Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next

* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next:
  Squashfs: Add an option to set dev block size to 4K

diff --combined fs/squashfs/Kconfig
index 048b59d,5586011..c70111e
--- 1/fs/squashfs/Kconfig
--- 2/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@@ -19,9 -19,9 +19,9 @@@ config SQUASHF
  
          If you want to compile this as a module ( = code which can be
          inserted in and removed from the running kernel whenever you want),
 -        say M here and read <file:Documentation/modules.txt>.  The module
 -        will be called squashfs.  Note that the root file system (the one
 -        containing the directory /) cannot be compiled as a module.
 +        say M here.  The module will be called squashfs.  Note that the root
 +        file system (the one containing the directory /) cannot be compiled
 +        as a module.
  
          If unsure, say N.
  
@@@ -78,6 -78,28 +78,28 @@@ config SQUASHFS_X
  
          If unsure, say N.
  
+ config SQUASHFS_4K_DEVBLK_SIZE
+       bool "Use 4K device block size?"
+       depends on SQUASHFS
+       help
+         By default Squashfs sets the dev block size (sb_min_blocksize)
+         to 1K or the smallest block size supported by the block device
+         (if larger).  This, because blocks are packed together and
+         unaligned in Squashfs, should reduce latency.
+ 
+         This, however, gives poor performance on MTD NAND devices where
+         the optimal I/O size is 4K (even though the devices can support
+         smaller block sizes).
+ 
+         Using a 4K device block size may also improve overall I/O
+         performance for some file access patterns (e.g. sequential
+         accesses of files in filesystem order) on all media.
+ 
+         Setting this option will force Squashfs to use a 4K device block
+         size by default.
+ 
+         If unsure, say N.
+ 
  config SQUASHFS_EMBEDDED
        bool "Additional option for memory-constrained systems"
        depends on SQUASHFS