[PATCH] (1/6) blksize_size[] removal

 - preliminary cleanups: make sure that swapoff restores original block
   size, kill set_blocksize() (and use of __bread()) in multipath.c,
   reorder opening device and finding its block size in mtdblock.c.

drivers/md/multipath.c

@@ -738,43 +738,56 @@ static int __check_consistency (mddev_t *mddev, int row)
 {
 	multipath_conf_t *conf = mddev_to_conf(mddev);
 	int disks = MD_SB_DISKS;
-	kdev_t dev;
 	struct block_device *bdev;
-	struct buffer_head *bh = NULL;
 	int i, rc = 0;
-	char *buffer = NULL;
+	char *buffer;
+	struct page *page = NULL;
+	int first = 1;
+	int order = PAGE_CACHE_SHIFT-PAGE_SHIFT;
+
+	buffer = (char *) __get_free_pages(GFP_KERNEL, order);
+	if (!buffer)
+		return rc;
 
 	for (i = 0; i < disks; i++) {
+		struct address_space *mapping;
+		char *p;
 		if (!conf->multipaths[i].operational)
 			continue;
 		printk("(checking disk %d)\n",i);
-		dev = conf->multipaths[i].dev;
 		bdev = conf->multipaths[i].bdev;
-		set_blocksize(dev, 4096);
-		if ((bh = __bread(bdev, row / 4, 4096)) == NULL)
+		mapping = bdev->bd_inode->i_mapping;
+		page = read_cache_page(mapping, row/(PAGE_CACHE_SIZE/1024),
+				(filler_t *)mapping->a_ops->readpage, NULL);
+		if (IS_ERR(page)) {
+			page = NULL;
 			break;
-		if (!buffer) {
-			buffer = (char *) __get_free_page(GFP_KERNEL);
-			if (!buffer)
+		}
+		wait_on_page_locked(page);
+		if (!PageUptodate(page))
+			break;
+		if (PageError(page))
 			break;
-			memcpy(buffer, bh->b_data, 4096);
-		} else if (memcmp(buffer, bh->b_data, 4096)) {
+		p = page_address(page);
+		if (first) {
+			memcpy(buffer, p, PAGE_CACHE_SIZE);
+			first = 0;
+		} else if (memcmp(buffer, p, PAGE_CACHE_SIZE)) {
 			rc = 1;
 			break;
 		}
-		bforget(bh);
+		page_cache_release(page);
 		fsync_bdev(bdev);
 		invalidate_bdev(bdev, 0);
-		bh = NULL;
+		page = NULL;
 	}
-	if (buffer)
-		free_page((unsigned long) buffer);
-	if (bh) {
-		bdev = bh->b_bdev;
-		bforget(bh);
+	if (page) {
+		bdev = page->mapping->host->i_bdev;
+		page_cache_release(page);
 		fsync_bdev(bdev);
 		invalidate_bdev(bdev, 0);
 	}
+	free_pages((unsigned long) buffer, order);
 	return rc;
 }
 

drivers/mtd/devices/blkmtd.c

@@ -1062,6 +1062,7 @@ static int __init init_blkmtd(void)
   int readonly = 0;
   int erase_size = CONFIG_MTD_BLKDEV_ERASESIZE;
   kdev_t rdev;
+  struct block_device *bdev;
   int err;
   int mode;
   int regions;
@@ -1127,8 +1128,13 @@ static int __init init_blkmtd(void)
     printk("blkmtd: attempting to use an MTD device as a block device\n");
     return 1;
   }
+  /* get the block device */
+  bdev = bdget(kdev_t_to_nr(mk_kdev(maj, min)));
+  err = blkdev_get(bdev, mode, 0, BDEV_RAW);
+  if (err)
+    return 1;
 
-  DEBUG(1, "blkmtd: devname = %s\n", __bdevname(rdev));
+  DEBUG(1, "blkmtd: devname = %s\n", bdevname(bdev));
   blocksize = BLOCK_SIZE;
 
   blocksize = bs ? bs : block_size(rdev);
@@ -1139,27 +1145,24 @@ static int __init init_blkmtd(void)
     i >>= 1;
   }
 
