Linux 3.10 compat: struct vmalloc_info moved

Linux kernel commmit torvalds/linux@db3808c1 moved the
vmalloc_info structure from a private to a public header.
Now that it's available for kernel modules use it.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #257
Linux 3.10 compat: replace PDE()->data with PDE_DATA()

Linux kernel commit torvalds/linux@d9dda78b renamed PDE() to
PDE_DATA().  To handle this detect the prefered interface
and define a PDE_DATA() wrapper for consistency.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #257
Linux 3.10 compat: add missing include of linux/slab.h

Linux kernel commit torvalds/linux@0d01ff2 changes some
includes we were depending on through linux/proc_fs.h.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #257
Linux 3.10 compat: Do not rely on struct proc_dir_entry definition

Linux kernel commit torvalds/linux#59d8053f moved the definition of
struct proc_dir_entry from include/linux/proc_fs.h to the private
header fs/proc/internal.h. The SPL relied on that to map Solaris'
kstat to entries in /proc/spl/kstat.

Since the proc_dir_entry structure is now private the only safe
thing to do is wrap the opaque proc handle with our own structure.
This actually ends up simplify the code and is good because it
moves us away from depending on implementation details of /proc.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #257
Merge branch 'linux-3.10'

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #257
Fix --enable-debug-kmem-tracking option

This code has gotten something stale and no longer builds cleanly
against modern kernels.  The two issues addressed here are as
follows:

* The hlist_*_rcu interfaces in the kernel have been relatively
  unstable.  Since this isn't performance critical code just use
  the long standing hlist_* variants.

* In older kernels the hash_ptr() function takes a 'void *' but
  in newer kernels it expects a 'const void *'.  To silence the
  compiler warnings about this explicitly cast it to a 'void *'.
  The memset function is a similar case but it always expects
  a 'void *'.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #256
Fix bogus kmem leak warning

Commit 5c7a036 correctly relocated the creation of a taskq
and the registraction of the kmem_cache_shrinker after the
initialization of the kmem tracking code.  However, the
cleanup of these structures was not done before the leak
checks in spl_kmem_fini().  This resulted in an incorrect
'kmem leaked' warning even though there was no actual leak.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes zfsonlinux/zfs#1569
Improve build instructions

Make it clear that when building directly from the Git tree
the configure script must be manually generated by running the
autogen.sh script.  This requires that the GNU autotools packages
be installed for your distribution.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes zfsonlinux/zfs#1448
Modify gethrestime to use current_kernel_time()

This allows us to get nanosecond resolution. It also means
we use the same time source as utimensat(now) etc.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #255