The quilt patch titled
Subject: dmapool: create/destroy cleanup
has been removed from the -mm tree. Its filename was
dmapool-create-destroy-cleanup.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Keith Busch <kbusch@xxxxxxxxxx>
Subject: dmapool: create/destroy cleanup
Date: Thu, 26 Jan 2023 13:51:25 -0800
Set the 'empty' bool directly from the result of the function that
determines its value instead of adding additional logic.
Link: https://lkml.kernel.org/r/20230126215125.4069751-13-kbusch@xxxxxxxx
Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Tony Battersby <tonyb@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/dmapool.c~dmapool-create-destroy-cleanup
+++ a/mm/dmapool.c
@@ -15,7 +15,7 @@
* represented by the 'struct dma_pool' which keeps a doubly-linked list of
* allocated pages. Each page in the page_list is split into blocks of at
* least 'size' bytes. Free blocks are tracked in an unsorted singly-linked
- * list of free blocks across all pages. Used blocks aren't tracked, but we
+ * list of free blocks within the page. Used blocks aren't tracked, but we
* keep a count of how many are currently allocated from each page.
*/
@@ -40,22 +40,13 @@
#define DMAPOOL_DEBUG 1
#endif
-struct dma_block {
- struct dma_block *next_block;
- dma_addr_t dma;
-};
-
struct dma_pool { /* the pool */
struct list_head page_list;
spinlock_t lock;
- struct dma_block *next_block;
- size_t nr_blocks;
- size_t nr_active;
- size_t nr_pages;
+ size_t size;
struct device *dev;
- unsigned int size;
- unsigned int allocation;
- unsigned int boundary;
+ size_t allocation;
+ size_t boundary;
char name[32];
struct list_head pools;
};
@@ -64,6 +55,8 @@ struct dma_page { /* cacheable header f
struct list_head page_list;
void *vaddr;
dma_addr_t dma;
+ unsigned int in_use;
+ unsigned int offset;
};
static DEFINE_MUTEX(pools_lock);
@@ -71,132 +64,45 @@ static DEFINE_MUTEX(pools_reg_lock);
static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf)
{
- struct dma_pool *pool;
+ unsigned temp;
unsigned size;
-
- size = sysfs_emit(buf, "poolinfo - 0.1\n");
-
- mutex_lock(&pools_lock);
- list_for_each_entry(pool, &dev->dma_pools, pools) {
- /* per-pool info, no real statistics yet */
- size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2zu\n",
- pool->name, pool->nr_active,
- pool->nr_blocks, pool->size,
- pool->nr_pages);
- }
- mutex_unlock(&pools_lock);
-
- return size;
-}
-
-static DEVICE_ATTR_RO(pools);
-
-#ifdef DMAPOOL_DEBUG
-static void pool_check_block(struct dma_pool *pool, struct dma_block *block,
- gfp_t mem_flags)
-{
- u8 *data = (void *)block;
- int i;
-
- for (i = sizeof(struct dma_block); i < pool->size; i++) {
- if (data[i] == POOL_POISON_FREED)
- continue;
- dev_err(pool->dev, "%s %s, %p (corrupted)\n", __func__,
- pool->name, block);
-
- /*
- * Dump the first 4 bytes even if they are not
- * POOL_POISON_FREED
- */
- print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
- data, pool->size, 1);
- break;
- }
-
- if (!want_init_on_alloc(mem_flags))
- memset(block, POOL_POISON_ALLOCATED, pool->size);
-}
-
-static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
-{
+ char *next;
struct dma_page *page;
+ struct dma_pool *pool;
- list_for_each_entry(page, &pool->page_list, page_list) {
- if (dma < page->dma)
- continue;
- if ((dma - page->dma) < pool->allocation)
- return page;
- }
- return NULL;
-}
+ next = buf;
+ size = PAGE_SIZE;
-static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
-{
- struct dma_block *block = pool->next_block;
- struct dma_page *page;
+ temp = scnprintf(next, size, "poolinfo - 0.1\n");
+ size -= temp;