-  size = (count ? count*blocksize : blkdev_size_in_bytes(rdev));
+  size = count ? count*blocksize : bdev->bd_inode->i_size;
 
   DEBUG(1, "blkmtd: size = %ld\n", (long int)size);
 
   if(size == 0) {
     printk("blkmtd: cant determine size\n");
+    blkdev_put(bdev, BDEV_RAW);
     return 1;
   }
 
   mtd_rawdevice = (mtd_raw_dev_data_t *)kmalloc(sizeof(mtd_raw_dev_data_t), GFP_KERNEL);
   if(mtd_rawdevice == NULL) {
+    blkdev_put(bdev, BDEV_RAW);
     err = -ENOMEM;
     goto init_err;
   }
   memset(mtd_rawdevice, 0, sizeof(mtd_raw_dev_data_t));
-  /* get the block device */
-  mtd_rawdevice->binding = bdget(kdev_t_to_nr(mk_kdev(maj, min)));
-  err = blkdev_get(mtd_rawdevice->binding, mode, 0, BDEV_RAW);
-  if (err) {
-    goto init_err;
-  }
+  mtd_rawdevice->binding = bdev;
   mtd_rawdevice->totalsize = size;
   mtd_rawdevice->sector_size = blocksize;
   mtd_rawdevice->sector_bits = blocksize_bits;

include/linux/swap.h

@@ -79,6 +79,7 @@ struct swap_info_struct {
 	unsigned int flags;
 	spinlock_t sdev_lock;
 	struct file *swap_file;
+	unsigned old_block_size;
 	unsigned short * swap_map;
 	unsigned int lowest_bit;
 	unsigned int highest_bit;

mm/swapfile.c

@@ -14,6 +14,7 @@
 #include <linux/vmalloc.h>
 #include <linux/pagemap.h>
 #include <linux/shm.h>
+#include <linux/blkdev.h>
 #include <linux/compiler.h>
 
 #include <asm/pgtable.h>
@@ -787,8 +788,12 @@ asmlinkage long sys_swapoff(const char * specialfile)
 	swap_device_unlock(p);
 	swap_list_unlock();
 	vfree(swap_map);
-	if (S_ISBLK(swap_file->f_dentry->d_inode->i_mode))
-		bd_release(swap_file->f_dentry->d_inode->i_bdev);
+	if (S_ISBLK(swap_file->f_dentry->d_inode->i_mode)) {
+		struct block_device *bdev;
+		bdev = swap_file->f_dentry->d_inode->i_bdev;
+		set_blocksize(to_kdev_t(bdev->bd_dev), p->old_block_size);
+		bd_release(bdev);
+	}
 	filp_close(swap_file, NULL);
 	err = 0;
 
@@ -879,6 +884,7 @@ asmlinkage long sys_swapon(const char * specialfile, int swap_flags)
 		nr_swapfiles = type+1;
 	p->flags = SWP_USED;
 	p->swap_file = NULL;
+	p->old_block_size = 0;
 	p->swap_map = NULL;
 	p->lowest_bit = 0;
 	p->highest_bit = 0;
@@ -914,6 +920,7 @@ asmlinkage long sys_swapon(const char * specialfile, int swap_flags)
 			bdev = NULL;
 			goto bad_swap;
 		}
+		p->old_block_size = block_size(to_kdev_t(bdev->bd_dev));
 		error = set_blocksize(swap_file->f_dentry->d_inode->i_rdev,
 				      PAGE_SIZE);
 		if (error < 0)
@@ -1066,8 +1073,10 @@ asmlinkage long sys_swapon(const char * specialfile, int swap_flags)
 	error = 0;
 	goto out;
 bad_swap:
-	if (bdev)
+	if (bdev) {
+		set_blocksize(to_kdev_t(bdev->bd_dev), p->old_block_size);
 		bd_release(bdev);
+	}
 bad_swap_2:
 	swap_list_lock();
 	swap_map = p->swap_map;