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Message-Id: <20190503084455.23436-12-alexander.shishkin@linux.intel.com>
Date: Fri, 3 May 2019 11:44:44 +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 11/22] 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 <alexander.shishkin@...ux.intel.com>
---
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]);
}
/**
--
2.20.1
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