+ next += temp;
- page = pool_find_page(pool, dma);
- if (!page) {
- dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n",
- __func__, pool->name, vaddr, &dma);
- return true;
- }
+ mutex_lock(&pools_lock);
+ list_for_each_entry(pool, &dev->dma_pools, pools) {
+ unsigned pages = 0;
+ unsigned blocks = 0;
- while (block) {
- if (block != vaddr) {
- block = block->next_block;
- continue;
+ spin_lock_irq(&pool->lock);
+ list_for_each_entry(page, &pool->page_list, page_list) {
+ pages++;
+ blocks += page->in_use;
}
- dev_err(pool->dev, "%s %s, dma %pad already free\n",
- __func__, pool->name, &dma);
- return true;
- }
-
- memset(vaddr, POOL_POISON_FREED, pool->size);
- return false;
-}
-
-static void pool_init_page(struct dma_pool *pool, struct dma_page *page)
-{
- memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
-}
-#else
-static void pool_check_block(struct dma_pool *pool, struct dma_block *block,
- gfp_t mem_flags)
-{
-}
-
-static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
-{
- if (want_init_on_free())
- memset(vaddr, 0, pool->size);
- return false;
-}
-
-static void pool_init_page(struct dma_pool *pool, struct dma_page *page)
-{
-}
-#endif
-
-static struct dma_block *pool_block_pop(struct dma_pool *pool)
-{
- struct dma_block *block = pool->next_block;
+ spin_unlock_irq(&pool->lock);
- if (block) {
- pool->next_block = block->next_block;
- pool->nr_active++;
+ /* per-pool info, no real statistics yet */
+ temp = scnprintf(next, size, "%-16s %4u %4zu %4zu %2u\n",
+ pool->name, blocks,
+ pages * (pool->allocation / pool->size),
+ pool->size, pages);
+ size -= temp;
+ next += temp;
}
- return block;
-}
+ mutex_unlock(&pools_lock);
-static void pool_block_push(struct dma_pool *pool, struct dma_block *block,
- dma_addr_t dma)
-{
- block->dma = dma;
- block->next_block = pool->next_block;
- pool->next_block = block;
+ return PAGE_SIZE - size;
}
+static DEVICE_ATTR_RO(pools);
/**
* dma_pool_create - Creates a pool of consistent memory blocks, for dma.
@@ -228,18 +134,15 @@ struct dma_pool *dma_pool_create(const c
size_t allocation;
bool empty = false;
- if (!dev)
- return NULL;
-
if (align == 0)
align = 1;
else if (align & (align - 1))
return NULL;
- if (size == 0 || size > INT_MAX)
+ if (size == 0)
return NULL;
- if (size < sizeof(struct dma_block))
- size = sizeof(struct dma_block);
+ else if (size < 4)
+ size = 4;
size = ALIGN(size, align);
allocation = max_t(size_t, size, PAGE_SIZE);
@@ -249,9 +152,7 @@ struct dma_pool *dma_pool_create(const c
else if ((boundary < size) || (boundary & (boundary - 1)))
return NULL;
- boundary = min(boundary, allocation);
-
- retval = kzalloc(sizeof(*retval), GFP_KERNEL);
+ retval = kmalloc(sizeof(*retval), GFP_KERNEL);
if (!retval)
return retval;
@@ -264,6 +165,7 @@ struct dma_pool *dma_pool_create(const c
retval->size = size;
retval->boundary = boundary;
retval->allocation = allocation;
+
INIT_LIST_HEAD(&retval->pools);
/*
@@ -300,36 +202,18 @@ EXPORT_SYMBOL(dma_pool_create);
static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
{
- unsigned int next_boundary = pool->boundary, offset = 0;
- struct dma_block *block, *first = NULL, *last = NULL;
+ unsigned int offset = 0;
+ unsigned int next_boundary = pool->boundary;
- pool_init_page(pool, page);
- while (offset + pool->size <= pool->allocation) {
- if (offset + pool->size > next_boundary) {
- offset = next_boundary;
+ do {
+ unsigned int next = offset + pool->size;
+ if (unlikely((next + pool->size) >= next_boundary)) {
+ next = next_boundary;
next_boundary += pool->boundary;
- continue;
}
-
- block = page->vaddr + offset;
