry(win, &msc->win_list, entry)
- if (pgoff >= win->pgoff && pgoff < win->pgoff + win->nr_blocks)
+ if (pgoff >= win->pgoff && pgoff < win->pgoff + win->nr_pages)
goto found;
return NULL;
found:
pgoff -= win->pgoff;
- return sg_page(&win->sgt.sgl[pgoff]);
+
+ for (blk = 0; blk < win->nr_blocks; blk++) {
+ struct page *page = sg_page(&win->sgt.sgl[blk]);
+ size_t pgsz = win->sgt.sgl[blk].length >> PAGE_SHIFT;
+
+ if (pgoff < pgsz)
+ return page + pgoff;
+
+ pgoff -= pgsz;
+ }
+
+ return NULL;
}
/**
@@ -1481,7 +1501,7 @@ nr_pages_show(struct device *dev, struct device_attribute *attr, char *buf)
else if (msc->mode == MSC_MODE_MULTI) {
list_for_each_entry(win, &msc->win_list, entry) {
count += scnprintf(buf + count, PAGE_SIZE - count,
- "%d%c", win->nr_blocks,
+ "%d%c", win->nr_pages,
msc_is_last_win(win) ? '\n' : ',');
}
} else {
--
2.20.1
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