linux-stable/drivers/dma/iovlock.c
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00

280 lines
7.3 KiB
C

/*
* Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
* Portions based on net/core/datagram.c and copyrighted by their authors.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59
* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* The full GNU General Public License is included in this distribution in the
* file called COPYING.
*/
/*
* This code allows the net stack to make use of a DMA engine for
* skb to iovec copies.
*/
#include <linux/dmaengine.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <net/tcp.h> /* for memcpy_toiovec */
#include <asm/io.h>
#include <asm/uaccess.h>
static int num_pages_spanned(struct iovec *iov)
{
return
((PAGE_ALIGN((unsigned long)iov->iov_base + iov->iov_len) -
((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT);
}
/*
* Pin down all the iovec pages needed for len bytes.
* Return a struct dma_pinned_list to keep track of pages pinned down.
*
* We are allocating a single chunk of memory, and then carving it up into
* 3 sections, the latter 2 whose size depends on the number of iovecs and the
* total number of pages, respectively.
*/
struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len)
{
struct dma_pinned_list *local_list;
struct page **pages;
int i;
int ret;
int nr_iovecs = 0;
int iovec_len_used = 0;
int iovec_pages_used = 0;
/* don't pin down non-user-based iovecs */
if (segment_eq(get_fs(), KERNEL_DS))
return NULL;
/* determine how many iovecs/pages there are, up front */
do {
iovec_len_used += iov[nr_iovecs].iov_len;
iovec_pages_used += num_pages_spanned(&iov[nr_iovecs]);
nr_iovecs++;
} while (iovec_len_used < len);
/* single kmalloc for pinned list, page_list[], and the page arrays */
local_list = kmalloc(sizeof(*local_list)
+ (nr_iovecs * sizeof (struct dma_page_list))
+ (iovec_pages_used * sizeof (struct page*)), GFP_KERNEL);
if (!local_list)
goto out;
/* list of pages starts right after the page list array */
pages = (struct page **) &local_list->page_list[nr_iovecs];
local_list->nr_iovecs = 0;
for (i = 0; i < nr_iovecs; i++) {
struct dma_page_list *page_list = &local_list->page_list[i];
len -= iov[i].iov_len;
if (!access_ok(VERIFY_WRITE, iov[i].iov_base, iov[i].iov_len))
goto unpin;
page_list->nr_pages = num_pages_spanned(&iov[i]);
page_list->base_address = iov[i].iov_base;
page_list->pages = pages;
pages += page_list->nr_pages;
/* pin pages down */
down_read(&current->mm->mmap_sem);
ret = get_user_pages(
current,
current->mm,
(unsigned long) iov[i].iov_base,
page_list->nr_pages,
1, /* write */
0, /* force */
page_list->pages,
NULL);
up_read(&current->mm->mmap_sem);
if (ret != page_list->nr_pages)
goto unpin;
local_list->nr_iovecs = i + 1;
}
return local_list;
unpin:
dma_unpin_iovec_pages(local_list);
out:
return NULL;
}
void dma_unpin_iovec_pages(struct dma_pinned_list *pinned_list)
{
int i, j;
if (!pinned_list)
return;
for (i = 0; i < pinned_list->nr_iovecs; i++) {
struct dma_page_list *page_list = &pinned_list->page_list[i];
for (j = 0; j < page_list->nr_pages; j++) {
set_page_dirty_lock(page_list->pages[j]);
page_cache_release(page_list->pages[j]);
}
}
kfree(pinned_list);
}
/*
* We have already pinned down the pages we will be using in the iovecs.
* Each entry in iov array has corresponding entry in pinned_list->page_list.
* Using array indexing to keep iov[] and page_list[] in sync.
* Initial elements in iov array's iov->iov_len will be 0 if already copied into
* by another call.
* iov array length remaining guaranteed to be bigger than len.
*/
dma_cookie_t dma_memcpy_to_iovec(struct dma_chan *chan, struct iovec *iov,
struct dma_pinned_list *pinned_list, unsigned char *kdata, size_t len)
{
int iov_byte_offset;
int copy;
dma_cookie_t dma_cookie = 0;
int iovec_idx;
int page_idx;
if (!chan)
return memcpy_toiovec(iov, kdata, len);
iovec_idx = 0;
while (iovec_idx < pinned_list->nr_iovecs) {
struct dma_page_list *page_list;
/* skip already used-up iovecs */
while (!iov[iovec_idx].iov_len)
iovec_idx++;
page_list = &pinned_list->page_list[iovec_idx];
iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK);
page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK)
- ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT;
/* break up copies to not cross page boundary */
while (iov[iovec_idx].iov_len) {
copy = min_t(int, PAGE_SIZE - iov_byte_offset, len);
copy = min_t(int, copy, iov[iovec_idx].iov_len);
dma_cookie = dma_async_memcpy_buf_to_pg(chan,
page_list->pages[page_idx],
iov_byte_offset,
kdata,
copy);
/* poll for a descriptor slot */
if (unlikely(dma_cookie < 0)) {
dma_async_issue_pending(chan);
continue;
}
len -= copy;
iov[iovec_idx].iov_len -= copy;
iov[iovec_idx].iov_base += copy;
if (!len)
return dma_cookie;
kdata += copy;
iov_byte_offset = 0;
page_idx++;
}
iovec_idx++;
}
/* really bad if we ever run out of iovecs */
BUG();
return -EFAULT;
}
dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov,
struct dma_pinned_list *pinned_list, struct page *page,
unsigned int offset, size_t len)
{
int iov_byte_offset;
int copy;
dma_cookie_t dma_cookie = 0;
int iovec_idx;
int page_idx;
int err;
/* this needs as-yet-unimplemented buf-to-buff, so punt. */
/* TODO: use dma for this */
if (!chan || !pinned_list) {
u8 *vaddr = kmap(page);
err = memcpy_toiovec(iov, vaddr + offset, len);
kunmap(page);
return err;
}
iovec_idx = 0;
while (iovec_idx < pinned_list->nr_iovecs) {
struct dma_page_list *page_list;
/* skip already used-up iovecs */
while (!iov[iovec_idx].iov_len)
iovec_idx++;
page_list = &pinned_list->page_list[iovec_idx];
iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK);
page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK)
- ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT;
/* break up copies to not cross page boundary */
while (iov[iovec_idx].iov_len) {
copy = min_t(int, PAGE_SIZE - iov_byte_offset, len);
copy = min_t(int, copy, iov[iovec_idx].iov_len);
dma_cookie = dma_async_memcpy_pg_to_pg(chan,
page_list->pages[page_idx],
iov_byte_offset,
page,
offset,
copy);
/* poll for a descriptor slot */
if (unlikely(dma_cookie < 0)) {
dma_async_issue_pending(chan);
continue;
}
len -= copy;
iov[iovec_idx].iov_len -= copy;
iov[iovec_idx].iov_base += copy;
if (!len)
return dma_cookie;
offset += copy;
iov_byte_offset = 0;
page_idx++;
}
iovec_idx++;
}
/* really bad if we ever run out of iovecs */
BUG();
return -EFAULT;
}