- block->dma = page->dma + offset;
- block->next_block = NULL;
-
- if (last)
- last->next_block = block;
- else
- first = block;
- last = block;
-
- offset += pool->size;
- pool->nr_blocks++;
- }
-
- last->next_block = pool->next_block;
- pool->next_block = first;
-
- list_add(&page->page_list, &pool->page_list);
- pool->nr_pages++;
+ *(int *)(page->vaddr + offset) = next;
+ offset = next;
+ } while (offset < pool->allocation);
}
static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
@@ -339,17 +223,39 @@ static struct dma_page *pool_alloc_page(
page = kmalloc(sizeof(*page), mem_flags);
if (!page)
return NULL;
-
page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
&page->dma, mem_flags);
- if (!page->vaddr) {
+ if (page->vaddr) {
+#ifdef DMAPOOL_DEBUG
+ memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
+#endif
+ pool_initialise_page(pool, page);
+ page->in_use = 0;
+ page->offset = 0;
+ } else {
kfree(page);
- return NULL;
+ page = NULL;
}
-
return page;
}
+static inline bool is_page_busy(struct dma_page *page)
+{
+ return page->in_use != 0;
+}
+
+static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
+{
+ dma_addr_t dma = page->dma;
+
+#ifdef DMAPOOL_DEBUG
+ memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
+#endif
+ dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
+ list_del(&page->page_list);
+ kfree(page);
+}
+
/**
* dma_pool_destroy - destroys a pool of dma memory blocks.
* @pool: dma pool that will be destroyed
@@ -361,7 +267,7 @@ static struct dma_page *pool_alloc_page(
void dma_pool_destroy(struct dma_pool *pool)
{
struct dma_page *page, *tmp;
- bool empty = false, busy = false;
+ bool empty = false;
if (unlikely(!pool))
return;
@@ -369,24 +275,26 @@ void dma_pool_destroy(struct dma_pool *p
mutex_lock(&pools_reg_lock);
mutex_lock(&pools_lock);
list_del(&pool->pools);
- if (list_empty(&pool->dev->dma_pools))
+ if (pool->dev && list_empty(&pool->dev->dma_pools))
empty = true;
mutex_unlock(&pools_lock);
if (empty)
device_remove_file(pool->dev, &dev_attr_pools);
mutex_unlock(&pools_reg_lock);
- if (pool->nr_active) {
- dev_err(pool->dev, "%s %s busy\n", __func__, pool->name);
- busy = true;
- }
-
list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) {
- if (!busy)
- dma_free_coherent(pool->dev, pool->allocation,
- page->vaddr, page->dma);
- list_del(&page->page_list);
- kfree(page);
+ if (is_page_busy(page)) {
+ if (pool->dev)
+ dev_err(pool->dev, "%s %s, %p busy\n", __func__,
+ pool->name, page->vaddr);
+ else
+ pr_err("%s %s, %p busy\n", __func__,
+ pool->name, page->vaddr);
+ /* leak the still-in-use consistent memory */
+ list_del(&page->page_list);
+ kfree(page);
+ } else
+ pool_free_page(pool, page);
}
kfree(pool);
@@ -406,40 +314,84 @@ EXPORT_SYMBOL(dma_pool_destroy);
void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
dma_addr_t *handle)
{
- struct dma_block *block;
- struct dma_page *page;
unsigned long flags;
+ struct dma_page *page;
+ size_t offset;
+ void *retval;
might_alloc(mem_flags);
spin_lock_irqsave(&pool->lock, flags);
- block = pool_block_pop(pool);
- if (!block) {
- /*
- * pool_alloc_page() might sleep, so temporarily drop
- * &pool->lock
- */
- spin_unlock_irqrestore(&pool->lock, flags);
+ list_for_each_entry(page, &pool->page_list, page_list) {
+ if (page->offset < pool->allocation)
+ goto ready;
+ }
- page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO));
- if (!page)
- return NULL;
+ /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */
+ spin_unlock_irqrestore(&pool->lock, flags);
- spin_lock_irqsave(&pool->lock, flags);
- pool_initialise_page(pool, page);
