flash: return size for flash_read() and flash_write()

include/flash.h

@@ -9,8 +9,8 @@ struct flash_ops {
 	void (* release)(struct flash_dev *dev);
 	size_t (* get_size)(struct flash_dev *dev);
 	size_t (* get_capacity)(struct flash_dev *dev);
-	int (* read)(struct flash_dev *dev, uint32_t addr, void *data, size_t len);
-	int (* write)(struct flash_dev *dev, uint32_t addr, const void *data,
+	size_t (* read)(struct flash_dev *dev, uint32_t addr, void *data, size_t len);
+	size_t (* write)(struct flash_dev *dev, uint32_t addr, const void *data,
 		size_t len);
 	int (* copy)(struct flash_dev *dev, uint32_t dst, uint32_t src, size_t len);
 	int (* is_erased)(struct flash_dev *dev, uint32_t addr);
@@ -30,8 +30,8 @@ struct flash_dev *flash_probe(void);
 void flash_release(struct flash_dev *dev);
 size_t flash_get_size(struct flash_dev *dev);
 size_t flash_get_capacity(struct flash_dev *dev);
-int flash_read(struct flash_dev *dev, uint32_t addr, void *data, size_t len);
-int flash_write(struct flash_dev *dev, uint32_t addr, const void *data,
+size_t flash_read(struct flash_dev *dev, uint32_t addr, void *data, size_t len);
+size_t flash_write(struct flash_dev *dev, uint32_t addr, const void *data,
 	size_t len);
 int flash_copy(struct flash_dev *dev, uint32_t dst, uint32_t src, size_t len);
 int flash_is_erased(struct flash_dev *dev, uint32_t addr, size_t len);

include/ftl.h

@@ -30,9 +30,9 @@ struct ftl_map {
 
 int ftl_init_map(struct ftl_map *map, struct flash_dev *dev);
 int ftl_resume_map(struct ftl_map *map);
-int ftl_write(struct ftl_map *map, uint32_t addr, const void *data,
+size_t ftl_write(struct ftl_map *map, uint32_t addr, const void *data,
 	size_t len);
-int ftl_read(struct ftl_map *map, void *data, size_t len, uint32_t va);
+size_t ftl_read(struct ftl_map *map, void *data, size_t len, uint32_t va);
 int ftl_trim(struct ftl_map *map, uint32_t va);
 uint32_t ftl_get_size(const struct ftl_map *map);
 uint32_t ftl_get_capacity(const struct ftl_map *map);

source/core/flash.c

@@ -8,7 +8,7 @@ int default_flash_is_erased(struct flash_dev *dev, uint32_t addr)
 	uint8_t data[1 << dev->log2_block_size];
 	size_t i;
 
-	if (flash_read(dev, addr, data, sizeof(data)) < 0)
+	if (flash_read(dev, addr, data, sizeof(data)) == 0)
 		return 0;
 
 	for (i = 0; i < sizeof(data); ++i) {
@@ -43,7 +43,7 @@ size_t flash_get_capacity(struct flash_dev *dev)
 	return dev->ops->get_capacity(dev);
 }
 
-int flash_read(struct flash_dev *dev, uint32_t addr, void *data, size_t len)
+size_t flash_read(struct flash_dev *dev, uint32_t addr, void *data, size_t len)
 {
 	if (!dev)
 		return -1;
@@ -51,7 +51,7 @@ int flash_read(struct flash_dev *dev, uint32_t addr, void *data, size_t len)
 	return dev->ops->read(dev, addr, data, len);
 }
 
-int flash_write(struct flash_dev *dev, uint32_t addr, const void *data,
+size_t flash_write(struct flash_dev *dev, uint32_t addr, const void *data,
 	size_t len)
 {
 	if (!dev)

source/drivers/sandbox_flash.c

@@ -19,9 +19,9 @@ struct stdio_flash_priv {
 };
 
 static size_t stdio_flash_get_size(struct flash_dev *dev);
-static int stdio_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
+static size_t stdio_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
 	size_t len);
-static int stdio_flash_write(struct flash_dev *dev, uint32_t addr,
+static size_t stdio_flash_write(struct flash_dev *dev, uint32_t addr,
 	const void *data, size_t len);
 static int stdio_flash_copy(struct flash_dev *dev, uint32_t dst, uint32_t src,
 	size_t len);
@@ -45,20 +45,23 @@ static size_t stdio_flash_get_size(struct flash_dev *dev)
 	return priv->size;
 }
 