- block = pool_block_pop(pool);
+ page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO));
+ if (!page)
+ return NULL;
+
+ spin_lock_irqsave(&pool->lock, flags);
+
+ list_add(&page->page_list, &pool->page_list);
+ ready:
+ page->in_use++;
+ offset = page->offset;
+ page->offset = *(int *)(page->vaddr + offset);
+ retval = offset + page->vaddr;
+ *handle = offset + page->dma;
+#ifdef DMAPOOL_DEBUG
+ {
+ int i;
+ u8 *data = retval;
+ /* page->offset is stored in first 4 bytes */
+ for (i = sizeof(page->offset); i < pool->size; i++) {
+ if (data[i] == POOL_POISON_FREED)
+ continue;
+ if (pool->dev)
+ dev_err(pool->dev, "%s %s, %p (corrupted)\n",
+ __func__, pool->name, retval);
+ else
+ pr_err("%s %s, %p (corrupted)\n",
+ __func__, pool->name, retval);
+
+ /*
+ * Dump the first 4 bytes even if they are not
+ * POOL_POISON_FREED
+ */
+ print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
+ data, pool->size, 1);
+ break;
+ }
}
+ if (!(mem_flags & __GFP_ZERO))
+ memset(retval, POOL_POISON_ALLOCATED, pool->size);
+#endif
spin_unlock_irqrestore(&pool->lock, flags);
- *handle = block->dma;
- pool_check_block(pool, block, mem_flags);
if (want_init_on_alloc(mem_flags))
- memset(block, 0, pool->size);
+ memset(retval, 0, pool->size);
- return block;
+ return retval;
}
EXPORT_SYMBOL(dma_pool_alloc);
+static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
+{
+ struct dma_page *page;
+
+ list_for_each_entry(page, &pool->page_list, page_list) {
+ if (dma < page->dma)
+ continue;
+ if ((dma - page->dma) < pool->allocation)
+ return page;
+ }
+ return NULL;
+}
+
/**
* dma_pool_free - put block back into dma pool
* @pool: the dma pool holding the block
@@ -451,14 +403,65 @@ EXPORT_SYMBOL(dma_pool_alloc);
*/
void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
{
- struct dma_block *block = vaddr;
+ struct dma_page *page;
unsigned long flags;
+ unsigned int offset;
spin_lock_irqsave(&pool->lock, flags);
- if (!pool_block_err(pool, vaddr, dma)) {
- pool_block_push(pool, block, dma);
- pool->nr_active--;
+ page = pool_find_page(pool, dma);
+ if (!page) {
+ spin_unlock_irqrestore(&pool->lock, flags);
+ if (pool->dev)
+ dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n",
+ __func__, pool->name, vaddr, &dma);
+ else
+ pr_err("%s %s, %p/%pad (bad dma)\n",
+ __func__, pool->name, vaddr, &dma);
+ return;
+ }
+
+ offset = vaddr - page->vaddr;
+ if (want_init_on_free())
+ memset(vaddr, 0, pool->size);
+#ifdef DMAPOOL_DEBUG
+ if ((dma - page->dma) != offset) {
+ spin_unlock_irqrestore(&pool->lock, flags);
+ if (pool->dev)
+ dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n",
+ __func__, pool->name, vaddr, &dma);
+ else
+ pr_err("%s %s, %p (bad vaddr)/%pad\n",
+ __func__, pool->name, vaddr, &dma);
+ return;
}
+ {
+ unsigned int chain = page->offset;
+ while (chain < pool->allocation) {
+ if (chain != offset) {
+ chain = *(int *)(page->vaddr + chain);
+ continue;
+ }
+ spin_unlock_irqrestore(&pool->lock, flags);
+ if (pool->dev)
+ dev_err(pool->dev, "%s %s, dma %pad already free\n",
+ __func__, pool->name, &dma);
+ else
+ pr_err("%s %s, dma %pad already free\n",
+ __func__, pool->name, &dma);
+ return;
+ }
+ }
+ memset(vaddr, POOL_POISON_FREED, pool->size);
+#endif
+
+ page->in_use--;
+ *(int *)vaddr = page->offset;
+ page->offset = offset;
+ /*
+ * Resist a temptation to do
+ * if (!is_page_busy(page)) pool_free_page(pool, page);
+ * Better have a few empty pages hang around.
+ */
spin_unlock_irqrestore(&pool->lock, flags);
}
EXPORT_SYMBOL(dma_pool_free);
_
Patches currently in -mm which might be from kbusch@xxxxxxxxxx are