-static int stdio_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
+static size_t stdio_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
 	size_t len)
 {
 	struct stdio_flash_priv *priv = dev->priv;
 
-	if (addr > priv->size || len > priv->size - addr)
-		return -1;
+	addr = min(addr, priv->size);
+	len = min(len, priv->size - addr);
+
+	if (!len)
+		return 0;
 
 	memcpy(data, priv->data + addr, len);
 
-	return 0;
+	return len;
 }
 
-static int stdio_flash_write(struct flash_dev *dev, uint32_t addr,
+static size_t stdio_flash_write(struct flash_dev *dev, uint32_t addr,
 	const void *data, size_t len)
 {
 	struct stdio_flash_priv *priv = dev->priv;
@@ -66,8 +69,11 @@ static int stdio_flash_write(struct flash_dev *dev, uint32_t addr,
 	char *dst;
 	size_t i;
 
-	if (addr > priv->size || len > priv->size - addr)
-		return -1;
+	addr = min(addr, priv->size);
+	len = min(len, priv->size - addr);
+
+	if (!len)
+		return 0;
 
 	src = data;
 	dst = priv->data + addr;
@@ -76,7 +82,7 @@ static int stdio_flash_write(struct flash_dev *dev, uint32_t addr,
 		dst[i] &= src[i];
 	}
 
-	return 0;
+	return len;
 }
 
 static int stdio_flash_copy(struct flash_dev *dev, uint32_t dst, uint32_t src,
@@ -88,10 +94,10 @@ static int stdio_flash_copy(struct flash_dev *dev, uint32_t dst, uint32_t src,
 	while (len) {
 		nbytes = min(sizeof data, len);
 
-		if (stdio_flash_read(dev, src, data, nbytes) < 0)
+		if (stdio_flash_read(dev, src, data, nbytes) == 0)
 			return -1;
 
-		if (stdio_flash_write(dev, dst, data, nbytes) < 0)
+		if (stdio_flash_write(dev, dst, data, nbytes) == 0)
 			return -1;
 
 		dst += nbytes;

source/ftl/dev.c

@@ -8,9 +8,9 @@
 
 static size_t ftl_flash_get_size(struct flash_dev *dev);
 static size_t ftl_flash_get_capacity(struct flash_dev *dev);
-static int ftl_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
+static size_t ftl_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
 	size_t len);
-static int ftl_flash_write(struct flash_dev *dev, uint32_t addr,
+static size_t ftl_flash_write(struct flash_dev *dev, uint32_t addr,
 	const void *data, size_t len);
 static int ftl_flash_erase(struct flash_dev *dev, uint32_t addr);
 static void ftl_flash_release(struct flash_dev *dev);
@@ -40,7 +40,7 @@ static size_t ftl_flash_get_capacity(struct flash_dev *dev)
 	return ftl_get_capacity(map);
 }
 
-static int ftl_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
+static size_t ftl_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
 	size_t len)
 {
 	struct ftl_map *map = dev->priv;
@@ -48,7 +48,7 @@ static int ftl_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
 	return ftl_read(map, data, len, addr);
 }
 
-static int ftl_flash_write(struct flash_dev *dev, uint32_t addr,
+static size_t ftl_flash_write(struct flash_dev *dev, uint32_t addr,
 	const void *data, size_t len)
 {
 	struct ftl_map *map = dev->priv;

source/ftl/ftl.c

@@ -12,7 +12,7 @@
 #include "gc.h"
 #include "map.h"
 
-int ftl_read(struct ftl_map *map, void *data, size_t len, uint32_t va)
+size_t ftl_read(struct ftl_map *map, void *data, size_t len, uint32_t va)
 {
 	int ret;
 	uint32_t mask, offset, page;
@@ -23,17 +23,19 @@ int ftl_read(struct ftl_map *map, void *data, size_t len, uint32_t va)
 
 	if ((ret = trace_path(map, NULL, &page, va)) < 0) {
 		memset(data, 0, len);
-		return ret;
+		return 0;
 	}
 
 	if (!data)
 		return 0;
 
+	len = min(len, (1 << map->log2_page_size) - offset);
+
 	return flash_read(map->dev, (page << map->log2_page_size) + offset, data,
-		min((1 << map->log2_page_size) - offset, len));
+		len);
 }
 
-int ftl_write(struct ftl_map *map, uint32_t va, const void *udata,
+size_t ftl_write(struct ftl_map *map, uint32_t va, const void *udata,
 	size_t len)
 {
 	char data[1 << map->log2_page_size];
@@ -43,7 +45,7 @@ int ftl_write(struct ftl_map *map, uint32_t va, const void *udata,
 
 	if (va >= ftl_get_capacity(map) &&
 	    !is_aligned(va, 1 << map->log2_page_size))
-		return -1;
+		return 0;
 
 	mask = ((1 << map->log2_page_size) - 1);
 	offset = va & mask;
@@ -51,21 +53,25 @@ int ftl_write(struct ftl_map *map, uint32_t va, const void *udata,
 
 	if ((ret = trace_path(map, &page_desc, &page, va)) < 0 &&
 		ret != -ERR_NOT_FOUND)
-		return -1;
+		return 0;
 
 	if (ret == -ERR_NOT_FOUND) {
 		memset(data, 0, 1 << map->log2_page_size);
 		++map->nused_pages;
 	} else if (flash_read(map->dev, page << map->log2_page_size, data,
-		1 << map->log2_page_size) < 0) {
-		return -1;
+		1 << map->log2_page_size) == 0) {
+		return 0;
 	}
 
 	page_desc.nused_pages = map->nused_pages;
 
-	memcpy(data + offset, udata, min((1 << map->log2_page_size) - offset, len));
+	len = min(len, (1 << map->log2_page_size) - offset);
+	memcpy(data + offset, udata, len);
+
+	if (write_upage(map, data, &page_desc) < 0)
+		return 0;
 
-	return write_upage(map, data, &page_desc);
+	return len;
 }
 
 int ftl_trim(struct ftl_map *map, uint32_t va)

source/ftl/map.c

@@ -53,7 +53,10 @@ int read_page_group(struct ftl_map *map,
 	page = ((group_no + 1) << map->log2_pages_per_group) - 1;
 	addr = page << map->log2_page_size;
 
-	return flash_read(map->dev, addr, group, sizeof *group);
+	if (flash_read(map->dev, addr, group, sizeof *group) == 0)
+		return -1;
+
+	return 0;
 }
 
 /* Given the page number of a user page, reads the page descriptor associated
@@ -71,7 +74,10 @@ int read_page_desc(struct ftl_map *map,
 	offset = sizeof(struct ftl_page_group) +
 		(upage & ((1 << map->log2_pages_per_group) - 1)) * sizeof *page_desc;
 
-	return flash_read(map->dev, addr + offset, page_desc, sizeof *page_desc);
+	if (flash_read(map->dev, addr + offset, page_desc, sizeof *page_desc) == 0)
+		return -1;
+
+	return 0;
 }
 
 /* Writes the page descriptor to the footer of the current page group and
@@ -93,14 +99,14 @@ static int write_page_desc(struct ftl_map *map,
 		group.epoch = map->epoch;
 		group.tail = map->tail;
 
-		if (flash_write(map->dev, addr, &group, sizeof group) < 0)
+		if (flash_write(map->dev, addr, &group, sizeof group) == 0)
 			return -1;
 	}
 
 	offset = sizeof group + (map->head & ((1 << map->log2_pages_per_group) - 1)) *
 		sizeof *page_desc;
 
-	if (flash_write(map->dev, addr + offset, page_desc, sizeof *page_desc) < 0)
+	if (flash_write(map->dev, addr + offset, page_desc, sizeof *page_desc) == 0)
 		return -1;
 
 	map->root = map->head;
@@ -126,7 +132,7 @@ int write_upage(struct ftl_map *map, const void *page,
 		return -1;
 
 	if (page && flash_write(map->dev, map->head << map->log2_page_size, page,
-		map->log2_page_size) < 0)
+		map->log2_page_size) == 0)
 		return -1;
 
 	return write_page_desc(map, page_desc);
@@ -179,7 +185,7 @@ static int find_block(struct ftl_map *map, struct ftl_page_group *group,
 		page = block << map->log2_block_size;
 		page |= ((UINT32_C(1) << map->log2_pages_per_group) - 1) << map->log2_page_size;
 
-		if (flash_read(map->dev, page, group, sizeof *group) < 0)
+		if (flash_read(map->dev, page, group, sizeof *group) == 0)
 			continue;
 
 		if (memcmp(group->magic, "FTL", sizeof group->magic) != 0)